I’m inspired to write this post by the fact that I’m lucky enough to have an office window overlooking my garden. We mainly manage it for wildlife, and at this time of year it’s a riot of growth and colour.
There are plenty of people who seem eager to paint renewables as a threat to other land uses – witness the Tories recent attack on solar farms as competing with farmland. (This despite the fact that they take up less land in the UK than golf courses.) If you’re prepared to look properly, there are plenty of creative examples of renewables and biodiversity, going hand-in-hand. Managed grazing under solar panels, protected marine areas around offshore windfarms – and the subject of this post, roadside verges managed for wildflowers… and gas.
There are 270,000 km of rural roads and motorways in the UK, most of which have roadside verges. The typical management regime is to cut them 2-3 times per year, and leave the clippings in situ, but this does little for biodiversity. Instead, they could be managed in the same way as a traditional wildflower meadow (like my back garden), encouraging more diverse plants, and the birds, insects and mammals that would follow. In effect we could have 270,000 km of much needed wildlife corridors connecting every nature reserve in the UK.
So what does the alternative management look like, and why don’t we do it? Well, we’d actually need to cut less often (twice per year), which would save money. But, we’d also need to collect the clippings, and that’s the problem. Collecting the clippings is essential, because diverse meadow needs poorly fertilised soil, otherwise it gets dominated by a few aggressive species like nettles and certain grasses. However, collecting the clippings needs specialist equipment that costs a lot more than a tractor and flail. Local/highway authorities generally can’t afford that extra expense.
So, could those clippings have a value that would effectively pay for collection? Well, as with any meadow, they can be turned into bales of silage and kept for months, but the roadside contamination (soot, tyre dust etc.) means that silage can’t be fed to animals. However, it turns out that it’s still excellent feedstock for an anaerobic digester – so it can readily be turned into renewable methane.
Lincolnshire County Council carried out a pilot a few years ago, which was written up by researchers from the University of Leeds and published in May 2020. Their headline finding was that silage from roadside verge clippings was a viable feedstock for anaerobic digesters, and that AD operators would pay enough for it to cover the cost of collection. So there you have it, a win-win, a nationwide network of biodiversity corridors and a huge new source of renewable gas all in one.
All of which only begs the question as to why we’re not seeing more verges managed in this way, three years on from that research? I suspect it’s partly reluctance to perceived ‘untidiness’, but piles of rough cut grass look pretty unsightly too, and I think once people see verges covered in a rich carpet of colour they’ll think differently (and maybe even drop less litter). Mostly I expect it’s a lack of capacity to change – local authorities don’t have the resource to try many new things, especially if it involves investing in new equipment.
But I think the more people know about this particular win-win scenario, the more wildflowers we’ll see – so share this post!