What’s next for electricity storage?
One of the themes to emerge from the 2016 Future Energy Scenarios (FES) is the growing industry interest in electricity storage. Lilian MacLeod, National Grid Power Supply Manager, explains the potential benefits of new storage technologies for system flexibility and the barriers that still need to be overcome.
What’s next for electricity storage?
“One of the critical challenges for developers is to gain access to multiple revenue streams”
Lilian MacLeod, Power Supply Manager, National Grid.
Consumer Power has the highest level of storage by 2040 across all four scenarios.
Source: 2016 Future Energy Scenarios.
The future importance of new storage technologies needs to be seen in the wider context of a rapidly changing generation mix in Great Britain.
As we move away from the historical reliance on coal and gas-fired generation there is greater diversity of supply in place than ever before. The rapid deployment of solar generation and other low carbon sources such as wind bring with them less predictable output. One of National Grid’s roles is to balance supply and demand in real-time and this is one area where storage could play a key role along other tools such as interconnectors and greater use of Demand Side Response.
The current picture
The concept of electricity storage is not new. In fact pumped hydro storage (PHS) has been around for many years. It effectively creates a reservoir of energy using water and currently provides a large proportion of GB’s existing 2.7GW of storage. This figure is about 3% of total installed generation capacity. In addition, there are a number of new technologies that could transform the storage landscape in coming years.
Solutions include compressed air energy storage, which is similar in storage capacity to PHS, but instead of pumping water when there is excess power, this technology uses compressed air which is stored under pressure underground before being heated and expanded in an expansion turbine to drive a generator and produce power. There is also liquid air energy storage, which uses electricity to cool air until it liquefies. This liquefied air is eventually brought back to a gaseous state and the gas turns a turbine to generate electricity.
However, it is in the field of battery storage that there is perhaps the greatest impetus and the largest opportunity to deliver a transformative technology. Batteries currently account for about 30MW of generation capacity, with one of the largest sites being UK Power Networks’ 6MW (10MWh) pilot at Leighton Buzzard.
There are lots of different ways that storage could benefit consumers and this versatility is one of its main attractions. Services could include providing balancing and additional services to National Grid as System Operator and these are likely to be a feature in the first wave of deployment.
Maintaining system frequency is critical to stable power supply and National Grid recently launched a tender seeking expressions of interest from industry for a new service called Enhanced Frequency Response. This is aimed predominantly at storage assets to provide frequency response in one second or less. In the initial interest stage we received 68 submissions totalling 1.3GW of capacity and of these, two thirds were from battery technology developers.
A second application for storage could be to deliver asset services to Transmission Owners and Distribution Network Operators, for example reducing network congestion management or to minimise network reinforcement costs. Thirdly, storage could play a role in wholesale and trading, helping market participants such as suppliers to balance their positions.
Barriers and next steps
While there is exciting potential for new storage technologies, it is clear that significant market, commercial and regulatory changes are needed to drive their large-scale deployment. There is not yet enough clarity on where new storage fits into a regulatory framework alongside other solutions such as interconnectors, Demand Side Response and flexible generation. The UK Government is due to publish a call for evidence this summer to examine the issues.
Of course for any new technology to be successful it must also be commercially viable and for developers one of the critical challenges is to gain access to multiple revenue streams. So-called ‘application stacking’ would make a stronger economic case, for example asset deferral services could be stacked with Short Term Operating Reserve (STOR), or voltage services with frequency.
National Grid’s role will be to continue to balance the system second-by-second, but we must also engage in wider dialogue with potential developers who need more certainty about the services that are required by the System Operator.
Our Power Responsive programme will focus on this need for greater clarity in the next 12 months, providing extra information to the market, identifying how we can package services in a more effective way and how we can give greater clarity, particularly for new entrants.
What the scenarios say
This year’s scenarios describe four very different futures for new storage technologies. Consumer Power is our market-driven scenario and also has the highest case for small-scale generation. Under Consumer Power, Britain would have 18.3GW of storage by 2040, the majority of this (13.2GW) connected to the distribution network due to the high level of support for local energy.
Gone Green also features high levels of storage at 11.4GW in 2040, with the highest level of transmission-connected storage (5.9GW) because of central policy intervention.
In the less ambitious scenarios, despite some developments in distribution-connected storage, Slow Progression only reaches a total of 6.4GW of storage in 2040, while there are minimal developments in No Progression, which sees 3.6GW of storage by the same date.
Seizing the opportunity
In summary, there are still many unanswered questions when discussing the potential of new electricity storage technologies. How will they develop and at what rate? Will these technologies be commercially viable? What is the likely timescale for deployment? Yet despite the uncertainty, and as we have seen with the rapid growth in the deployment of solar technology, the energy mix can be altered substantially in a relatively short period of time.
So, will it be an untapped opportunity or an exciting technological breakthrough? The regulatory and commercial decisions that are taken in the next 12 months will start to make the future clearer.
There is more information at the Future Energy Scenarios website.
Alice Etheridge, National Grid Insights Manager, explains how the Future Energy Scenarios (FES) are used and examines what each scenario might mean for how we live our lives in 2040.