How Much Electricity Can be Generated from 1kg of Hydrogen with a Fuel Cell?

The amount of electricity generated from 1 kilogram (kg) of hydrogen in a fuel cell can be estimated using the lower heating value (LHV) of hydrogen and the efficiency of the fuel cell. Understanding these factors provides insight into the potential energy output and efficiency of hydrogen as a power source.

Energy Content of Hydrogen

The lower heating value (LHV) of hydrogen is approximately 33.33 kilowatt-hours (kWh) per kg. This value represents the amount of energy that can be released by the complete combustion of hydrogen gas.

Fuel Cell Efficiency

Fuel cells convert the chemical energy of hydrogen into electrical energy with varying efficiency. Average fuel cell efficiencies range from 40% to 60%. For this calculation, we will use an average efficiency of 50%.

Calculating the Electricity Produced

To calculate the electricity produced from 1 kg of hydrogen, we use the following formula:

[ text{Electricity produced} text{Energy content} times text{Efficiency} ]

Namaes:

[ text{Electricity produced} 33.33 , text{kWh/kg} times 0.50 16.67 , text{kWh} ]

Therefore, approximately 16.67 kWh of electricity can be produced from 1 kg of hydrogen using a fuel cell with an efficiency of 50%.

Advantages of Hydrogen’s Energy Density

Hydrogen’s energy density is significantly higher than that of common fossil fuels such as diesel and gasoline. Diesel fuel has an energy density of 45.5 megajoules (MJ) per kg, slightly lower than gasoline's 45.8 MJ/kg. In comparison, hydrogen has an energy density of about 120 MJ/kg, which is nearly three times greater than diesel or gasoline.

Electronically, the energy density of hydrogen is approximately 33.6 kWh of usable energy per kg, whereas diesel holds about 12 to 14 kWh per kg. This means that 1 kg of hydrogen used in a fuel cell to power an electric motor contains the same energy as a gallon of diesel.

Real-World Impact

These high energy densities have practical implications. For instance, Nikola Corporation claims that their hydrogen-powered vehicles can achieve 12 to 15 miles per gallon (mpg) equivalent, which is significantly above the national average for diesel trucks, which are around 6.4 mpg.

The high energy density of hydrogen makes it a promising alternative for energy storage and transportation applications, offering a cleaner and more efficient solution compared to traditional fossil fuels.