Razgovor:Ain Beni Mathar power station

The Integrated Solar Combined Cycle (ISCC) Ain Beni Mathar (also known as ISCC Ain Beni Mathar or Aïn Beni Mathar ISCC), is a 472 MWe power plant which integrates a 20 MWe parabolic trough solar field. Located in the municipality of Beni Mathar in the province of Jerada (northeastern Morocco), the plant site has a total area of 160 hectares. The Ain Beni Mathar (ABM) power plant is part of the Government of Morocco's strategy for the valorization of energy sources to produce electricity. Description The plant uses natural gas as fuel. It is powered via a 12.6 km long pipeline (connected to the Maghreb-Europe Gas Pipeline (MEG)). Consisting of two gas turbines operating on natural gas, a steam turbine, two Heat Recovery Steam Generators (HRSG), a solar field and a solar heat exchanger. The power plant collects solar energy at the parabolic reflectors and increases the steam flow produced at the HRSGs. The energy produced is transmitted to the electrical substations of Oujda and Bourdim via three 225 kV lines. The final cost of the project was 456.32 million Euros. The African Development Bank has been the largest contributor with more than 63% of the final cost. For its part, the ONE (L'Office National de l'Électricité) met its financial commitments with a contribution of 9%. Contributions from the Global Environment Facility (GEF) and Spanish Cooperation were 6% and 22% respectively of the final cost. Design principles The Ain Beni Mathar (ABM) power plant is a gas-fired combined cycle (CC) configuration supplemented by solar-generated steam to produce additional power using solar energy. This ISCC (integrated solar combined-cycle) approach serves to increase the overall plant electrical output while offering certain advantages with regard to solar thermal implementation. The plant’s general concept is depicted in Fig. 3. The ISCC integrates solar steam into the Rankine steam cycle (Fig. 4) of a combined-cycle power plant : In the Heat Recovery Steam Generators (HRSG) CR1 and CR2, via a heat exchanger, the water in the circuit is transformed into steam (1 to 4). Each HRSG is divided into three parts. The first is an economizer, which heats the liquid water (1 to 2). The second corresponds to the evaporator which converts the liquid water into vapor water at a constant temperature (2 to 3). The last part corresponds to the superheater which is heating the steam (3 to 4). This vapor passes through gas turbines TG1 and TG2 and undergoes expansion to convert heat energy into mechanical energy (4 to 5). The turbine starts to spin, driving an alternator that generates electricity. The steam is sent to the condenser (ACC) where cold water circulates. The exchange of heat between the cold water and the steam causes the condensation of the steam (5 to 6). This water is again sent to the boiler (6 to 1). The hot exhaust air of the gas turbine (TG) is used to generate steam in a Heat Recovery Steam Generator (CR), which then drives the steam turbine (TV). At ABM, the solar field produces steam in solar heat exchangers that is sent to the high pressure steam drum of the HRSG to supplement the steam being generated by the exhaust air of the gas turbine. The solar-generated electricity adds a modest 4% to the total plant power output (MWe), with an annual energy contribution (MWh) closer to 1%. Technical components The layout at ABM contains two Alstom gas turbines (Model GT13E) of 155 MWe net capacity each and a single Alstom steam turbine (Model DKYZ2-1N41B COMAX) of 171 MWe net capacity. Without solar integration, e.g. in the evening, the design plant output of the plant is about 450 MWe. At the times that solar steam is integrated into the Heat Recovery Steam Generator at design capacity, the design plant output increases to 472 MWe. Thus, the solar system adds approximately 20 MWe to the plant output (or 4.2%). The table below shows the key technical design data for the solar field and Combined Cycle at Ain Beni Mathar. This is based on a typical weather year for which the solar radiation totals 2,350 MWh/m2. Reference