Why the Grid needs greening
In 2020, the UK consumed 68.4 million metric tons of gas for heating, electricity generation and industrial processes. The vast majority of this is natural gas, a fossil fuel that is extracted from natural reservoirs underground. It is delivered to UK homes and businesses through long distance pipelines, or shipped in liquid form from the Middle East and elsewhere.
Extracting and distributing natural gas requires large amounts of energy, and as such its use carries a substantial carbon footprint. In addition, methane leaks throughout the supply chain are a significant contributor to climate change.
Yet the UK cannot dispense with gas anytime soon. 85% of British homes use gas central heating, and even the most ambitious plans to replace gas heating with heat pumps or other alternatives cannot be completed overnight. The reality is that for years to come, millions of people will continue to depend on a regular gas supply.
To meet our climate targets, there’s an urgent demand for greening the UK’s gas Grid through more sustainable methods of natural gas production. Apsley Farms has been fulfilling this need for almost a decade.
Our sustainable biogas and electricity
Since 2012, Apsley Farms has been producing its own biomethane and electricity. Initially, our gas simply fuelled our own activities and allowed us to export some sustainably produced electricity. However, as our business expanded, we were soon able to export biomethane to the UK grid.
Looking at the end-to-end production process, the biogas we produce has just one-twentieth of the carbon footprint of fossil-fuel natural gas. Local production and tightly controlled manufacturing also mean massively reduced methane leakage.
At the time of writing, we are currently the third largest producer of biomethane in the UK. By digesting arable crops that have little economic use for farmers, we now provide around 4% of the UK’s sustainably produced biogas.
The gas we produce is sufficient to heat around 8,500 typical homes, while our exported electricity meets the needs of almost 4000 people. In fact, since we began exporting, we estimate that our activities have reduced the UK’s energy-related CO2 emissions by around 150,000 tonnes of CO2.
The biomethane we produce at Apsley Farms has just one-fifth of the carbon footprint of fossil-fuel natural gas.
How we do it
Grow and harvest
In essence, Apsley Farms takes arable crops such as rye and maize, and ferments them to produce methane. The crops we use are ‘alternate’ or ‘break’ crops, which means they are principally used in rotation to enrich the soil for the main crop.
Our process allows this soil enrichment to take place, which in turn converts the low-value harvest into sustainable gas and electricity.
Digest and generate
The plant material is processed and fed into our biodigesters. Here, natural anaerobic digestion processes turn it into biogas (mainly methane and CO2) and a nutrient-rich digestate. Some of the biogas is used to power our farm operations, or used to generate electricity. What’s left over is fed into the national grid.
Clean and export
The biogas is ‘cleaned’ and ‘improved’. CO2 is separated, for use in the food industry, and the remaining gas – now called biomethane – is made ready for the gas grid.
How green is our biogas?
Debates about the ‘greenness’ of biomethane can generate more heat than light, with critics and advocates both taking extreme positions.
We firmly believe that any fair, informed assessment would draw two conclusions:
1. Our biogas is considerably more sustainable than any fossil fuel alternative.
2. Biogas has a significant role to play in reducing the UK’s greenhouse emissions.
However, there’s no doubt that the use of biogas raises important questions.
Are biofuels carbon neutral?
One of the criticisms of biofuels in general is that they are only carbon neutral in the long term. This is certainly true of biofuels derived from burning wood products. Trees grow slowly, and it can take decades for newly planted forests to absorb enough CO2 to balance that released from burning wood.
However, this argument doesn’t apply when the crop is replaced on an annual basis. Virtually all of the CO2 released from burning our biofuel had already been in the atmosphere in just the previous year, before the plants ‘fixed’ it as new growth.
Shouldn’t land be used for food, not fuel?
Another criticism levelled at biofuel production is that land could be used more efficiently to grow crops for human consumption. Our view is that using crops for energy makes better use of traditional crop rotations which would be occurring anyway.
Farmers have used crop rotations for centuries. It involves planting an ‘alternate’ crop between the growing cycles of their cash crops. This can enrich the soil and allow it to recover. Often, this crop has little economic value it may be used as animal feed or simply go to waste. In both cases, this releases two potent greenhouse gases – methane and CO2 – into the atmosphere.
Apsley Farms uses these crops far more efficiently than traditional farm processes, extracting more energy from them to fuel the UK.
In addition, our biodigesters produce high quality soil improvers, which reduce the need for chemical fertilisers.
Shouldn’t we skip gas and go straight to wind and solar power?
What about the argument that we should not be burning gas full stop, no matter where it comes from?
Proponents of this view favour more well-known green energy sources, such as wind and solar. However, both wind and solar are intermittent and presently need to be supplemented by the use of gas. As we saw in Autumn 2021, long periods of calm days can send our gas use soaring.
In the long run, improved storage and distribution of electrical energy will overcome these issues. But until then, there is a pressing need to back up intermittent sources with a reliable base load. Our biomethane helps to meet this need in a far more sustainable way than fossil-fuel natural gas.