Grid scale energy storage, a big part of the solution

This week we host another blog from one of our MSc Students, Mervin Azeta, for her thesis she is researching learning rates in grid-scale energy storage.

“Energy is the golden thread that connects economic growth, increased social equity, and an environment that allows the world to thrive.”
– Sustainable Energy for All, UN, 2013.

Energy access and security have both been recognized as crucial factors for improved standards of living, economic growth and prosperity. However with the current electricity system, finite, expensive and dirty fossil fuel resources, and intermittent as well as unpredictable renewable energy sources these are not easy to achieve. There are also significant challenges posed by strict, ambitious, emissions regulations or mandates and the required huge investment for electricity generation, transmission and distribution infrastructure.

Despite this, efforts are being made by a number of countries – US, UK, Germany, China, to mention but a few – with a drive from the UN, EU, and the likes, to achieve these elements of the energy trilemma. An outstanding solution recognized to achieve such global targets is energy storage.


During my undergraduate study at the University of Benin, where I obtained a bachelor’s degree in Chemical Engineering, I became particularly interested in energy storage. Its relevance for off-grid applications with solar photovoltaic systems deployment was the subject of my undergraduate research, which earned me the award of the best project in the department. An interest in the subject resulted from an understanding of its amazing potential to change the way the world used energy; but more importantly, it could contribute to a comprehensive and sustainable energy strategy for Nigeria, a country endowed with abundant energy resources yet unable to meet its energy needs.

This was a challenge I grew up aspiring to address. To change the status quo for the energy sector, I had to get my career ducks in a row – a rich work experience in the Oil and Gas sector immediately after my National Service and a postgraduate study in sustainable energy, as short term goals. I chose the Imperial College MSc in Sustainable Energy Futures because it offered the opportunity to acquire the desired top-notch technical knowledge and management skills, in preparation for roles I would be leading.

Cross-linked with other technologies related to generation, transmission, distribution, and consumer consumption, energy storage, in general, presents the capability to capture, store and use energy anytime and anywhere. The effective integration of its wide range of technologies, including the mature pumped hydro energy storage, growing lithium-ion batteries and nascent flow and metal-air batteries, in our energy system at grid scale has the potential to ensure security of supply and reduce the incredibly high capital cost of managing peak demands, irrespective of how brief these peak demands might be. Rather than having to invest in a number of generators that would be ramped up and down to balance out the supply and demand imposed on the grid a portfolio of storage technologies and/or systems could be deployed. Beyond alleviating peak demands and reducing cost, they could significantly contribute to reducing fossil fuel demand as well as minimising environmental degradation.

Despite its potential to deliver the desired benefits, facilitating the realisation of a transition to a sustainable energy mix in the society, its deployment is stalled by a number of factors. These include inadequate government policies, regulatory and market support mechanisms, and most significantly, high capital investments and costs. According to reports by the International Energy Agency (IEA) and the International Renewable Energy Agency (IRENA), the storage cost of large-scale energy storage projects typically ranges from $1000 (US Dollars) to around $8500 per kW, and these could vary significantly depending on the technology to be deployed. The figure below provides a perspective on the variations in these costs.

Representative costs of grid-scale energy technologies in kW [Source: SBC Energy Institute, 2013]
Representative costs of grid-scale energy technologies in kW [Source: SBC Energy Institute, 2013
How soon would grid-scale energy storage technologies get to the target costs at which they become competitive? How much should be produced or installed to achieve such target costs? What supports are required to make them competitive? These and a few more questions are to be addressed in my research. An equation model to project the costs of a suite of promising technologies would be employed. Costs data for promising technologies, over a specified period of time, are being assembled and the implied learning rates would be estimated. This would be used to forecast the costs of the technologies in the short term, and assess their potential to meet cost targets. Currently it is expected we need to get towards $250/kWh initially for a business and commercial system, which interestingly is the optimistic cost of the recently announced Tesla Powerpack, and eventually hit $100/kWh for widespread deployment, even in rural areas. The cost information could then be applied in technology and policy assessments as well as related greenhouse gas emissions assessments and long-term energy strategies formulations. However, achieving these objectives precisely remains unclear, owing generally to uncertainties surrounding grid-scale energy storage technologies and associated costs data, as well as difficulties with making predictions about the future.

This research, presenting a novel opportunity to explore the learning rates for technologies in a nascent sector of the energy industry, as well as the respective market pull and technological push implications, will serve as a base for future studies. It is also believed the insights gained on the few developed technologies to be investigated would be relevant to relatively new technologies.

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