SIEMENS

Paper, plastic, glass — today all of these products are collected and recycled. But a lot of forestry wastes are not reused, even though they would make excellent fuels. Similarly, much of the industrial waste heat from the cement, glass, and steel industries, for example, goes unused. In both cases, combined heat and power (CHP) plants based on ORC (Organic Rankine Cycle) technology from Maxxtec, a company based in Sinsheim, Germany, could be used to generate electricity and heat inexpensively. Maxxtec uses a ther mal oil to transfer heat to an ORC module, where a silicone oil vaporizes at temperatures of around 240 degrees Celsius. The silicone oil vapor drives a generator, and a condenser is used to transfer the residual heat of the vapor to a district heating system. The remarkable thing about such a plant is that it can be operated at a much lower temperature than a steam power plant using water vapor. Water must be heated to well above the boiling point (over 500 degrees Celsius) in order to prevent the steam from condensing into droplets, which act like tiny projectiles and would destroy turbine blades over time. Silicone oil is different. Although it vaporizes at 160 degrees Celsius, it can then be used immediately over a broad range of temperatures to drive a generator. This enables the generator to be operated at partial load — all the way down to just 15 percent of its maximum output. Furthermore, the CHP plant can be started up and shut down in a matter of minutes. This is advantageous in situations where industrial waste heat is only available at certain times. The entire cogeneration plant is so reliable that personnel don't have to be present at the plant full-time. A total of 120 such power plants have been brought online in Europe since 1989. Maxxtec has delivered components, including patented systems developed in-house, for more than two-thirds of them. The company has built more than 50 CHP plants and 500 heat transfer systems worldwide since 2005. It is the only company anywhere offering heat transfer systems and ORC modules from a single source. In Bielefeld, Germany, for instance, Maxxtec erected an ORC biomass CHP plant with an electrical output of 1,350 kilowatts (kW) and a thermal output of 5,780 kW — enough electricity for 2,700 households and heat for 15,400 households. The plant is fueled with chips made from forestry wood waste, such as tree tops and branches, as well as landscaping wood waste collected within a 100 kilometer radius around Bielefeld.

Ideal Partner. Maxxtec currently offers plants with electrical outputs ranging from 300 kW to 2.5 megawatts (MW); smaller units up to 80 kW are under development. The company would like to further expand production and international distribution. The market is there. For instance, some 1,000 plants fired with waste wood could be built in Germany alone. Capital for Maxxtec's growth was provided by Siemens Venture Capital (SVC), which acquired a 20 percent stake in Maxxtec in 2009. This marked the first occasion on which SVC had provided growth capital financing — investment in a more mature company in the expansion phase. Maxxtec and Siemens are a good fit, since both have a lot of experience in the energy sector but serve different capacity ranges. “Siemens is the ideal partner for us. We benefit from both know-how transfer and contact with Siemens customers and suppliers worldwide,” says Rolf Schleicher, founder and Chief Executive Officer of Maxxtec. Siemens also expects a good return on its investment, since Maxxtec combines rapid growth in an attractive market segment with comprehensive project experience and an innovative technology. “Maxxtec's ORC technology permits the use of valuable industrial waste heat, thereby enabling further expansion of renewable energy infrastructures. Clearly, Maxxtec is operating in a sustainable growth market,” says Rudolf Ohnesorge, an investment parter at SVC.