Relight the Fire – Stoking our Economy with Heat

by Martin Freer (Birmingham Energy Institute (BEI)/Biofuels Digest) As the Bank of England predicts a decline in the UK’s economy with a shrinkage of 14%, the worst recession on record, with dramatic impact for UK jobs, there is a feeling of helplessness as the country emerges cautiously from the lockdown. This is heaped on the potential economic impact associated with a potential no-deal Brexit, and the almost forgotten need to do something about climate change.

There will be a line that less travelling and the 20% lower energy use during the reign of Covid-19, has fixed the need to decarbonise and all we need to do is carry on our lives in the “new normal”. The bad news is that even if we did, that is not enough and the loss of momentum that has resulted, for example the delays to COP26, may actually be more damaging than any short-term gain.

There is then the question of how do we simultaneously address the twin issues of redoubling efforts on decarbonisation of energy and transport and stimulating the economy. The answer may lie in heat. When many think of energy they will think of electricity. However, energy is much more diverse and it turns out that the sector in which least progress has been made, in terms of decarbonisation, is heat. Heat is one of the largest uses of energy and is mostly generated domestically through burning methane gas and that combustion produces CO2.

There are EfW technologies such as anaerobic digestion (AD), and pyrolysis and gasification plants, which could play an integral part in the circular economy, but need to be supported to do so.

Displacement of methane by green gases will be an important contribution to the future decarbonisation of heat. AD takes organic matter and digests it to produce biogas (methane and carbon dioxide) and a nutrient-rich digestate that displaces slurry and fossil fertilizer. The biogas can be burned directly to generate electricity; upgraded to biomethane and injected into the gas grid; or converted into transport fuel. The process also gives off useful waste heat which in principle can be captured.

The greenhouse gas emissions savings from AD are large because it reduces methane emissions to the atmosphere from landfill; generates electricity or fuels; converts the methane into much less atmospherically damaging CO2; displaces carbon intensive fossil fertiliser; and produces valuable waste heat. At scale, the methane it produces can be injected into the gas grid. AD is also properly circular in that it turns agricultural and food waste into digestate that restores nutrients to the land. READ MORE