14 April 2016


Could electric vehicles power the stationary storage market?

Author: Jason Deign, Solarplaza

Germany’s electric vehicle market could ultimately drive the economics of stationary storage in the country, an expert has claimed. “The electrification of transport revolutionises not just the battery space but also the whole electric system,” said Gerard Reid, founder and managing partner of finance consultants Alexa Capital.

Reid, who is penning an upcoming report on second-life batteries for the German Renewable Energy Federation (Bundesverband Erneuerbare Energie), said that Germany has around 20 million houses but 40 million cars. Thus a wholesale switch to electric vehicles would represent a massive increase in the number of connections to the grid. “People haven’t really grasped this,” he said. “There’s a lot of thinking about this that hasn’t gone on yet, in terms of the grid but also the business model.”

The aggregated storage capacity of mass-market electric vehicle adoption is significant, according to Reid.
“A million Teslas on the road would equate to some 80 GWh of storage. The thing that’s clear to me is you’re going to have lots of batteries.”

At the same time, it is unclear how much of their time these batteries will actually spend inside vehicles. “An electric car is a pretty extreme environment for a battery,” Reid said. “Realistically, they are going to replace these batteries after five years. That means you have cheap batteries for off-grid, residential and grid applications.”

Reconditioned electric vehicle batteries might be able to last an extra 10 years under the less stressful conditions typical of stationary storage applications, Reid theorised. “It’s very clear to me that manufacturers will do this,” he said.

Already, he noted, car companies had started to make inroads into the stationary storage market. The most prominent of these is Tesla.

But in Germany Daimler has launched a residential storage system and BMW has signed an agreement with Solarwatt, E.ON’s storage system supplier, to provide solar-powered carports for its electric car owners.  
Since electric cars have fewer moving parts than traditional vehicles, Reid believes their lower servicing costs will increasingly force carmakers to seek alternative revenue streams. Stationary storage, based on second-life batteries, is an obvious choice, he said. “There is zero marginal cost because [the batteries] are paid for,” he stated.

Not all industry players share this view, however. Dr Michiel Van Schalkwijk, group director for international sales at Solarwatt, pointed out: “There are differences in voltages between what cars and homes need.”

Electric car battery storage capacities are of the order of 22 kWh for a BMW and 80 kWh for a Tesla, while the average household requirement for 70% solar self-consumption in Germany is between 4 kWh and 6 kWh, Van Schalkwijk claimed. Also, “for home storage you need a very stable battery with no losses,” he said. “In a car, losses are not so crucial.”
“It’s not easy to say that what’s left over from cars is what’s best for home storage, unless it’s cheap.”

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