One flush can lead to new source of energy

FLUSHING the toilet is now powering homes in a corner of Oxfordshire, thanks to Pressure Technologies

The AIM-listed firm is leading the drive to create power from waste through its biogas 'upgrading' division.

It recently celebrated its first injection of biogas into the national gas grid, from an upgrading plant at a sewage works in Didcot.

"It's a good Yorkshire trait to make money out of muck," said Pressure chief executive John Hayward. "The process is very clean, it uses very little energy and it does not use nasty chemicals."

Pressure's biogas 'upgrading' system captures and purifies waste methane, a by-product from decomposing sewage, using 'water scrubbing' technology.

This removes contaminants such as water, carbon dioxide, hydrogen sulphide and siloxanes. The resultant gas has around 97 per cent purity and can be injected into the national grid for use in cooking, heating and vehicle fuel.

The Didcot plant produces enough renewable gas to supply up to 200 homes. A joint venture between Thames Water, British Gas, Scotia Gas Networks and Pressure's Chesterfield BioGas division, it took six months to complete and cost 2.5m.

Pressure is also targeting landfill sites, farms and food producers.

Its upgrading systems use technology developed by industry experts Greenlane Biogas. A cooperation deal gives it exclusive rights to sell the New Zealand firm's technology in the UK and Ireland.

Pressure has worked with Greenlane's parent company, Flotech, for more than a decade on biogas projects in Scandinavia.

"It's done in the rest of Europe but we have this suspicion in the UK that when you cross the Channel the laws of chemistry and physics change," said Mr Hayward.

"If you look at Scandinavia, there's a cultural difference. They are very much focused on what sort of world are we going to leave for our children.

"That's been a large driver for it."

Germany is home to the world's largest biogas injection plant. The Gstrow site injects 6,500 cubic metres of gas an hour into the country's national grid, using Greenlane Biogas technology.

Interest is growing in the UK – Pressure supplied Sheffield City Council with a natural gas fuelling station to power a fleet of 10 vehicles. The group is also making a trailer for Greenwich Council to hold compressed natural gas.

But before biogas can become a common fuel in Britain, Mr Hayward said the UK needs to make it viable by paying sufficient subsidies.

Upgrading plants range from 500,000 for a system producing 80 cubic metres an hour, to 2m for a 2,000 cubic metre system.

Injection of biogas into the national grid is currently supported by feed-in tariffs paid under the Renewable Heat Incentive (RHI), and are widely expected to be ruled on this month.

"Really what it needs to take off is a reasonable level of RHI with a long-term commitment to it," he said. "It will trigger bigger plants and that's really where the money is."

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