Renewable energy: the search for storage

Boxing Day, 2011. I was having lunch with my dad and some of his neighbours in the quaint little market town of Eye, north Suffolk.


Local tempers had been fraying about the planned construction of a modest wind farm comprising three smallish turbines on a nearby disused military airbase. Our host had placed me next to a notorious local climate change sceptic: a retired director of a well-known oil company, who cheerfully explained to me that the turbines would be next to useless.


The fact that we can’t control wind supply, and can’t store the energy it generates, meant that half the energy it created would go to waste, he said (and a lot more besides).


I chose not to rise to the bait and focused instead on annihilating my sherry trifle.


It’s true that one of the biggest barriers to ramping up renewable energy use is its intermittency. It’s up to the gods how much sun we get, and how strong the wind blows, on any given day. Sometimes, particularly at this time of year, the sun doesn’t even bother showing its face.


This is very different to energy from fossil fuels, where power stations can be brought into use whenever we choose.


So what can be done about this?


We can manage and reduce our demand for energy


Well, before looking at how we control energy supply, we can look at demand. Why not get people and organisations who are able to postpone some of their electricity consumption to do so at times of peak demand, and reward them for doing so?


Emerging cleantech companies like KiwiPower and Flexitricity have taken advantage of a National Grid scheme to pay larger power consumers in both the private and public sector to reduce consumption during peak hours. For example, KiwiPower’s demand response partnership with Colchester Hospital University NHS Foundation Trust has enabled the Trust to develop a new income stream amounting to a nifty £100,000 a year.


Demand response management is already fairly advanced with large corporates, though it’s still early days for extending this to smaller businesses, let alone domestic users.


As well as managing peaks and troughs in demand for energy, we can also use less of it in the first place – in our buildings, road vehicles, aeroplanes and so on. And big savings are possible. For example, Infosys in India decreased its electricity consumption per staff member by 44% across its Indian business campuses – saving a phenomenal $80 million in the process. And the National Trust cut its energy bills in its Welsh properties by over 40% over two years, through a combination of energy efficiency and behaviour change measures.


We can store energy


But the biggest nut to crack of all is of course, storage. Storing electricity is currently only possible at low density, so you need a lot of space to store it – and it gets very heavy. Just think how weighty your average car engine battery feels. The batteries in a Nissan Leaf – the first mass production electric car to be built in the UK – tip the scales at 300 kilograms, the weight of four people.


Although storage is already being used at large installations like Dinorwig and Ffestiniog pumped storage power stations in Wales, which pump water from  a low to a high reservoir then let it flow back down generating power – sites like these are in short supply.


Innovating to make batteries smaller, lighter, and longer-lasting, is obviously key; and there are some exciting developments here.


For example, cleantech pioneer Moixa has invented a domestic storage battery called the ‘Maslow’. Bioregional has worked with it in an Oxfordshire housing estate for the past few years to demonstrate the benefits of storing and using locally generated solar power in local homes. Some 205kW of solar PV panels have been placed on the roofs of homes and the local community centre, with 82 homes kitted out with their own Maslow battery. The batteries are linked via the internet to create a virtual local energy grid.


As well as radically boosting the amount of electricity that can be retained and used locally, this reduces the need for expensive grid upgrades needed to cope with big exports of solar electricity and saves residents money. 


And it’s not just smaller companies that are entering this market – so too are some global giants. In 2015, Elon Musk of Tesla unveiled its new home storage battery called a ‘Powerwall’ – a lithium-ion battery that can be mounted on the wall or floor of your home. It comes with an app so you can monitor your solar energy use and also get alerts if cloudy weather is on the way. The first installations are set to begin in January.


Convergence is bringing new opportunities


There’s also convergence in the offing among the worlds of technology, lower-impact transport, renewable energy generation and storage.


Earlier this year Nissan unveiled a new power system where electric cars feed energy back to the grid. As chairman of Nissan Europe Paul Wilcox said: “We believe electric vehicles can become mobile power units supplying cities and their homes, schools and hospitals. Some may think this is science fiction but we believe it is science fact.”


One of the most exciting things about all of this is that there is a market. Progress isn’t happening because people think it’s worthy, or because it’ll help tackle climate change (which it will). It’s happening because there’s a business case.


There’s even potential for the development of an online trading system in energy. Just imagine, in less than 10 years’ time, you could be driving home from work in your electric car with a battery that has been fully charged by the solar panels on your office roof.


You know that you only need a quarter battery charge to get back to the office the next day. So you plug into the mains when you get home and then, that evening, you sell more than half of the electricity in your car to the grid at a time of peak demand.


An app works out that the cost of the electricity purchased from your office roof is lower than the price of the power you can sell to the grid in the evening, and carries out the transactions for you.


Without you even needing to think about it, your car is earning money just by sitting in your driveway!


So, Mr Climate Change Sceptic of Eye, Suffolk, stick that in your oil pipeline and smoke it. 


Julia Hawkins is Head of Communications and Policy at Bioregional. 


Photograph: Shutterstock.

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