Why Nimbys are wrong about solar farms

Tory leadership loser Robert Jenrick said that solar panels are “for roofs not fields” when asked by i last month if he supported a proposed giant solar farm in his Nottinghamshire constituency.

He is by no means alone in that view, which is a common argument given by opponents of solar farms.

Those who protest against solar farm developments argue fields would be better used for growing food, while solar panels could and should be concentrated on roofs, of which there are quite literally millions in the UK.

“I’ve said that we must ban solar farms from prime agricultural land and I mean it. These facilities are despoiling our beautiful countryside and jeopardising our food security. We must end it,” Mr Jenrick added.

But since Labour came to power Energy Secretary Ed Miliband has approved four of the five biggest solar farms to be given planning permission in the UK.

Mr Miliband has vowed to take on “the blockers, the delayers, the obstructionists” who oppose large solar and onshore wind development to help the UK meet its ambitious targets to make the country’s energy supply virtually carbon neutral in just six years.

As the Government steps up its campaign to drive through new solar and wind projects, it is likely we will be seeing more projects of a similar scale too that opposed by Mr Jenrick in the coming years.

i asked experts whether it was feasible for the UK to do without new solar farms and instead confine new solar panel installations to the rooftops of households, offices and other business properties, and what effect this could have on food security.

Experts were clear that there needs to be a huge and rapid increase in renewable energy generation if the UK is to have any chance of meeting its highly ambitious climate targets.

And, as the cheapest source of renewable energy – now costing less than onshore and offshore wind, according to government figures – solar will inevitably play a key role in the transformation of the UK’s energy supply.

The Conservative’s British Energy Strategy in April 2022 outlines the need for 70 gigawatts (GW) of solar power to be installed by 2035 – enough to power 20 million homes, according to National Grid.

As of June 2024, the UK only had about 17GW installed capacity (powering around 4.5million homes), meaning the country needs to quadruple its solar power generation in the next 11 years.

Two thirds of the current solar power is generated by solar farms with panels on the ground – known as “ground mount” – with the remaining third coming from the rooftops of businesses and over 1.5 million homes.

Meanwhile, government advisor the Climate Change Committee estimates that we will need 90GW of solar by 2050 (5.3 times current capacity) if we are to hit our legally binding target of becoming Net Zero.

Dr Simon Harrison, a member of the Government’s new advisory commission to help make the UK’s power generation virtually carbon neutral by 2030, told i the task is so great that it’s “going to require vastly more renewable energy generation” – meaning that “in practice both solar farms and roof top solar will be needed at scale to meet our needs”.

“There’s a significant role for both,” added Professor Rob Gross, who also sits on the commission.

The first major advantage of solar farms is the sheer amount of energy they produce.

The 600 MW Cottam Solar farm that was granted planning permission in September would be the UK’s largest – supplying 180,000 homes, or 1,500 homes for every 5MW of energy generated.

By contrast, large solar rooftop installs, say over an airport or large of space, typically generate hundreds of kilowatts (kW) potentially up to a few megawatts (MW).

While the average solar rooftop installation size on someone’s home for their own use is typically 4kW.

So the Cottam Solar project would generate at least 200 times the electricity of the very largest commercial roof top installations and around 150,000 times as much as a typical household solar panel setup.

Tony Slade, technical director of Beaverbrook Energy, which designs, finances and builds low-carbon energy generators, told i: “Ground mounted solar farms also suffer from less ‘shading’ (blocking of direct sunlight through obstacles and obstructions) and ‘directional losses’ by being angled in the wrong direction.

“About 50 per cent of roofs face the wrong way and of those that face the right way about 25 per cent suffer from shading issues,” he said.

Yes, in part because they benefit from economies of scale. In other words, the bigger the solar farm, the cheaper each unit of electricity will be, as more panels can benefit from the infrastructure.

Professor Gross, who is also director of the UK Energy Research Centre coalition of researchers, told i “the principal advantages are economic”.

“It is far cheaper to install each solar panel in a large array of thousands of panels than it is to install a handful of panels on a roof.

“Ground mounted is cheapest, followed by larger arrays on commercial units, followed by new build, followed by residential retrofit. All categories are getting cheaper but it is impossible to get away from the fundamentals – the cheapest solar will always be the simplest to install, in the largest arrays,” he said.

“And ground mounted developers building large schemes may also be able to negotiate the best deals for panels and equipment,” he added.

Mr Slade explains that greenfield ground mount solar panels on fields typically cost two thirds as much, per unit of energy, as large scale solar panel arrays on commercial buildings such as warehouses, shopping centres and factories – as well as new build domestic and commercial buildings, where the solar panels are fitted as part of the original construction.

Meanwhile, installing solar panels above car parks is typically twice as expensive as wind farms and retrofitting homes is about three times as expensive, he said.

Opponents of large solar farms often argue that the land would be better used for agriculture and that too many of them could impact food security.

But the Department for Energy Security and Net Zero firmly rebuts those suggestions, arguing the amount of agricultural land involved would make very little difference to the UK’s food production.

“Our plans to boost solar power do not risk the UK’s food security. The total area of agricultural land used for solar is very small and is often the lowest grade quality for food production.

“Even in the most ambitious scenarios, solar would still occupy less than 1 per cent of the UK’s agricultural land, while bringing huge benefits for the British public and our energy security,” the spokesperson added.

Meanwhile, in July, National Farmers’ Union boss Tom Bradshaw warned MPs against making “sensationalist” claims about food security.

“It’s a small amount of land which is being taken out of production,” he told the Politico Europe website.

“They can potentially play a very important role, accounting for perhaps 40 per cent of new installation of solar. But it’s important to be clear that rooftop and ground based are additive not competitive,” Professor Gross said.

Dr Harrison says “there are serious considerations to make on where solar is placed”, meaning that sometimes roof top solar power can be far more suitable than those in fields.

“In the simplest terms, there is more space in rural areas for solar panel installations and it is often easier to optimise their positioning for greater energy capture. But they are generally further from existing grid connections and with sometimes competing requirements for land use,” he said.

“On the other hand, rooftop solar, most commonly in urban settings, often avoids use of congested electricity networks, especially when combined with local batteries, and when used in homes tends to drive greater awareness and action by residents in other areas such as energy efficiency improvements, as well as reducing bills. In practice both will be needed at scale to meet our needs.”

The Government estimates there are 250,000 hectares of south-facing, industrial roof space across the country. That’s an area bigger than London and Manchester combined, with the potential for a vast amount of solar panels.

Even a very conservative estimate suggests that this commercial roof space could provide an area big enough to generate approximately 25GW of energy.

This amounts to nearly half the total amount recommended by the Climate Change Committee (CCC), according research by University College London for the Campaign to Protect Rural England (CPRE).

Mr Ramandani agrees that fields and rooftops can play different, complementary, roles in UK energy generation.

“We need about 18GW more of rooftop solar to hit 70GW by 2035 to keep us on the right path to Net Zero. So it will play a massive role,” he said.

“Rooftop solar can power people’s homes and business onsite without needing to pull from the grid, and excess generation can be stored or exported back to the grid, which supports the flexibility and security of the grid. And they operate at a smaller scale with some export to the overall grid system.

“Solar farms, meanwhile, are not onsite generation – they operate at a much bigger scale and power the grid with greater quantities of energy, which is used by the whole system and not specific to a home or business (before they export the excess generation that they don’t use or store).”

UK households are already waking up to solar panels, receiving record sums last year for the amount of excess energy they generated that they sold back to the grid, Ofgem said last week.

Homeowners received more than £30m for the energy they didn’t need in the year to March 2024, four times the £7.2m they made the previous year.

Although this amounted to a relatively small amount of energy – enough to power 88,000 homes – experts say there is considerable scope to increase this and they expect this to happen in the coming years.

“There is definite major role for rooftop solar in the UKs future energy mix,” said Mr Slade. “As installations become cheaper and the market for excess generation becomes fairer to the home owner rooftop domestic solar will continue to grow,” he said.

Mr Ramandani says: “Onsite solar rooftop generation takes money off consumer’s bills as they purchase less from the grid, and excess generation can be exported to the grid for income. This in turn creates a stable grid system with less demand side pressure, as well as supplementary energy generation from homes and businesses.

For a typical house, installing a PV system could lower bills by the equivalent of nearly 330 every year over the 30-year lifespan of the system, according to a study by Cambridge University and the Think Three property development company for Solar Energy UK.