Sunday, 24 October 2010

Beware Anaerobic Digesters could be a threat to pasture based dairy farms

Anaerobic Digesters could prove to be a real threat to the profits of grass based dairy farmers in the UK. This might seem an odd thing to say when there is so much talk of green renewable energy opportunities. Successive Govt ministers are actively promoting Anaerobic Digesters as a major source of renewable energy. If you haven’t seen an Anaerobic Digester the best description is that it is exactly like a giant rumen. It requires daily feeding of a high energy feed & it needs a liquid mix in the “rumen”. The products of digestion are energy (gas), heat & some waste slurry. The higher the energy values of the feed the more efficient the output of energy. Therefore the preferred feed in Europe is maize silage. In Germany we saw very little dairy slurry being used which was a surprise.
Grass based Dairy farmers in the UK are looking at alternate energy generating opportunities I don’t think Anaerobic Digesters should be one of the viable options.
Firstly pasture based dairy farms simple don’t produce enough slurry that could feed a Digester. Maybe this is an option for a fully housed dairy farm but even then I’m certain they would start feeding it with maize. Second point is that land rentals & cattle feed prices are likely in the future be driven by the owners of Anaerobic Digesters who will buy vast amounts of maize silage. This is likely to create monocultures of maize which is not soil friendly & possibly environmentally unfriendly. Land rentals in Northern Germany are very very high & completely driven by the Anaerobic Digesters securing maize land. The third issue is that to fully capture the efficiency of a Digester you must be able to sell the heat say to a near by village for heating houses. Few ADs in Germany were able to sell the heat so it was lost to the atmosphere. This will only be possible near populated areas perhaps by city councils not farmers. Lastly the Digesters are very expensive to maintain. You have a huge engine running 24hrs a day….this is not cheap. Also the plants/tanks have a build up of sulphur which is very corrosive on all surfaces…this is becoming a major issue. If stones or waste metal are picked up by the maize harvesters this can create havoc with pumps. If Anaerobic Digesters have a place it’s near a city using waste products like vegetables or food waste. We saw a very profitable one near Amsterdam using chicken litter from farms that had NVZ problems. This seemed very sensible & environmentally friendly.
So beware Anaerobic Digesters I don’t think they are the answer. The Anaerobic Digesters we saw in Germany were professionally run by experts but they were struggling to make them pay dispite the feed in tariffs.

Friday, 15 October 2010

Solar PV looks a "No Brainer"

Ezra & Katharina are enthusiastic & highly efficient pasture based organic dairy farmers near Flensburg in Northern Germany. Imagine being so isolated from like minded farmers…..Katharina described it as “swimming against the stream or river currents” because so few dairyfarmers were trying to use low input pasture based farming methods. However isolation wont win over determination & innovation.

Alternate on-farm Energy production in Germany, Denmark & the Netherlands seem to be way ahead of the UK with many farmers & entrepreneurs already producing energy. This was the conclusion of a grass based “Pasture to Profit” discussion group who visited those countries last week. However valuable lessons can be learnt from the farmers in Europe as to which options look the most promising for grass based dairy farmers in the UK.

There is a very real opportunity for profitable dairy farmers to produce milk, surplus heifers & ENERGY from their low input systems.
The general consensus was that Solar PV with the current Feed-in-Tariffs farm scale units would have a payback of up to 8 yrs & an annual return of between 10-20% depending on purchase costs. It is important to make your decision before 2012 & grants may reduce the payback period.
This is an exciting new era with real possibilities to not only grow your business but to do it in a very green environmentally friendly way & to effectively cut or even neutralise the carbon foot print of your business.

Ezra & Katharina (“Pasture to Profit” Network members who live & farm in Northern Germany) helped to organise a fantastic study tour of their region & onto dairy farms that were producing alternate ENERGY. So we were privileged to visit efficient & well run alternate energy production on dairy farms & saw Anaerobic Digesters, Solar PV & Wind Turbines.
In this blog I want to concentrate on Solar PV as we came to the conclusion that this was a very positive option for most grass based dairy farmers in the UK… fact I think it is a “No Brainer” based on the generation Tariffs or Feed-in-tariffs (which are Retail Price Index linked)
Solar Photovoltaic (PV)
is a simple solution for generating your own electricity, reducing your energy bills & reducing your carbon foot print. The UK has committed to a plan to produce the equivalent of 31% of its electricity from renewable sources by 2020.

Solar PV is an attractive option owing to the generous Feed-in-Tariffs ranging from 26.8-41.3 p/kwh for the next 25 years. Solar PV cells will pay back the energy used to produce then within 2 years of their 25 yr lifetime. Look for the fact sheets on Solar PV systems.

Solar PV in the UK produces energy from Daylight not direct sunlight, so cloud cover will not be prohibitive. Obviously if the sun does shine, then the greater the current that is generated. The electricity that is produced is direct current (DC) this is converted by an inverter to alternating current (AC).
A certified installer will do the installation for you but ideally the surface should face south at an angle of 30 degrees. Farm Shed roofs will be ideal so long as they can carry the extra weight (approx an extra 20kgs per Sq metre). Check that the shed has the same expected lifetime as the solar PV panels. One of the attractions of Solar PV is that it is a very low maintenance system.
From farms we visited in Germany new shed design included the Solar PV panel installation….roof pitch, height & North South orientation. In fact the Solar PV was designed to pay for the new sheds. I would expect shed design to change quite radically to include Solar PV installation.
However if the roof orientation does not allow flat instalment on the roof they can be pitched to the south as seen on the photo. There are also computer tracking devises that allow the panel to track the sun. Even whole field projects are being considered over 25 year leases/rentals but the ability to export to the National Grid must be considered.

More information can be obtained from:-

On the 16th November “Farming Futures” will be holding their next Solar PV event in Somerset

So what do you think?