Energy use: It's harvest time

My neighbours are farmers and this year’s harvest seems to have come early. The dairy farmer has already put his silage and maize into the clamps in his covered barns and created a local landmark with his pink bales (see the funky farmer on YouTube). These will be used to provide feed over winter for his herd of Holstein Friesian cows.

Storing today in times of plenty for use in winter is a fundamental part of the farming system.

Elsewhere in our society - particularly when it comes to energy - storing at times of excess for use later hasn’t been part of the system. We have relied instead upon geological stores and meeting demand instantly. The outcome has been an energy system where generation capacity was engineered around meeting the annual peak - usually a few hours of coincident bad weather, a major TV event and a need for tea. But that approach is in the process of changing and we are all going to be part of the new dynamic system.

Last month, the government launched its smart energy strategy, called Upgrading our energy system: smart systems and flexibility plan. The big news was an increase of support for energy storage, in particular batteries. This wasn’t really surprising given the ambition to move away from the internal combustion engine toward battery powered vehicles.

Batteries are an obvious technology to support given their rapidly falling costs and cross-sector use

Batteries, as part of the smart energy grid, are to be supported by a variety of mechanisms that will ensure that those who invest in the new storage technology are able to get a return on that investment. This includes time-of-day tariffs to encourage users to charge batteries during periods of low demand (and low prices) and then use this stored energy when the grid is under pressure at peak times. Widespread use of such mechanisms will lessen the need for peak capacity - usually fossil fuel reliant generation - and enable greater use of intermittent energy sources such as wind and solar.

Batteries are an obvious technology to support given their rapidly falling costs and cross-sector use. Lithium ion battery process have fallen by 50 per cent since 2012. They are already being used as part of the grid to provide balancing services. There are of course other ways to store energy, hydropower being the best known alternative.

Domestically, batteries may form part of a hierarchical strategy of energy storage whereby locally generated power from roof integrated PV is used in order of preference; to meet demand, charge the battery, heat (via heat pump) the hot water and charge the heating thermal store (again assuming a heat pump). To implement such a strategy requires a shift to the electrification of heating and the reintroduction of hot water tanks in the home - something our space-optimising housebuilders might find difficult to contemplate.

As we move away from fossil fuels, we need to look at ways for storing energy, smoothing out the peaks and troughs

At the Rushlight 2017 event in London I saw a presentation on a novel way of reusing our industrial past and legacy to deliver grid scale storage. The proposal was to use old mine shafts to provide “gravity” energy storage. The concept was simple enough: install a heavy weight in a mineshaft, wind it up using cheap off-peak electricity, equivalent to charging a battery - then to reverse the process to generate electricity at peak times by allowing the weight to fall back down the shaft.

Energy storage is becoming a greater part of our energy system. As we move away from fossil fuels - which after all are simply solar energy stored in chemical form - we need to look at ways for storing energy, smoothing out the peaks and troughs. Although inevitably the initial costs will be higher and fall on those who integrate the technology, the longer-term benefits for our energy infrastructure and economy are positive, ensuring that the assets are used more effectively and productively. The benefits can be passed onto those who are willing to invest in storage through the various market mechanisms available to the power industry and government.

Our industry should embrace energy storage, whether battery or other forms, and follow through the logic of its integration with existing building systems. If done well there are financial and environmental benefits around the corner for users.

Nick Cullen is a partner at Hoare Lea