I charged my car this afternoon (the amber alert signs have been warning about this all day), while we were (as a state) overproducing electricity, and set the thermostat on the house up 4 degrees 30 minutes ago.
Now, the solar I overbuilt to charge the car is dumping electricity on to the grid.
It'd be completely sorted, except that I can't tell the house battery (which I bought as a backup and to time-shift electricity into the car overnight) to discharge directly onto the grid. Instead, I lowered its reserve, so it will cut our demand all night (instead of peak selling for an hour or two).
Nice of you to be able to afford solar panels and be home and have job flexibility to charge when you want. Not everyone is so privileged, so it still needs to be sorted
Solar panels also cannot support apartment buildings, since the ratio of roof to living space is far too low. Batteries would also be impractical to install in apartments, where space is at a premium.
One of the tradeoffs to building dense is that it makes it harder to decentralize the grid.
>One of the tradeoffs to building dense is that it makes it harder to decentralize the grid.
The other side of that is that with dense living, people need dramatically less energy to begin with. Less energy for heating and cooling, and far less energy to transportation if they live close to wherever they go and can just walk there.
Community net metering solves this problem. It's not available in CA, but is in other states
The apartment dwellers just buy some percentage of a solar farm, then the power company pretends that percentage of the farm's production came from the apartment's roof.
Denser housing uses much less energy, so it takes much less solar per person to offset the apartment's power usage.
Similarly, room can be made for batteries elsewhere, and they can be packed extremely tightly wherever they are installed. (This only works for time shifting, not individual home backup.)
Heating and cooling are the primary energy use and decrease faster than roof area increases for low rise apartments.
Average apartment size is about 80m^2 so in a 3 story building that's about 30m^2 each or roughly 5kWh/day. 200W doesn't allow you to be wasteful, but it's plenty for a 1-2 bedroom apartment. Hybrid cells with slightly better efficiency and low light tolerance would get you to 10kWh/d
Tokyo is around 7000 people per km^2. A 2 bedroom apartment can happily house two or three people, so with a reasonable amount of roof area per apartment you have 80-90% of your area available for not-housing.
High density just means not dedicating a freestanding house worth of land area per resident to force them into cars, it doesn't need to mean highrise.
Even with manila levels of density you can still get lighting, climate control (if well insulated), a washing machine, a few entertainment devices at 10-20W and basic cooking (nothing for the ground level commercial or infrastructure though) with about half your area left for not-housing. So that's some level of semi-decentralisation even in the worst case.
Mid-winter in high latitudes you might struggle without long term storage, but it's not unsolvable.
Batteries take up approximately 0 space. If the better part of a month's worth of energy can fit in a car it's fine.
You’re just displacing baseload generation by overgenerating at a time of the day when demand is minimal. You’re actually one of the roots of the problem
Today, we used normal amounts (for us - AC was on instead of car charging) of power until 10am, then exported power till 5pm (the car was elsewhere, importing power to charge). For the rest of the demand emergency, we had zero gross import and export. We're back to using power over night.
The next obvious thing to fix is that the battery software can't be told to avoid charging during the morning demand spike. (This would have started lowering our energy usage at 7:15 AM and let us flip to exporting power at 8:15 instead of 10am. The same thing happens every day.)
Overnight baseload generation is still an issue, but at least there is an obvious path to smoothing the morning / evening spikes. We'd need a house battery with about 1.5x the car battery's capacity to get through the night while also charging the car overnight.
The transition to BEVs may require more grid capacity, but BEVs also add a _lot_ of storage to the grid, which can reduce the impact of peak demand events. In circumstances like this, car owners can opt to discharge their batteries into the grid and be paid higher-than-normal rates for that energy.
Even without vehicle-to-grid programs, electric car owners can already choose to charge later at night when the demand peak has passed (and power is cheaper).
I am curious if your home happens to contains a small datacenter and/or crypto mine.
40kW is a shitload of power. You could run 10 tons of HVAC and still have over 24kW remaining to play with. Which is plenty to charge 2 Teslas at the same time using 2 different Wall Connectors at maximum output and still have a few kW margin...
Yes but you can't really buy generators with more than 22kw and even that is plenty to run the AC for a 5500 sq ft home with plenty of breathing room to run the electric washer/dryer
Oh of course you can buy generators that will run the utility circuit of a nuclear power plant, they need to come from somewhere. Somebody will sell you one. I have not personally seen a residential generator larger than 22.5kw when searching for homes in hurricane country. This is in response to a guy saying he has a giant 30+kw generator for his home, which would be... extremely unusual unless he was also running an off grid welding shop or something equally unlikely
5kw is the normal running consumption. Startup currents are higher than normal operation and so you need to have a beefier generator. But yes, 40kVA is a lot, big houses should do fine even with high transient loads with a 22kVA generator.
But let’s not forget this is HN, maybe OPs house is humongous
My A/C is 10kw running, with 18kw tankless water heater. You oversize generators when drawing lots of current from switch mode power supplies as harmonics confuse the AVR. Aka tankless water heater.
I have a home lab, full rack. Around 4kw including a dedicated A/C.
I have excess power and will run an extension cord to neighbors if needed.
I’d also want capacity to charge an EV should I get one.
Price between 22kw and 40kw was negligible relative to total project cost. The only downside is I have to turn on everything in the house twice a year to exercise it and avoid wet stacking.
Final note is that in order to use an automatic transfer switch you must have sufficient capacity for connected loads. A smaller generator would have forced me to install a second sub panel for loads I want to run during an emergency.
> California ISO power grid peak demand hit 52,061 MW, a new all-time record. Still holding in EEA3 - no load shed. Conservation is making a difference. ow.ly/brMu50KBKHT
Unless the official CalISO twitter account is lying, this could be a local issue for specific substations etc. With the weather there could be transformers overheating and failing, for example. In a large state, power goes out _somewhere_ quite often.
The bag of tricks CalISO has to lower demand at peak is fascinating - for example, there are large consumers with significant generation resources (like emergency generators) that sign in to turn the generators on and get off the grid for a couple of hours. This produces drops in demand without blackouts per-se. Distributed power generation is generally more resilient.
Thanks. Interesting, indeed. Maybe they're using different terminology; otherwise it's not clear how both Caiso and these local utilities can be truthful at the same time.
There may be no rolling blackouts needed, but at least part of that is because of the involuntary ones. There's a lot of red (>5000 people) and orange (1000-5000 people) in the current map [1]
Too bad they spent ~60 years doing everything in their power to not allow new power plants and generally kowtowing to green and eco lunatics.
The coming water ones are going to be the ones that hurt. Only had most of a century to look at and work on other, long term truly sustainable option, like desalination etc. Also see the last part of above ^
I remember the heat wave of 2006 in California, it got above 110 near san jose where I lived at the time, and we had no power disruptions of any kind. It kind of shows you how far the state of California has fallen into dysfunction, Oh and Governor Newsom and his cronies are also trying to kill off green power - California's nuclear reactors. And he thinks banning gas cars in 13 years is a goo idea with a electrical grid that can't even power the electric cars we have today.
We have backouts two days in a roll now at south bay. Both lasted over 6 hours, right at the honest hours of the day. My bedroom temperature reached 90 degree last night. This is maddening.
39 comments
[ 5.0 ms ] story [ 98.1 ms ] threadI charged my car this afternoon (the amber alert signs have been warning about this all day), while we were (as a state) overproducing electricity, and set the thermostat on the house up 4 degrees 30 minutes ago.
Now, the solar I overbuilt to charge the car is dumping electricity on to the grid.
It'd be completely sorted, except that I can't tell the house battery (which I bought as a backup and to time-shift electricity into the car overnight) to discharge directly onto the grid. Instead, I lowered its reserve, so it will cut our demand all night (instead of peak selling for an hour or two).
One of the tradeoffs to building dense is that it makes it harder to decentralize the grid.
Solar windows might help there: https://www.solarwindow.com/
The other side of that is that with dense living, people need dramatically less energy to begin with. Less energy for heating and cooling, and far less energy to transportation if they live close to wherever they go and can just walk there.
The apartment dwellers just buy some percentage of a solar farm, then the power company pretends that percentage of the farm's production came from the apartment's roof.
Denser housing uses much less energy, so it takes much less solar per person to offset the apartment's power usage.
Similarly, room can be made for batteries elsewhere, and they can be packed extremely tightly wherever they are installed. (This only works for time shifting, not individual home backup.)
Average apartment size is about 80m^2 so in a 3 story building that's about 30m^2 each or roughly 5kWh/day. 200W doesn't allow you to be wasteful, but it's plenty for a 1-2 bedroom apartment. Hybrid cells with slightly better efficiency and low light tolerance would get you to 10kWh/d
Tokyo is around 7000 people per km^2. A 2 bedroom apartment can happily house two or three people, so with a reasonable amount of roof area per apartment you have 80-90% of your area available for not-housing.
High density just means not dedicating a freestanding house worth of land area per resident to force them into cars, it doesn't need to mean highrise.
Even with manila levels of density you can still get lighting, climate control (if well insulated), a washing machine, a few entertainment devices at 10-20W and basic cooking (nothing for the ground level commercial or infrastructure though) with about half your area left for not-housing. So that's some level of semi-decentralisation even in the worst case.
Mid-winter in high latitudes you might struggle without long term storage, but it's not unsolvable.
Batteries take up approximately 0 space. If the better part of a month's worth of energy can fit in a car it's fine.
Work has solar panels and chargers. Even if they didn't, there are plenty of commercial chargers across the street.
Anyway, the car lets us shift about one house of normal demand into peak hours.
The next obvious thing to fix is that the battery software can't be told to avoid charging during the morning demand spike. (This would have started lowering our energy usage at 7:15 AM and let us flip to exporting power at 8:15 instead of 10am. The same thing happens every day.)
Overnight baseload generation is still an issue, but at least there is an obvious path to smoothing the morning / evening spikes. We'd need a house battery with about 1.5x the car battery's capacity to get through the night while also charging the car overnight.
California is already experimenting with these programs, e.g.: https://www.utilitydive.com/news/california-approves-117m-ve...
Even without vehicle-to-grid programs, electric car owners can already choose to charge later at night when the demand peak has passed (and power is cheaper).
40kW is a shitload of power. You could run 10 tons of HVAC and still have over 24kW remaining to play with. Which is plenty to charge 2 Teslas at the same time using 2 different Wall Connectors at maximum output and still have a few kW margin...
I have a home lab, full rack. Around 4kw including a dedicated A/C.
I have excess power and will run an extension cord to neighbors if needed.
I’d also want capacity to charge an EV should I get one.
Price between 22kw and 40kw was negligible relative to total project cost. The only downside is I have to turn on everything in the house twice a year to exercise it and avoid wet stacking.
Final note is that in order to use an automatic transfer switch you must have sufficient capacity for connected loads. A smaller generator would have forced me to install a second sub panel for loads I want to run during an emergency.
> California ISO power grid peak demand hit 52,061 MW, a new all-time record. Still holding in EEA3 - no load shed. Conservation is making a difference. ow.ly/brMu50KBKHT
0. https://twitter.com/California_ISO/status/156733473761784627...
The bag of tricks CalISO has to lower demand at peak is fascinating - for example, there are large consumers with significant generation resources (like emergency generators) that sign in to turn the generators on and get off the grid for a couple of hours. This produces drops in demand without blackouts per-se. Distributed power generation is generally more resilient.
https://twitter.com/nukebarbarian/status/1567358316174622720
[1] https://pgealerts.alerts.pge.com/outagecenter/
The coming water ones are going to be the ones that hurt. Only had most of a century to look at and work on other, long term truly sustainable option, like desalination etc. Also see the last part of above ^
2006 heat wave - https://en.wikipedia.org/wiki/2006_North_American_heat_wave