Polls suggest that 85% of the UK public are concerned about climate change and similar numbers are strong supporters of renewable energy.
However, when it comes to large, ground-mounted solar farms on good quality agricultural land, many of us find ourselves torn. On the one hand, energy security means that we need all the clean renewable power we can get. On the other hand, food security means we need to use good quality agricultural land for growing food.
One solution is “Agrivoltaics”, i.e growing crops (particularly fruit and vegetables) under solar panels.
This can be more profitable than either alone, while the panels help reduce the need for irrigation. It’s being used successfully in many countries, from greenhouses in France to deserts in China. There’s a pilot scheme underway near Ely, but as we’re the driest part of the UK and a key vegetable growing region, we should clearly be exploring agrivoltaics vigorously.
A recent German study showed that in agricultural applications it can be just as productive putting the panels vertically, facing in an east west direction. As these produce their peak power in the mornings and evenings, this also helps even out power generation across the day.
However, we must also prioritise putting solar panels on existing buildings, especially where they will use a high proportion of the power that’s generated. This maximises the financial savings and avoids problems with the limited capacity of the local power grid.
Most people would like solar panels, but for those that can’t afford the initial cost, there are a couple of useful schemes. For households, there’s Cambridgeshire’s excellent “Solar Together” group buying scheme.
For larger rooftop installations there is now an exciting new scheme, set up by the cooperative BigSolar.coop This is aiming to widen access to subsidy-free solar on commercial and community buildings, in order to help cut carbon and reduce energy costs.
In this new approach, the panels are installed for free by BigSolar.coop which then sells the panel’s power to the building occupier at a rate that’s guaranteed to be less than the rate they’re paying for grid electricity.
A key to the project’s success is that community groups such as Carbon Neutral Cambridge help identify suitable sites and find interested building owners/occupiers. This makes the scheme financially viable despite the ending of subsidies. BigSolar.coop itself is funded by some philanthropic grants and individual “Investor Members”, who get paid interest (they’re targeting 4%).
The most suitable local buildings are likely to be those with an unshaded roof area of over 300m2 (i.e tennis court sized) ideally sloping south, east or west, and that can use at least 50% of the power generated. Likely local possibilities include healthcare facilities, care homes and hospices; schools, some agricultural and food production sites; laboratories and data centres.
Its quite easy to use Google Satellite images to find potential sites with at least a tennis court sized area of roof. It requires a bit more investigation (for example using the web, or by personal contacts) to discover whether the occupants are likely to be able to make use of the energy thats generated, and whether they’re likely to be interested in helping decarbonise Cambridge (whether or not thats with BigSolar.coop, or self funded). Cycling over to the site can also help discover which way the roof slopes, whether its likely to be too shaded, or any other potential problems
We think this is a great idea, so do join us and help, either by helping discover, or letting us know about possible sites at firstname.lastname@example.org or by becoming an “Investor Member” of BigSolar.coop.
Do register for our online AGM, lunchtime 19th Sept, with Richard Hales, Energy and Sustainability Manager at Addenbrookes