What’s next for household energy efficiency?

Loft insulation and condensing boilers are not exactly aspirational, and most people outside the energy community are left curiously unexcited about wall insulation or air-tightness. There were blips on the nation’s ECG (electrocardiogram, which shows heartbeats) for double-glazing in the 1970s and 80s, and PV in the early 2010s, but even amid the most boisterous period of home-improvement we can remember (thanks partly to Grand Designs and its imitators), very few people currently put energy efficiency near the top of their wish list of upgrades for their home.

Bi-fold doors take precedence over energy efficiency.

We’ve been reviewing development of a new range of energy products and services intended to provide household ‘demand-side response’ (DSR): basically, allowing people to wind down their use of electricity when a lot of power is needed, and wind it up again during low-demand periods. Could these technologies be the alluring new gizmos needed to reinvigorate household energy efficiency?

This tech is mainly focused on the peak 4-7pm evening peak when most people come home from work or education, cook their evening meal, and often do other energy-consuming activities at the same time – washing clothes, watching TV, checking emails and charging electronics devices. The evening peak is an even bigger deal on cold days in winter when about 20% of homes use some form of electric heating on top of their usual (gas, oil or storage heater) heating system.

Evening peaks are set to become far more pressured as the UK transitions to low-carbon electric heating and as more people make the switch to electric vehicles, which they will often charge when they get home. Both of these are very likely to push up demand for power. This creates supply-side problems – not only for generators with limited capacity and often slow ramp-up periods at the start of the peak, but also for the transmission network (which takes high-voltage power at 11 to 132kV from the power stations to regional distribution networks all over the UK), and particularly for the six network operators who get power from National Grid to homes and businesses in every street of the land.

The networks benefit too

These network operators already face intense challenges on their distribution grids, and their reinforcement costs make up a significant proportion of the £32billion of investment Ofgem thinks we will need in new wires and pipes over the next decade – including laying 47,000 miles of new electricity cable.[1]

Potentially, making household demand for electricity more flexible could dramatically cut the vast, multiple investments needed to keep the lights on. The new products and services have different ingredients, combined in different ways, but one common configuration is a PV system, a smart controller, a large battery (often 5-20kWh), and a flexible tariff – so households pay less for off-peak power.

Of course, there are concerns about the embodied energy and upstream and downstream environmental impacts of manufacturing batteries on a huge scale. These systems also tend to be expensive (£5,000 per dwelling or more for a battery plus control system), which pushes them out of reach of all but the wealthiest households. Spend that same £5,000 on other less titillating energy efficiency improvements and – unless you’ve already done all the easy upgrades – you might well save more carbon. However, compared to other things you might spend £5,000 on (say, a cruise, a skiing trip for the family, or jetting to the Bahamas for two weeks) the environmental impact is very likely lower – and there are significant carbon-saving and demand-flattening advantages.

Leading the charge

Overall, we found evidence of 25 technology providers that are working on household DSR or linked services. There are currently five front runners, with the most mature technology, and all of these five are already selling equipment and software allowing households to control appliances and/or batteries to save the households money and at the same time provide a benefit to the electricity network:

  1. Kaluza (part of the supplier Ovo), which has a platform and algorithms to control domestic appliances and heating, home batteries and electric vehicle charging to optimise the energy system for households and the grid. It also has ‘micro regional voltage measurement’ to spot points of strain on the grid, and redirect power accordingly.
  2. Moixa, which focuses on supplying batteries to households with PV who wish to increase self-consumption. They have cloud-based software called GridShare that monitors consumption, generation and the weather, which creates an optimised charging plan, with a dashboard for households. GridShare also allows network operators to monitor stress points on the network, and it links households to offer virtual power plants. Moixa currently pays households £50 a year for three years as an incentive to use GridShare (on top of savings from increased self-consumption).
  3. Powervault is similarly geared to storing PV electricity in order to use electricity generated in the daytime (and off-peak electricity) to power homes in the evening. It has opt-in GridFLEX software, which automatically manages energy imported from or exported to the grid cost-effectively. Customers who opt in receive a payment in return for supporting the grid.
  4. Octopus (an energy supplier, now serving 1.2 million customers), which has the ‘If This Then That’ app, with links to smart appliances and heating, and integrated with Octopus’s Agile time-of-use tariff to make it easier for households to shift consumption to low-cost times of day. Octopus also leases EVs, and provides vehicle-to-grid services for customers in the South East and East Anglia.
  5. Social Energy (another smaller supplier), which is actively marketing PV storage that provides sub-second balancing services to National Grid, using an in-home hub and an app. They say they can control any load at any time, and optimise charge/discharge for any storage asset. They claim typical savings of £226 a year for customers.

Currently on the second tier (at least in the UK), Electron also has related systems, but aimed more at network and system operators, suppliers and aggregators (who combine together small quantities of flexibility as a large package, sufficient to interest the energy companies, who they then trade with). It is piloting different flex services, including demand turn-up (actually increasing demand, for when there is excess generation) and curtailment (stopping energy use), as part of the TraDER project with EDF and Kaluza.

Hitachi (partnering with PassivSystems and Moixa) is also trialling the Universal Smart Energy Framework (USEF), an emerging standard for aggregation and trading of flexibility. They are trading flexibility locally on the Western Power Distribution network, using network constraint signals and turning demand up or down according to need – and at the same time maintaining comfort for tenants.

Sonnen also has a trial in Northern Ireland using a microgrid, frequency response and aggregation to offer flex services (as it does in Germany). However, it needs to install more batteries in the UK before it becomes viable to build a Virtual Power Plant here.

Honda has an experimental PV-battery-grid monitoring system, HEMSx, which it is trialling in the US but not marketing in the UK.

Let’s not forget our local talent geo, Cambridge-based UK leader in supplying In-Home Displays for Smart Meters. Geo is developing the Core4Grid package with EDF and others, and trialling their system of battery, smart controller and day-ahead trading in 24 homes with PV and/or electric vehicles.

If you do happen to have an electric vehicle, it is easier than ever to provide flexibility to the grid – by charging when demand is low and exporting back to the grid at peak periods. Smart charging products like those from Ohme and Zap-Map make this very straightforward.

We wouldn’t claim that any of these systems will capture imaginations in the same way as bi-fold doors, so beloved on TV home-makeover programmes. That electrocardiagram is certainly flat now. Energy flex services and products currently have only limited, niche appeal. But given the recent uplift in awareness of carbon emissions and energy use (the Greta-Extinction Rebellion effect), and the UN Climate Change negotiations (COP26) happening in Glasgow next year, more ‘ordinary’ people are thinking about what they can do to address their own carbon emissions. For some people, these systems could provide an answer – saving them money and increasing household energy literacy into the bargain.

[1] Energy Networks Association (2020) ENA Guide to the UK and Ireland Energy Networks. London: ENA.