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Old Electric-Car Batteries Put Into Service For Home Energy Storage
Hugh Pickens writes "Josie Garthwaite writes that old electric car batteries degraded below acceptable performance levels for autos still have enough life to serve the grid for at least ten years with a prototype announced by GM and ABB lashing five Chevy Volt battery packs together in an array with a capacity of 10 kilowatt-hours — enough to provide electricity for three to five average houses for two hours. 'In a car, you want immediate power, and you want a lot of it,' says Alexandra Goodson. 'We're discharging for two hours instead of immediately accelerating. It's not nearly as demanding on the system.'" (Read on, below.)
Pickens continues: "Deployed on the grid, community energy storage devices could help utilities integrate highly variable renewables like solar and wind into the power supply, while absorbing spikes in demand from electric-car charging. 'Wind, it's a nightmare for grid operators to manage,' says Britta Gross, director of global energy systems and infrastructure commercialization for GM. 'It's up, down, it doesn't blow for three days. It's very labor-intensive to manage.' The batteries would allow for storage of power during inexpensive periods for use during expensive peak demand, or help make up for gaps in solar, wind or other renewable power generation. One final advantage of re-using electric car batteries is that the battery — the most expensive part of an electric car — remains an asset beyond its useful life in the vehicle. 'If there is a market in stationary power for spent batteries, consumers could recognize this as an increased resale value at end of life, however small,' says Kevin See."
Your house uses more than 10kw? I really have to ask, what the heck are you doing??
I have a modest 4x2 house, with a stay-at-home wife and 2 kids. Big screen TV, and all the other creature comforts and I wouldn't even come close to use 10Kw.
In this instance I have to say 'you're doing it wrong'.
This is for grid-level storage, not in-your-home backup. Space and weight are a distant concern compared to cost.
There is an important concept called demand (or load) leveling. How much electricity the grid demands changes significantly over the course of the day, so you much design your power plants and infrastructure to handle the peak load. However the peak load is only experienced a small fraction of the time, meaning you are considerably overbuilt for maybe 16 to 18 hours of the day - especially late at night when most people sleep. The problem is so severe that many utility providers offer Time-Of-Use rates where electricity during off-peak hours is considerably cheaper (and on-peak considerably more expensive) to encourage people and businesses to use less during the day and more at night.
Batteries connect to the grid though a charge controlling inverter - a single piece of equipment. During the off-peak hours they absorb excess energy by charging, meaning the generation equipment runs more efficiently and more economically. During peak hours they release the energy decreasing the demand on the system so it doesn't have to be so overbuilt and therefore less expensive to maintain and operate.
The process of shifting load from peak to off-peak is sometimes referred to "filling the bathtub" and utility providers love it since it makes their lives much easier. Battery storage is a great way to achieve this at the grid level and anyone who manages to develop a cost effective solution stands to make a LOT of money selling and installing such systems.
=Smidge=