Ok so curious how do you ensure that when power goes out that your feed does not cause injuries to power company workers. From my basic understanding, there needs to be an automated switch that detects when power goes out and turns off the solar power. How do you accomplish this.
Yes, it is implemented in the grid invertor. Actually a generation should be synchronised with a grid phase, so it is not working without grid voltage at all.
Is it at all practical to just run DC power lines through your house? Would that save some efficiency lost during transforming knowing that will end up as DC in a lot of household appliances?
One problem is the DC voltage requirement is different for every device. Look at the wall-warts in your house. I have in my lab: 24V, 19V, 17V, 12V, 5V, 3.3V. Yeesh.
If you delivered 48VDC you'd still need a DC SMPS at each point, but an SMPS is way more efficient than a transformer.
Every time I look into this the conclusion I end up with is "not enough things are produced using 24V/48V DC to be worthwhile".
It seems like you could replace a certain fraction of room wiring with PoE from an energy budget point of view -- lights, lamps, chargers and other doodads don't need to draw more than a few watts each, so you could get by with just an outlet or two per room for large power draws everywhere but the kitchen, and PoE for all the rest.
No. If you run low voltage DC that matches what devices need (5V or 12V, typically), your wiring is staggeringly huge. Not only do you need the fat wire to carry the current safely, you don't have much room for voltage drop. Dropping 5V on 120V under load isn't a big deal, dropping 5V on 12V under load is literally unusable for most devices (12V stuff won't run on 7V).
If you run something sane, like 48V or so, then you still need conversion electronics at each point of use, and you don't gain much over just running 120/240VAC, except that now your converters are really expensive because they're less common and "weird." 120VAC to 5V is super common, 48VDC to 5VDC is less so. Some switch mode power supplies will work on DC, some won't, and it's harder on the bridge rectifier diodes, so they don't tend to last very long in that sort of use.
It's the sort of thing that sound good in isolation, but in practice leads to spending a lot of money to gain little or nothing in terms of efficiency.
The exception is for a small system where you can run 12VDC to LEDs and stuff (think a camper), and avoid bringing the inverter online at all. Inverters have a significant idle draw more or less proportional to peak power delivered (my 2kVA inverter idles at 30W DC, a 6kVA one that can hold 18kVA for 20 seconds idles at 100W DC).
I'm imagining a world where the converters are commodity but it seems they're not right now. I found this reddit thread of someone trying to do exactly this. Run 48VDC from solar panels to a usb-c PD device so it can power negotiation at each device. Seems like this is still really impractical.
Can you just start pumping current into the transformer on the pole outside your house, just like that? Even if the meter doesn't "spin backwards", is that safe to do? (Not considering the other top-level comment about the grid going out, just general delivery.)
Transformers work both ways so I personally don't see a problem, but even if they didn't, you'd have to have a lot of panels before you will be running the transformer "backwards" as you'd have to first power all the others users of that transformer.
From an electrical standpoint it's safe as long as your inverter cuts off when grid power goes out. Grid tie inverters are designed to do that.
Some meters will be unhappy running backwards. They may not register the right numbers but they won't blow up.
From a regulatory standpoint your utility won't be happy with you feeding power to the grid if you haven't notified them ahead of time. How unsafe that is depends on your local laws. The dangers here are fines and service cutoffs, not fires and electrocution.
I re-run the numbers every year, but solar just does not make fiscal sense for my house. For 2022, my utility lowered the our set rate from 6.98 cents/kWh to 6.5, which puts me at about half the national average.
If you live near fracking Wells they have byproduct natural gas that is basically throw away cheap since it's difficult to transport without those unpopular pipelines.
In Québec we have similar prices throughout the province. "We" massively invested in hydro power back in the 60s-70s, and it's paying off very nicely.
What's funny is that everyone still complains about their Hydro bill, but that's because virtually every house is heated with electricity (baseboard heaters), and we have a pretty cold climate. For example, yesterday my house consumed ~180kWh and the outside temperature peaked down to -20°C.
Yeah, if you happen to live near hydroelectric capable rivers then it's one of the best forms of green energy possible. In fact it is so good that most places where it makes sense have already been installed.
Most of them are not very close at all, but "we" also invested in long-distance transport at 735 kV (among the highest voltages in use at the time), which reduces losses. A good chunk of it came down in the late 1990s due to a freezing rain storm, plunging half of Québec in the dark, but ut was rebuilt pretty quickly.
You can do your own solar install for about $1.50/W in the US - ground mount or roof, doesn't really matter (the cost of the per panel electronics for NEC 2017 and later rapid shutdown requirements are about the same as the cost of a ground mount).
It's a lot of work, but can make sense, even in low power cost areas.
It'd be interesting to see what the payback would be like with a small-scale battery system. Obviously it'd be a lot longer and more suited to places with common outages but interesting nonetheless
"Never. By a long shot." At least in terms of financial outcomes.
If it improves reliability, it's common enough, but a solar + battery system does well to come in at 4-5x grid rates, even in expensive areas.
My office system (off-grid solar + battery) has now dropped below $1/kWh delivered... but not by much. And the batteries are more than halfway through their expected service life (10 years, flooded lead acid).
I do it because it's interesting to learn and experiment with, and because trenching power out here would suck, but I don't pretend it's cheap.
On the other hand, it is more reliable than the power grid...
Batteries are getting cheaper every day (well, not so much lately), but if your grid is reasonably stable and your power company does net metering they just don't buy you very much.
If you live in an area where the power is regularly going out (or are off grid entirely) then they give you a whole home UPS which is nice, but it doesn't save you money. The only other major use case is when your local power company is run by unrepentant assholes and they screw you over on excess production so it makes sense to try to save that excess production instead of feeding it back to the grid. But this is a penalty reduction instead of an actual savings.
I just got solar panels. I was crunching the numbers and it's a long payback. I am really waiting to see how it turns out.
Currently, the days are very short - 9 hours of sunlight. It's been cloudy and/or snowy quite a few days - which means zero production. Partly cloudy also drops production significantly.
On a good day we might generate 25-30kWh of electricity. But that is also approximately what we use. I'm hoping that during different seasons we will have higher production and/or more days of the week generating.
Because otherwise, our electric bill every month is not a huge part of our expenditures, and we've paid a large upfront cost to (currently) only reduce that by a portion.
For us the payback is about 3.5-4 years depending on how much I use myself and how much I sell back on the grid. Granted, I got the panels at a discount.
I got a 2.4kw array on my smallish roof in London. I was tracking payback at ~24 years but all of a sudden I'm paying 25p/kwh instead of 12p/kwh, which means my payback is considerably shorter!
Yup. I did a very quick calculation based on last years yield and if the new energy prizes remain at this level it seems our 2.7kWp is going to pay itself back in about 4 years (!) instead of about 9-10 years. Crazy.
You might have spent too much on the array. Most people target a 10-15 year payback period. But benchmarking it on December/January production is also likely to blow up your projections as you noted.
If you're net zero in the middle of winter you're probably going to be positive in the summer unless you live in a very hot climate. IMHO sizing an array to be net positive over the course of a year is probably a mistake, as this draws the ire of your power company and they'll probably screw you on overproduction. If you're planning to buy an electric car or something in the near future then it might not be a problem, but generally the best plan is to buy for about 100% of your total yearly usage. Solar panel production typically decreases by 2% during the first year of operation (0.5% every subsequent year) so you'll be slightly net negative which keeps you on good terms with the power company.
One nice thing with the panels is that they effectively lock in your power rate at whatever you paid. You won't get burned by ever increasing power rates. It's a hedge against future rate hikes.
I also recently got solar panels, they were calculated to provide more then my household consumes year-round, and should pay themselves back in 6-7 years based on 2021 energy prices and regulations. I anticipate having to get an electric car to use up all that energy :-)
One thing the author missed is that in the Netherlands you can re-claim the VAT paid on the solar installation, saving 21% of costs. Probably not worth the effort for a very small installation, but for a bigger one it saves considerably.
> The last thing which is important to know is how we can send the electricity to the grid. It is simple from a technical point of view [..]
It's not simple from a technical point of view. It's bewilderingly complex, in fact. If not done right, it can threaten the stability of the grid. It requires parts of the grid to have increased capacity. In/out balance needs to be maintained at all times.
Decentralized production is great, but it could really benefit from more decentralized storage. Might be useful to start installing sizeable batteries near all medium->low voltage substations. Seems like the right place for it.
Also he didn't mention an auto disconnect if the power goes out, and as I understand it this is required in most places. You could be responsible for killing someone with out it.
The power is out and the lines are being worked on.
The line is supposed to be dead.
Your solar system is making power and sends it out of the house, back on the grid.
He did. He’s using a grid tie inverter which requires the grid to provide a synchronisation signal for the output AC waveform. No power, no grid signal, no output AC waveform.
This is a standard feature of every grid tie inverter. Unfortunately it also means you can't power your house when the grid is out unless you also have a battery attached.
Not that you would want to run appliances with the power dipping out randomly anyway. Maybe to charge a laptop/phone or run basic incandescent bulb/electric space heater/toaster type loads.
Pretty much. Unless your neighbour has enough generating capacity to power the entire section of the grid your connected too (which would blow every fuse in the supply unit, and melt every cable between them and nearest transformer).
Any power either you or your neighbour tired to put into the grid would be immediately consumed by all of your other neighbours (and of course your own appliances) that it would drag your AC waveform completely out of spec (I.e. it should be 230V AC, but your equipment can only supply enough juice to support 0.01V AC). So you’re inverter would shutdown due to lack of recognisable grid compliant waveform. Either that or catch fire from trying to drive thousands of amps (from 100 acre solar farm on your balcony) into your power socket, which would also catch fire, along with all the cable in the wall, well, you get the idea.
In short physics and simple supply and demand ensure that no home scale inverter would ever be able to maintain an even vaguely compliant AC waveform during a blackout.
Even balancing the grid is pretty simple from a technical perspective. You just watch the grid frequency, if it falls then add more power in (or disconnect load), if it rises add less power in (or connect more loads).
No need to decentralise storage, decentralised production is very unlikely to ever be enough that distribution lines and unable to transport the power out. Additionally medium->low voltage substations are located near customers, which means the land is expensive. So putting in batteries with a material amount of storage is also expensive, assuming there’s even enough space.
I suspect you're not trying to be facetious, so I'll do my best to reply in kind. But seriously, just adding more power or just shed load is not easy. Where do you magically find more power in a decentralized system where something as fickle as a cloud can cause huge spikes in power generation?
Load is easier to predict, but far harder to shed on short notice.
Decentralized production absolutely can be enough to max out power lines. In most parts of the world, power grids aren't exactly crown jewels. Many grids are basically held together with proverbial duct tape. Here in Belgium the grid is such a pile of rubbish that instead of trying to adapt to decentralized production, we're now actively going to punish people for using power during peak hours.
I agree that land and batteries are expensive. But they're a lot less expensive than rebuilding the grid.
> But seriously, just adding more power or just shed load is not easy.
It’s all a question of scale, you need coordination to handle the macro level balancing of power. Making sure there’s enough power stations running to keep the lights on, and that the grid is roughly balanced. But that level of balancing is planned hours to days in advanced, because power stations take hours to days to spool up depending on the tech. So it’s a system incapable of responding to moment-by-moment changes.
For handling instantaneous fluctuation, the first defence the the rotational inertia of all the generators in every power station. These things have tons of spinning mass, and are the reason grid frequency fluctuates with power draw, pull more power than provided, and the grid makes up for it by stealing stored spinning energy in the generators. Then speed governors on the generators notice the slow down and provide more steam/gas/coal whatever to speed the generator back up. Both covering the stolen inertial energy and bumping total grid input.
For larger fluctuations that can’t be covered by rotational mass and modulating power station output, you’ll have a variety of fast response loads and supplies. Energy consumers that have agreements to modulate their usage or production in response to frequency fluctuations, and who get paid for providing the service. Some examples include steel and aluminium smelters. They can shutdown temporarily to shed load, and just rely on thermal mass to prevent their equips freezing. Water tower pumps, you’ll have plenty of stored water, pumps for canals, fridges and freezers can turn their compressors off, so can AC units, and even data centres that will swap to their backup generators and take their load off the grid.
Now all of the above loads heading only works for a limited amount of time, all of those consumers can only reduce their load for so much time. So you also have power producers, people who have diesel generators sitting around that can be turned on and connected to the grid, rapid response power stations that can cold start in 15-20mins etc. All of these will be started by a drop in frequency, and expected to pickup the load without any central coordination.
Between the fast response load shedding and fast response producers a grid can handle a substantial amount of production variation without any central coordination. In normal operations you’ll only be relying on fast response load shedding of non-critical loads like water pumps, and cascading to more drastic load shedding and power production if the grid can’t recover quickly by upping production at major producers (who won’t be running a 100% under normal conditions).
> Decentralized production absolutely can be enough to max out power lines.
> <snip>
> Here in Belgium the grid is such a pile of rubbish that instead of trying to adapt to decentralized production, we're now actively going to punish people for using power during peak hours.
Yes and no. Normally the behaviour you describe isn’t caused because the infrastructure can’t handle the production (after all peak distributed production is extremely unlikely to ever be higher than peak load, you simply can’t fit that many solar panels on a roof). But rather that distribution companies run on the assumption that power only passes in one direction in their network, from grid to consumer. All of their modelling, and more importantly, their financial agreements with the grid and each other depend on this predicate.
As a result their objective is to ensure there is zero supply back to the grid, and that all distributed generation is always consumed within their grid, preferably within the same substation so there are zero backward flows anywhere. This doesn’t mean the equipment couldn’t support reverse flows, it’s just that figuring that out would cost money, and they have no incentive to figure it out. They get paid the same regardless of if they support reverse flows or not, so it’s better to ob...
Balancing the grid is so simple that a whole flock of startupish ecosystem is flourishing around this very problem - building flywheels and other offsetting facilities to solve it.
I really hope at some point we can stop having every conversation about renewable and electrifying tech be about "payback". Especially among people who can afford to take some loss on it for the greater good (ie. much of the HN demographic).
There are benefits besides money from removing your dependencies on fossil fuels. The fact that it's even in the ballpark of breaking even is a very nice side effect, but it's not the point.
In rural, very red California, solar is installed everywhere. I doubt its being done because of climate change, or "for the environment". Its the payback.
Personal electricity generation can be surprisingly diverse. You have hippie homesteaders, catastrophe bunker preppers, libertarians who just want to be off grid because they want to, etc. Environmentalists are just one of many groups that solar sellers are targeting.
Also, if you are extremely remote, getting the grid built out to you might cost tens of thousands, to the point that the up-front costs of nongrid power are even more palatable.
Could unreliability from their power provider be a bigger factor? No one wants to suffer rotating blackouts and have their freezer food spoil or miss meetings when working from home.
Everyone seems convinced Californian's are all suffering from blackouts all the time. I'm in Sac area, and I've only experienced one in the last three years, and it was just a few hours.
Thanks that is good to know. PG&E put out some stats...
System Average Interruption Duration Index (SAIDI). This index is based on the amount of time the average PG&E customer experiences a sustained outage (being without power for more than five minutes) in a given year. In 2020, the PG&E SAIDI was about 153.2 minutes per customer.
System Average Interruption Frequency Index (SAIFI). This metric represents the number of times the average PG&E customer experiences a sustained outage in a given year. In 2020, the PG&E SAIFI was about 1.179, or slightly more than one per customer.
Customer Average Interruption Duration Index (CAIDI). This index represents the average restoration time when customers are impacted by a sustained outage. It is determined by dividing SAIDI by SAIFI. In 2020, the PG&E CAIDI was 130.0 minutes.
Momentary Average Interruption Frequency Index (MAIFI). This index is based on the number of times the average customer is interrupted by Momentary Outage events each year. Momentary Outage events are outages that last 5 minutes or less. In 2020, the PG&E MAIFI was 1.317 per customer.
Unless you install a fairly pricey battery system in addition to the solar array it doesn't help with blackouts at all. When the grid goes down the inverter shuts off and the whole system produces no power.
Adding the battery increases the payback window, often adding 50-100% to the hardware costs of the install. Plus they are in very short supply currently, so including a battery in your build may push it back several months.
Ok. Can you agree that it should at least be an improvement in carbon emissions?
Grid tied solar often manages this, though exceedingly poor panel utilization as in the article typically won't. By the time you start adding batteries, you're unlikely to be net carbon negative during the system life. It's hard to get solid numbers for modern battery construction, though. They tend to be trade secret sort of values.
Do you think I wouldn't agree with that? What a weird thing to ask. I'm literally saying "the conversation should be dominated by the long term benefits rather than your wallet." That means ghg.
A lot of this depends a lot on where you live and what your energy mix is to begin with, so there's no one size fits all answer. My issue isn't with any of these specifics though, it's that the conversation is always dominated entirely by "will it result in me paying less in the short term?" which is exactly the kind of short term thinking that's gotten us into this mess.
Anyways, I think it's too early for widespread use of battery systems, for sure. I'm also personally not keen to put a giant fire hazard into my house or garage if I don't have to. I think the tech for solar and the tech for batteries are on similar but offset curves, where battery storage for an entire home just isn't quite there yet like panels are.
Along these lines, as someone in the demographic you mention, I was just thinking about this the other day, about whether replacing my HVAC system, which is on its last legs, with a heat pump system would be good for the environment, even if the payback is not really there. But given where I live, I wasn't actually sure if it is net good for the environment.
But resources are kind of hard to find. Is there a good list of things you could consider that would be environmentally helpful upgrades to your home? Heat pump, solar, electric car, native plant garden, the latest and greatest in insulation, that sort of thing?
I "augmented" my HVAC system by putting a heat pump (mini split) in my living room. Mainly because with heat wave in Seattle, I wanted cooling, also it was relatively inexpensive. (The unit was ~$850 USD, it heats and cools, is more efficient. I installed it myself with $150 in tools).
I don't really consider myself an expert, honestly. Part of my frustration with the bent of this kind of conversation is how hard it makes it to really suss out answers to these kinds of questions honestly.
That said, I live in an area where most home heating is done by natural gas delivered to homes and installed a heat pump last year. I had a lot of trouble finding an hvac company that would do it because it's still quite uncommon where I live, and even they had a lot of misinformation about it. I had a lot of reasons for doing this both related and unrelated to climate change:
- The heat dome demonstrated that our house, which is relatively new and built to modern standards so is designed to soak up heat like a sponge, could not be comfortable without AC in a summer like that, of which I expect many more in the future.
- If I was getting an AC anyways, there's literally no reason not to have a heat pump and use it for heating in the milder months and reduce my direct use of gas to only when it's absolutely necessary (ie. the last few weeks where we've had a shockingly long cold snap).
- And if I was going to run AC I should absolutely have solar as well so I'm not using grid energy to power it (where I live grid energy is very much dominated by coal and natural gas, though coal is thankfully reducing quickly).
- Even though the energy mix is mostly GHG-emitting where I live, down to some specific temperature (probably around -10 to -15C with the expensive heat pump I got), a heat pump simply uses far less electric energy than an equivalent amount of gas burned in the house. It's quite a big difference. It doesn't look like it because electricity is priced much higher per kWh-equivalent than gas.
But I think there's a lot of more complicated things people 'should' do as well? Since my house is new, the trees on the lot are quite small so provide very little shade in summer. Hopefully this improves as they grow, and maybe we'll plant some more. We're also probably going to install awnings on the windows that are more or less positioned to block direct sunlight in the summer and let it through in the winter. Generally finding ways to passively heat and cool your house is the best thing you can possibly do and even though I'm doing the above as part of electrifying, I plan to do a lot more of the other sorts of things as well.
Ok, I do. Congrats. My "support" though is doing very little against inertia, because unlike solar on my own roof I can't unilaterally cause a nuclear plant to be built. Let me know if you invent a safe back yard nuclear plant and maybe I'll install one.
I also didn't say anything about what I expect "people en masse" to do. You'd think I shot someone's dog when all I did was say "maybe we could talk about something other than money?"
I definitely share your opinion. I do think those more fortunate should put less weight on one's "wallet" and be "good samaritans". But I don't think that's a good solution to invoke the widespread change necessary for the environment.
Consider a similar "tragedy of the commons" externality-- air pollution.
LA smog was quite infamously disastrous for decades. This was not fixed by "good Samaritans" trailblazing, but rather regulation enabled by the Clean Air Act, in which California was especially liberal in using-- car smog checks, centralized landfills, catalytic cracker carbon controls, etc.
This was, in my opinion, wildly successful. Just look around LA. It's not the hellhole it once was. But these controls were, and still are, mildly unpopular [1].
The point I want to make is this-- change will not happen with single trailblazers e.g. the HN demographic. It has to happen with widespread change. That can either happen top down (e.g. air pollution) or bottoms up (e.g. making costs/revenues break even).
I personally don't think a top-down approach will ever happen in today's political climate. Thus, the reality is, we need a hyper-focus on making breakeven. Because that's the reality of the vast majority of people, not just the HN community.
I agree with pretty much everything you're saying, except your conclusion.
I definitely see the value as a way to sell solar. And I agree with it. I think many people will only do it if it makes financial sense. But I don't think that means it needs to be the only carrot or stick. I don't think we really have time to pretend that only One Simple Pitch will get us there.
Nor do I think it means that the conversations about it need to be so thoroughly dominated by it. I'm not talking about the OP here, I'm talking about this thread, on which nearly every top level post is just someone declaring whether solar breaks even for them or not. I don't think this is terribly useful dialog, and it makes it very hard to talk about anything else.
Using excess energy to heat a thermal mass is infinitely better for the person who owns the solar panels / efficiency than piping it back into the grid, where you a) need more electrical work (paying an electrician to install a grid-tie inverter costs thousands and also negates your ability to use the power off-grid if you ever wanted to add batteries) and b) best case get credits that are deliberately priced next to nothing.
The price of LifePo4 lithium batteries has also plummeted in recent years.
You're both overgeneralizing and overstating the case here. PV is superior to solar thermal in a number of important ways, and grid-tie systems can be extremely cost-effective relative to storage.
The article here https://www.greenbuildingadvisor.com/article/solar-thermal-i... details them, but the TL;DR is that solar thermal is only useful for when a) the sun has been shining for the last few hours and b) your household currently can use a source of (low-grade) heat.
In contrast, PV can be used for all sorts of things (transportation, cooling) and can be exported to your neighbors via the electric grid.
Thermal storage is also not especially space-efficient. Best-case scenario is that you can store about 100 Wh (~US 1¢) of energy per kilogram of mass, which pretty much rules out any kind of seasonal storage.
Also grid-tie systems are a phenomenal deal compared to battery storage.
I live in a place with a pretty favorable regulatory environment, but the net effect of my grid-tie system is that I get to rent an 8 megawatt-hour battery for around US$8 per month. A battery system like that would likely cost in the single-digit millions if I were to purchase it.
I think the person you are replying to is suggesting using PV panels to heat a thermal mass (using resistive heating or possibly a DC heat pump) to avoid the expense of an inverter and other electronics necessary to connect to the grid. This is actually a pretty good idea now that PV panels are a much smaller percentage of the total cost of solar nowadays.
Solar generally pays off if your state/municipality offers SRECs and you get the Federal tax credit. In some places, like Washington DC, it goes as far being lucrative fast. My entire system will be paid off in under 5 years. After that, no electricity bills plus SREC income for another 10+ years.
If economic feasibility is based on government incentives (unsustainable) for solar, and perhaps electric cars, is the big green transition that is currently being pushed ever going to be sustainable?
I mean, it's not like there's no government incentives on the other side. I'm pretty sure government spending on ghg-emitting energy sources (especially when you take all the externalities into account) are quite a lot more than the rather piddling amount being spent on renewals by comparison.
Large scale solar has substantially better economics that distributed solar. The economies of scale should be pretty obvious.
But even distributed solar has a positive ROI, it’s just a long pay off period (20 years etc) without government incentives. But there are plenty of investments out there with lower ROI and longer payoffs that people still invest in.
So it’s all economically feasible and has been for almost a decade (which is why we’re seeing so much solar and wind deployment at the moment). Government incentives just accelerate a trend that was going to happen regardless.
The downside of Utility Scale solar installations is that my utility provider has zero interest in creating them. Rooftop solar is something I can do that's more effective than creating an online petition to convince my local utility to pursue solar.
Why would you want your utility provider to provide solar? Electricity is bought and sold in markets. Anyone with the capital can build a solar farm, sell the energy into grid, and allow local utility providers to buy it. If that energy happens to be the cheapest, then your utility provider will buy it. Thankfully wind and solar tend to be the cheapest forms of wholesale energy production.
If you personally want to invest in solar, then you should look for cooperatives that are raising funds to build solar farms and put some capital in.
But your utility provider should have nothing to do with this, they just provide the cables and buy energy to resell to you (exactly what they're responsible changes region to region, in some parts of the world they just buy and resell energy, and others maintain the cables). Expecting them to build solar would be like expecting your supermarket to manufacture every item on their shelves. They may manufacture some products because it makes sense for them to do so, but the majority are made by others.
I believe the goal of the government incentives is to stand up the industry to the point where economics of scale will help with affordability. Nascent green tech is, after all, competing against heavily developed fossil fuel technology (which has also been subsidized pretty heavily at various times).
I guess what I’m getting at, is total energy needs/usage rather than an issue of fossil fuel or renewable energy.
If our society requires more energy than is sustainable regardless of source, we need to construct societies that use less energy.
So let’s think about transportation. It’s not about switching from ICE to electric cars, but from private cars and suburbs to mass transit and dense cities.
Government is subsidizing unsustainable energy consumption rather than transforming society to lower consumption.
I mean, money isn't a Real Thing. It's a social construct and in so far as government 'subsidizes' anything, it's really just changing the rules of the game we're all forced to play to favour a different outcome.
They could certainly also subsidize shifts away from energy use in general, but these things aren't mutually exclusive and we probably can't actually get to carbon negative so long as we're burning fossil fuels, which is what we actually need to do.
But what's the long game here? EVs have dropped in price by a factor of ~3 and solar power dropped in cost by a factor of 10 over the past decade. The incentives seem to be achieving exactly what they sought to achieve.
So even in a world where all incentives were removed, it seems oil, coal, and gas are organically on the way out. What's holding that back, as usual, is $$$ people. And it's fascinating that California not only wants to all but discontinue paying for electricity from rooftop solar panels, but plans to go even further and impose a $96/year de facto tax per kW of solar panel installed.
Are solar panels worth it if you live at higher latitudes? I'd like to see a comparison between New England, NYC and Arizona in terms of how fast they go net positive.
I live in the Pacific Northwest where it is cloudy for the majority of the year. In our last house we had panels installed. The amount of money we paid each month toward paying down the loan for the panels was less than what we had been paying each month for electricity prior to the panels being installed. About $50 less per month. Where we live, any excess energy is fed back into the grid and counted as a credit the rolls over year to year. We generated enough electricity to cover our needs, even during the cloudiest/rainiest months. We never had an electric bill more than the required $12 hookup to the grid fee.
The article is in the Netherlands. Amsterdam is 52N, which is further north than the US (aside from Alaska obv.), indeed there are parts of Alaska that are further south.
It really depends on your electricity prices. For example, here in Québec (where electricity if very cheap) we don't really see solar panels, but cross over to Ontario and you'll see fields of them.
The solar panels I see around here are mostly off-grid applications (boats, RVs, roadside signs).
While an interesting experiment, trying to calculate ROI on an a small/inefficient system isn't a very useful metric.
- You can get panels for USD $0.38/watt (vs 0.81 in the article), or used for 1/2 that.
- Non optimal angle, no mention of what direction the balcony is facing
- Standard grid tie systems use microinverters
>the panels are illuminated by the sun at different angles, and the maximum possible angle occurs only once a day
What would it take to put these on motors that follow the sun? How much of the energy being generated by the panels would be eaten up by the motors? Would it be a net benefit to have the panels being at the maximum possible angle throughout a greater part of the day, even if part of the energy is having to drive motors?
Most big installs have motors. The motors don't take much power to slowly move the panels through the day. The downside is the extra expense of the motors and setup.
Motor mounts don't generally work for rooftop unless you have a flat roof like a commercial/industrial install. They're also more failure prone so in most cases it's easier to just install more panels.
Even ground mounts are generally not motorized for home installs.
Side question, I've been thinking about adding on above my garage. One side of the new roof would face S-SW (currently the roof of our house only faces east and west). How would I figure out the optimal angle to build the roof for my latitude so that solar panels would get the maximum exposure?
The optimal angle is perpendicular to the sun at all times. Which changes throughout the day, and also throughout the year.
My recommendation would be to let the structural, material, and economic factors determine the pitch of the roof, and let the installers determine the optimal angle of the solar panels.
Mathematically, you want to be perpendicular to the sun, so typically you'd take your latitude and set that as the angle to horizontal. Some systems allow you to adjust the angle seasonally, angling down to latitude+23 degrees for the middle of winter and up to latitude-23 for the middle of summer, but your roof probably doesn't support that. Also, you might want to bias a little towards the sky rather than the ground; on cloudy days the light comes from all over the sky (less comes from the low-albedo dirt), and if it's fixed year round, again bias it a little towards summer angles because there's less solar energy and more clouds in the winter.
Realistically, though, the angle just doesn't matter that much. More silicon area covers a multitude of inefficiencies. You're already proving this by setting a constant azimuth of S-SW because that's where the house aims, doing that again with the angle of elevation isn't that bad.
A conversation with a roofer/contractor might go something like this: "Not sure what this nonsense about the arctangent of the latitude is, but you want a slope of 13 7/8 in 12?!?! That's ridiculous, I don't know if I could even get a permit for that, much less trusses or shingles. I did hear of a guy who did something like that for a custom house, he's probably booked out for 20 months and I hear he charges $900/square, talk to him not me if you really, really want that. I can do 9/12 pitch [36.87 degrees] at $600 per square [hundred square feet]. If you go down to 6/12 [26.57 degrees] my guys can walk it and get the job done faster, I'd go $550/square, final offer."
Just match existing architecture and reinvest the savings in more panels.
Here's an excellent article with some links to papers and calculators:
110kWh in one year from 320W is quite bad. One would at least expect 250kWh normally, even more under ideal circumstances. So a better setup can easily half the time until break even. Also, the inverter needs to be scaled to the panels, obviously. If your inverter can do xW, your panels should at least do xW (or more with east/west orientation), or you effectively lose money.
So a balcony installation is obviously not the best approach, but one has to wonder about a rooftop installation. What if every apartment would get some part of the roof allocated for private solar? It stands to reason that such an installation could pay for itself in 10 years or less.
I live around 49°N and get an average of ~3 hours of rated output per day over the course of the year. OP's is closer to 1 hour per day.
My array does have a clear view of the southern sky, and the angle is supposedly ideal for a fixed array at my latitude. And our longest days tend to also be our sunniest, but it looks like rooftop is much better than balcony, where it's feasible.
(Interesting aside: everywhere on earth (to a first order approximation) gets the same number of hours of daylight over the course of a year. Thus the biggest downside of a higher latitude solar installation is that the sun is passing through more atmosphere on its way to your panel).
As an experiment I installed a set of the cheapest panels and inverter on my garage last year. 1500 euros for about 2000 watt peak. The mounting materials were a bit more than a third of that. Also paid about 300 euros for the installation. So 1800 euros
all-in. Surprisingly, the system is performing quite well, delivering those 2000 watts reliably in the hours around noon, but also working quite well in more cloudy conditions. Bottom line: for around 1 euro per watt you can easily install solar (without subsidies), so as far as I’m concerned it’s a no brainer if you have the space.
Yes, tied to the grid. Simply hooked up to a dedicated breaker circuit. This is in The Netherlands, which means you don’t need a permit to install or connect solar. Practically everyone here has a meter which records power usage and return. Currently, what you return is subtracted from your usage (yearly cumulatives) as an incentive to install domestic solar, although that arrangement will probably be phased out step-by-step after 2023.
> Practically everyone here has a meter which records power usage and return.
Be aware that this is not common in the rest of the world. Most meters are non-directional, which means if you hook a solar panel up to it and then produce extra power, the power company will read it as if you consumed that power from the grid. Effectively you pay the power company for every extra watt generated. Part of the solar install involves calling up the power company to have them come out and swap the meter.
Requirements to install Solar vary by community, state, and nation. It even matters where you install the panels. Ground mount and non-inhabited structures (sheds) and often more loosely regulated than rooftop arrays. Even if you are planning to do it yourself it is worth it to call a local installer and discuss the process and local laws. You may need to get permission from the HOA, town, county, power company, state, and even federal government depending on where you live.
> Most meters are non-directional, which means if you hook a solar panel up to it and then produce extra power, the power company will read it as if you consumed that power from the grid.
Smart meters can be configured either way, though the one I'm familiar with from talking to the various inspectors and such (our type) has two different registers, one that counts "net energy" and one that counts "total energy passed through" - counting up in both directions.
I imagine if you're not on a net metering agreement and those two begin to differ, you'll have a visit from a power company truck at some point. They're quite clear in the various rate schedules that if you've got non-permitted solar installed, they'll come turn it off, and if they can't easily do so, they'll simply take their meter (disconnecting you entirely from the grid).
I imagine quite a lot of installations are still using old fashioned rotating disk meters. These are quite definitely bidirectional unless fitted with a ratchet that prevents them running backwards.
I only got a smart meter a couple of years ago here in Norway and we are way ahead of most countries.
The old spinning disk meters can run backwards, but newer electronic meters are apparently dumber unless they are specifically made to be bidirectional (so called "Net Meters").
My parents have solar panels on their house since 2007. So if anyone is interested in long term data from central europe (Thuringia), take a a look here: https://www.graefenroda-solar.de/
In this particular case I think the main factor is purely where the panels are placed and their rather steep angle. Normal paybacks for rooftop are often half of that, if not better.
I just got a 19.98 kWh array (20kWh is the limit) and it cost a bunch but due to the local net billing, we're going to be able to sell back enough that it will wipe out our bill plus some most months.* Specifically, for December, we generated enough to pay the entire bill and create a $70 credit on January's bill. We can't project a trend from a single month but I'm optimistic.
* ymmv - Our rooftop is southwest-facing with zero obstructions and we've applied a number of energy-saving tactics inside.
Also.. fun side thing on timing. We signed the contract in June. They did the site survey in July. The cells+batteries took 8 weeks for delivery (normally 2-4 weeks) and install has taken forever. Talking with the crew recently, the stated delivery time is 12+ weeks but they're seeing almost 18 weeks. It's a bad time to do this at scale.
Are there any safety or other technical issues with a setup like this? I am comfortable with small-scale solar setups because I've built one for a van, but I had no idea you could build a simple grid tied system like this. Is the inverter really just plugged into a wall outlet?
If it's this simple, I might just throw together a system with some spare panels in my garage.
If I am reading this right (and I am not an expert at all), if wanted to subsidize my current electric bill I could just buy a few solar panels and a grid tie inverter that I just plug into any random outlet and as long as my house consumes more energy than the panels provide and I don't exceed the amperage on the breaker I can effectively do this that simply? (even if the ROI doesn't make sense?)
In the United States, the answer is a very clear "No" almost everywhere - those plug in inverters aren't permitted under NEC. Power companies generally require you to have interconnect agreements for any amount of self generation that could interact with the grid (off grid system, have at it, it touches the house wiring, you need to talk to them).
The problem with plugging that sort of thing into a random outlet is that now you've violated the assumptions on the circuit protection. If you have a string of outlets, protected at 20A at the panel, then nothing plugged into any one outlet can pull more than 20A sustained (or the breaker will pop), and the wiring will never see more than 20A sustained.
If you plug in another source at the far end of that circuit, outlets in the middle and branches off the main wiring run could be seeing 30A without popping a breaker - and that's a fire hazard. A 20A outlet won't pass 30A forever, and wiring rated for 20A can overheat at 30A sustained.
In some other countries, you can install some amount of solar and backfeed it like that, but I'm not familiar with those regulations, not living there.
> the answer is a very clear "No" almost everywhere - those plug in inverters aren't permitted under NEC
Of course plug in inverters are not permitted under the NEC, just as kitchen appliances aren't permitted under the NEC, nor are the power lines outside your house permitted under the NEC. The NEC applies to premises wiring, which none of those things are. Plug in devices sold on the consumer market are regulated by UL/ETL/etc, and the power grid is designed by power company engineers working to some other standard. If you look at your service entrance you'll see the wires coming from your house are nice and thick as dictated by the NEC, but connected to a smaller aerial feeder that doesn't meet the sizing requirements of the NEC.
Your power company might have some private contractual prohibitions here and you may be opening yourself up to liability from the results of your actions - similar to them getting perturbed if you use a "suicide plug" to power your home from a generator. But it's not generally a priori illegal like you're making it out to be.
(Your point about overloading branch circuit wiring is very important though. I'd be more worried about feeding in between the panel and a large load, thereby putting extra current into the intermediate wiring.)
In run 15 kw solar array on the roof and 5kw over pool, in addition to plenty of daily energy and good grid buyback prices I have nice view from a drone :) also have some monitoring based on grafana and mqtt, both my invertors have proprietary protocols and it was fun to hack them to get data. I think every roof should have pv panels with grid tie connection, so many photons are missed :)
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[ 3.2 ms ] story [ 186 ms ] threadIf you delivered 48VDC you'd still need a DC SMPS at each point, but an SMPS is way more efficient than a transformer.
Add up the losses in each conversion, plus the losses from the house wiring.
https://www.ecfr.gov/current/title-10/chapter-II/subchapter-...
It seems like you could replace a certain fraction of room wiring with PoE from an energy budget point of view -- lights, lamps, chargers and other doodads don't need to draw more than a few watts each, so you could get by with just an outlet or two per room for large power draws everywhere but the kitchen, and PoE for all the rest.
But the world just isn't built for it.
If you run something sane, like 48V or so, then you still need conversion electronics at each point of use, and you don't gain much over just running 120/240VAC, except that now your converters are really expensive because they're less common and "weird." 120VAC to 5V is super common, 48VDC to 5VDC is less so. Some switch mode power supplies will work on DC, some won't, and it's harder on the bridge rectifier diodes, so they don't tend to last very long in that sort of use.
It's the sort of thing that sound good in isolation, but in practice leads to spending a lot of money to gain little or nothing in terms of efficiency.
The exception is for a small system where you can run 12VDC to LEDs and stuff (think a camper), and avoid bringing the inverter online at all. Inverters have a significant idle draw more or less proportional to peak power delivered (my 2kVA inverter idles at 30W DC, a 6kVA one that can hold 18kVA for 20 seconds idles at 100W DC).
https://www.reddit.com/r/UsbCHardware/comments/phl211/48v_dc...
Some meters will be unhappy running backwards. They may not register the right numbers but they won't blow up.
From a regulatory standpoint your utility won't be happy with you feeding power to the grid if you haven't notified them ahead of time. How unsafe that is depends on your local laws. The dangers here are fines and service cutoffs, not fires and electrocution.
Overview: https://www.youtube.com/watch?v=FKhszB4E1_M
Build instructions: https://www.youtube.com/watch?v=knlQFlxCwrs
https://archive.fo/RbJtG
What's funny is that everyone still complains about their Hydro bill, but that's because virtually every house is heated with electricity (baseboard heaters), and we have a pretty cold climate. For example, yesterday my house consumed ~180kWh and the outside temperature peaked down to -20°C.
EDIT: mistyped a number
It's a lot of work, but can make sense, even in low power cost areas.
If it improves reliability, it's common enough, but a solar + battery system does well to come in at 4-5x grid rates, even in expensive areas.
My office system (off-grid solar + battery) has now dropped below $1/kWh delivered... but not by much. And the batteries are more than halfway through their expected service life (10 years, flooded lead acid).
I do it because it's interesting to learn and experiment with, and because trenching power out here would suck, but I don't pretend it's cheap.
On the other hand, it is more reliable than the power grid...
If you live in an area where the power is regularly going out (or are off grid entirely) then they give you a whole home UPS which is nice, but it doesn't save you money. The only other major use case is when your local power company is run by unrepentant assholes and they screw you over on excess production so it makes sense to try to save that excess production instead of feeding it back to the grid. But this is a penalty reduction instead of an actual savings.
Currently, the days are very short - 9 hours of sunlight. It's been cloudy and/or snowy quite a few days - which means zero production. Partly cloudy also drops production significantly.
On a good day we might generate 25-30kWh of electricity. But that is also approximately what we use. I'm hoping that during different seasons we will have higher production and/or more days of the week generating.
Because otherwise, our electric bill every month is not a huge part of our expenditures, and we've paid a large upfront cost to (currently) only reduce that by a portion.
If you're net zero in the middle of winter you're probably going to be positive in the summer unless you live in a very hot climate. IMHO sizing an array to be net positive over the course of a year is probably a mistake, as this draws the ire of your power company and they'll probably screw you on overproduction. If you're planning to buy an electric car or something in the near future then it might not be a problem, but generally the best plan is to buy for about 100% of your total yearly usage. Solar panel production typically decreases by 2% during the first year of operation (0.5% every subsequent year) so you'll be slightly net negative which keeps you on good terms with the power company.
One nice thing with the panels is that they effectively lock in your power rate at whatever you paid. You won't get burned by ever increasing power rates. It's a hedge against future rate hikes.
Only net zero on good days. And so far there have been plenty of bad days.
I would love to have gotten more because I'd like to add an electric car as well as some heat pumps. But my roof is only so big.
I didn't know that about the power companies being unhappy though.
One thing the author missed is that in the Netherlands you can re-claim the VAT paid on the solar installation, saving 21% of costs. Probably not worth the effort for a very small installation, but for a bigger one it saves considerably.
It's not simple from a technical point of view. It's bewilderingly complex, in fact. If not done right, it can threaten the stability of the grid. It requires parts of the grid to have increased capacity. In/out balance needs to be maintained at all times.
Decentralized production is great, but it could really benefit from more decentralized storage. Might be useful to start installing sizeable batteries near all medium->low voltage substations. Seems like the right place for it.
The power is out and the lines are being worked on. The line is supposed to be dead. Your solar system is making power and sends it out of the house, back on the grid.
Not that you would want to run appliances with the power dipping out randomly anyway. Maybe to charge a laptop/phone or run basic incandescent bulb/electric space heater/toaster type loads.
Any power either you or your neighbour tired to put into the grid would be immediately consumed by all of your other neighbours (and of course your own appliances) that it would drag your AC waveform completely out of spec (I.e. it should be 230V AC, but your equipment can only supply enough juice to support 0.01V AC). So you’re inverter would shutdown due to lack of recognisable grid compliant waveform. Either that or catch fire from trying to drive thousands of amps (from 100 acre solar farm on your balcony) into your power socket, which would also catch fire, along with all the cable in the wall, well, you get the idea.
In short physics and simple supply and demand ensure that no home scale inverter would ever be able to maintain an even vaguely compliant AC waveform during a blackout.
No need to decentralise storage, decentralised production is very unlikely to ever be enough that distribution lines and unable to transport the power out. Additionally medium->low voltage substations are located near customers, which means the land is expensive. So putting in batteries with a material amount of storage is also expensive, assuming there’s even enough space.
Load is easier to predict, but far harder to shed on short notice.
Decentralized production absolutely can be enough to max out power lines. In most parts of the world, power grids aren't exactly crown jewels. Many grids are basically held together with proverbial duct tape. Here in Belgium the grid is such a pile of rubbish that instead of trying to adapt to decentralized production, we're now actively going to punish people for using power during peak hours.
I agree that land and batteries are expensive. But they're a lot less expensive than rebuilding the grid.
It’s all a question of scale, you need coordination to handle the macro level balancing of power. Making sure there’s enough power stations running to keep the lights on, and that the grid is roughly balanced. But that level of balancing is planned hours to days in advanced, because power stations take hours to days to spool up depending on the tech. So it’s a system incapable of responding to moment-by-moment changes.
For handling instantaneous fluctuation, the first defence the the rotational inertia of all the generators in every power station. These things have tons of spinning mass, and are the reason grid frequency fluctuates with power draw, pull more power than provided, and the grid makes up for it by stealing stored spinning energy in the generators. Then speed governors on the generators notice the slow down and provide more steam/gas/coal whatever to speed the generator back up. Both covering the stolen inertial energy and bumping total grid input.
For larger fluctuations that can’t be covered by rotational mass and modulating power station output, you’ll have a variety of fast response loads and supplies. Energy consumers that have agreements to modulate their usage or production in response to frequency fluctuations, and who get paid for providing the service. Some examples include steel and aluminium smelters. They can shutdown temporarily to shed load, and just rely on thermal mass to prevent their equips freezing. Water tower pumps, you’ll have plenty of stored water, pumps for canals, fridges and freezers can turn their compressors off, so can AC units, and even data centres that will swap to their backup generators and take their load off the grid.
Now all of the above loads heading only works for a limited amount of time, all of those consumers can only reduce their load for so much time. So you also have power producers, people who have diesel generators sitting around that can be turned on and connected to the grid, rapid response power stations that can cold start in 15-20mins etc. All of these will be started by a drop in frequency, and expected to pickup the load without any central coordination.
Between the fast response load shedding and fast response producers a grid can handle a substantial amount of production variation without any central coordination. In normal operations you’ll only be relying on fast response load shedding of non-critical loads like water pumps, and cascading to more drastic load shedding and power production if the grid can’t recover quickly by upping production at major producers (who won’t be running a 100% under normal conditions).
> Decentralized production absolutely can be enough to max out power lines.
> <snip>
> Here in Belgium the grid is such a pile of rubbish that instead of trying to adapt to decentralized production, we're now actively going to punish people for using power during peak hours.
Yes and no. Normally the behaviour you describe isn’t caused because the infrastructure can’t handle the production (after all peak distributed production is extremely unlikely to ever be higher than peak load, you simply can’t fit that many solar panels on a roof). But rather that distribution companies run on the assumption that power only passes in one direction in their network, from grid to consumer. All of their modelling, and more importantly, their financial agreements with the grid and each other depend on this predicate.
As a result their objective is to ensure there is zero supply back to the grid, and that all distributed generation is always consumed within their grid, preferably within the same substation so there are zero backward flows anywhere. This doesn’t mean the equipment couldn’t support reverse flows, it’s just that figuring that out would cost money, and they have no incentive to figure it out. They get paid the same regardless of if they support reverse flows or not, so it’s better to ob...
Aren’t we have to do it anyway in future? EV’s, eVTOL’s and heck knows what else is just gonna use more and more power.
There are benefits besides money from removing your dependencies on fossil fuels. The fact that it's even in the ballpark of breaking even is a very nice side effect, but it's not the point.
Also, if you are extremely remote, getting the grid built out to you might cost tens of thousands, to the point that the up-front costs of nongrid power are even more palatable.
System Average Interruption Duration Index (SAIDI). This index is based on the amount of time the average PG&E customer experiences a sustained outage (being without power for more than five minutes) in a given year. In 2020, the PG&E SAIDI was about 153.2 minutes per customer.
System Average Interruption Frequency Index (SAIFI). This metric represents the number of times the average PG&E customer experiences a sustained outage in a given year. In 2020, the PG&E SAIFI was about 1.179, or slightly more than one per customer.
Customer Average Interruption Duration Index (CAIDI). This index represents the average restoration time when customers are impacted by a sustained outage. It is determined by dividing SAIDI by SAIFI. In 2020, the PG&E CAIDI was 130.0 minutes.
Momentary Average Interruption Frequency Index (MAIFI). This index is based on the number of times the average customer is interrupted by Momentary Outage events each year. Momentary Outage events are outages that last 5 minutes or less. In 2020, the PG&E MAIFI was 1.317 per customer.
https://www.pge.com/en_US/residential/outages/planning-and-p...
Adding the battery increases the payback window, often adding 50-100% to the hardware costs of the install. Plus they are in very short supply currently, so including a battery in your build may push it back several months.
Grid tied solar often manages this, though exceedingly poor panel utilization as in the article typically won't. By the time you start adding batteries, you're unlikely to be net carbon negative during the system life. It's hard to get solid numbers for modern battery construction, though. They tend to be trade secret sort of values.
A lot of this depends a lot on where you live and what your energy mix is to begin with, so there's no one size fits all answer. My issue isn't with any of these specifics though, it's that the conversation is always dominated entirely by "will it result in me paying less in the short term?" which is exactly the kind of short term thinking that's gotten us into this mess.
Anyways, I think it's too early for widespread use of battery systems, for sure. I'm also personally not keen to put a giant fire hazard into my house or garage if I don't have to. I think the tech for solar and the tech for batteries are on similar but offset curves, where battery storage for an entire home just isn't quite there yet like panels are.
Batteries are around 100kg of CO2 per kWh of capacity on a really dirty grid (China).
So after the usual 2000 cycles a LiFePO4 battery can stand it will amount to around 50g of CO2 per kWh delivered (or 60g taking into account losses).
Solar panels are 45-80g per kWh so worst case scenario you're doubling the system's footprint if you're going for 1 hour of full capacity.
But resources are kind of hard to find. Is there a good list of things you could consider that would be environmentally helpful upgrades to your home? Heat pump, solar, electric car, native plant garden, the latest and greatest in insulation, that sort of thing?
That said, I live in an area where most home heating is done by natural gas delivered to homes and installed a heat pump last year. I had a lot of trouble finding an hvac company that would do it because it's still quite uncommon where I live, and even they had a lot of misinformation about it. I had a lot of reasons for doing this both related and unrelated to climate change:
- The heat dome demonstrated that our house, which is relatively new and built to modern standards so is designed to soak up heat like a sponge, could not be comfortable without AC in a summer like that, of which I expect many more in the future.
- If I was getting an AC anyways, there's literally no reason not to have a heat pump and use it for heating in the milder months and reduce my direct use of gas to only when it's absolutely necessary (ie. the last few weeks where we've had a shockingly long cold snap).
- And if I was going to run AC I should absolutely have solar as well so I'm not using grid energy to power it (where I live grid energy is very much dominated by coal and natural gas, though coal is thankfully reducing quickly).
- Even though the energy mix is mostly GHG-emitting where I live, down to some specific temperature (probably around -10 to -15C with the expensive heat pump I got), a heat pump simply uses far less electric energy than an equivalent amount of gas burned in the house. It's quite a big difference. It doesn't look like it because electricity is priced much higher per kWh-equivalent than gas.
But I think there's a lot of more complicated things people 'should' do as well? Since my house is new, the trees on the lot are quite small so provide very little shade in summer. Hopefully this improves as they grow, and maybe we'll plant some more. We're also probably going to install awnings on the windows that are more or less positioned to block direct sunlight in the summer and let it through in the winter. Generally finding ways to passively heat and cool your house is the best thing you can possibly do and even though I'm doing the above as part of electrifying, I plan to do a lot more of the other sorts of things as well.
I also didn't say anything about what I expect "people en masse" to do. You'd think I shot someone's dog when all I did was say "maybe we could talk about something other than money?"
The time and money it takes to get a new nuclear plant up is meaningless now, just put down solar and wind
Consider a similar "tragedy of the commons" externality-- air pollution.
LA smog was quite infamously disastrous for decades. This was not fixed by "good Samaritans" trailblazing, but rather regulation enabled by the Clean Air Act, in which California was especially liberal in using-- car smog checks, centralized landfills, catalytic cracker carbon controls, etc.
This was, in my opinion, wildly successful. Just look around LA. It's not the hellhole it once was. But these controls were, and still are, mildly unpopular [1].
The point I want to make is this-- change will not happen with single trailblazers e.g. the HN demographic. It has to happen with widespread change. That can either happen top down (e.g. air pollution) or bottoms up (e.g. making costs/revenues break even).
I personally don't think a top-down approach will ever happen in today's political climate. Thus, the reality is, we need a hyper-focus on making breakeven. Because that's the reality of the vast majority of people, not just the HN community.
[1]: https://publicintegrity.org/environment/a-california-regulat...
I definitely see the value as a way to sell solar. And I agree with it. I think many people will only do it if it makes financial sense. But I don't think that means it needs to be the only carrot or stick. I don't think we really have time to pretend that only One Simple Pitch will get us there.
Nor do I think it means that the conversations about it need to be so thoroughly dominated by it. I'm not talking about the OP here, I'm talking about this thread, on which nearly every top level post is just someone declaring whether solar breaks even for them or not. I don't think this is terribly useful dialog, and it makes it very hard to talk about anything else.
The price of LifePo4 lithium batteries has also plummeted in recent years.
Cool project though!
The article here https://www.greenbuildingadvisor.com/article/solar-thermal-i... details them, but the TL;DR is that solar thermal is only useful for when a) the sun has been shining for the last few hours and b) your household currently can use a source of (low-grade) heat.
In contrast, PV can be used for all sorts of things (transportation, cooling) and can be exported to your neighbors via the electric grid.
Thermal storage is also not especially space-efficient. Best-case scenario is that you can store about 100 Wh (~US 1¢) of energy per kilogram of mass, which pretty much rules out any kind of seasonal storage.
Also grid-tie systems are a phenomenal deal compared to battery storage.
I live in a place with a pretty favorable regulatory environment, but the net effect of my grid-tie system is that I get to rent an 8 megawatt-hour battery for around US$8 per month. A battery system like that would likely cost in the single-digit millions if I were to purchase it.
But even distributed solar has a positive ROI, it’s just a long pay off period (20 years etc) without government incentives. But there are plenty of investments out there with lower ROI and longer payoffs that people still invest in.
So it’s all economically feasible and has been for almost a decade (which is why we’re seeing so much solar and wind deployment at the moment). Government incentives just accelerate a trend that was going to happen regardless.
If you personally want to invest in solar, then you should look for cooperatives that are raising funds to build solar farms and put some capital in.
But your utility provider should have nothing to do with this, they just provide the cables and buy energy to resell to you (exactly what they're responsible changes region to region, in some parts of the world they just buy and resell energy, and others maintain the cables). Expecting them to build solar would be like expecting your supermarket to manufacture every item on their shelves. They may manufacture some products because it makes sense for them to do so, but the majority are made by others.
If our society requires more energy than is sustainable regardless of source, we need to construct societies that use less energy.
So let’s think about transportation. It’s not about switching from ICE to electric cars, but from private cars and suburbs to mass transit and dense cities.
Government is subsidizing unsustainable energy consumption rather than transforming society to lower consumption.
They could certainly also subsidize shifts away from energy use in general, but these things aren't mutually exclusive and we probably can't actually get to carbon negative so long as we're burning fossil fuels, which is what we actually need to do.
https://e360.yale.edu/digest/fossil-fuels-received-5-9-trill...
But what's the long game here? EVs have dropped in price by a factor of ~3 and solar power dropped in cost by a factor of 10 over the past decade. The incentives seem to be achieving exactly what they sought to achieve.
https://www.greentechmedia.com/articles/read/solar-pv-has-be...
So even in a world where all incentives were removed, it seems oil, coal, and gas are organically on the way out. What's holding that back, as usual, is $$$ people. And it's fascinating that California not only wants to all but discontinue paying for electricity from rooftop solar panels, but plans to go even further and impose a $96/year de facto tax per kW of solar panel installed.
https://nrgcleanpower.com/learning-center/nem-what-changes-a...
I think our leaders have no idea what they're doing across the board personally.
The solar panels I see around here are mostly off-grid applications (boats, RVs, roadside signs).
- You can get panels for USD $0.38/watt (vs 0.81 in the article), or used for 1/2 that. - Non optimal angle, no mention of what direction the balcony is facing - Standard grid tie systems use microinverters
I have a flat and a balcony, it would not be possible for me to have anything bigger than author.
I don't have to run such an experiment and I already see that any "backup power" shizzle I would buy on amazon would be loss of money.
Better get small fuel generator for any blackouts that can happen.
What would it take to put these on motors that follow the sun? How much of the energy being generated by the panels would be eaten up by the motors? Would it be a net benefit to have the panels being at the maximum possible angle throughout a greater part of the day, even if part of the energy is having to drive motors?
Even ground mounts are generally not motorized for home installs.
My recommendation would be to let the structural, material, and economic factors determine the pitch of the roof, and let the installers determine the optimal angle of the solar panels.
Realistically, though, the angle just doesn't matter that much. More silicon area covers a multitude of inefficiencies. You're already proving this by setting a constant azimuth of S-SW because that's where the house aims, doing that again with the angle of elevation isn't that bad.
A conversation with a roofer/contractor might go something like this: "Not sure what this nonsense about the arctangent of the latitude is, but you want a slope of 13 7/8 in 12?!?! That's ridiculous, I don't know if I could even get a permit for that, much less trusses or shingles. I did hear of a guy who did something like that for a custom house, he's probably booked out for 20 months and I hear he charges $900/square, talk to him not me if you really, really want that. I can do 9/12 pitch [36.87 degrees] at $600 per square [hundred square feet]. If you go down to 6/12 [26.57 degrees] my guys can walk it and get the job done faster, I'd go $550/square, final offer."
Just match existing architecture and reinvest the savings in more panels.
Here's an excellent article with some links to papers and calculators:
https://www.thesolarnerd.com/blog/optimal-solar-panel-tilt-m...
I also have the same issue with only getting sun past 16:00 on my balcony so in the winter, the yield is very low.
I run my blog on solar + batteries, I don’t deliver power to the grid. On the contrary, I recharge the batteries from the grid in the winter.
[0]: https://louwrentius.com/this-blog-is-now-running-on-solar-po...
So a balcony installation is obviously not the best approach, but one has to wonder about a rooftop installation. What if every apartment would get some part of the roof allocated for private solar? It stands to reason that such an installation could pay for itself in 10 years or less.
My array does have a clear view of the southern sky, and the angle is supposedly ideal for a fixed array at my latitude. And our longest days tend to also be our sunniest, but it looks like rooftop is much better than balcony, where it's feasible.
(Interesting aside: everywhere on earth (to a first order approximation) gets the same number of hours of daylight over the course of a year. Thus the biggest downside of a higher latitude solar installation is that the sun is passing through more atmosphere on its way to your panel).
Be aware that this is not common in the rest of the world. Most meters are non-directional, which means if you hook a solar panel up to it and then produce extra power, the power company will read it as if you consumed that power from the grid. Effectively you pay the power company for every extra watt generated. Part of the solar install involves calling up the power company to have them come out and swap the meter.
Requirements to install Solar vary by community, state, and nation. It even matters where you install the panels. Ground mount and non-inhabited structures (sheds) and often more loosely regulated than rooftop arrays. Even if you are planning to do it yourself it is worth it to call a local installer and discuss the process and local laws. You may need to get permission from the HOA, town, county, power company, state, and even federal government depending on where you live.
Smart meters can be configured either way, though the one I'm familiar with from talking to the various inspectors and such (our type) has two different registers, one that counts "net energy" and one that counts "total energy passed through" - counting up in both directions.
I imagine if you're not on a net metering agreement and those two begin to differ, you'll have a visit from a power company truck at some point. They're quite clear in the various rate schedules that if you've got non-permitted solar installed, they'll come turn it off, and if they can't easily do so, they'll simply take their meter (disconnecting you entirely from the grid).
(mountain west United States)
(Europe with 3-phase power)
Really? Can you provide a link?
I imagine quite a lot of installations are still using old fashioned rotating disk meters. These are quite definitely bidirectional unless fitted with a ratchet that prevents them running backwards.
I only got a smart meter a couple of years ago here in Norway and we are way ahead of most countries.
https://www.lgenergy.com.au/faq/solar-panels/after-my-solar-...
https://www.synergy.net.au/Your-home/Help-and-advice/Solar-c...
https://www.solarreviews.com/blog/pros-and-cons-of-buying-di...
The old spinning disk meters can run backwards, but newer electronic meters are apparently dumber unless they are specifically made to be bidirectional (so called "Net Meters").
* ymmv - Our rooftop is southwest-facing with zero obstructions and we've applied a number of energy-saving tactics inside.
Also.. fun side thing on timing. We signed the contract in June. They did the site survey in July. The cells+batteries took 8 weeks for delivery (normally 2-4 weeks) and install has taken forever. Talking with the crew recently, the stated delivery time is 12+ weeks but they're seeing almost 18 weeks. It's a bad time to do this at scale.
If it's this simple, I might just throw together a system with some spare panels in my garage.
In the United States, the answer is a very clear "No" almost everywhere - those plug in inverters aren't permitted under NEC. Power companies generally require you to have interconnect agreements for any amount of self generation that could interact with the grid (off grid system, have at it, it touches the house wiring, you need to talk to them).
The problem with plugging that sort of thing into a random outlet is that now you've violated the assumptions on the circuit protection. If you have a string of outlets, protected at 20A at the panel, then nothing plugged into any one outlet can pull more than 20A sustained (or the breaker will pop), and the wiring will never see more than 20A sustained.
If you plug in another source at the far end of that circuit, outlets in the middle and branches off the main wiring run could be seeing 30A without popping a breaker - and that's a fire hazard. A 20A outlet won't pass 30A forever, and wiring rated for 20A can overheat at 30A sustained.
In some other countries, you can install some amount of solar and backfeed it like that, but I'm not familiar with those regulations, not living there.
Of course plug in inverters are not permitted under the NEC, just as kitchen appliances aren't permitted under the NEC, nor are the power lines outside your house permitted under the NEC. The NEC applies to premises wiring, which none of those things are. Plug in devices sold on the consumer market are regulated by UL/ETL/etc, and the power grid is designed by power company engineers working to some other standard. If you look at your service entrance you'll see the wires coming from your house are nice and thick as dictated by the NEC, but connected to a smaller aerial feeder that doesn't meet the sizing requirements of the NEC.
Your power company might have some private contractual prohibitions here and you may be opening yourself up to liability from the results of your actions - similar to them getting perturbed if you use a "suicide plug" to power your home from a generator. But it's not generally a priori illegal like you're making it out to be.
(Your point about overloading branch circuit wiring is very important though. I'd be more worried about feeding in between the panel and a large load, thereby putting extra current into the intermediate wiring.)