One of the biggest electricity suppliers in the United States has 600,000 lithium-ion batteries charged with electricity from local wind turbines. The new opportunities to store energy over long periods of time in this way look likely to help drive the transition to greener energy systems.

Energy Storage Underpinning Green Energy Development

Optimising energy use and finding new sources of power began to rise up the agenda some time ago for two entirely different reasons: on the one hand fears that fossil energy sources might be running out and evidence that on the other hand carbon dioxide emissions from burning existing fossil fuels was bringing about harmful climate change. On top of that, highly-publicised problems with energy infrastructure, such as the incident at the Fukishima nuclear power plant in March 2011, have raised more question marks over some established power generation models and strengthened the argument for switching over to green energy, with solar and wind power at the top of the wish list. In the United States, power suppliers underestimate electricity consumption around 1% of the time, which means they have to switch on ‘peaker plants’ – generally natural gas-fired turbines, plus some oil-fired equipment – which are run only to meet peak demand for electricity, usually in high summer. There are lots of demand management initiatives in the pipeline. One example is Ohmconnect, a tech startup which encourages consumers to lower their electricity consumption at such peak times. Meanwhile, out in the Mojave desert, Southern California Edison is storing energy produced by wind turbines in the form of small batteries and is looking to replace ageing power plants by calling on stored power.

Step One: Bringing Costs Down

Electricity is very hard to store in large quantities. Hence the current need for peaker plants to back up the ‘baseload’ power plants. So the first requirement is to improve energy storage techniques so as to be able to meet energy demands more smoothly. One of the main problems today is that storage batteries are still too expensive to be used on a large scale. Sofia Savvantidou, an analyst at Citigroup, believes that the price of storage batteries will halve in the next seven to eight years, and that demand for efficient batteries will continue to grow, especially from the automobile sector. The price of lithium-ion batteries used by electric car manufacturers has already fallen by 50% since 2010 and currently stands at $500 per kWh of electricity.  Elon Musk, whose firm Tesla Motors is taking matters into its own hands and building the largest-ever lithium-ion battery plant, dubbed the ‘Gigafactory’, predicts that the price of the batteries for his cars will fall to $100 over the next ten years.

Southern California Edison’s project is part of the wider movement driving energy transition in the United States with the aid of improved storage technologies. The plant sits astride the three sunniest states in the country, and contains 600,000 batteries which store energy generated from solar panels and some 5,000 wind turbines. However, though wind is a plentiful and renewable energy source, wind power only accounted for 4.1% of all energy produced in the US in 2013. Another Elon Musk company, Solar City, is working to put household-generated solar power to best use.  This idea is increasingly popular and the waiting list for installing solar panels is currently around eight months. By 2020, the US authorities intend to have a third of all national electricity produced from renewable energy sources, which may well be attainable, given that California already produces more electricity than state residents and firms consume during some periods in the autumn. However, as the sun does not shine, nor the wind blow, all the time, a lot depends on storage.  If storage technology costs can be brought down, this will provide an effective means of injecting power into the grid exactly when it is needed.

Storage driving the move to ‘smart’ grids

In the United States, baseload electricity is generated in line with historical consumption data on a just-in-time basis. Baseload –mainly coal-fired and nuclear power plants – currently meets 58% of household electricity consumption – the ‘peaker plants’ being switched on to help meet peak load.  Batteries will therefore have an essential role to play – storing excess power produced by green technologies. Experts reckon excess capacity could reach 10 - 15,000 MWs installed in California alone and many believe that consumers are likely to take to the whole concept of energy storage quite naturally. Patrick Hummel, an energy analyst at UBS, explains that electric car batteries will be able to provide an important means of storing energy for use in a smart power grid. He predicts that drivers will leave their cars recharging while they are at work, and will then be able to re-inject surplus power back into the grid in the evening during periods of peak demand, avoiding the need to switch on peaker plants and resulting in much lower consumption of natural gas and oil, with some reduction in coal burning. Germany, today one of the pioneers in the transition to greener energy, has made battery technology a central plank of its national energy strategy. German citizens can obtain loans to install batteries capable of storing power generated by their solar panels; already 4,000 households have gone this route.

In short, power storage is a major component in the overall drive to create smart electricity grids – based on the three Ss: storage, solar and software – which are one day going to make the present-day infrastructure look extremely primitive.  However, take-up of storage technologies, which were actually already under development ten years ago, is slow as they are still complex and very expensive. Much is at stake. Power storage technology could provide the foundations for a controlled move to a widespread green energy system, as well as being a means of supplying electricity in far-off places where infrastructure is costly and inefficient, and so bringing power to some of the 1.4 billion people all over the world who are still without access to electricity.

By Arthur de Villemandy