The heat is on

The Government have today announced the long awaited Renewable Heat Incentive but will it be enough to make Anaerobic Digestion (AD) financially attractive to farmers?

In the UK we have all the right ingredients for a strong farm-based AD industry. Each year, UK farming produces over 90 million tonnes of manures and slurries suitable for AD; the majority of which comes from small- to medium-scale dairy or pig farms.

However, less than 35 on-farm AD plants have been built to date; a figure which dwarfs the 1000 plants the NFU believe we need by 2020. So why the shortfall?

Until now true farm-scale AD has simply not been economically viable, incentives weren’t enough for many farmers to justify spending thousands or in some cases millions on a new AD plant.

Now it’s hoped the new Renewable Heat Incentive, together with the forthcoming review of the electricity Feed-in Tariffs, will make AD more commercially attractive at this scale. But just how attractive?

Taking the average size of a UK dairy farm as 100 cows plus followers; using slurry from this supplemented with silage from 20 hectares of grass could produce 500,000 kWh of heat each year from AD; and that would be  enough to heat the farmhouse and adjacent buildings on site, thus avoiding the need to buy in fossil fuel. This will be particularly attractive in off-grid areas where gas is not an option and where more costly fuels such as oil and coal are still relied on.

Installing an AD plant of this scale would cost, a not insignificant, half a million pounds but thanks to the RHI farmers can now expect to see a return on their investment within 10 years, according to the NNFCC’s AD calculator, whilst claiming the RHI (and also potentially FITs) payments for a period of 20 years.

Consideration will be given to larger farm-scale plants from next year, above 200kWth – for the time being this larger scale could only benefit from FITs and not yet the RHI.

The new incentives should be sufficient to generate a positive response from the smaller farms, which just leaves the problems of securing a supply of feedstock and gaining planning permission for your plant. Regardless the future for farm-based AD in the UK looks a little brighter today.

Dr. Matthew Aylott is Science and Technology Writer for the NNFCC, the UK’s National Centre for biorenewable energy, fuels and materials.

For more information on AD visit the Official Information Portal on AD, www.biogas-info.co.uk. Here you’ll find the NNFCC’s free, independent and comprehensive AD cost calculator, developed with the Andersons Centre.