The UK would need to generate more than 100 gigawatts of extra wind and solar power if it hopes to achieve net-zero emissions by 2050, a report has said.

According to Aurora Energy Research, low-carbon capacity will need to accelerate from the present 33 gigawatts to more than 140 gigawatts, as Britain tries to move away from traditional power generation to clean energy in the next three decades.

The Oxford-based consultancy said 20 gigawatts of new nuclear and three gigawatts of carbon capture and storage (CCS) facilities would have to be added to the equation as well.

Given the intermittent nature of wind and solar, the report, urges for 30 gigawatts of short-duration energy storage to help balance the grid in the event of a shortfall.

An additional 20 gigawatts of extended-duration back-up capacity has to be catered for low-wind scenarios during winter.

As per Aurora's historical data, windless periods occur for around two weeks each year, resulting in a reduction in wind energy.

Ana Barillas, principal at Aurora Energy Research, said: "Dispatchable generation is required to meet supply when the wind does not blow and the sun does not shine. This back-up is currently provided by unabated gas-fired generation, but an alternative is required if we are to do this with zero emissions. 

"This requirement could be met in a net-zero world with either very long-duration storage [upwards of one week] or gas with CCS."

Barillas also emphasized the role nuclear energy could play in Britain's attempts to generate low-carbon energy.

"Nuclear capacity is a long-term investment, and as coal and unabated gas exits the system, nuclear can help meet baseload demand and participate in a market alongside wind and solar."

"Getting to net zero requires a complete transformation of the power system. The most efficient way of doing this is by adopting a mix of technologies that can fulfill different system requirements without emitting CO2 emission," Barillas said.

Experts and activists, however, have voiced reservations.

Dustin Benton, policy director at independent think tank Green Alliance, said the nuclear industry has failed to compete on cost and deliver the reactors it has promised to build.

"Having failed in its goal to be the cheap source of zero-carbon power, the industry needs to focus on doing something useful – either providing flexibility to go alongside a renewables-dominated electricity system – perhaps by generating hydrogen – or to provide high-temperature heat for industry," he said. "It still faces competition from batteries and CCS, so it will have to innovate rapidly."

Benton thinks the UK is in a good position to achieve net zero emissions without nuclear power.

"We will need more renewables and storage, and much more process innovation in heavy industry, alongside a circular economy approach to getting more value out of the materials – like steel and concrete – that we depend on," he said.

The Campaign for Nuclear Disarmament (CND) backed the argument by referring to the steep costs of nuclear power.

Ian Chamberlain, the spokesperson for CND, said: "Nuclear energy is very expensive – far more expensive than wind. When huge amounts of money are sunk into nuclear energy, the opportunity cost is that those billions are not invested in the technologies that can help solve the climate crisis."

"A shift to 100 percent renewables is now technically feasible and economically viable. It's also politically possible to do this given the upsurge of interest in addressing climate change."

Chamberlain went on to further highlight the downsides of nuclear.

"Nuclear power has uniquely serious risks associated with it including the toxic qualities of nuclear waste and the absence of any safe storage space for the waste, and the possibility of nuclear accidents."

But Tom Greatrex, CEO of the Nuclear Industry Association stressed the important role nuclear energy could play in the UK's attempts to achieve net zero emissions by 2050.

"Wind, solar, and other zero carbon renewables have an important part to play, but nuclear can provide the high volumes of constantly available, reliable, clean power that's needed as a complement.

"Now we have begun building new plants in the UK, we need to continue the momentum and benefit from experience at home, as well as where stations have been successfully built abroad. A new funding model can bring in a wider pool of investors and, along with repeat builds, bring costs down."