I recently attended Intersolar in Munich “the world’s leading exhibition for the solar industry and its partners”.  One technology causing a stir was ‘energy storage’.  Much attention was directed towards stationary batteries from domestic through to industrial scale but there was also plenty of interest in electric vehicles (EVs).

 Image courtesy of www.hackaday.com

Image courtesy of www.hackaday.com

The large number of energy storage systems for residential applications reflects the demand for these systems in Europe, with Germany topping the charts. Tesla was exhibiting the Powerwall which was announced earlier this year but is not yet available.  Mercedes-Benz and BMW were present.  The former showing off its stylish stationary battery system and a very popular all electric car, the SLS AMG.

The main benefits of these residential systems are to maximise self consumption of electricity generated by solar PV systems, and to provide backup power.  On a larger scale, energy storage can help to balance the grid and facilitate more renewable energy generation.

Second life for EV batteries

Applying battery technology developed for cars to stationary energy storage is a great idea.  Some R&D costs are shared and there are further gains from economies of scale.  There is another significant benefit.  Batteries used in cars can be given a second life as a stationary battery.  Batteries in an EV typically have a useful life of 8-10 years.  After this they would normally be recycled.  While no longer fit for use in an EV these batteries can still be used in stationary applications (due to space and weight being less critical).  The result is lower cost batteries for both applications because manufacturing and recycling costs can be shared.  Nissan will be installing an energy storage system at one of their facilities this year that will use second life batteries from the Nissan Leaf.

Electric vehicles

In the UK this year 9,000 Ultra Low Emission Vehicles were registered in Q1.  That is a 366% rise over the same period in 2014.  If the trend continues in a few years there will be a large number of batteries available to be re-used in this way in the UK.  Let’s not forget China which has now overtaken the US as the largest EV market in the world.

Clean electricity generation used to power EVs. EV batteries given a second life as stationary storage.   Stationary storage used to facilitate more renewable energy generation.  It makes sense.