Less and more efficient energy consumption
Efficient power plants
Increasing the efficiency of our fossil-fired power stations leads to using less fuel to generate each unit of electricity. This reduces the specific CO2 emissions from 1.32 metric tons/MWh, which is typical for an old lignite-fired power plant with 30% efficiency, to the level of 0.92 metric tons/MWh with an advanced lignite-fired power station with 43% efficiency. Parallel to starting up commercial operation of the two new lignite-fired units with optimized plant technology ‘Optimised Units’ (BoA 2&3) with combined capacity of around 2,100 MW, we will have decommissioned a total of 16 lignite-fired units each with an output of approximately 150 MW by the close of 2012. These are our oldest lignite-fired power stations in the Rhineland mining district. Four of these 150 MW units had already been shut down by 31 December 2011 (area for action Climate Protection).
The two hard-coal power stations currently being constructed at Hamm and Eemshaven have an efficiency of 46% which is the highest currently attainable with hard coal. Commissioning of these power stations is scheduled for 2013 and 2014 respectively (area for action Climate Protection). After completion of our latest power plant renewal programme, compared with 2010 we are anticipating as from 2013 an overall increase in the mean efficiency of approximately 3 percentage points for our coal-fired power stations.
Development of the next generation of power plants
We are expecting an efficiency of more than 45% for the next generation of lignite-fired power plants. This means we will get very close to the same efficiency as the latest, most efficient hard-coal power plants in the world. We plan to achieve this further increase in efficiency of 2 percentage points using the system of ‘fluidised bed drying with internal waste-heat utilisation’ developed by RWE. This system has been proved in the fluidised-bed pilot plant located in Niederaußem since 2009 (area for action Innovation).
The trial operation of the fluidised-bed prototype plant was successful and we now want to combine the next generation of lignite-fired power stations with the fluidised-bed system. We are currently reviewing the feasibility of the construction of the 1,100 MW lignite-fired power station designated BoAplus (‘Optimised Unit Plus’) with two boilers producing electrical output of 550 MW each. The power station would be built at the Bergheim-Niederaußem site (area for action Climate Protection). The installation of two smaller boilers rather than one large boiler will make the power station much more flexible and therefore help to give priority to feeding electricity from renewable energies into the grid.
We intend to increase steam temperatures to 700°C in order to increase the efficiency of hard-coal and lignite-fired power plants by a further 2 percentage points from 45% to 47%. We are working on the development of power-plant components that are resistant to such high temperatures (area for action Innovation).