Members of the renewable energy industry have responded to comments made by the late Sir David Mackay, who said in his final interview that further deployment of solar capacity was not an effective energy strategy for the UK.

Speaking before his death on 14 April 2016, the author and former chief scientific advisor to the Department of Energy and Climate Change (DECC) claimed the intermittency and land requirements of renewable technologies like solar and wind meant they could not provide the energy needed to meet UK needs.

Discussing the possible contributions of individual renewable energy sources, MacKay said: “There's this appalling delusion that people have that we can take this thing that we are currently using to deliver 1% of all our energy and we could just scale it up.

“I think it’s so dangerous for humanity that people allow themselves to have these delusions that they're willing to not think carefully about the realities and the laws of physics.” 

He claimed that solar is not well matched to demand in this country as British winters are considerably darker, meaning it cannot offer the levels of electricity needed to meet the additional demand of the season.

“It's always country specific so for the UK I think we want a zero carbon solution and it has to work in the winter.”

While the assertion that solar’s potential is diminished in winter is not in question, recent data from EnAppSys has shown that solar was still able to supply over 7% of UK renewable energy during the first quarter of 2016.

DECC figures for 2015 also showed that solar PV accounted for 9.1% of renewable generation, which the government says supplied just under a quarter (24.7%) of all electricity in the UK.

However, McKay said renewables cannot reach much higher due to the space required to do so and has instead argued that nuclear and carbon capture and storage (CSS) is the way forward for low carbon energy production.

“The sensible thing to do for a country like the UK is focus on CCS, which the world needs anyway, and nuclear. If you think what's optimal to bring out of wind and solar to add in as well, the answer is going to be almost zero because if you can make it through the winter with your CCS and your nuclear there's actually no point in having any wind and solar,” he said.

“It's actually a waste of money if you have a low carbon solution that gets you through the winter.”

MacKay also questioned the potential of battery storage working alongside solar, a combination which many have argued offers better value clean energy than technologies like nuclear.

“People seem satisfied with these simple statements that the prices are coming down so it's all going to be fine, but they haven't done the numbers to think through actually how big the batteries will need to be if you're going to do a solar and batteries only solution,” he argued.

“In Britain the average intensity of sunshine is nine times smaller [in winter] than it is in the summer…so you need absurdly large batteries and what you actually need to happen to the price of the batteries for that to become a realistic option; they need to come down by a factor of 100 or so.”

However, MacKay added that this was not the case everywhere, suggesting that solar and storage could be a successful combination in other countries around the world.

He added: “Anywhere where you've got a correlation between solar and demand then it definitely looks like solar is a really good idea and batteries are cheap enough that you can store energy overnight. So solar plus batteries in a place like Las Vegas I can definitely see playing a large role.”

Despite the former government advisor’s claims that nuclear offers the most effective low carbon energy strategy, opposition to wider deployment of the technology remains within the renewables industry.

James Court, head of policy and external affairs at the Renewable Energy Association, said: “We are already seeing government make ideological decisions against their public statements of pursuing the lowest cost options.

“Unlike solar, nuclear prices are rising and is looking increasingly unlikely whilst CCS is still stuck in R+D, unlike energy storage technologies which are already commercially viable.”

Court added that storage technologies can offer an effective alternative to large generation projects like Hinkley Point C nuclear station which is rapidly descending into high cost controversy as the final investment decision continues to drag on.

“Any future energy mix has to be technology neutral, fact based and addressing the needs of the energy trilemma. The steep cost reduction of solar has caught many by surprise, as has the technological and cost advances in storage. These sectors are real and deploying now, both at grid and domestic level and offer a transformative route to a low cost, low carbon and energy secure Britain,” he said.

The move away from centralised energy generation has been suggested by many in recent months, particularly with the rapid growth of solar deployment in the UK. Speaking to World Energy Focus last year, former National Grid chief executive Steve Holliday said “the idea of a baseload power is already outdated”.

Leonie Greene, head of external affairs at the Solar Trade Association, commented: “There is striking consensus now in the energy industry about the shape of a clean energy system and it is smart, highly distributed, much more active on demand-management and centred around consumers who may also be producers.

“The technological challenges Professor MacKay defined are readily surmountable and the plummeting costs of renewables are our best hope of averting dangerous climate change.”