Comment by Jon Saltmarsh, Chief Technology Officer at Energy Systems Catapult 

If you ask anyone what’s important to them about their use of energy, being able to use it when they need it will rate high up on their priority list. On the face of it, a technology that requires consumers to change when and how they use energy is unlikely to get much traction. Why then does the entire energy sector see flexibility as an essential component of the future energy system?

What is flexibility?

What do we mean by ‘flexibility’? At a top level everyone agrees that flexibility is about managing constraints and balancing supply and demand to enable the future Net Zero energy system, but that’s where consistency of views diverge. Who provides flexibility? How is it provided? How much is needed? What is it needed for? These are not so much areas of active debate, more questions where there are many with very clear but ultimately contradictory perspectives on the right answer.

What’s needed is a common vision for flexibility.

A key point to recognise about flexibility is that it’s a cost play. As argued above, no one wants flexibility for its own sake, but they may be willing to tolerate a degree of inconvenience if this delivers lower energy costs. So, we need to look at flexibility from the twin lenses of how we minimise impact on the citizens who provide it, and how we maximise its impact on cost reduction.

Domestic flexibility can reduce costs in two substantial ways, by reducing the number of generation and storage assets needed to meet the needs of the energy system and by deferring the need for reinforcement of the electricity grid. While the availability of domestic flexibility could provide other benefits for example in ancillary services, it is likely these would be of secondary importance.

Flexibility: reducing cost of new generation

An efficient energy system minimises wasted energy. While high efficiency does not ensure low costs, ideally, we should seek to use every megawatt hour of electricity we generate. In the past this was achieved by turning fossil fuelled power stations up and down to match supply to demand.

In the future Net Zero energy system, most of the generating assets (nuclear, wind, solar) will have very low operating costs and high capital costs. In an ideal world, they should always run at the maximum output possible to deliver most economic benefit. Flexibility can allow us to do this, by shifting demand to times of surplus generation. In other words, matching demand to supply. Not only can this maximise useful output from generation assets, it can also minimise the need for long duration electricity storage assets to manage overall generation surplus or deficit on a day to day, or longer term basis.

Flexibility: deferring work on network reinforcement

The other way flexibility can reduce costs is to defer the need for reinforcement of the electricity distribution and, potentially, transmission networks. Demand for electricity will increase as transport, business and homes switch from fossil fuels to electricity. This will result in areas of the electricity network that are no longer able to cope with peak electricity demand without new cabling and transformer substations.

This is a huge undertaking, and it is unlikely network operators will be able to reinforce all their networks at the rate required to meet the need of all those wishing to connect electric vehicles and heat pumps. Flexibility should allow some of this work to be deferred by limiting peak demand on a particular electricity substation or feeder by shifting some consumption to a different time. In a domestic setting this could mean charging an electric vehicle outside this peak period or turning a heating system down.

Delivering flexibility in practice

These two roles for flexibility raise a whole host of questions about how such a solution will be managed in practice. In my opinion some of the first questions that should be answered are:

1. Equity – how do we ensure that supply isn’t prioritised for the well-paid executive charging their electric vehicle over the means tested pensioner trying to heat their home?
2. Markets and monopolies – how do we balance the need for a single entity to manage flexibility assets to meet constraints at a single substation with the desire for consumer choice?
3. Top down or bottom up – can we reconcile the competing needs from balancing supply and demand at a regional or national level with managing local grid constraints?
4. Engaging in flexibility – how can we make it attractive and easy for consumers to act in ways that best support the system’s need for flexibility?

While on the face of it flexibility might be considered a technology unlikely to get much traction, a closer look at the detail will uncover the true potential of an initiative that has hand-in-hand benefits for the consumer and energy networks.

To get that common vision for flexibility, all parts of industry need to come together to find and develop solutions that are desirable for consumers and beneficial for Distribution System Operators. From clean tech innovators and consumer engagement groups, to networks and energy retailers, each perspective will provide valuable insight for the progress needed for Net Zero by 2050.

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