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Batteries and renewable energy – what’s in store?

One of the great questions concerning take-up of small-scale renewable energy is that of energy storage. For years, the cost of batteries and other forms of storage has been prohibitive, and safety has been called into question too. This has meant that the intermittent energy supplies that are wind and sunlight have generally remained just that. Our microgeneration expert Ian Cuthbert explains:

Generating electricity when there is an intermittent supply of wind or solar energy presents a problem when trying to match with demand. This can make householders import electricity at times of low supply and/or high demand and exporting electricity at times of high supply and/or low demand.  This is not economical for the householder given that the tariff they receive for each unit they export is significantly less than each unit they pay to import.”

But now, there is significant noise from across the Atlantic about a potential cost breakthrough in what’s known as flow batteries, which can store energy on a large scale in tanks external to the battery itself. With talk on electricity supply increasingly turning towards smart grids, this is bound to excite those in the business of supply and demand.

The Harvard team has come up with a flow battery that avoids the expensive precious metal-based chemistry of previous models and works with carbon-based compounds called quinones. Remember those science lessons about plant photosynthesis? Well, we’re talking raw materials along those lines.  Professor Michael Aziz who leads the team behind the development seems confident:

What do you do when the sun isn't shining and the wind isn't blowing? This problem is the one we think we can solve with a way to store massive amounts of electrical energy, if we can make it cost effective and safe. And we think we've taken a big step in that direction now." 

There is a chance here for power to be literally in the hands of the people more than it’s ever been possible before. But Ian Cuthbert has a note of caution:

Batteries can offer a solution to this problem by reducing as low as possible the amount exported.  However, to do this batteries need to be cost effective; in other words they can only be cost effective if their cost is less than the sum of the savings they’ll make over their lifetime.  They also have the advantage of being less carbon intensive as there is less need to import the more carbon intensive electricity from the grid.  Overall, batteries certainly have a role to play so it will be interesting to see how the market develops over the coming years.”

Gary Hartley is Energy Saving Trust's expert blogger. He has extensive experience researching and writing on a number of topics, with particular expertise in sustainable energy, policy, literature and sport. As well as providing regular blog content, Gary has also been published in numerous magazines and journals.

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Is the battery technology available in the UK now? There is a company promoting a Samsung battery pack along with solar panels

The storage device is only one part of the equation. System control is the other side of the storage equation. We can only store energy that is actually generated, therefore it is critical the control system employed must first be responsive enough to maintain generation from renewable sources at all times. Not only must the control system be able to maintain system stability from multiple renewable generation sources but also be able to handle volatility from the grid in grid tied situations. Our experience to date is that all control systems are not equal and extreme caution must be exercised when choosing a control system and price is certainly not the most important consideration.