There was something emblematic about the closure of Britain’s last coal-fired power plant in September 2024. The gigantic cooling towers of Ratcliffe-on-Soar seem redolent of dinosaurs in a world focusing on renewables and app-governed ‘smart’ systems.

The national grid has had to adjust to the intermittency of power supplied by sun and wind, with renewables last year accounting for over 40% of total production. Managing this entails boosting battery storage alongside smart approaches so that domestic demand is in sync with grid supply.

But whether power is produced by coal, gas or wind, one major preoccupation of householders – how to pay their bills – remains timeless. Financial incentives to alter consumption patterns began to take root a couple of years ago when the National Grid Electricity System Operator (now the National Energy System Operator, or NESO) introduced its demand flexibility service (DFS).

The service was confined to customers with suitable smart meters, as the ESO could only cope with electricity suppliers and aggregators able to deliver verifiable data in 30-minute increments. In June 2024, plans were announced to reintroduce DFS for a third year but with a difference. Instead of being a winter contingency, it will be used as a normal commercial service to support high demand periods throughout the year.

Last year, over 2.6 million households and businesses took part, reducing or shifting electricity consumption at key times. This year the ESO expects the excess generation on which it can call at peak demand during a cold spell to be higher (5.6 GW/9.4% for winter 2024/2025 compared to 4.4 GW/ 7.4% last winter). That, it believes, reduces the need for DFS to function only as a winter contingency.

In April 2024, tech firm Smart Metering Systems (SMS) announced its involvement in the UK government’s flexibility innovation programme (FIP). SMS and its partners Engage Consulting and the Netherlands Measurement Institute, are focusing on how ‘behind-the-meter’ energy smart appliances (ESAs) such as electric vehicle (EV) chargers, batteries, heat pumps and white goods can achieve interoperability to ‘optimise’ the demand flexibility potential of UK homes.

The plan is to increase the number of ESAs installed across British homes to help balance the intermittency of renewable generation and further wean the grid off its dependency on fossil fuels.

SMS has developed a new version of its FlexiGrid aggregation platform to test ESAs against new software (IDSR – Inspection Data Summary Report) applications. The company is also expanding its smart metering facilities in Bolton to test mock domestic settings. SMS Director Tom Woolley says that while a ‘step change in interoperability… needs to come soon, it won’t be simple for manufacturers.’

How do grid flexibility trials work?
Octopus has plenty to say about grid management in the age of renewables, especially power going to waste where generation exceeds demand. In the 2022 National Grid forecast it was predicted that at least 15 TWh would be curtailed (squandered) by 2030. Octopus foresees a future where ‘on a windy, sunny day’ there might be 60–70 GW of renewable power being generated compared to ‘a normal summer peak’ of electricity demand around 35 GW. ‘If we want to keep costs down we need smart and sensible ways to use this excess,’ the firm says.

Energy demand peaks between 4:00–7:00pm on a winter night. However, says Octopus, if there’s lots of wind at 6:00pm, consumers should be charging their cars and running heat pumps on boost to use up surplus energy – boosting demand when electricity is cheapest and most plentiful.

With this in mind, the firm has devised its Intelligent Octopus tariff. This targets the owners of EVs. It factors in electricity prices over the next 24 hours, the time you need your car ready by and the state of other essential components of the power network. The tariff can also calculate when a heat pump needs to go into ‘super boost’ and when a home battery should charge or discharge.

If Intelligent Octopus is communicating with a customer’s heat pump and EV, it can turn down both devices. The company boldly claims it will ‘always take care’ to ensure the car is ready when the customer needs it, and only turn down the heat pump ‘in a way that doesn’t affect the temperature of the house’. Intelligent Octopus’ scheduled operating time is between 11:30pm and 5:30am, but the car can be charged outside these hours ‘if it’s better for the grid… you’ll still be charged the cheaper rate’.

You need to be an Octopus customer and own a compatible EV. The list includes Tesla, Ford, Audi, BMW, Mini, Skoda, Cupra, Porsche, Seat, Volkswagen and Nissan Aariya – or any car using an Ohme, Wallbox, Myenergi Zappi or Hypervolt charger. The customer should have access to an Apple (iOS v14.0 or later) or Android (v7 or later) smartphone to manage charging through the app. They will also need a smart meter able to send half-hourly readings.

Once the account is running, the customer simply plugs in the car on arriving home and tells Octopus, via the app, how much charge is needed and by what time. The car will be charged ‘intelligently’ at the cheaper rate. Octopus claims this tariff is now managing around 200,000 car batteries.

The company believes ‘intelligent demand’ can help NESO manage the electricity system. One of NESO’s roles is to cope with demand imbalances through buying the right amount of electricity in the right place. Octopus says its contribution has been to ‘bundle’ all the smart consumer devices together and offer ‘aggregated turn-down (or turn-up) demand’.

‘If we want to keep costs down we need smart and sensible ways to use this excess.’ – Octopus Energy

Scottish Power is also tapping into the EV smart-charge market. In September 2024, the company launched its EV Optimise tariff, another scheme offering customers the chance to reduce bills by charging when demand on the power network is low. The company claims to have more than 10,000 EV customers and has installed over 4,000 home chargers. EV Optimise works as an add-on to an existing Scottish Power tariff, giving customers a monthly credit for allowing the firm to manage their home car-charging remotely.

It works in a similar way to Intelligent Octopus. Drivers use an app to set when they need the car charged by and how much charge is needed. Scottish Power connects to the EV and schedules charging based on when energy is ‘cheapest and greenest’. Customers can charge at a reduced rate day and night. EV Optimise can be added to any tariff excluding Scottish Power’s Time of Use. The conditions are simply to have a smart meter, agree to pay by direct debit and consent to half-hourly reads.

In February 2024, a new EV charging trial, lasting six months, was launched by charger manufacturer Pod Point and Centrica, parent company of British Gas. Over 2,000 joint British Gas and Pod Point customers were recruited. The pilot focused on delivering flexibility services to customers using Centrica’s demand-side response (DSR) platform, which, like others, encourages customers to switch electricity use away from peak times. Participants stood to receive a credit of up to £50 on their gas bills.

Should EV owners go for a flexible tariff?
This experiment follows a previous trial led by the ESO, which ran from September 2023 to January 2024, and demonstrated the willingness of householders with EV chargers to adapt charging times guided by ESO-sent instructions. The Centrica/Pod Point trial aimed to underscore that EV charging can become a valuable source of flexibility in the balancing mechanism. Its findings are expected to shape new rules aimed at opening up this mechanism more widely to flexible EV charging.

All these variations on a theme depend not only on willing participants but workable technology. It can be maddening when this fails, and alleged frustrations with one tariff provider have surfaced on consumer affairs websites such as moneysavingexpert.com

One user complained of issues arising on the app or the website – ‘No matter what EV or charger combination you use, you just get a generic “something went wrong” error message on the app when trying to go to the next step.’

Another complainant told of being unable to get the system to work with his Audi Q4 E-tron and charger: ‘I followed all the instructions… it gets right through to connected and when I press “complete”… it doesn’t.’

The tariff provider admitted having problems and that it didn’t have ‘a fix for the on-boarding problem’, at the time. The firm has since posted a warning on its website that because the technology relies on the UK’s smart meter network, ‘there can occasionally be issues we don’t have control over’.

Some industry-standard tech providers allegedly claim that their app systems ‘might not work perfectly and installations may take longer than we’d like’.

Can smart be too smart? With sales of EVs stalling and manufacturers being forced to offer discounts, the migration towards EVs no longer appears inexorable. Time will tell at what rate the demand for app-controlled off-peak charging continues. Maybe these innovations should be viewed as small steps along the road towards net zero which, inevitably, will have more bumps.

• Further reading: ‘Bidirectional charging turns EVs into mobile power banks’. As electric vehicles become more prevalent, the focus has been on enhancing their efficiency, range and overall performance. However, just by adding the potential for vehicles to return charge along the same cables provides a number of transformative benefits for the owner, community and the grid.
• Find out why Great Britain is going towards a ‘whole system’ network transmission approach to energy operations.