Professional Engineering

It is good to see the growing recognition of energy storage as a key enabling technology for the effective capture of intermittent energy from renewables. This has been highlighted most recently in the IMechE’s own position paper on electricity storage. 

However, while the headlines have tended to focus on large-scale installations, for example operating alongside established pumped hydro schemes, I must emphasise that energy storage offers considerable practical advantages across the value chain, from generation right through to transmission and distribution to the consumer.

Firstly, energy storage can help large renewable generation plants to improve their network capability by smoothing intermittent generation and reducing ramp rates so that it comes on and off line in a controlled way. Capacity firming also maintains production within a predictable window. Furthermore, energy storage can provide local dynamic voltage support to help improve network stability.

For transmission grids, energy storage can address the stability issues relating to the increased penetration of intermittent and unpredictable energy sources. This includes providing vital ancillary services to ensure that synchronised reserves are available, instantly, without the need for fuel-consuming back-up generators. It can also contribute to frequency and area regulation.

At the distribution level, energy storage can help relieve the pressure on highly stressed parts of the grid that are operating close to their maximum load. For example, it can defer or even eliminate the need for big investments in network infrastructure to handle demand peaks. It can also provide dynamic voltage support and optimise power flows within smart grids.

Energy storage also has a role to play in local energy management for distributed installations, such as residential, community energy storage and commercial or small industrial systems. Here it provides effective “time-shifting” of energy from low-value to high-value periods, providing operators and developers of renewable energy schemes with an optimum return on their investment. It also de-links supply from demand, reduces peak demands and improves power quality and reliability.

From Saft’s perspective there are no insurmountable technical barriers to the deployment of energy storage. We are already implementing commercialised solutions based on well-proven lithium-ion (Li-ion) battery technology that offers significant advantages in power grid applications in terms of performance, storage efficiency and service life compared with conventional batteries.

The barriers are essentially economic, since as with all new technologies the initial investment is high. However, as energy storage becomes more widespread and production volumes increase, then I anticipate that projects will become more affordable for investors, especially when they consider the whole-life costs of their installations and the very real benefits they will bring to electricity networks.

My view is that we cannot regard renewable energy generation, such as wind and solar photovoltaic sources, as a viable element within the global energy mix unless it is supported by effective and efficient energy storage. Energy storage is set to play a vital role in ensuring the economic viability of renewable energy by addressing its intermittency issues to make it available on demand. Equally, energy storage can play an important political role in the change to a low-carbon economy by ensuring that the lights always stay on.

At the individual level, I can see a time when domestic Li-ion energy storage systems, no bigger than a fridge-freezer and linked to roof-mounted solar arrays, become as unremarkable as PCs are today.