Theoretical Power generation

Concepts and Comments
Max Energy From H2 in Fuel Cell - Thermodynamic Limit

at room T and P (300K and 1atm)

$$H_2 + 0.5 O_2 = H_2O$$

Enthalpy ($$\Delta H$$) and Entropy ($$T\Delta S$$)

$$\Delta H = -285.8 kJ/mol H_2$$

$$T\Delta S = -48.7 kJ/mol H_2$$

Gibbs Free Energy (available for work)

$$\Delta G = \Delta H - T\Delta S$$

$$\Delta G = -237.1kJ/mol H_2 = -136.5 MJ/kg H_2$$

Links
NREL Cost Analaysis of Algae H2 Production

Thermodynamics of Fuel Cell H2 Energy Conversion