The Crown Joules: Interview with Jo Coleman, Energy Technologies Institute

Improving the ability to store energy has long been seen as vital in addressing the UK's CO2 output. But, while energy security and the overall energy mix is a hotbed of discussion for mainstream media, the topic of energy storage – at the national scale at least – tends to come in and out of fashion. Indeed, a recent report by the Institute of Mechanical Engineers (IMechE) called it 'the missing link in the UK's energy commitments'. "More value could be derived by increasing the UK's ability to store energy and there is no doubt its role must grow in the future," says Jo Coleman, director of strategy development at the Energy Technologies Institute (ETI). "But, there is no single solution. The challenges and opportunities are different depending on the region, the sector, and the network configuration. So there may well be many types of storage technologies developed that need to be effective in different roles." The ETI is a public-private partnership between global energy and engineering companies and the UK Government. The aim is to bring together academia, industry and Government to accelerate the development of low carbon technologies, and ultimately decarbonise the UK's energy production and use. "We hear a lot of focus on electricity, about the Electricity Market Reform (EMR), but for the UK in particular, there is a big challenge around decarbonising heat," says Coleman. "We see a big role for storage here, with a number of technologies already under development. There are considerable challenges, not least in reducing development and implementation costs, but there are also benefits. Over the long term there could be significant scope to reduce the overall cost associated with energy in the UK." Despite its introduction nearly 10 years ago, the European Union Emission Trading Scheme (ETS) has not been as effective as many hoped in capping emissions and reducing CO2 production. It means that low carbon technologies being developed to provide storage or system flexibility have to compete with gas fired power stations using open cycle gas turbines. Though gas turbines are relatively large CO2 emitters, they are cost effective and one of the cleaner fossil fuel burning options. "Energy storage can only start to play a role if we begin to see a higher carbon price or a situation where the storage technologies can help reduce the cost of energy," says Coleman. "We are working with companies that are developing technologies that could compete with gas turbines in the future, and that's exciting to see." An example is Hampshire based Isentropic, which is developing a system known as Pumped Heat Electricity Storage (PHES). It purports to offer a cheap and efficient means of storing and recovering electricity, potentially on the industrial scale needed. The system works by essentially transforming electrical energy into a temperature difference between two volumes of crushed mineral material. The system then recovers electricity from that temperature difference with a 'round-trip efficiency' of 72-80%. The ETI has provided funding to develop a 1.5MW/6MWh electricity storage unit, a prototype of which should be completed in 2015. If successful a full scale unit will be deployed a couple of years later on a UK primary substation in the Midlands. There is, however, another barrier to entry for storage technologies and that is the market structure itself. "There is no mechanism for storage operators at a distribution level to buy or sell electricity," says Coleman. "Current markets haven't dealt with the complexity of selling storage services across multiple parties and yet one of the places storage could be most valuable is where it can replace the upgrade of a distribution system to increase capacity." The premise is that storage operators can buy electricity when demand from the grid is low and the cost of electricity is therefore low. This can then be stored until peak periods, when it can be put back into the grid to meet demand. In essence, the use of greater storage capacity within a grid could minimise the need for 'peaking power stations', which produce power when demand goes above the base load normally supplied. The current system of 'use it or lose it' results in a higher base load than is sometimes needed to avoid black- or brown-outs. It could also make renewable energy systems more effective by storing the electricity produced. "Building large-scale energy storage systems into distribution networks would have benefits in overall operational efficiency," says Coleman, "It does come with a cost, although storage systems do not need to be subsidised to be effective. What's needed is a change to energy markets, policy and regulation to better allow these technologies to come forward." It is clear that there is no single solution when it comes to energy storage and that a range of technologies are likely to be needed at different stages throughout the energy network from the home, to the distribution network, and perhaps also in pre-grid networks. Jo Coleman Jo Coleman is director of strategy development at the Energy Technologies Institute (ETI). Prior to the ETI she worked for Shell for over 20 years in a number of technical, commercial and managerial roles across the world. She is a Chartered Engineer and a Fellow of the Institute of Mechanical Engineers.