The Sleeping Catalyst for Net Zero: Small Scale Solar

One of the more commonly discussed catch 22s, holding back the growth of the solar sector, is the fact that panels have to go somewhere. And too commonly, they are in the form of large-scale, ground mounted solar. A central reason for this is that they are easier to fund than rooftop solar as they more predictable. This is due to the conversely transient nature of tenancy, leases, and the changes-of-hands common with rooftop ownership. Moreover, large scale solar projects are able to achieve carbon emergency targets in one go. Finally, they are thought of as cheaper, due to their solar economies of scale.

This trend not only visually strains public support as solar farms aren’t great to look at, but also poses a massive socio-economic problem: that land being used for solar could otherwise be used for agriculture, forests, conservation areas, and housing. In Europe, as well as in other high-population density regions across the globe, this mis-alignment of land use has even greater implications.

The UK is forecasted to add 2,711Mw of new solar by 2023. If we assume 50% of it to be ground mounted solar and at an average of 5 acres of land per Mw of solar - that means that roughly 6,750 acres of land, approximately GBP1.01billion worth of land at today's value, will be committed to it for the next 25 years. According to the UK gov website, average wheat production is 9 tons per year, for 2.5 acres (or 1 hectare) of land; therefore, foregoing nearly 972 tons per year (or 24,300 tons) of wheat during the life of all that solar. And of course, this is just one crop.

Aside from wasted land, other inefficiencies with large scale solar in general are connectivity with the grid, and energy losses. While utilities continue to imply that large-scale solar projects are more economical than small ones, the data is telling another story. The costs for transmission and distribution of utility-scale solar energy may largely undermine the modestly better economics at the point of generation.

Consider all of the unused, wasted space of every combined rooftop in the UK, across the EU, and globally. EU rooftop solar panel systems could produce approximately 680TWh of electricity annually, which is equivalent to 24.4% of the current consumption. The UK alone, has an estimated 250,000 hectares of south facing commercial roof space, which could provide roughly 15% of the UK's electricity demand if utilized with photovoltaics (PV). But just imagine the potential of using every rooftop in the UK, including residential.

The potential upside for residential and commercial rooftop solar versus ground mounted is massive. But locating roofs ideal for solar, has typically been time consuming, expensive, and challenged by information asymmetry; and we are really excited to be evaluating the results of our beta trials with customers across the UK, using the PowerMarket solar analytics platform to identify great rooftops - with the aim of empowering small scale solar projects. Community-led solar would enable regions, communities, and even neighbourhoods to mobilize solar efforts by making data accessible and easy to understand, and even to crowd-fund community projects.

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Endnotes

1. Langstaff, Craig. “How Much Does One Acre Of Land Cost.” The Small Farmer Life, 23/10/2019.
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2. Vourvoulias, Aris, et al. “UK Solar Capacity: Is the Future of Solar Cloudy?” Greenmatch, 20/07/2020.
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3. Department for Environment Food & Rural Affairs. “Farming Statistics Provisional crop areas, yields and livestock populations” National Statistics, 10/05/2019.
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4. Bódis, Katalin, et al. “A High-Resolution Geospatial Assessment of the Rooftop Solar Photovoltaic Potential in the European Union.” Renewable and Sustainable Energy Reviews, vol. 114, 2019, p. 109309., doi:10.1016/j.rser.2019.109309.

5. The European Commission Joint Research Centre and the European Institute of Innovation & Technology. “Research highlights potential of rooftop solar.” The Construction Index, 31/10/2019.
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