mtu Onsite Energy: power and energy-efficiency for the future

Posted on September 02, 2008

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  • Decentralized energy systems based on diesel and gas engines, fuel cells and gas turbines
  • Applications spanning emergency, peak-demand and continuous duty power, and combined heat, cooling and power plants
  • Outputs ranging from 20 kilowatts to 50 megawatts
  • CO2-neutral energy generation using biogas-fuelled gas-engine and fuel-cell plants

Friedrichshafen. Under the banner of the mtu Onsite Energy brand, the Tognum Group offers energy-efficient decentralized energy generation solutions. The product range of the multinational propulsion and energy systems specialist encompasses diesel generator sets for emergency power, base and peak-load duty as well as plants for cogeneration of heat and power (CHP) based on gas engines, fuel cells and gas turbines. Electrical outputs range from 20 kilowatts to 50 megawatts. The Tognum subsidiaries involved in decentralized energy production – CFC Solutions, Katolight, MDE and mtu Power Generation –will be brought together under the umbrella of the mtu Onsite Energy brand as of September 2008.
The term onsite energy refers to decentralized energy systems that are independent of the national or regional power grid and supply electricity, heat and cooling to a specific site or facility. The products are manufactured and in some cases also developed at the mtu facilities in Friedrichshafen, Detroit/USA and Suzhou/China, and also at MDE in Augsburg, CFC in Ottobrunn near Munich and Katolight in Mankato/USA. Christof von Branconi, member of the Tognum Executive Board and responsible for the Business Unit Onsite Energy & Components, says about the new brand, “mtu Onsite Energy underlines our position as the world’s leading innovators in development and supply of energy-efficient, clean and economical energy plants.” And he adds, “We offer our clients customized solutions for generating electricity, heat and cooling anywhere and any time. And always taking account of the globally rising demand for energy.”

Diesel engines and gensets for emergency, peak-demand and continuous power

High-speed diesel engines are the traditional core business of the Tognum Company MTU Friedrichshafen and the central component of energy system applications up to a rating of 6,250 kilowatts. They are to be found all over the world working 24/7 in the remotest locations to provide a guaranteed energy supply in places as inhospitable as raw material mines in the desert. They are also used as emergency backup systems to maintain the power supply if there is a mains outage, and as peak-load plants for providing additional grid capacity at high-demand periods.
One of the advantages of the mtu engines is their high specific power output combined with long service intervals, continuous-duty capability and outstanding availability. What is more, they are fuel-efficient too. Modular standard solutions combine economy with fast delivery times. Customized systems can be implemented rapidly from design to installation.
Preassembled and ready-tested diesel-powered container gensets are an example of a specialized application. They can be quickly and easily transported from one location to the next. The generator output is on stream within 15 seconds of the start signal.
mtu has been known for its comprehensive system engineering skills for many years. They encompass all services from initial technical advice to specialist support during commissioning and handover of the installation through to long-term maintenance. In Katolight the Tognum Group has in its portfolio a specialist with many years of experience in the development and production of gensets with outputs ranging from 20 to 3,000 kilowatts.

Gas-engine systems for combined heat (cooling) and power plants

Energy systems based on gas engines offer an economical means of locally generating electricity and heat/cooling. The heat can be used for space heating or as process heat. The electrical energy is used directly or fed into the public power grid. As well as natural gas, clean-burning fuels such as biogas, sewage gas or landfill gas can be used. The gas-engine plants – also called combined heat and power plants (CHP) – are developed and built in Augsburg and provide up to 2,000 kilowatts of electricity. The range of applications is extremely diverse – they are used in the agricultural industry as well as in public amenities with a high heat demand such as swimming baths, in commercial and office buildings to provide cooling for air conditioning, and in district heating systems.
One of the more specialized applications are biogas plants, which are primarily used in agriculture and burn methane-based gases obtained from fuel crops, dung or manure. The heat produced as a byproduct can be utilized for the biomass fermentation process, which then produces more biogas. As the process of growing the fuel crops removes as much CO2 from the atmosphere as is released when the biogas produced from them is burned, biogas power plants are CO2-neutral in operation.
Sewage gas applications are another specialized type of use. The use of sewage gas in combined heat and power plants is ideally suited to the sewage treatment process because of the large number of energy consumers. Sewage gas production functions very effectively at temperatures between 35 and 40 °C and thus benefits virtually all year round from the heat supply, while examples of constant consumers of electricity are items such as pumps, mixers and fans. The supply of sewage sludge is virtually continuous, thus ensuring a constant rate of sewage gas production and consequently all-year-round efficient operation of the energy modules.

Fuel cell systems for using sewage gas and biogas

The HotModule fuel cell produced by mtu Onsite Energy represents a forward-looking solution for combined heat (cooling) and power generation based on a carbonate fuel cell (MCFC). The plants currently generate up to 360 kilowatts of electrical output by electrochemical means while also producing heat at a high temperature of around 400 °C. That makes the fuel cell ideally suited to localized energy generation close to the point of consumption.
A key feature of the fuel cell is its versatility in terms of the use of different types of fuel. Although the HotModule uses hydrogen like any other fuel cell, it obtains it internally at an operating temperature of 650 °C by an integral process for reforming gases that contain methane. And that includes not only natural gas but also sewage gas and biogas, for instance.
The development and production of plants with outputs up to two megawatts is planned for the near future. At present there are over ten HotModules in Europe supplying sites such as data centers and industrial plants that value the simultaneous provision of electricity and heat or cooling. There are also fuel cells in sewage plants and organic waste processing facilities to efficiently generate electricity from the gas produced by decomposition. Biogas is used as a substitute for fossil fuels, thus making the HotModule CO2-neutral because only the same amount of CO2 is emitted as is absorbed by the plants while they are growing. In hospitals, fuel cells provide a reliable supply of electricity and steam as a source of heat or for sterilizing beds and mattresses. While in district heating systems they have proven their qualities as silent heat generators.
When putting together the optimum energy mix, different energy extraction technologies are examined and combined with one another if required according to the client’s requirements and particular circumstances. A recent addition to the choices available is a hybrid system that combines gas engines and fuel cells and can be used for applications such as sewage plants.

Gas turbine plants for industry, local utilities and power plants

Gas turbine systems are environmentally friendly and decentralized energy generation alternatives with a range of electrical outputs from 20 to 50 megawatts (electric) and thermal outputs of 28 to 60 megawatts. Those maximum outputs are sufficient to supply roughly 100,000 households with electricity and around 10,000 one-family-houses with heat.
The fuels used for the mtu-designed installations are natural gas and diesel. The systems are generally used as combined heat and power (CHP) plants. That includes district heating provided by local utilities, power plants that produce steam to drive additional turbines, and peak-load power plants. In energy-intensive industrial plants as well, such as paper factories, gas turbine systems are capable of generating large quantities of electricity and heat. The key figures for the gas turbine installations are 88 percent fuel utilization in CHP mode with an electrical efficiency of around 40 percent and a low nitrogen-oxide emission level of 50 mg/m3. The plant is capable of fast startup and can be running at maximum output in less than ten minutes.
As a propulsion system and energy specialist, mtu offers not only individual development and commissioning but also long-term maintenance contracts and complete overhauls after 25,000 and 50,000 hours of duty.