Will Heat Pumps Cause Blackouts?

The pathway to meeting the world’s climate targets is electric. Fossil fuel boilers and vehicles are giving way to electric alternatives, and heavy industry is preparing to swap gas for low-carbon power. This transition presents an unprecedented challenge for electricity grids in developed economies, which were originally built to transmit power from a few large power stations to homes and businesses with lower overall demand.

Heat pumps are expected to significantly impact electricity grids. A cold spell could cause a surge in power demand from millions of households. But are these challenges too great for grid operators? Can households expect power blackouts in exchange for a greener energy system?

 The Claim

Critics fear that heat pumps could lead to a surge in electricity demand, particularly during winter cold snaps, potentially outstripping the UK's electricity supplies or overwhelming local power grids, causing blackouts. These concerns have been voiced by organizations such as the Stove Industry Association, which represents companies in the wood-burning stove industry. Erica Malkin, the group’s spokesperson, told the Daily Express there were "concerns about the expansion of the energy network" and the "very real potential for power outages."

Malkin argued that while the electrification of heat is beneficial for carbon-saving, the grid's current state is inadequate to meet the needs of complete electrification. In the event of a blackout, households would not be able to heat their homes, making wood-burning stoves a beneficial alternative.

 The Science

National Grid ESO (NESO), responsible for balancing Britain’s electricity supply and demand, disputes the notion that there is no "satisfactory explanation" for how it will maintain power in a green electricity future. NESO produces detailed annual forecasts outlining various potential routes towards climate goals, analysing changes expected in power supplies and electricity demand. These reports serve as blueprints for industry and government officials to prepare the grid for the future.

By January 2035, the UK’s annual electricity demand is expected to have doubled due to the rollout of heat pumps and electric vehicles. On a typical winter day, NESO models assume renewable energy will constitute 40% of the UK's total generation due to low solar and wind power generation. The UK would meet its power demand using extra gas and biomass power plants with carbon capture technology, power imports from neighbouring countries, and green hydrogen derived from renewable electricity.

An increasingly digital power grid will make better use of renewable energy sources. Homes and businesses can charge electric vehicles or batteries overnight when power demand is lower, helping to keep daily power use peaks from climbing too high. These energy stores could also help maintain the grid by releasing electricity back when demand peaks.

 Network Operators' Plans

Electricity network operators are actively preparing for the uptake of heat pumps. Scottish Power, for example, has developed an AI-powered "digital twin" of its electricity networks to simulate changes by 2045. This simulation found that flexible use of heat pumps could reduce their contribution to peak demand by up to 32%, aiding grid stability.

UK Power Networks (UKPN) monitors real-time data from homes with electric heating, electric vehicle chargers, solar panels, or batteries to understand heat pumps' impact on the grid. Their project, in collaboration with the Energy Systems Catapult (ESC), aims to manage these changes efficiently and reduce customer bills.

 The Caveats

The electricity grid is a dynamic and evolving situation for system operators. NESO's forecasts were prepared under the UK’s previous government, which aimed for a net zero electricity grid by 2035. The new Labour government aims to achieve this by 2030, necessitating a faster rollout of renewables, which could complicate managing the influx of heat pumps.

Additionally, while current targets suggest a combination of heat pumps and hydrogen boilers, hydrogen boilers are expected to play a more limited role, potentially increasing the reliance on heat pumps beyond NESO's initial preparations. The government will decide on hydrogen heating's role in the net zero future by 2026, but until then, forecasts will include hydrogen heating.

 The Verdict

There is still time for energy grids to evolve before heat pumps significantly impact the UK’s electricity system. Although it will be more challenging for grid operators to maintain stability, there is no reason to believe that the UK will experience more blackouts due to heat pumps if careful modelling and upgrades continue.