The learning curve
Having passed our two year milestone in September we are settling down well in our ability to manufacture Biogas on demand and to regulate the output.
Glycerol
One of the key tools for doing this is the use of Glycerol which although used in small quantities is very responsive in accelerating gas production. It is rich in carbon and enables the feedstocks we use, the cow slurry and the maize silage, to be much more productive. It is a catalyst of great value to the process and enables the feedstocks to produce 50% more methane.
The market for Glycerol has hardened of late and as we now have our new Environmental Permit we are only allowed to use Glycerol produced in connection with the manufacture of Biodiesel from Virgin Oil unless we pasteurise our Digestate which would be very expensive.
Glycerol from Virgin oil is difficult and expensive to source. Most Biodiesel is produced from Used Cooking Oil which the Environment Agency treats as a waste. Once labelled a waste the products produced down the line are treated as a waste until they qualify for End of Waste status.
We are in discussions with the EA to determine that the End of Waste as far as Glycerol is concerned happens before we acquire it. A recent court case ruled that End of Waste transpires when certain processes occur in the formation of a specifically manufactured product for which there is a market and which also presents no hazard to the environment. The three tests which the EA have come up with to determine End of Waste are quite reasonable and we feel that the product that we want to use meets those tests. We now need to persuade the EA to agree.
Reliability
During the last two or three months our CHP (Combined Heat and Power) unit has been testing our patience. Reliability is key to maintaining output and we have learnt a lot over the last two years.
One thing I would recommend to anyone looking at Biogas production is to have more than one engine unit as there are a great many reasons to suffer a shut down. With only one engine we are either generating or we are not. When we are not generating the running of the plant becomes an on cost and there is no income.
Farming is the key to AD
Looking forward we are very confident that this technology is made for the farm.
Farmers own the key to AD because they have the means to distribute the Digestate on the farm and big plants produce a lot of Digestate (the residue from the Digester) which is expensive to distribute.
The value of Digestate
We are seeing the benefit of being able to use Digestate in place of bought in artificial fertiliser which is made from fossil fuel. The organic content of the Digestate dramatically improves soil condition holding in moisture and encouraging worm activity.
We are turning a source of methane which is so much more damaging to the global warming situation back into the less damaging CO2, we are improving the crop quality and durability, reducing costs and because we supplement the diet of our cows with trace elements and minerals these vital ingredients are being returned to the land where we know that plant take up supplies them in a readily available form in the food you eat. It’s a win/win situation on a massive scale.
Almost as an afterthought the farm is supplying renewable energy to the national grid and heat to the dairy and the cottages our workers live in.
It is such massive benefit to the environment that sometimes when I am writing yet another pleading letter to the EA I stop to wonder who really cares about the environment. It makes you wonder sometimes.
We all need to get behind this technology and make it work for the Environment, for Farming and for Britain.
CRHR
16/12/10