The climate protection targets cannot be achieved by simply replacing conventional power plants by renewable energies. All economic sectors, especially transport, industry and households must contribute by significant reductions of their specific greenhouse gas emissions. In general, renewable energy from wind, photovoltaic, hydropower and biomass is limited in its temporal availability. With an increasing share of the highly volatile power from wind and photovoltaics, their fluctuating nature demands reliable, efficient energy storage systems and back-up power to level out the mismatch between demand and renewable power generation. These requirements offer an opportunity for coupling of the energy and the transport sector and are unlocking the potential for CCU (Carbon Capture and Utilization). While batteries could provide the electric energy for the urban e-mobility and transport over short distances it seems unlikely that they will be the preferred solution for long-distance transports, heavy-duty trucks or building machinery in the next decades. Also their potential to replace jet fuel or marine fuels in ship transport is small. Highly flexible batteries can help to stabilize distribution grids and short fluctuations in the range of seconds. But for long-term and large-scale energy storage in the capacity range of dozens of TWh their technological status is not sufficient.
Methanol is one of the most common and widespread platform chemicals and is also widely used as a fuel in gasoline blends. Methanol is traditionally produced from natural gas or coal. In the last decade the consumption has been steadily increased, especially in Asia. Methanol is one of the target molecules for CCU and sector coupling. Goal of the MefCO2 project is to produce methanol from carbon dioxide CO2 and to reduce the CO2 emissions of industrial sources as fossil-fired power plants and processes such as steel or cement production. The other synthesis reactant, hydrogen H2 is generated from water electrolysis using renewable energy. The more renewable energy is used in the process, the lower is the carbon footprint of the CCU product.
The idea behind MefCO2 offers more than substitution of fossil fuels by the CCU-product methanol and the reduction of CO2 emissions. Additional benefits are: support of the renewable power generation by long-term energy storage and peak-load/back-up power generation to stabilize the grid, providing a feedstock for the industry of different economic sectors, as well as the use as fuel for the transport sector with extremely low emissions (SOx, particulates/soot). Additionally, CCU and sector coupling open up the chance of a gliding transformation process of the supply system for power and feedstocks and the transport sector from „fossil“ to „renewable“ by using the existing infrastructure. This approach can help to avoid structural ruptures, supports the financial feasibility of transformation and minimises risk for the security of supply.
The MefCO2 pilot plant will be operated at RWE Power’s Coal Innovation Centre at Niederaussem. The CO2 for the process is provided from the CO2 capture pilot plant at the lignite-fired power plant on site. The preparation of the installation site for the MefCO2 pilot plant is nearly completed and the erection of the plant components will start soon.
Dr. Peter Moser