At-a-glance guide to energy costs

by 5m Editor
19 February 2004, at 12:00am

UK - To meet their Climate Change Agreement targets, pig producers must reduce energy consumption. But where is the energy used, and how much can be saved? Nick Bird of the NPA Climate Change Group has translated a range of commonly used electrical devices into their "pig equivalent".


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NPA is active on members' behalf in Brussels & Whitehall, and with processors, supermarkets and caterers - fighting for the growth and pros-perity of the UK pig industry.

The table shows that if a unit spends 31.67 in electricity to produce a 90kg pig, then a single fluorescent light running all the time will use up 21 pigs' worth of electricity, or 335. If you can reduce the use of the light by half, you have saved ten pigs' worth of electricity.

The aim for a typical 500-sow birth-to-slaughter unit is to save about 2000 "pig equivalents" a year, which would put an extra 33,000 on the unit's bottom line.

Savings may be made by using more efficient heating, lighting and ventilation methods, or by making more efficient use of existing methods.


  • Fluorescent tubes or low energy bulbs give out more light per unit of electricity but lighting a corridor when no one is there is a waste. Keeping lights on in pig rooms all the time (as opposed, say, to only 12 hours a day) has no identifiable benefits in pig productivity.

  • Small, but always on, electrical loads contribute significantly to overall energy consumption. A controller with a 4-digit LED display has up to 28 LEDs on at any one time. Annually, that's a pig's-worth of electricity. Regulating several small rooms from one controller shares the overhead. Using half a dozen dropout magnets in a room - where one, or maybe none at all might do - wastes three or four pigs' worth of electricity, without contributing to output.

  • Reducing power levels isn't necessarily the right approach. Using a 60w light instead of 100w is fine if it does the job but using an 80w heatpad when you really need 120w, or 1kW of heating where you really need 4kW can be false economy. Using insufficient for the job tends to mean using more altogether.

  • Around half the energy is used as heat, in creep and flat deck heating. Electrical heating is in many ways, the simplest technically. You put in 1kW of electricity, and get 1kW of heat out. Unlike with gas heaters - where efficiencies at converting gas energy into useful heat may vary - there is no real difference between types of heater in terms of efficiency. However, as a recent study has shown, about 90 percent of flat deck heating for example is usually wasted. It's a question of better targeting, rather than a wholesale reduction. Use the 10 percent that is useful and reduce the other 90 percent.

  • Better targeting is about better control. This doesn't necessarily mean more automatic control equipment, though that may be the best and most effective way to do it. For example, you could switch lights on and off manually as needed, but the enthusiasm wanes. Automatic lighting control - either by lighting timers, movement detectors or ambient light sensors - soon repay the effort.

  • nergy saving claims have become a somewhat devalued currency. With so many products claiming to "save 3 3 3 3s" producers might be forgiven for being confused or having inflated expectations. It's easy to be dismissive of something that only claims to payback in five years, when another says "payback in a year" but very few products truly offer a immediate payback where nothing is changed except that they use far less energy. In fact, low energy bulbs is about it.

  • For the most part, energy saving is not achieved without altering or affecting the process in some way. For example, ACNV uses less electrical power than fans. Although its general function may be similar - resulting in a ventilation rate related to heat balance - it works in a different way. ACNV and fans should not be considered entirely equivalent or interchangeable.

  • Most energy saving methods require an ongoing commitment to get the best out of them and payback is usually over a number of years, rather than straight away. However, it is generally the case that more energy-efficient processes are also more economically efficient in the long term.

As a matter of interest, a small but sometimes significant waste of power is in "cable loss". Under the supply regulations, you may have up to 6v of voltage drop between the incoming supply and the electrical load. It's not usually that high, though on some farms it's sometimes far higher. You pay for any cable loss (after the meter) but it does nothing useful for you. For a 3kW (nominal) load, it would be roughly 10 "pig equivalents" a year.

Technical bit.
Under the Climate Change Agreements, the UK pig industry has a target for energy use in terms of kWhp per kg of pig meat produced. The target is currently set at 0.966 kWhp per kg output by 2010 (starting from 1.17 in the base year). The "p" refers to "primary" energy use - this takes account of the energy lost in the electricity generating station, if it the energy is electricity, or the energy in the fuel, if it's directly burnt on the farm. Most supplementary energy used on a pig farm is as electricity.

To read the full FarmEx article, please click here

Source: National Pig Association and FarmEx - 18th February 2004

5m Editor