S&C Electric Co in the UK has just announced the country’s largest battery grid storage project for storing renewable energy in the grid. The UK has huge amounts of offshore and onshore wind energy; grid energy storage accommodates mismatches between grid power supply and demand.
The grid battery can store 10 MWh of energy, with provisions to expand up to 18 MWh. Storage batteries are typically discharged at relatively slow rates; the battery can supply up to 6 MW to the grid. The project is claimed to cost 18.7 million pounds, or $28M ($4.7/W).
Now let’s compare the decentralized approach – EV grid storage.
Nichicon has a Vehicle-to-Home (V2H) EV power station that will both charge and discharge a Nissan Leaf from the grid at 6 kW. 1000 Nissan LEAFs attached to these power stations could provide 6 MW discharge/charge, and substantially more total energy storage at 24 MWh. Unit costs with installation are claimed to be $4.2k after Japanese government incentives and taxes .. say $5k without incentives.
Document courtesy Nichicon
Assume the typical LEAF owner is plugged in at home or work for 2/3 of the day, averaged throughout the year. You’d need 1500 LEAFs plugged in to provide a similar 6 MW of power on average and 36 MWh of energy storage, which means 3000 V2H power stations installed at home and at work. You could possibly improve cost efficiency (fewer LEAF vehicles required) by installing some number of units at common long-term points; parks, movie theaters, dining establishments, parking garages, airports, etc.
Obviously there are details to be worked out; the utility would need to provide guarantees to allow for the vehicle to be fully charged when the user plans to depart, and the utility would have access to only the top portion of the battery – say top third – in case the user needs to depart unexpectedly. 24 kWh * 1500 units * 1/3 = 12 MWh, still more total energy available than in the grid battery.
At $5k per unit, installing 3000 V2H chargers will cost $15M.
That leaves $5M to $13M for per-unit LEAF subsidies .. with 1500 vehicles, $8.7k.
The 2013 Nissan LEAF S is available (delivered) at just under $31k today with the CHAdeMO inlet. The price is reduced to $24.5k with federal subsidies, and as low as $22k with state subsidies.
Utility subsidies could drop the per-unit price down to $16k including the federal subsidy, or $13k with various state subsidies. Notably this also includes 6 kW (4 hour) chargers installed at work and at home.
How many people would buy a LEAF at $13k, with the stipulation that the utility is able to access the top 1/3 of the battery while still providing for a full charge at a scheduled departure? I think it would be pretty popular.