Low-temperature heat for operating a TLC power plant is available from many sources.
Industrial waste heat, especially in the steel, cement, plastics or chemical industries, offers the most easily accessible potential. Currently, this waste heat is often “blown into the air.” There is no economically viable way to utilize it.
The amounts of waste heat generated are very high. Depending on the source, it is estimated that more than 100 TWh to 250 TWh of low-temperature waste heat is produced annually in Germany alone.
Current figures for individual German companies are presented on the “Waste Heat Platform” of the Federal Office for Economic Affairs and Export Control.
In addition, there are the amounts of thermal energy generated during waste incineration, as well as the thermal disposal of residual or hazardous materials.
Biogas plants generate electrical energy in gas engines with efficiencies of 25% to 40%. This means that more than 50% of the energy originally contained in the biogas remains in the hot exhaust gases. With an installed electrical capacity of more than 3 GW in Germany, there is a similarly large potential for energy generation from these exhaust gases.
The ideal scenario would be to operate a TLC thermal power plant as a biogas power plant in mono-mode, i.e., with direct heating of the working medium by the biogas.
Mono-mode operation also eliminates the need for the pre-cleaning of the biogas required for internal combustion engines.
Sewage gas plants are “relatives” of biogas plants and also generate electrical energy from sewage gas in gas engines. Usually, the majority of the electrical energy generated is consumed directly in the sewage treatment plant. Here, too, the energy contained in the hot exhaust gases remains unused.
The temperatures of geothermal energy in Germany range from 80 to 150°C, which is why geothermal energy is mostly used only for heating purposes in winter. Operating a TLC power plant can help refinance the costs of drilling a borehole.
In summer, geothermal energy could be used solely for energy generation.
In winter, operation as a combined heat and power (CHP) plant is possible by utilizing the condensation heat for heating purposes.
In inexpensive vacuum tube collectors, solar heat can be obtained at temperatures up to 200°C, and with special concentrator systems, up to 400°C. Here, too, operation for energy generation in summer and as a combined heat and power (CHP) plant in winter is an ideal solution.
Another area of application for TLC thermal power plants is the support of thermal energy storage systems, either from so-called sand storage or latent heat storage, also known as Carnot batteries.
The condensation heat is used directly for heating purposes, while the generated electrical energy can be used to operate heat pumps and increase the thermal output.
Extensive research is currently underway on thermal storage, and the first companies with commercial thermal storage systems are emerging.