Req 7d — Fuel Cells
Fuel cells make electricity through an electrochemical reaction instead of by burning fuel to make heat first. Hydrogen fuel cells are the best-known example. They combine hydrogen and oxygen to produce electricity, water, and heat.
Technology improvements
Engineers work to improve catalysts, membranes, durability, startup times, and cost. A key goal is getting more electricity from the same amount of fuel while making fuel cells last longer. Better storage and delivery of hydrogen also matter.
Cost
Fuel cells can be expensive because of specialized materials, fuel handling, and manufacturing costs. The cost of producing and transporting hydrogen can also be a major factor. That is one reason fuel cells are promising in some applications but not everywhere.
Environmental impacts
At the point of use, hydrogen fuel cells can be very clean because they mainly produce water. But the bigger environmental question is how the hydrogen was made. If it came from fossil fuels without carbon controls, the overall impact is different than if it came from low-carbon electricity.
Safety concerns
Hydrogen is highly flammable and must be stored and handled carefully. Pressurized systems, fuel leaks, and electrical hazards are important safety issues.
U.S. Department of Energy — Hydrogen and Fuel Cell Technologies Office DOE overview of fuel cells, hydrogen systems, current uses, and technology challenges. Link: U.S. Department of Energy — Hydrogen and Fuel Cell Technologies Office — https://www.energy.gov/eere/fuelcells/hydrogen-and-fuel-cell-technologies-officeYou have looked at a system that skips ordinary combustion. Next, move underground and see how engineers try to use the Earth’s own heat as a power source.