Maxine Frerk, director of Grid Edge Policy, explores the potential of electric storage heating as a solution to the decarbonisation of domestic heat and asks why it has been overlooked in so many influential reports on the subject.

With the country in Covid-19 lockdown it is hard to think about, or write about, much else. It risks appearing to make light of the current situation. But, personally, I find comfort in the hope that we can take something positive from the current extraordinary situation, to emerge in a better and more sustainable world. And for those of us not directly involved on the front line, it is important to stay focussed on how we address what is an even bigger, albeit it less immediate, global threat – climate change.

In that spirit, I’ve just finished a report on electric storage heating and the potential role it could play in the de-carbonisation of heat. What is striking is how the issues raised reflect a microcosm of the wider challenges that the energy sector has to address.

The first is how to de-carbonise heat. The answer is far from clear but there are two main pathways being debated – repurposing the gas grid to carry hydrogen or electrification of the grid (using heat pumps). There are variants on these pathways – including hybrid heat pumps or district heating – and a growing consensus that a combination of solutions will be required. But what is striking is that none of the leading reports – by the Committee on Climate Change (CCC), the National Infrastructure Commission or BEIS – talk at all about electric storage heating. The CCC has commissioned a study on hard to de-carbonise homes which includes what they term “space constrained” properties for which electric storage heating is seen as the best solution – but these smaller homes have a relatively small carbon footprint anyway which means that the cost in £/CO2e is high and hence they risk being left until last.

Addressing fuel poverty

The second, more immediate, challenge is fuel poverty. There are 2.2 million electrically heated homes of which 1.4 million use electric storage heaters (with almost all the rest using panel heaters). These homes are predominantly low income and the rate of fuel poverty in electrically heated homes is roughly double that in gas heated homes.

Legacy storage heaters have a bad reputation. They leak heat throughout the day so that by the time people get home in the evenings there is no heat left and they end up using expensive supplementary heaters. However modern storage heaters (such the Glen Dimplex Quantum heater) are smart and much less leaky. With the ability to control temperatures by room, programmed for up to a week ahead, electric storage heating really is a much more attractive consumer proposition as the significant trials that have taken place have shown. Even retrofitting of existing heaters with smart controls has been shown to have benefits.

The original DSR product

The third challenge facing the sector is how to move to a smart, flexible energy system. Storage heating scores here too as it really was the original domestic demand side response product. Night storage heaters were introduced in the 1970s to make use of surplus (nuclear) energy at night. And when that led in some areas to unhelpful night time peaks, the radio tele-switch system (RTS) was introduced to spread out the load, by running different heat schedules, and with the potential for the DNO to curtail demand in extremis in Load Managed Areas where otherwise they would need to carry out reinforcement.

Looking more closely at the electric storage heating and RTS experience highlights a number of issues that will need to be addressed if we are to deliver domestic flexibility.

First it remains the case that customers do not understand even the basic Economy 7 tariffs that are used by most storage heating customers – what times they apply, whether hot water and other uses are included or just the heaters – and how to work the controls on the heating. Suppliers need to get much better at helping customers understand these more complex tariffs and ensuring that they are appropriate for their needs.

Secondly, with the loss of the RTS in 2022, networks like SSEN are trying to work out how to avoid having to carry out expensive reinforcement. This brings to life the debates that have been happening around the role of the DSO and whether flexibility should be delivered through price signals or contracts. Price signals can get load to shift on mass – to charge up the heaters overnight in this case – but what they can’t deliver is the diversity of demand that networks depend on, or very localised shifts in demand to deal with particular constraints. For these it seems likely SSEN will need to put in place contracts. That would cost them more (as they currently get this flexibility for free) but would ultimately be a fairer solution.

Thirdly, that still leaves a question as to whether – as now – the networks should have the right in extremis to curtail heat demand. This is an active debate at present in the context of EV charging where SSEN has put forward a code modification to allow them to over-ride EV charging schedules. This has attracted some pushback from both Ofgem (who would like to see such services competitively tendered) and from Citizens Advice (who would like to see customers having an over-ride). However, what it really boils down to is where “emergency” rules come in. The events of last August are a reminder that ultimately DNOs do have to shed load when told to do by the system operator to keep the overall system standing. At present that is done in a blanket way but those events should be prompting a wider reflection on what load shedding looks like in a smart world and whether shedding particular types of load ahead of others would be one way forward.

Finally, there are a whole set of wider issues that impact on whether electric storage heating will sink or swim. These include rules around smart metering, network charging, appliance and building standards, consumer information and funding. Each of these policy areas is pursuing thinking in isolation but to deliver an effective heat de-carbonisation strategy requires whole systems policy thinking.

Modern storage heaters can provide a much better experience for customers who have historically struggled to keep warm and can, at the same time provide a flexible solution that supports the shift to heat de-carbonisation. Policy makers should acknowledge the role they can play and work to keep that option on the table.

The report (“An Electric Heat Pathway: Looking Beyond Heat Pumps”) was funded by SSE Networks and will be available from the ENA Smarter Networks Portal

This article first appeared in Network magazine, which has now been incorporated into Utility Week

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