Additive manufacturing amps up fuel cells , drives down cost
Keeping the electricity grid up and running through summer heat waves and winter deep freezes is an ongoing balancing act . Power lines that stretch for miles are vulnerable to wind and fire . Surges in demand for heating and cooling strain capacity , which can lead to blackouts . Air pollution is an ongoing issue . Although meeting today ’ s energy needs requires the use of traditional hydrocarbon fuel sources , alternative-energy solutions such as solar , wind-power , and hydrogen are rising up in the supply curve as the drive to decarbonize electricity gains momentum . Of these , hydrogen stands out , given its potential to produce clean electricity at a steady rate .
By Lynn Manning , President , Parker Group
View of an oil-free anode offgas recycle blower ( AORB ) made by Mohawk Innovative Technology Inc .
A promising approach , now emerging from the research stage into commercialization , is solid-oxide fuel cell ( SOFC ) technology . The US Department of Energy ( DOE ) has invested in SOFCs for years ( USD 750 million since 1995 , according to their website ) as part of the ongoing effort to decarbonize energy production . The DOE describes an SOFC as an electrochemical device that produces electricity directly from the oxidation of hydrogen , generally produced by reformation of a hydrocarbon fuel ( usually natural gas ), while eliminating the actual combustion step . Basically , an SOFC acts like an infinite-life battery that is constantly
Cross-section of a Mohawk AORB highlights the main internal components being recharged – without burning the gas that recharges it .
Small package , big energy output “ Solid oxide fuel cells are very attractive because they produce a lot of energy in very small packages ,” says Jose Luis Cordova , Ph . D ., VP of Engineering at Mohawk Innovative Technology Inc . ( MITI ). Working on a number of DOE-funded programs , Mohawk is a 28-year-old , Albany , New York-based company specializing in the design of high-efficiency , cost-effective , environmentally lowimpact , oil-free turbomachinery products including renewable energy turbogenerators , oil-free turbocompressors / blowers , and electric motors . “ SOFCs are compact and can be built at a factory , then transported to the specific site where they ’ re needed to support distributed-energy production ,” says Cordova . “ Contrast that with the usual centralized , multimegawatt power plant that takes billions of dollars and many years to set up . SOFCs are also very efficient . Unlike a regular battery , they don ’ t lose power over time because as long as you supply the reagents you can continue the electrochemical reactions pretty much indefinitely .” Sounds ideal , and more than 40,000 units of 100-kilowatt fuel cells ( each able to power 50 homes ) were
shipped worldwide in 2019 . But there have been bumps in the road slowing more widespread adoption of the technology : many SOFC components are expensive to manufacture and , due to exposure to the very gases that make their operation so efficient , they wear out frustratingly quickly .
Facing cost and durability issues To help overcome such challenges , Mohawk has designed some of those critical parts for longer lives and greater efficiency . One example is the anode offgas recycle blower ( AORB ), an essential component of the ‘ balance of plant ’ – the machinery that supports the SOFC ’ s fuel stack . During operation , each fuel cell only uses about 70 % of the gas it ’ s fed ; some 30 % passes right through the system along with water ( a product of the electrochemical reaction ). “ You don ’ t want to throw away the leftover gas or water , you want to send them back to the beginning of the process ,” says Cordova . “ And that ’ s where the AORB comes in ; it ’ s essentially a low-pressure compressor or fan that recycles the exhaust and returns it to the front of the fuel cell .” “ SOFC balance-of-plant designers were thinking that this blower would be an off-the-shelf unit ,” says Cordova ( a typical 250 kW SOFC plant would employ two of them ). “ But due to the process gases in the system ,
30 Stainless Steel World March 2023 www . stainless-steel-world . net