• Calorific value
    The calorific value represents the thermal energy that is emitted during the combustion of gas or other fuels. In simple terms, thermal energy is often referred to as "heat". The calorific value indicates the energy that is emitted during the complete combustion (as opposed to the heating value with steam and exhaust gas). The calorific value is usually stated in kWh/m³. In contrast, the heating value does not take this "hidden" heat into consideration. It is therefore always lower than the calorific value. For natural gas, the difference between the calorific value and the heating value is 11 percent.
  • CNG
    CNG stands for compressed natural gas. Natural gas is compressed under high pressure and is used primarily for the operation of natural gas-fuelled vehicles.
  • CCGT
    In a combined cycle gas turbine (CCGT) plant, a gas turbine serves as heat source for a downstream exhaust heat boiler that in turn serves as steam generator for the steam turbine. The efficiency achieved with this combined operation is higher than in conventionally powered gas power plants. With efficiencies of up to about 60 percent, CCGT power plants are currently among the most efficient power plants fuelled with fossil energy.
  • CEGH
    The Central European Gas Hub (CEGH), headquartered in Austria, is one of Central Europe's largest market places for natural gas.
  • CHP
    A combined heat and power (CHP) plant is a plant that concurrently generates power and heat. The plant is preferably run at the decentralised location of the heat consumption. Diesel or gas engines, but also gas turbines or fuel cells can be used as drives. Compared to the conventional combination of local heating system and central power plant, the use of the exhaust heat during the power generation enables a higher efficiency. The power generation efficiency is about 25 to 50 percent. However, thanks to the local use of the exhaust heat, more than 90 percent of the engaged primary energy is used. Thus, combined heat and power plants can save up to 40 percent of primary energy.
  • Cogeneration
    Cogeneration is the concurrent generation of mechanical energy, which is usually directly converted to power, and usable heat for heating purposes or process heat. In most cases, cogeneration plants provide district heat for public and private buildings or, as industrial power plants, supply companies with process heat. Cogeneration plants are promoted with a statutory subsidy.
  • Control zone
    The grid control cooperation in Germany is split into four geographical areas referred to as control zones. The operator of the transmission network is responsible for controlling the respective control zone and thus for balancing the entry and exit power volumes.

    The four transmission network operators are:
    • 50Hertz Transmission,
    • TransnetBW,
    • Tennet TSO and
    • Amprion.