The Free Piston Electric Power Plant
The increasing expansion of fluctuating renewable energy sources such as solar power plants and wind turbines means new challenges for the energy market. To guarantee both stability in the power grid and the usual reliability of the supply, power plant managers must now deal not just with a volatile demand for electricity but also volatile electricity generation. There is a need for flexible, controllable power plants that, as reserve plants, can react quickly to possible fluctuations.
As a controllable electricity generator in a free piston electric power plant, the FreeP can meet the demands placed on such reserve plants. It is versatile and can be used on all scales. As a combined heat and power unit, in the private domain the FreeP can achieve cogeneration and in so doing utilise over 90 % of the energy stored in the fuel. In exactly the same way, the free piston electric power plant can also serve as a “conventional” power plant purely for electricity generation, or can be used as a “controllable electricity generator” in a virtual power plant. In this context, efficiency, future viability, modularity and costs ensure the free piston electric power plant a decisive advantage over other technologies on the market.
Controllable, Decentralised Energy Supply
The power output of the free piston electric power plant can be quickly regulated across a wide power range (modulation). Due to the absence of a crankshaft and the integration of the linear generator, no new developments in a different size are necessary for scaling the power. Instead, several identical modules are merely operated together and connected electrically in parallel.
The entire performance spectrum up to about 2 megawatts can be covered extremely economically by just two different module sizes. For this, up to 10 modules are used in an electricity generation unit. Such plants, which tend to be from small to medium-sized in comparison with conventional power plants, permit the trend towards decentralised energy supply and are also predestined for use as part of a virtual power plant.
The efficiencies of the free piston electric power plant are at least 43 % indexed and 36.6 % at overall plant level, depending on the design. Overall, the efficiency of the FreeP is at the top end of the values that can be obtained with the best competing systems under optimum conditions. The low investment costs give the free piston electric power plant the crucial advantage. At just 165 €/kW, it is 80 % cheaper than existing comparable systems. The reason for the enormous savings potential is the use of the standardised modular system and the correspondingly large volumes. The vast majority of the components are even identical to the corresponding parts of the free piston electric vehicle, thereby massively increasing the volumes once again.
Low Costs, Great Performance
The quality of bio-gas varies greatly in practice. One way by which manufacturers solve these problems is by reducing the compression ratio, thereby reducing efficiency. The free piston electric power plant on the other hand adapts itself to different fuels and fuel qualities thanks to its adaptive software control. This enables quality differences in bio-gas and natural gas to be balanced out, and the maximum compression ratio to be set so as to obtain maximum efficiency in each case. Possible fuels are natural gas, bio-gas, sewage gas, liquid gas and heating oil, with only one of these often being available depending on the application scenario.