Not long ago, I wrote on these pages about heat pumps. the miraculous contraptions with which Britain will decarbonise domestic heating. Yet while it’s true they will help in driving down emissions – being far, far less polluting than your typical gas boiler – it would be wrong to say they are inherently climate-neutral.
That’s because heat pumps may not use gas, but they certainly do use electricity to run. And though power in the UK has been massively cleaned up in the last decade by weaning ourselves off coal, and ramping up renewables, it still has a pretty hefty carbon footprint. The Government might have an ambition to fully decarbonise electricity by 2035, but last year we were still pumping out 177g of CO2 for every kilowatt hour of power consumed.
Indeed, this technicality is a stick often used by climate sceptics to beat a variety of green technologies with (as if none of the engineers and scientists developing them were aware anyway…). Be it electric vehicles, recycled steel, green hydrogen or, indeed, heat pumps – none of are truly ‘net zero compliant’ unless the electricity they run on is sourced entirely from clean power.
Squaring this circle means doubling down on the energy trends of recent years. First and foremost, we must deploy a considerable amount of additional renewables capacity. Wind energy is an area where the UK already does well, but we need to up our game when it comes to solar power.
And, as with heat pumps, this is yet another area where finnicky planning rules are getting in the way of progress.
For a lot of our building stock, solar panels can be reasonably easily added to a classic sloping roof, without needing to seek planning permission first. But for those buildings with flat roofs, if they want to position panels upright at an angle – as opposed to laying them horizontally – you need permission from the local council.
Is that such a big deal though?
Unfortunately, the answer is yes. The key thing to note is that, when plonked down flush against a roof, solar panels lose efficiency in terms of capturing the maximum amount of energy possible. Generally speaking, pitching them at 30-40°, due south is the optimal configuration. For various reasons, solar panels on flat roofs tend to be mounted at 10°, but even this slight elevation is enough for an installation to breach the maximum 200mm threshold which determines whether panels need planning permission or not.
Optimising how much sunlight a panel captures is not the only reason for pitching them at an angle. By arranging them this way, it means that they can be kept in better condition. Rainwater can easily run off, keeping them free from dirt and debris. This boosts their longevity – and lowers the need for ongoing maintenance. All this adds up to ensuring they are as efficient as possible in converting sunshine into electricity, bringing down the all-important cost per kilowatt hour.
As with the rules that limit where you can site a heat pump, I don’t believe the regulation which limits solar panels on flat roofs was ever meant to deliberately throw sand in the gears. Nor is it at all unreasonable to have some restrictions on what sorts of paraphernalia you can attach to a building.
By the same token, I don’t believe those drafting the regulations would have expected them to hinder us from decarbonising the UK’s electricity supply, particularly when energy prices have gone through the roof.
A carve-out to the ‘200mm rule’ specifically to allow a small solar panel installation – for which most homeowners will eventually get planning permission anyway – would be a common sense approach, while still allowing the regulations to effectively do what they were designed to achieve.
There is a whole ecosystem of entrepreneurs who stand to benefit from such policy reform – from teams of scientists in university labs who are advancing solar tech year on year, to manufacturers based on industrial estates who fabricate them, to the tradespeople who will eventually install them. There really is a wealth of well paid green jobs waiting to be seized.
To decarbonise our power grid, the role of decentralised energy sources like rooftop solar will need to expand. Regulations need to keep pace too – and this small tweak would allow just that.
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