Thanks to ORC equipment: geothermal power station becomes more efficient
Bietigheim, March 2015 – An Organic Rankine Cycle (ORC) unit engineered by Dürr Cyplan will be commissioned at a geothermal power station in Indonesia during the summer of 2015. Its purpose is to boost the efficiency of the power station overall. Before being shipped to the Southeast Asian country, the full capacity of the ORC module was tested at the Dürr headquarters in Bietigheim using a test center that is likely to be one-of-a-kind in terms of its size.
Indonesia has about 40% of the world's proven geothermal resources and is a pioneer in the field of electricity generation using geothermal energy. However, existing power stations are not yet able to fully exploit this heat potential. A German research institute is currently carrying out a pilot project on site which utilizes the ORC equipment manufactured by Dürr Cyplan. The ORC unit has an electrical rating of 500 kW and will increase the efficiency of the power station overall. The use of this technology will allow up to 10% more electricity to be generated.
The geothermal power stations in Indonesia use steam to drive turbines and generate electricity. Hot water rises under high pressure from deep below the Earth's surface through a well and evaporates as pressure drops in the power station. The steam is fed to a turbine driving a generator that produces electricity. The proportion of hot water that does not evaporate is injected back underground. The ORC unit will be inserted into the circuit upstream in the future. Using the thermal energy contained in the water, it will be able to generate additional electricity.
Test conditions to match those in Indonesia
To simulate the conditions found in Indonesia, the test center used a gas-fuelled boiler capable of heating water up to 204° C as a heat source. The ORC module was connected to the boiler via a close hot-water circuit. The thermal energy passing through the ORC module was converted into electrical energy and waste heat. The electricity was fed to the public grid and to the Dürr corporate power grid. As a heat sink, Dürr Cyplan used two dry coolers connected to the ORC module.
The employees from the company operating the geothermal power station in Indonesia were given a week-long ORC training course by Dürr Cyplan, and they are now familiar with the handling of the unit. A further benefit of using the test center: the extensive testing already carried out will save the customer time and money during the commissioning in Indonesia.
The test center is unique across the globe in terms of its size. It allows all the geothermal characteristics to be simulated: water temperatures of between 70° C and 204° C, thermal capacities up to 4,600 kW, as well as any ambient temperatures. The complete ORC module, including electronics, fits onto a single base frame. It will be shipped to Indonesia fully assembled: 11 meters long, 2.4 meters wide and 3.3 meters high.