Tuesday, 16 September 2014
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Storage could be the key to UK's energy future

Occupying my usual quiet corner at the Royal Academy of Engineering for the latest in its series of innovation seminars — this time on energy — I was heartened by the presence on the programme of some representatives of the often neglected and overlooked part of the energy mix, namely storage.

It’s a bit of a mystery why we hear so little about energy storage as it’s an absolutely vital part of the ongoing task of decarbonising energy. In a world where energy is harder to come by, owing to depletion of hydrocarbons or an unwillingness to burn them, it becomes ever more important to be able to store energy which isn’t being used at any given moment, in whatever form of energy you store it — chemical, electricity, motion or heat.

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Inside Dinorwig power station, a pumped-storage system in the Welsh mountains

Energy storage is one of the Technology Strategy Board’s targets for funding in emerging energy systems, but as yet we’ve seen no large scale trials of grid-connected energy storage. And this isn’t because technologies don’t exist. There are several, ranging from container-sized batteries using lithium-ion and other chemistries, able to store about a megawatt-hour, to Highview Power’s cryogenic system which uses momentarily-unneeded generating capacity to liquefy air, which can then be vapourised and expanded through a gas turbine to regenerate the electricity when it’s needed. Another intriguing possibility raised at the RAEng meeting is to use the same unneeded capacity to electrolyse water and store the resulting hydrogen in the UK’s existing natural gas grid; hydrogen and methane mix very well, and the addition of hydrogen in moderate amounts does not affect methane’s combustion characteristics. Adding biogas methane as well would, explained Graham Cooley, CEO of ITM Power, go some way towards decarbonising heating, which is responsible for some 40 per cent of CO2 emissions and a significant quantity of natural gas consumption in the UK.

’Wind and waves are certainly intermittent, but that intermittency is extremely localised

Energy storage is, of course, most often connected with the growth in renewable generation. This, the thinking goes, is so intermittent that it can’t work at all without some method to store electricity gluts so that they can be shunted onto the grid when there’s no wind, or it clouds over, the sea is calm or the tide is slack. This isn’t actually true. Wind and waves are certainly intermittent, but that intermittency is extremely localised: if it isn’t windy at one windfarm site, there’s a very high chance that nearby ones will have good wind characteristics; similarly, the latest generations of photovoltaics still generate in cloudy conditions. Moreover, wind, wave and solar tend to complement each other, if deployed as an array; if it’s windy, the waves will be high a little later; and sunny weather tends to occur in calmer conditions. Despite this, it is true that storage, possibly organised on a regional basis, is needed. Another possibility is to use pumped hydroelectric storage: Norway is already developing a business storing Germany’s excess electricity in its fjords, and if no new pumped-storage systems could be built in the UK (it’s highly geography-dependent, and most of the suitable landscape in Britain is protected) could also take advantage of this.

However it’s done, it must be a priority to establish storage as part of the British energy landscape as soon as possible. It will not only help prepare us for the future energy landscape, it will help calm those sceptics who doubt the practicality of low-carbon energy generation.


Readers' comments (29)

  • If we utilized wave energy there would be far less need to incorporate energy storage, if you look at wave energy patterns over the year they tend to follow energy demands!

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  • Do you have any data you can point to on this?

  • As this blog is written for engineers, it would be good to see some scoping numbers on the options, even if, at this point, they are estimates and extrapolations from lab work. Efficiencies? Cost, area and volume per megawatt?

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  • Stored energy usually means energy that is stored in order to generate power on-demand. Pumped storage as mentioned by the author is a well proven method with an efficiency of around 60%. The only other proven methods that I am aware of are: batteries storage; compressed air storage and fuel storage for gas turbine generation. There is some potential for flywheel storage but this seems to be a long way off.

    I believe that Cardiff University had a department dealing with stored energy about 30 years ago; largely heat storage as I remember.

    If the wind farms drove water pumps to storage the efficiency would be much higher than converting it to electricity then having the problem of load matching.

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  • Yes, look at Godfrey Boyle (2004) 'Renewable Energy' ISBN 0-19-926178-4.

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  • Perhaps one of the reasons we hear so little about storage is that it provides a pathway for distributed energy solutions to further penetrate into the consumer market.

    Our large scale domestic energy providers have a lot to lose if homes can be powered 24/7 by home generated solar/wind "micro" systems at competitive prices and so go off-grid.

    Personally I have been watching the Vanadium Redox battery developments. Australia has a lot of vanadium and at the moment vanadium resource companies are "dirt" cheap. http://www.australian-shares.com/vanadium-australia.html might provide a useful starting point for those interested in the sector.

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  • There is a long-running confusion over whether generation or distribution companies hould operate storage, or whether it should be a third sector.

  • Having worked at both Dinorwig and Blaneau Ffestiniog power stations, the power generation company would operate any storage system as that is how that system works.

    It would make sense if the wind power generation (or wave power) could be utilised overnight, at a time when pumped storage sites would be purchasing "cheap" power from thermal stations to refill the upper reservoirs. The problem would be whether the "green" power generators could supply enough power overnight or would thermal supplies still be required.

    I am surprised that new pumped storage systems have not been investigated, instead of the economically and technically uncertain wind and tidal power generation systems that are subsidised by government and ultimately, by us the public.

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  • I notice in other work that whenever there's doubt about which way to do something the answer is usually "both ways".

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  • Don't forget that in the fullness of time electric vehicles will provide a massive energy storage capacity when the 30 million cars in the UK and the billion or so worldwide are all electric powered.

    See Prof David MacKay's "Sustainable energy - without the hot air" - pages 194 to 195. This 350 plus page book is available free to download at www.withouthotair.com

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  • "could be" is wide of the mark. The headline should read "IS"

    We just need the industry to understand the urgency, but there's no sign of that happening any time soon. As a previous piece in The Engineer noted - it's a "carousel", where everyone's passing the buck. There's no incentive to build storage and the government hasn't created a 'market' in the Energy Act.

    The Conservative MP for Bracknell admitted, in the Commons this afternoon, that the 'market' was not a good way to run an electricity supply. How many of his colleagues would agree?

    It would help if we made a distinction between energy storage and electricity storage. The former would be a huge, efficient asset, as long as it's located before-generator. The latter will always be second best, more costly and less efficient.

    Working to those fundamental parameters, it becomes a simple engineering problem with a simple engineering solution. let's get on with it.

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  • @david smart: agree entirely - left to its own devices, the 'free market' will never produce a solution to an extremely complex problem like de-carbonising our economy. Nicholas Stern said it, didn't he - "climate change is a result of the greatest market failure that the world has seen."

    Incumbent energy market players are risk averse and want to milk existing assets (see SSE, Drax), new entrants only have the resources to develop niche products or services.

    What is needed to tackle the most serious issue facing mankind is a comprehensive, thought-through plan. Not a series of policy swings and free market knee jerk reactions.

    Regarding storage itself - two comments.

    First - Storage is there to improve the match between supply and demand in a world where supply is less and less controllable. The other side of the coin is matching demand to supply.

    Second - Heat storage for dwellings could/should be making a bigger contribution. Specifically solar heat harvested in summer to provide heating in winter. It works - Drake Landing in Canada was one of the first developments (http://www.dlsc.ca/index.htm).How many housing schemes in the UK are this innovative? Instead,what we see are tiny solar water heating systems on rooftops that can only store heat for use that day or the next, mostly in the height of summer when it has much less value and may be used profligately.

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