We were thrilled to be told yesterday that M&S Energy have pledged £5000 to our crowdfunding campaign to support our use of renewable energy and energy efficiency measures in our cheese dairy project. This project reduces our need for energy by creating a cheese-friendly ‘cave-like’ environment for the cheese storage and by linking in with our on-farm renewable energy systems. It will mean our entire cheese making system will be close to being energy self-sufficient.
As we have mentioned before, one of the reasons why we describe our farming approach as ‘ethical’ is our goal to create a sustainable, circular, low input food producing system that does no harm to the environment, and is ultimately designed to regenerate the land and improve biodiversity.
A key element of that is repurposing waste, so we thought this was a good moment to introduce you to our anaerobic digester and to explain how important that is to our system and to our longer term plans.
We had read about the benefits of anaerobic digestion about a decade ago but were told that to be viable we would need about a million quid to invest and about 300 cows to produce the slurry to run it – three times our herd size! We looked into how we could make this work on a smaller scale and we spoke to a Shropshire-based company who offered to design something to our specification - cheap, farmer-friendly and using only farm wastes. We built it ourselves and we’ve had it running successfully since 2013.
Anaerobic digestion is where organic material, such as agricultural or food waste, is broken down (by the naturally occurring bugs in the slurry) in a sealed, oxygen-free tank to produce biogas and digestate, which is used as a biofertiliser. We collect all the organic waste on the farm, add it to the slurry and pump it into a sealed store from which we collect the methane emissions and burn them; either in a gas-fired boiler to raise hot water or in an engine that turns a small, 25kWe, turbine.
The AD system will produce hot water for the underfloor heating in the new cheese dairy and it will also provide the heat to keep our the production temperature steady in our new cheese making room. This means once we have our new cheese dairy up and running our whole cheese making process will be powered almost entirely by cow poo!
But the environmental benefits of AD are about much more than simply reducing our reliance on mains electricity. Dairy farms produce a lot of slurry – which is basically manure, which can be used as a fertiliser to put nitrogen back into the soil. Before we had the AD system working we used to apply raw slurry by tanker splash-plate each spring to our grass. This would get rid of the farm waste and the farm birds would love us. Why? Because as soon as the slurry went on, up would come the worms and other soil invertebrates gasping for air.
The AD makes an enormous difference because the product of the digester (digestate) is a more effective and less polluting fertiliser than the raw slurry – with the added benefit that it does not smell! By installing the AD, at a stroke we reduced our CO2 emissions by 30%, our negative impact on soil invertebrates, our dependence on purchased feed, fuel and fertilisers (we don’t buy soluble fertilisers, but if we did...), the carry-over of weed seeds in the slurry and removed complaints about the smell of raw slurry.
Our digestate needs careful handling to maximise the benefit; an umbilical system to minimise compaction, slurry placement to minimise aerosol losses and mid-April application to maximise utilisation. But when all this is done it produces a yield enhancement of around 20% compared to previous years. So it’s a win-win all round.
Well, for everyone except the birds who have to work a bit harder to find the worms!
We’ll write a more in depth article on the importance of ruminants on grass, land management and carbon sequestration in soil soon, but for now this is just a quick heads up to say thank you to M&S Energy for supporting innovation in energy!
Our Crowdfunding Campaign
If you like what we are doing and would like to support us, details of our crowdfunder can be found here. A huge thank you to everyone who has supported the crowdfunder so far. We are pleased that so many people share our vision for a kinder, more sustainable approach to dairy farming. Please share our story with your friends and family to help raise awareness of our dairy revolution! Thank you.