Wind and solar energy sources can provide large scale cheap, stable, carbon neutral energy for the UK if supported by a flexible grid that allows for better energy storage and trade.
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Wind and solar power are the most popular sources of renewable energy in the UK. They produce 19% of the UK’s electricity output. But both suffer from a lack of stability: if the wind does not blow, and the sun does not shine, how do we keep the lights on and our homes warm?
Not-for-profit green energy body the Energy & Climate Intelligence Unit (ECIU) has stress tested a model of the UK’s future energy portfolio in which wind and solar generate 50% of the UK’s energy demand in 2030 and coal and oil power stations have been decommissioned. The model assumes that during periods of low demand, nuclear, biomass and hydropower operate at maximum capacity.
Excess energy can be stored during periods of low demand, with this fed back into the grid during peak demand.
The model shows that with the development of a smart and flexible grid, a reliable energy supply can be maintained even during an extreme three-week winter lull.
Report author Hugo Chandler says: “We wanted to set our future grid a tough test; what happens if the wind doesn’t blow for an extended period during winter, when solar is also restricted and demand is highest?
“Our modelling shows that the lights would stay on, and key to making this happen is ensuring that our future grid is truly a smart, flexible one,” he says.
Developing this flexible grid involves changing demand, storing energy, trade and flexible power plants.
DEMAND SHIFTING, OR DEMAND-SIDE RESPONSE
Demand-side response (DSR) involves altering customers’ energy use, encouraging them to bring consumption forward or delay it, so more electricity is used outside peak demand periods.
Smart meters could play a great role in facilitating DSR, as they can communicate consumption data to suppliers every half hour, allowing them to make changes accordingly.
More investment in energy storage is needed. Energy storage
infrastructure has the benefit of “two direction” flexibility compared to additional generation capacity. Excess energy can be stored during periods of low demand, with this fed back into the grid during peak demand.
This storage can be in the form of conventional lead-acid batteries, or as a potential energy in pumped storage schemes or compressed air which can be released to drive electricity generating turbines.
Another way to increase electricity supply flexibility is by installing
high voltage interconnector cables between Britain and Europe. The government’s independent Committee on Climate Change expects the UK to increase interconnector capacity from 4GW to 11GW by 2030.
FLEXIBLE USE OF GAS-FIRED POWER PLANTS
The ECIU estimates that there may still be some need for fossil fuel- burning plants in the future. These plants will be required to rapidly ramp up to full capacity, and wind down again to plug short-term supply gaps.
Improvements in gas-fired technology mean that new plants can achieve this on-demand method of operation. For example, a new
GE combined cycle gas plant in Le Bouchain, France, can reach its full 570MW output in just 30 minutes.