Used EV Batteries to Stabilize the Grid

by Emil Morhardt

If a single used electric vehicle (EV) battery, still functional but with it’s storage capacity degraded by 20%, could be used to store energy from photovoltaic panels at home (see Dec 30 post), a bank of them could be used to stabilize the whole grid, according to Gillian Lacey and colleagues (2013) at Northumbria University in the UK. Their particular emphasis is “peak shaving”—supplying enough electricity at times of peak demand that additional fossil-fuel generation can remained turned off. This would also help regulate the line voltage and allow some “upgrade deferral”­—putting off investing in needed new or more efficient sources of energy. A particular value of this type of storage is that it would be at the low voltage end of the distribution system, closer to the end user, thus decreasing the potential line losses that would occur if peak power were supplied by regular generation systems, and increasing the life of transformers which are particularly stressed under peak loads. This might also mean that this type of storage would be “distributed”—maybe one battery per residential transformer. Since most large-scale current photovoltaic generation stations generate at low voltage, used EV batteries might be useful there as well. Continue reading

Used Electric Vehicle Batteries for Home Energy Storage?

by Emil Morhardt

Why would you want to store electricity generated at home when you have a perfectly good connection to the grid and the power company buys back all the electricity your solar panels generate at the cost you pay for electricity? You wouldn’t. But what if the power company started paying much less for the electricity you are shipping back than you could have purchased it from them—as they have been doing recently in Australia (Muenzel et al. 2014)—or decided to charge so much for transmission of electricity back to the grid that there was little point in selling it to them in the first place (as it appears they are contemplating doing in California from the radio spots I hear recently.) Now you might want a battery large enough to prevent any of the electricity you generate getting back to the grid, and ideally meeting all of your routine electricity demands. A cost-effective solution might be about to arrive just in time to offset these likely policy changes; used electric vehicle batteries. Continue reading