The idea of using electric cars to store energy for the power grid is a good one, I think. Unfortunately, it may be too expensive at this time to make any sense, according to one recent cost analyst. The same high cost problems that have hindered electric cars in the past mean it may not make sense for the future even beyond 2020, unless the costs come down.
Then again, advancements in battery technology seem to be happening on a daily basis, so maybe it doesn’t make sense today, but tomorrow could be a different story.
The analysis was done by Black and Veatech, an engineering, construction, and energy consultation company. Energy storage is vital for future technologies like wind and solar power, so energy can be stored during times of high output and low demand. They compared current storage methods: compressed air , flywheels, pumped hydro, and sodium sulfur batteries.
Sodium sulfur batteries are currently used for grid energy storage due to their inexpensive nature and high energy density. These are not the same kinds of batteries used in cars though, because they tend to run at temperatures between 300 and 350 degrees Celsius (572 to 662 degrees F).
Unfortunately, this analysis does not compare the potential storage capacity of say, 1000 small electric car batteries in 1000 separate cars in terms of cost compared to energy. I mean, since the batteries will be there anyway, might as well use them if needed, right? They are already paid for, and should demand increase during times of low output could be used to supply power. But compared to compressed air energy storage, sodium sulfur batteries don’t appear all that efficient.
Compressed air energy storage (CAES) is where excess energy is used to power air compressors, which fill a high pressure tank for temporary storage. When the energy is needed, the air is released to power air turbines, putting the power back into the grid. This… sounds like a better idea than batteries.
Pumped hydro uses the same idea, though less efficiently. It pumps water from a low reservoir to a high one, and then gravity takes effect, pulling the water down hill and turning turbines. Flywheels also may offer better energy storage, as they are essentially just giant wheels spinning in a vacuum until excess energy is needed.
This isn’t the first time batteries have been declared “too expensive” though. This is why people are working on making them better. But we should be open to all options, and any technology that doesn’t use toxic minerals we need dig up, transport, and process is all right by me.