The town of Offenburg in south-western Germany is now getting environmentally-friendly thermal energy from a natural-gas-fueled combined heat-and-power plant from mtu Onsite Energy. “This plant is one of the first in Germany to have its exhaust gases cleaned by an SCR-type catalytic converter,” explained Peter Grüner, responsible at mtu Onsite Energy for gas engine sales in Germany. The new '16V4000 GS' CHP plant was taken into service by local power producer 'E-Werk Mittelbaden' in November, supplying 1,557 kW of electricity and 2,000 kW of thermal energy. Additional heat pumps make it possible to convert up to 96% of the plant's input energy. The thermal energy – in the form of hot water – is used to heat a care and treatment center as well as residential homes and the municipal hospital. The electricity is fed into the public grid.
“Producing heat and power together, and distributing it through local city-center heating grids is the most efficient and most environmentally-friendly form of heating,” said Dr. Ulrich Kleine, Vice-President of operator E-Werk Mittelbaden at the opening ceremony. The plant is intended to run for 5,000 hours per year and is being cared for under a maintenance agreement with mtu Onsite Energy. Plans for the new plant were drawn up by E-Werk Mittelbaden in conjunction with consulting engineers Eser, Dittmann, Nehring and Partners in Tamm, near Stuttgart.
Exhaust gases treated by built-in selective catalytic reduction (SCR) unit
mtu Onsite Energy supplied the gas engine generator set featuring a 6,300 volt generator, plus the electric switchgear, heat exchangers, oil system, ventilation system, pumps and system pipework as well as the exhaust gas aftertreatment system complete with SCR-type catalytic converter. This keeps exhaust emissions below 100 mg/Nm³ of nitrous oxides, below 100 mg/Nm³ of carbon monoxide and below 20 mg/Nm³ of formaldehyde, thus meeting the Technical Instructions on Air Quality Control (TIAQC) due to come into force in 2018. These TIAQC requirements are intended to protect against detrimental impact on the environment, affecting both people and the environment. The Instructions stipulate that the airborne pollutants given off by a system to be approved are not allowed to exceed certain levels.
A Series 4000 gas engine was installed at the University Hospital of Freiburg back in 2004, and meanwhile over 300 Series 4000 gensets from mtu Onsite Energy are now operational in Germany. “The combination of low capital expenditure and modest maintenance costs, high levels of efficiency and constant product development and refinement activity on our part make this a winning proposition for our customers,” said Grüner.