Food waste to power a town

15th October 2016 | Residential Energy

There is a plant, currently under construction in Keynsham, a town with 16,000 residents between Bath and Bristol, will use anaerobic digestion to generate electricity from food waste. It is designed to make enough electricity to supply 80 per cent of the town’s needs.

The idea is not new and anaerobic digestion of sewage is common across the world. Several European countries, notably Germany, have invested in power plants run partly on food waste, whose energy yield is generally higher than that for sewage slurry.

The potentially ground-breaking part about Keynsham’s plant, which is being built by the company Resourceful Energy, aims to the first in a national network of small waste recycling/ power production facilities designed to service individual communities. Rather than shipping expensively extracted fuels to large centralized power plants and then transmitting that electricity across long distances, this scaled-down approach uses a resource which is locally abundant – food waste from nearby residents – and distributes the power it creates within the same area.

This model is generally more efficient and resilient than the more common centralised generation power network, especially if, as in Keynsham, the plants consume renewable sources of energy. And the benefits continue to multiply: reduced carbon emissions, smaller landfills, less power transmission infrastructure and cheaper electricity for residents. And the construction cost of £8m, the plant isn’t too capital intensive.

The technology is relatively simple: locally sourced food waste is digested by bacteria in an airless environment and this produces methane. This is then captured and burned to produce electricity, which will start in Keynsham in spring 2017. Although prices haven’t been published yet, it is hoped that they will be far lower than “normally sourced” electricity.

The residue which is left over after the extraction of the methane – called digestate – can then be pasteurised and used as a fertilizer.

More information available on the website below