Energy Management
Introduction
Energy costs money, but it is an invisible resource and
therefore easy to waste. Furthermore without meticulous records, it is
difficult to assign the quarterly fuel bill to different parts of the
business. Most energy is generated from fossil fuels which are themselves a
finite resource and which increases the burden of atmospheric carbon dioxide
when they are burnt. So on both economic and environmental grounds, it makes
sense to make the best use of energy on the farm. This means increasing
the efficiency of energy use, and eliminating waste.
The three most commonly used fuels on the farm are fossil
fuels, gas and electricity to meet energy requirements in the form of heat,
light and power. However, it should not be forgotten that fertilisers
(especially nitrogen) and to a lesser extent, pesticides represent
significant but essential inputs of energy in addition to the one major
natural source - sunlight.
Fertilisers and
pesticides are discussed in other chapters. Here we are concerned
with the use of fossil fuels.
The main energy consuming functions on any farm are:
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Powering farm vehicles and field machinery such as
combine harvesters, balers, sugar beet harvesters;
-
Powering static machinery such as driers, ventilators,
grain elevators, milking equipment, pumps;
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Lighting the farm buildings, livestock houses,
glasshouses, offices and any domestic premises;
-
Heating (or cooling) in livestock houses, cold stores,
refrigeration units, offices and domestic premises.
Practical steps to reduce consumption
Most people are conscious of the need to turn off lights and
shut doors in the home to conserve energy. Similarly, driving a car well
within its performance capability without undue use of accelerator and brake
is a technique likely to improve fuel economy and prolong the life of the
vehicle. Integrated Crop Management requires that the same principles are
applied to the whole farm business in a more structured and formalised
manner.
Part of this process might be, for example, the substitution of
one type of machinery for another. A good example is the handling and
treatment of liquid animal waste, which can be a big problem on the farm.
Electric pumps are easily installed, can be remotely controlled and can
utilise cheaper night rate electricity. In this way tractor power can be
released for other work. In the field, careful management of fertiliser and
pesticides use, the use of flotation tyres and tracks, and careful adjustment
of tyre pressures are all energy-saving measures.
Sensible judgements about managing energy can only be made with
a detailed analysis of current practice. A farm energy audit which sets down
all costs and energy consumption is the only way to start. Even if the audit
reveals that some important records are not kept, it will have served a
valuable purpose! After that, the various activities can be studies in more
detail and a farm energy plan formulated.
...vehicles and machinery
Economy starts at the time of purchase; fuel consumption should
be a major consideration. the tractors on the farm should be a capable of
meeting predicted needs. This requires careful assessment of the overall
demand for power so that horsepower can be matched to need. All farm vehicles
and machinery should be regularly serviced and this should include fuel
consumption and emission measurements, as well as adjustments of tyre
pressures for maximum efficiency of operation.
Paradoxically, having obtained the equipment, the aim should be
to minimise its use. An obvious but often overlooked, waste is vehicle
idling. Clearly a balance has to be struck between frequent restarting and
leaving machines running, but extended idling is not good for the machine
itself. Field operations, such as cultivations and drilling, or drilling and
rolling, should be combined wherever possible so that the number of passes
over the land are minimised. This has to be balanced against power that might
be needed and the consequent extra damage to soil structure.
Haulage distances and general vehicle movements can often by
reduced by spending some time planning ahead. This can be helped by measures
such as providing an in-field water supply when spraying, and the use of
radio or telephone to improve communications between staff on the farm.
Careful record keeping is the only way to manage fuel
consumption. Consumption figures should be kept for each vehicle and machine
so that the overall cost can be correctly apportioned. This will then give an
indication of comparative performance and efficiency which will become a
guideline at the time of the next purchase.
Static machinery
Many of the same considerations are relevant, but the principle
of 'out of site, out of mind' can easily apply to a machine like a pump or a
drier that is left to run, perhaps for 24 hours a day. So long as it
sounds alright the temptation is to assume that it is
alright. Static machines need to be maintained on a regular basis and their
fuel consumption and emissions monitored. The possibility of updating and
modernising equipment should be constantly reviewed in the context of
improved efficiency.
Other steps to consider are the installation of remote or
automatic control equipment such as time switches and thermostats. In the
case of electrical equipment, control equipment to take advantage of low cost
tariffs is another possibility.
...grain storage
Grain needs to be stored on the farm whether for the purpose of
orderly marketing or for keeping for livestock feed. The process requires
control of the moisture content and temperature so that organisms that cause
deterioration cannot develop. Where the incoming grain is at too high a
moisture content, it must be dried at the beginning of the storage period.
The process is expensive in terms of energy consumption, especially where
continuous flow or other high temperature driers are used to evaporate the
surplus moisture rapidly. However, on most farms the major component in
drying costs is the overhead cost of the equipment itself. Any cost-saving
plan should address this aspect first before considering energy consumption.
However, if the grain is to be kept on the farm after drying, energy costs
can be reduced by combining the functions of drying and storage. Of course,
major savings can be made by timely harvesting of a clean crop which requires
no drying prior to storage.
...vegetable storage
Conditioning and storage of fresh vegetable produce to meet a
market demand that is far wider than the normal harvest 'window' is a
precision task. In most cases it is necessary to create a gradual steady
temperature drop in the store from the 'field' temperature to the optimum
storage temperature. Often this is close to 0 C, but it is also necessary to
prevent any frost damage if temperatures fall lower than this. Although
manual control of ventilation can be used, it entails a considerable degree
of management and supervision. This can be replaced by the use of a
differential electrical thermostat with probes in the produce and in the
outside atmosphere. Almost certainly this will represent a more efficient use
of electrical energy as well as significantly reducing the risk of storage
losses.
Lighting and heating
Any requirements for lighting for safety or security should not
be compromised. However, the use of time switches, movement sensing switches
and energy efficient bulbs (e.g. fluorescent tubes) are all worth
considering. Heating equipment, especially oil-fired boilers, can become
inefficient with age, even with regular servicing. At the time of updating or
modernising, simultaneous consideration can be given to switching fuel, from
oil to gas for example.
The term 'environmental control' in agriculture refers to
the balancing of temperature by ventilation and heating. It is mainly
used in controlling the climate in livestock housing, but it can also refer
to controlling the equipment in crop and produce stores. in the latter case
it may also include adjustment of carbon dioxide, oxygen and nitrogen levels.
The extent of energy input required will nearly always be determined by the
insulation in the fabric of the building.
Most householders know that the biggest single reason for loss
of heat from the home is poor insulation in the roof, the walls and the
windows. The same applies to farm buildings. Improving the insulation of
existing buildings can be difficult if they are very old but energy
conservation should have high priority in the planning of any new building.
Alternatives
As technology advances , the possibility of using alternative
sources of energy should be continually reviewed. Solar energy and wind can
be harnessed, although often at some environmental cost. Some crop residues,
for example straw, prunings and forestry waste are sources of energy, albeit
limited. growing willow or poplar biomass or bio-diesel from rape oil are all
future possible alternatives to the use of fossil fuels.
The recently published National Biomass Strategy from
the UK Government outlines a five-year plan for encouraging the development
of renewable energy production from crops such as short rotational coppice
and agricultural by-products such has straw, poultry litter and slurry.
Conclusion
As with everything else in ICM, energy consumption and
utilisation can only be managed if measured. Investment of one or two hours
on a farm energy audit together with regular monitoring and meticulous
record-keeping are the ways forward. Existing practices can be
assessed and future improvements planned. The audit provides the baseline
against which progress can be measured.
Inefficient use of non-renewable fossil energy is costly and
wasteful in any business. To be compatible with the principles of ICM, energy
consumption needs to be monitored and optimised.