Paul Davies, Key Account Manager for Landia UK, considers the outlook for the biogas sector under a new Labour government – and explains where the industry needs to get its own house in order
Watch almost any news story about renewable energy, and it immediately zooms in on wind and solar power. Yes, very worthy, but on the extremely rare occasions that biogas is mentioned, it is presented in Junior Newsround fashion, as if we’re still learning to tie our shoelaces.
And worse still, if the ‘news’ is something to do with renewable energy at a sewage treatment plant, cue incredibly childish references to ‘Poo Power’. No wonder biogas isn’t taken anywhere near as seriously as it should be.
This is crying shame, because the industry has such enormous potential. Labour says it wants to ‘make Britain a clean energy superpower’ – but not a word so far on biogas. Lots of pretty pictures of solar panels and butterflies, but anaerobic digestion?
If Kier Starmer, Ed Miliband and their colleagues are really that keen, then maybe they could come and visit a biogas plant to see how clean, green renewable energy can be created from sludge, or from the never-ending mountain of food waste that we produce. And yes, a proper fact-finding visit, not just a photo opportunity.
Labour says it wants to ‘tackle the cost-of-living crisis and make Britain energy independent once again’ – but after a disastrous season this year for farmers, which sends home-grown prices through the roof, we’re not exactly off to a flying start.
As much as I’d like to, I can’t blame the bad weather on the politicians, but if more and more farmers’ fields give way to solar panels, then there’s less and less chance of people being able to afford British-grown crops. Also, should more questions be asked about the huge amount of maize that is grown and often transported over long distances; not for anyone to eat, but simply to feed hungry biogas plants?
Shouldn’t we be using food waste instead, rather than see so much of it not collected, or sent to landfill, or for composting? And what about the farmer, who is trying to do the right thing by diversifying with a biogas plant investment?
He wants to put slurry to good use; generating energy and using the final, nutrient-rich digestate as an organic fertiliser, only to find that the power company wants to charge him far more for his grid connection than the biogas plant cost to build! Are the government going to step in and stop farmers being held to ‘ransom’?
Fair play to the new party in power for also saying (promising?) that they will ‘force water companies to clean up rivers’. Good. But how about forcing or encouraging water companies so that they can produce biogas, not just from sewage sludge (please don’t use the ‘P’ word), but from co-digesting it with organic (food) waste/effluent.
For many, the prospect of water companies further increasing their dividends, payouts and profits from lucrative co-digestion will make them shudder, but it is proper, joined-up thinking, that at the moment (much as we of course need legislation to control it), is bogged down in an endless mountain of tedious paperwork.
Everything is easier for digester mixing if the wearing parts can be accessed from outside the tank
I’m very reluctant to use the word ‘waste’, because that mindset is a big part of the problem that is holding everything back in the water industry sector; thinking of it and treating it as a ‘waste product’.
Severn Trent’s Minworth plant (with Cambi’s THP system) is a great example of what can be achieved with the right equipment. Likewise, with Scottish Water’s sludge facility at Nigg, near Aberdeen, and Yorkshire Water’s Energy & Recycling Facility at Huddersfield. But there are umpteen water company digesters that are producing some gas – just.
You can put your hand up against the lower third of many a digester to find that it is cold. And that’s because that lower part of the tank is full of grit because it is not being mixed properly.
Not any old mixer will do. The industry needs to realise that good mixing is crucial, and to think much more in terms of creating commercial digesters, or as we do regularly, retrofit the tank with a mixing system that keeps all of those unwanted solids in suspension. Grit accumulating at the bottom of the digester will typically reduce the process capacity by 25%-35%.
Spectacularly, mixing systems that do a below-average mix, and have all wearing parts inaccessible, inside the digester are still being installed. This is despite the fact that all too many biogas plants are failing or totally underperforming because the broken propellers can’t be retrieved without the operationally and financially damaging emptying of the tank.
This can take a biogas plant offline for several weeks before the biological process can start producing gas again, which is quite ridiculous. Will the industry ever learn?
