Energy efficiency on the farm
David Trimble, Renewable Energy Technologist, CAFRE
What is energy efficiency?
This is the first step you take to reduce your energy bills. You carry out an energy audit on your unit to identify any savings that can be made by doing things differently. Once these savings have been made then the renewable energy options can be considered.
Over the past three years the College has carried out energy audits on a wide range of agricultural businesses. In almost every case these audits of farm enterprises or horticultural units have identified ways in which money can be saved and energy used more efficiently.
A simple example
At its simplest, energy efficiency can mean replacing an old light bulb with a new low energy bulb. The financial savings are both immediate and very significant:
Action: Replace a 100 W bulb with a 20 W low energy bulb
- The bulb is used on average four hours a day (1460 hours/year)
Savings:
- The 100W bulb uses 1460 x 0.1 = 146kWh / year
- The 20W bulb uses 1460 x 0.02 = 29.2kWh / year
- The saving in electricity = 116.8kWh
- At 14.87 pence / kWh the financial saving = £17.37 each year
In each enterprise there are key areas where savings can be made, often without any financial investment being necessary.
Dairying
- Check your tariff. Up to one in five of the farmers taking part in the CAFRE electricity benchmarking exercise were on the wrong tariff. This is a loss of around £10 per cow each year.
- Have a suitably sized plate cooler with a time delay on the water solenoid. This will save 60 percent on your milk cooling costs.
- Save on water heating by good insulation of water heaters and associated pipe-work. An uninsulated tank will lose 50 percent of its heat in 17 hours, compared to just 5 percent losses with good insulation.
- Watch those lights. Make the best use of low energy bulbs and appropriate use of timers, sensors and proximity switches.
- Large units of over 200 cows should consider installing vacuum on demand pumps and heat recovery systems to capture waste heat from the milk cooling condensers.
Pigs
- Check your tariff. Larger units can negotiate the price with the electricity supply companies
- Have a good control system for heating and air movement
- Savings with low energy lighting can be very significant
- Insulation and draft proofing are critical
Mushrooms
CAFRE carried out energy audits on a number of mushroom units in June 2008. The main areas identified for action are:
- Insulation of the hot water distribution pipe-work
- Change the tariff to benefit from the cheaper night rate
- More efficient air movement by the removal of unnecessary louvres and increasing the size of air inlets
- Installing low energy lighting
- Installing and managing an integrated environmental control system
Beef and Sheep
Beef and sheep enterprises have a relatively low usage of electricity. The main efficiency measure is the installation of high efficiency light bulbs in sheds and work areas.
Field work and arable
Fuel efficiency on tractors and harvesters can be improved in several ways:
- Regular maintenance. Excessive dust on radiators can waste as much as 5 percent of the fuel
- Maintain the correct tyre pressure - 20 percent over-inflation can reduce fuel efficiency by up to 30 percent
- Use the electronic engine management technology. This improves fuel efficiency by giving a rapid response to changing load demand.
For further information contact David Trimble at (028) 9442 6682 or david.trimble@dardni.gov.uk
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