ESO highlights importance of flexibility for decarbonisation

The electricity system operator (ESO) at National Grid has highlighted the importance of flexibility to achieving net zero emissions by 2050 in latest of its annual Future Energy Scenarios.

The ESO said the three of its four scenarios that align with the target all require significant growth in flexibility both on the demand and supply sides.

Demand side

The annual report, which was released earlier this morning (27 July), said the spread of electric vehicles and heat pumps will both create large requirements and sources of flexibility. If fully electrified heating becomes the norm, then peak power demand could pass 95GW by the middle of the century.

Peak electricity demand

Nevertheless, the ESO said its net zero scenarios all rely on the use of thermal storage, such as hot water tanks or phase change materials, to limit peak demand from heat pumps. Up 40 per cent of properties with one installed are also expected to fit thermal storage of some kind, reducing peak electricity demand from heat pumps by up to a third.

The ESO said that up to 83 per cent of households will adopt a time-of-use tariff by 2050, whilst up to 83 per cent of electric vehicle (EV) drivers will utilise smart charging. Up to 45 per cent of EV drivers will also agree to offer vehicle-to-grid charging, providing 38GW of flexible capacity – almost as much as the combined capacity of all other electrical storage.

Uptake of time-of-use tariffs (TOUT) and vehicle-to-grid (V2G) charging

It said proliferation of time-of-use tariffs will make other forms of flexibility appealing to consumers, adding that smart appliances and lighting could shift up to 1.5GW – 11.4 per cent – their total demand at peak times.

“Load shifting from appliances is low in the 2020s when this would need to be scheduled manually,” the report explained. “However, we expect white goods like dishwashers, washing machines and refrigerators which can respond automatically to price signals to add greater demand side response potential as smart appliances become more widely available in the 2030s.”

The production of green hydrogen using electrolysis is additionally expected to provide an important outlet for surplus renewable generation that would otherwise need to be curtailed, with the capacity of grid-connected electrolysers reaching almost 73GW in several of the net zero scenarios. Flexibility from industrial and commercial customers is forecast to rise steadily to as much as 13GW by 2050.

Supply side

By contrast, the ESO expects the capacity of dispatchable thermal generation to fall in all of its net zero scenarios – by around half in two of them – as the 39GW of gas generation currently installed closes over time and is partly replaced by either hydrogen generation or bioenergy, mainly combined with carbon capture and storage (CCS) in the case of the latter.

Interconnector capacity is forecast to increase as much as five-fold from almost 5GW currently to up to 27GW by 2050.

Although the existing cables are primarily used to import power from Europe – hence their inclusion on the supply side of the equation – the drive towards net zero is expected to lead Great Britain to become a net exporter of electricity as interconnectors become a large source of flexible demand. That said, Britain is also anticipated to remain a net importer during peak periods.

Power imports and exports

Meanwhile, electrical storage capacity, including pumped hydro and batteries (although not from EVs), is expected to increase up to 10 times from less than 4GW currently to more than 40GW. The volume of energy that can be stored is forecast to reach up to 200GWh.

The report’s focus on flexibility was welcomed by Jorge Pikunic, managing director of Centrica Business Solutions, who said: “As the UK moves towards a net zero future, it’s critical that the system can operate flexibly to manage the peaks and troughs associated with an increased level of renewable generation.

“By encouraging the use of flexible technologies such as demand response and battery storage and by evolving the energy market to give consumers and industries the ability to contribute, the UK can optimise its use of green power at least cost to consumers. To support this, we encourage the government to use the upcoming energy white paper to set a policy objective for the deployment of flexibility at a national and local level.”

Clear here to read Utility Week’s initial coverage of the report, including an explanation of the four different scenarios.