Inside the sludge drying plant at Teeside

Generating electricity for sale to the electricity Pool, under the NFFO obligation, SHP supplies over 100 commercial and public buildings and over 3,000 high-rise homes in the city centre with heat generated by burning Sheffield’s refuse in the City Council’s municipal waste incinerator.

The company is now entering a new phase having project managed the refurbishment and upgrading of the waste incinerator to meet strict new European and UK emissions limits and added a steam turbine to generate electricity as well heat for the CHP scheme. Electricity generated in the 6.8MW turbine is used both to provide power for use on site and for sale to the electricity Pool.

SHP is now studying further expansion plans to develop a series of small-scale, stand-alone CHP units around the city and to distribute cooling alongside heat.

The Government is practising what is preaches on CHP, according to Michael Meacher, Environment Minister. Speaking at the CHP 2000 conference earlier this year, where he listed a detailed range of measures that the Government was now pursuing with industry for CHP to meet the environmental and business agenda for the Millennium, he said his own Department’s two new HQ buildings had CHP, the RAF was running CHP on six sites and that CHP was being introduced into a new Whitehall District Heating Scheme.

Including 10 Downing Street and the Foreign Office, the project involves the commissioning a gas turbine. A feature of the new CHP plant is a massive 40.64% reduction in annual carbon dioxide emissions compared with the former old boilers. Nitrogen oxides emissions should also show a reduction of nearly 14%.

Sweet solution

British Sugar is also investing heavily in CHP. A fuel-efficient Combined Heat and Power generating plant at the company’s factory at Bury St Edmunds, Suffolk, was the first to be given consent by the Government while its review of energy sources for power generation is under way.

Although decisions on power station consents were being deferred DTI Minister John Battle said that the merits of that particular project meant that a decision ought to be made to ensure that the plant could be operational in time for the 1999 sugar beet harvest. The new gas-fired CHP generating plant, with a capacity of about 80MW, and representing an investment of £30 million, will replace steam and electricity generation by existing heavy fuel oil- and gas-fired boiler plant. Use of the waste steam and heat in the sugar factory means that it will have a high fuel efficiency of 80%.

British Sugar has a similar project under construction at Europe+s largest sugar factory at Wissington near Downham market.

Environmental consultancy group Entec is heavily involved in the growth in CHP, having worked on the environmental and regulatory requirements of four CHP schemes, ranging in size form 40 to 250MW, in the past year, together with the design and project management of two further schemes.

One of Entec’s recent projects was to help Eastern Generation in the development of a 240MW CHP scheme to supply electricity and steam to the Shotton Paper Company paper mill in North Wales. The work focused on preparing an environmental statement which hinged on such key issues as the effect of atmospheric emissions to human health, flora and fauna, noise, visual intrusion, ground contamination and landscape and visual impact.

The consultancy has also been involved in Northumbrian Water’s flagship development to provide a solution to dealing with the end of the disposal of sewage sludge to the sea.

The project, at Bran Sands on Teesside, which is well advanced, comprises a 300,000m3/d treatment works, serving the whole of Teesside and a Regional Sludge Treatment Centre (RSTC), which will process 85% of the entire region’s sludge in a thermal drying plant.

Thermal gasification

Entec prepared a feasibility study to determine the optimum solution for energy supply to the site. With a well-matched heat and power demand the site was seen as ideally suited to CHP. The installation is two-phase, featuring three 5MWe single cycle turbines, fired by natural gas.

The next phase of development of the RSTC is now under way, looking at energy recovery from the dried sewage sludge. Northumbrian Water proposes to develop a gasification demonstration plant (GDP) to demonstrate the technical, environmental and economic viability of generating electricity by thermal gasificatio n of sewage sludge produced at the RSTC.

The scheme is supported by a grant under the EC’s Thermie/Joule programme for the demonstration of innovative energy technology.

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