[ electrolysis ] consumption on average than AWE ( 56 kWh / kg ) as well as a shorter stack lifetime on average ( 60,000 h ). 3 , 4
Regarding the materials , PEM is the more demanding technology in terms of raw materials , as it uses large quantities of Ti , Pt , and Ir . Ti is used in some of the stack components , such as bipolar plates and porous transport layers ( PTLs ), due to its good performance and stability in the service conditions ( high potentials in acidic media ). Pt and Ir are used as catalysts to carry out the high-demanding electrocatalytic reaction in acidic media , with loads of Ir and Pt about 0.3 kg / MW and 0.7 kg / MW respectively . 5 In addition , Pt is also used as a coating for some of the Ti components described above ( mainly PTLs ). One of the main advantages of PEM technology is the use of fewer balance-ofsystem components , as no electrolyte tanks or gas separators are needed . However , the use of stainless steel for system tubing
is still necessary , as is the case with AWE technologies .
As in the case of AWE , Table 2 shows the projections for CAPEX , OPEX and the LCOH of PEMWE for 2030 . It is expected that there will be a considerable decrease in CAPEX as coated stainless steel components will be able to replace Ti components in both bipolar plates and PTLs . In addition , a decrease in catalyst loading will be achieved for both Pt and Ir due to improved manufacturing techniques that will lead to catalysts with a much larger surface area . This will also improve both electrical efficiencies and durability , decreasing the OPEX . The expected projections for CAPEX and OPEX (€ 500 / kW , 50 kWh / kg and € 18,000 per kg / h ) will also allow this technology to produce hydrogen with a competitive LCOH .
Solid oxide electrolysis
Solid oxide electrolysers ( SOECs ) are characterised by their ability to operate at
Hydrogen Tech World | Issue 9 | April 2023 33