Hydrogen Fuel Cell Basics

Question 1

Hydrogen Fuel Cell Basics

Answer 1

• Hydrogen is used as a renewable, alternative fuel source to fossil fuels
• H2 and O2 are inputs used to generate electricity; H2O is the waste product
• H2 gas enters fuel cell where it’s split into protons (H+) and electrons (e-) by an electrolyte membrane that only lets protons pass through [electrons take an alternative route around the membrane which generates an electrical current]
• O2 molecules enter and break apart into two and combine with H2 to form water
• Most common application is in vehicles [replaces gasoline with hydrogen fuel]

Question 2

Creating H2 Gas

Answer 2

• KEY CHALLENGE: obtaining pure H gas is difficult (b/c it doesn’t exist by itself as a gas naturally
• Splitting H2 gas from other molecules like H2O or CH4 is very intensive

TWO MAIN PROCESSES:
- Steam Reforming [95%]: burning natural gas and using steam to separate the H gas from methane [disadv. emits CO2]

• Electrolysis: electrical current is applied to water, breaking it into O2 and H2 [requires electricity]

Question 3

Hydrogen Pros

Answer 3

• Can be used as an energy carrier [because H2 can be stores in pressurized tanks, it can be transported unlike solar, hydro, and wind where electricity must be used as soon as it’s generated]
• Can be used as a fuel for vehicles
• Can be used to create ammonia or fertilizer
• 80% efficient in converting chemical energy in H2 and O2 into electricity (Coal is 35%)

Question 4

Hydrogen Cons

Answer 4

• 95% of H2 production requires methane, which is based on a non-renewable and CO2 releasing energy source
• If electrolysis is used, the method is only as sustainable as the method required for the electricity
• Widespread H fuel cell use would require building widespread H distribution network
• H fuel stored in gas form in vehicles would require much larger tanks than current gasoline tanks