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Cutting energy costs

Course: Farm and renewable energy | Last Updates: 7th October 2015

 
Andrew Kneeshaw
Managing director
Farm Energy Centre
Biography >>
FADS2

You may strive to get the lowest tariff prices, and it certainly doesn't help to pay more than you need, but the only real way to reduce long-term costs is to use less. In order to use less, you need to know what you are using in the first place.

Measure and record

Sadly, in most farm businesses the only time energy use is considered is when the cheque is made out to pay the bill. And this is usually well after the energy has been consumed. There is little that can be done about it then. With estimated readings being all too common on energy accounts, your grasp of what has really been used gets even looser.

The answer is to read your meter regularly, record use in a spreadsheet and work out some benchmarks. If you can relate the amount of energy used over a period to a unit of agricultural production or storage, you have a chance of comparing your use with other periods and other sites.

You can calculate a benchmark by dividing energy use (kWh) over a period by a key energy use driver. This is called a "metric". For a dairy farmer this might be:

kWh/number of cows

Or it could also be:

kWh/litres of milk

For a potato store or grain drier it might be:

kWh/tonnes of crop

Do this and you have an immediate benchmark against which you can gauge future use, or use on another site. If your benchmark is high in comparison it is time to start looking around for reasons why.

man doing thermal imaging 012

Incorrectly set thermostats or timer switches and poor insulation could be costing your farm business dear, but are easily put right.

Reasons for high use

Some primary reasons for high use might be:

1 Bad control: For heating or refrigeration this might be to do with temperature, such as incorrectly set thermostats, bad calibration or controls that allow wide temperature swings. So, for housed animals like pigs and poultry or for refrigerated storage you need accurate, well-calibrated and well-spaced temperature sensors. Also have a look at timing. Does the heating need to be left on all weekend in the office just to make sure it is warm on Monday morning?

2 Bad containment: With heating and refrigeration this is all about the performance of insulation and controlling air change rates. Remember that the current recommendation for domestic loft insulation has gone up to 270mm (10½ inches) of fibre. Only a few years ago 100mm (4 inches) was the recommendation. Think of these standards in the context of agricultural buildings which are often operated around the clock at extremes of temperature (320C for broiler poultry or -10C for onion stores). Is 50mm of insulation sufficient, or should you be thinking of 140mm now? On air leakage, appreciate that doors and louvres in storage and livestock buildings are potential areas of significant heat leakage. Again think how well your agricultural buildings are sealed compared to you own house, which probably has double glazing with rubber-sealed opening panels and well-fitting doors with draft excluders. So spend some time sealing buildings properly.

3 Lack of maintenance: Energy-driven equipment which is not looked after will end up costing more to run. Refrigeration equipment is particularly sensitive to this. Refrigeration systems use a thermodynamic pump to transfer heat from a cold place to a hotter place. When the refrigeration gas is allowed to deplete, or when something inhibits the equipment's ability to "dump" the heat that it has absorbed, the system becomes prone to efficiency fall-offs. In the dairy industry, milk cooling equipment is particularly prone to this problem. Compressors and condenser coils which are stuck up in hot dusty lofts often struggle to work well and efficiency drops by over 35% in many cases.

4 Inefficient equipment: Like motor cars, farm energy appliances have become more efficient over the years. Where my old Ford Escort struggled to return 35mpg, my new Prius does 60mpg, and goes faster. So it is with new motors, fans, lights, refrigeration equipment etc. A few examples are listed in the table below.

table


Also remember that fixed equipment often works for long periods. So where a car runs for maybe 400 hours a year, an electric pump or light fitting might run for 4,000 hours a year. Even a quite modest increase in efficiency will have a dramatic effect on lifetime running costs.

Few people realise that a motor will consume its own purchase price in energy costs within 30 days if it is running continuously; irrespective of its power rating. Investing a little more in the initial purchase price to get a higher efficiency motor can pay back that investment many times over.

New technology is pushing efficiency improvements dramatically in some areas. Lighting is a good example, with rapid developments in discharge lighting and the introduction of LEDs (lighting emitting diode) pushing lighting efficiencies to new heights.

New developments in lighting technology promise light-emitting thin films – a sort of glowing wall paper – which will probably revolutionise the lighting for layer poultry, where we struggle to get lighting efficiently into new enriched cages.

5 Behaviour: The Harvard leadership guru Ronald Heifetz made a fundamental distinction between a technical challenge and an adaptive one.

A technical challenge is one that can be solved by an expert. You are ill; you go to a doctor; he prescribes a pill. Your car breaks down; you call a mechanic; he replaces the broken part. They are the easy problems.

An adaptive challenge is where we are part of the problem, and it is we who have to change: when the doctor tells us that if we are to avoid a serious condition we are going to have to change our lifestyle or when the mechanic tells us the problem is not the car: it is how we drive it.

Most of us don't like having to change, so we are constantly tempted to look for a technical solution. Let somebody else fix it, not us. In so many cases with energy it's behaviour that causes inefficiency. We waste because we can't be bothered to switch things off, repair a leak or reset a time switch. Being bothered to do these things can save a lot.

In the current energy climate, everyone is excited about renewable energy and energy efficiency often gets forgotten. But there's no point in generating energy just to waste it.

In a recent series of energy surveys across 51 Welsh dairy farms, carried out by the Dairy Development Centre, energy efficiency savings averaged at £1,700 a year a farm, with an estimated implementation expenditure of £4,250 a farm, giving a simple return on investment of 2.5 years. Renewables studies on the same farms showed return on capital averaging 8.3 years.

It might not get the heart racing, but energy efficiency is the rational and cost-effective way to cut energy costs.

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