An opportunity is being missed to boost future fuel sources.
A report from the Renewable Energy Association (REA) on the economic benefits of separate biowaste collections reveals that almost all of the two million tonnes of food waste from UK commercial producers each year is either incinerated or sent to landfill.
Most is irretrievably mixed up with other waste before disposal, requiring it to be separated. Collecting it separately would save companies money in pay-by-weight costs of disposal and increase the efficiency of dry waste recycling. Local councils could also make financial savings if they operated separate domestic food waste collections. Only half currently do so.
This is interesting from a waste collection point of view, but why did the REA publish the report? What does it have to do with renewable energy? The answer is anaerobic digestion (AD).
Recently I visited an AD plant in south London and saw first hand what it was doing with food waste, most of which had been collected from businesses that were willing to separate it from other wastes. On the one site, the AD company receives and refines the collected waste, puts it in huge digester domes, and produces biomethane and a high-quality digestate for use as organic fertiliser.
Some of the biogas is used to produce electricity, most of which powers the facility; the rest is cleaned up and injected straight into the gas mains. There are about 50 AD plants in the UK working along the same lines as the one in south London.
Biomethane and other green gases can help lower the carbon content of the gas we use, and in the end can tackle the big conundrum of decarbonisation: what to do about the 47% of energy that heats homes and offices.
But there is one problem. Even the relatively low number of AD plants operating cannot get enough food waste to fuel their operations. The plant in south London is running at about 50% capacity, and it could double its present size and run at full capacity if supplies were forthcoming. There are three such digesters operating around London, but there would easily be room for about ten if supplies were more reliable and organised.
A small amendment to regulations about separating food waste could have huge implications for the availability of ideal feedstock for AD and green gas.
