Steam set to provide clean energy

A new generation of ‘mini-power stations’ that allow local communities to convert their everyday waste into clean steam energy is poised for full commercialisation.

A new generation of ‘mini-power stations’ that allow local communities, hospitals and businesses to convert their everyday waste into clean steam energy is poised for full commercialisation.

Bristol-based Compact Power uses a patented thermal conversion technology to combine a variety of waste-to-energy processes into a single unit.

The units can process clinical waste, sewage sludge and most forms of municipal and industrial material. They channel up to 80 per cent of the energy content of the waste into generating steam, which can then be used to supply power or heating back to the user site.

The company’s technology incorporates pyrolysis – decomposition through heat – gasification and high-temperature oxidation into a three-stage steam-generation process.

According to Compact Power, they also produce an extremely low level of emissions compared to mass-burn incinerators, which meets or beats all relevant environmental guidelines.

The firm this week made its debut as a publicly listed company, floating on the Alternative Investment Market in a bid to raise more than £7m to fund commercial exploitation of its technology. This follows the successful commissioning of a small test plant at Avonmouth, which opened in January for processing clinical waste.

Compact Power recently received planning permission for a second unit in Dumfries. This will process waste into enough electricity to power 24,000 homes.

John Acton, the company’s chief executive, said this week’s flotation and the successful commissioning of the Avonmouth plant left Compact Power well placed to market its technology in the UK and abroad.

Acton said the advantages of having small, local waste-to-energy plants were considerable, not least because it reduces the need to transport large quantities of waste to huge central disposal points.

‘The technology has been specifically developed with local communities in mind,’ he said. ‘Because our units can handle virtually any sort of material, we can deal with most of the waste a local community generates and give it back in the form of energy.’

Waste is compacted on arrival at the unit and fed into tubes for pyrolysis. This involves heating the material in oxygen-free conditions at temperatures of up to 800 degrees C, causing organic material to break down into combustible ‘pyrogas’ and leaving residues of carbon and other materials, such as metals and glass.

The residue is then mixed with high-temperature steam to produce hydrogen and carbon monoxide, known as water gas. The pyrogas and water gas are passed through a thermal oxidiser at 1250 degrees C. Air is introduced to allow the complete oxidation of the gases and the release of heat, which is then converted to steam in the final stage of the process.

On the web