What is renewable energy and how do farmers help to produce it?

Oliver Collingham Nottinghamshire - web crop_59570

What is renewable energy?

Renewable energy is the name given to energy that is collected from renewable resources, such as sunlight, wind, rain, tides, waves, and geothermal heat, which can be naturally replaced on a human timescale. A human timescale is generally taken to mean roughly a human lifespan, or a little more, (up to a maximum of 100 years). This is in contrast to fossil fuels, which take hundreds of millions of years to form.

What is a fossil fuel?

Fossil fuel is a general term for the buried deposits of organic materials formed from decayed plants and animals that have been converted to oil, coal and natural gas over hundreds of millions of years, through exposure to heat and pressure in the earth's crust. Since the beginning of the Industrial revolution, these deposits have been burned as fuel.

What are the main sources of renewable energy?

The five major renewable energy resources are:

Solar power – converting energy from the sun into electricity or heat
Wind power – using air flow through wind turbines to provide the mechanical power to turn electric generators
Hydropower – harnessing the energy created by moving water
Biomass - fuel that is derived from organic material from plants and animals
Geothermal – energy from the Earth’s internal heat

Why is renewable energy important?

Fossil fuels are non-renewable. They will eventually run out, becoming too expensive, and it is now clear that they are too environmentally damaging to continue using. Renewable energy provides a wide range of alternative options and reduces our dependence on imported fuels.

Is renewable energy better for the environment?

Burning fossil fuels releases greenhouse gases ¬¬- mostly carbon dioxide, but also smaller amounts of methane and nitrous oxide. These gases are called greenhouse gases because they trap heat in the earth’s atmosphere, which leads to global warming. In contrast, wind, solar and sustainable bioenergy systems produce electricity, heat and fuels with greatly reduced air and climate pollution emissions.

Why don’t we use renewable energy more?

People and businesses need to have a reliable source of power. If there’s no wind or less sunlight, for example, turbines and solar panels cannot generate as much electricity, although bioenergy can be more easily controlled. Some fossil fuels, such as natural gas, will continue to be used for the medium term to support the integration of intermittent renewable sources of energy.

What are farmers doing to produce renewable energy?

Clare Morgan Solar panels_38678

Farmland has been used for both food and energy production for hundreds of years. Today, nearly 40% of farmers and growers are using the sun, wind, farm by-products and energy crops to produce electricity and heat for use on farm.

Two of the most used renewable technologies on British farms are solar PV panels for electricity and heat generation from biomass.

Solar power

John Charles-Jones Nottinghamshire_58433

Farmers have a long history of using the sun’s energy to grow and dry crops. The development of solar power technology (often referred to as photovoltaics or solar PV) means light energy can also be captured to produce an electric current.

PV panels or modules can work for a long time (up to 40-50 years) and require very little maintenance. Solar PV is regarded by many experts as one of the most environmentally-friendly renewable energy technologies.

Many farmers have installed solar panels on their buildings and land. There are three main ways solar panels can be installed:

PV panels mounted on top of existing roofs or integrated into new roofs and buildings
Ground-mounted panels in unplanted areas – for example around the edges of fields
Large arrays of panels across entire fields

Anaerobic digestion

Anaerobic Digestion at Joel Beckett's farm_59073

Anaerobic digestion (AD) is the controlled breakdown of organic material in a closed ‘digester’ vessel. Anaerobic means ‘without air’, as opposed to composting, which takes place in the presence of air.

After 20 to 60 days, depending on the configuration and internal temperature of the digester, a methane-rich ‘biogas’ is produced. This gas is used for electricity and heat generation, and may also be upgraded for other applications. Another product of the AD process is an odour-free ‘digestate’ which can be spread on farmland as a fertiliser.

Material suitable for the AD process includes:

Animal manure and slurry
Energy crops such as maize or ryegrass silage and fodder beet
Food processing by-products
Food waste from retailers
Biodegradable household waste

See how farmers are using renewable energy on their farms

Meet the farmer - Joel Beckett

Joel Beckett is a dairy farmer from the West Midlands. On his farm, an anaerobic digestion system is used to process the slurry produced by the dairy cows to provide all the electricity they need for the farm and the business, as well as surplus power that goes back to the national grid.

“Now we’ve got our own source of sustainably produced electricity, we’re using less energy produced by conventional sources,” Joel says. “The solid digestate that remains after the gas has been removed is valuable as well because it’s got a higher availability of nitrogen within it than the slurry had previously. We spread it on the fields and it’s more useful to the crop.”

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