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Last edited 27 Nov 2020

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BSRIA Institute / association Website

The use of batteries to store electricity for buildings

BSRIA’s Henry Lawson assesses the use of batteries to store electricity for buildings.

For years, renewable energy, especially solar power and wind, has offered the tantalising prospect of almost zero carbon energy; tantalising because, even as costs fall, solar and wind are inherently unreliable, especially in temperate climates such as those that we ‘enjoy‘ in regions like Western Europe and much of North America, not to mention most of the developed world.

While a lot of progress has been made in demand response, which manages the energy that we need to match that which is available at any given time, we need a cheap, safe and efficient way of storing electrical power. Until now, storage of electrical power in particular has been expensive and inefficient, and sometimes a bit scary.

The electrical vehicle market already faces this problem. Electric cars are never likely to become main-stream as long as they need to go through a lengthy recharge process every 200 miles or so. It is therefore no surprise that much of the progress is being made by manufacturers of vehicle batteries.

Tesla’s announcement that it is moving into the home energy storage market could represent a significant step. Being able to store electrical power not only makes local wind and solar power generation more practicable, it could also be invaluable in the many areas of the world where the grid is unreliable or virtually non-existent.

The biggest barrier, at least initially, is likely to be the price tag. The 7kW battery which could, for example power a laptop for two days, or run one full cycle of a washing machine, or boil 10 kettles, will cost $3,000 to buy. That’s a very pricey home laundry service, and a frighteningly expensive cup of coffee, especially if you only need to use it occasionally. The 10kW version represents slightly better value.

At this stage this is surely going to appeal only to wealthier individuals living away from a reliable grid, or those willing to pay to make a green gesture. However, as with other technology initially aimed at the ‘smart home’ we may well find that much of the demand is actually from businesses. If you are running a business, even a small one, then any loss of service can do immense damage. If an investment of a few thousand pounds or dollars can help guarantee that you will keep running, then it may well seem like an attractive return on investment.

A further significant sign is Tesla’s announcement of an alliance with the international Energy Intelligence software supplier EnerNOC, which already has a presence in the USA, Canada, Germany, the UK, Switzerland, Ireland, Brazil, Australia and New Zealand.

Ultimately, success for energy storage in buildings, as in vehicles is likely to hinge on the two Cs: cost and capacity. It is a familiar catch-22 situation with most new and emerging technologies, where the market is waiting for the price to fall, but, other things being equal, production costs will only fall once you have achieved real economies of scale. The other factors that could influence the market are regulation, requiring builders or building owners to make provision for storage, or someone willing to take a loss-leading initiative.

Safety concerns will also need to be allayed, given problems that have occurred with various types of battery technology, whether in laptops or vehicles. Storing a lot of energy in a very small space, inside the home is always going to raise concerns. And while batteries may offer the most promising option at the moment, other forms of energy storage might prove more effective in the end.

Still, the paradox is that sometimes problems get solved precisely because they are so big. The whole direction that the world is moving in, the growing realisation that we need to slash CO2 emissions, demands cheap, efficient, safe energy storage. It seems likely that companies like Tesla, along with the other major energy companies involved in energy storage will continue to concentrate their fire power on this until a viable solution emerges. And for the first few who get this right, or even approximately right, the potential returns are huge.