A pilot plant for direct solar fuel synthesis started operation in Lanzhou, the capital city of northwest China’s Gansu Province. CO₂, H₂O, and solar energy are converted into transportable liquid fuels such as methanol. Three technological units are used: solar photovoltaics to generate electricity, an electrolyzer to split H₂O to produce H₂, and CO₂ hydrogenation to produce methanol.

Can Li and colleagues, Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Science, have developed a new type of electrocatalytic H₂O splitting for the process. The technology reduces the energy consumption to 4.0 to 4.2 Kwh/Nm³-H₂ for large scale H₂ production at a rate of 1,000 Nm³-H₂/h. This is the highest energy conversion efficiency reported so far for large-scale alkaline water electrolysis.

The team also developed a ZnO-ZrO₂ solid solution bimetallic oxide catalyst for CO₂ hydrogenation to methanol. According to the researchers, the methanol selectivity is over 90 % for a single pass in the fixed-bed reaction process. The performance loss was less than 3 % after 3,000 hours of operation under industrial conditions. The methanol produced in this PV-E-C (photovoltaic-electrolyzer-catalyst) process is reported to be more than 10 % solar energy conversion efficiency. This is superior to the ca. 1 % of solar energy conversion efficiency achieved by natural photosynthesis of most plants.

The researchers see their green solar methanol production demonstrated in Lanzhou as a revolutionary step and as a model for energy transition from fossil fuels to renewable energy.

• Thousand-tonne Seale Demonstration of Solar Fuel Synthesis Starts Operation in Lanzhou, China,
  Zhang Nannan,
  Chinese Academy of Science 2020-01-17