TL/DR;
- An energy crisis due to a seasonal heat-wave in California was possibly averted by large batteries that stored excess generation capacity
- The policies supporting a transition to EVs could help with future energy crises if the batteries become extra energy storage on the grid
Background
On August 25, 2022, California announced that by 2035 100% of new cars and light trucks sold in the state will be zero-emission vehicles.
On September 1, 2022 (exactly one week later) I got a loud notification on my phone, a Flex Alert from the state to reduce my use of electricity during the hours of 4 to 9 p.m, including avoiding charging electric vehicles (EVs).
These two facts seem to make California out of touch with reality. However, I think the policy has the potential to make sense.
Here's why:
We use electricity. Lot's and lot's of it
To get electricity you need two things:
- Energy Source (gas, coal, potential energy of water in a reservoir, uranium, sun light, wind, waves)
- Electric Generation (energy sources are consumed to spin electric generators, photo voltaic cells convert sunlight, etc.).
When you need it, you need it
We've been spoiled by Amazon's fast delivery times, but when I turn on my light or computer or TV or washing machine, I don't want a text notification that tells me my electricity will be delivered in a few minutes. I expect to get it instantly and power companies manage to provide it. They put another electric generator online and start consuming some of the stored energy.
Energy use varies during the day. Use is lowest while most of us sleep and our refrigerators are the main consumers. It increases as we awake and turn on lights and appliances. It peaks around noon as we enlist our air conditioners to keep us cool.
Avoid Peak Usage
We used to be told to use appliances in the morning or evening to avoid adding demand during peak usage. Now, with widespread solar installations on homes and businesses, peak solar generation coincides with peak air conditioning usage and the new peak is when we get home from school and work and turn on lights and appliances.
During extra hot days, when air conditioners run longer, the generation grid can get stressed near the max. Any failures of equipment can be catastrophic.
This is when Flex Alert notices are sent out, basically asking for citizens to help out.
Why not just build more Power Plants?
The extra generation capacity could be added to avoid this problem, but that would mean spending billions of dollars just to provide extra capacity during a a few hours for a few weeks of the year.
California already has extra capacity as it can generate 45 gigawatts of power while the demand during hot months is about 38 gigawatts (1).
Wouldn't it be better if California could use it's excess capacity during lower demand times and store up the electricity? Yes it would!
Offsetting Capacity by Storing Electricity
The Olivenhain Dam is a gravity dam near Escondido California above Lake Hodges (2). During the peak hours, water flows through hydroelectric generators to Lake Hodges. At night, when there is excessive generation capacity from other sources, that capacity is used to pump water back into the Olivenhain reservoir.
More recently, massive industrial grade batteries have been used to store the extra capacity(3) and helped avert an energy crisis (4). How much capacity do these batteries have? More than the output of the Diablo Nuclear power plant .