A town plans to store summer solar electricity as hydrogen and to get of electricity…

PHYSICS · Multi-part · Fermi University Physics · Earth, Climate & Energy Physics · Energy systems, storage and demand · Energy systems, storage and demand

Energy from Physics, Ch Storing energy: cells, rotors, air, heat and hydrogen

Problem

A town plans to store summer solar electricity as hydrogen and to get

10\,\mathrm{GWh}

of electricity back in winter. Its electrolyser runs at

1.8\,\mathrm{V}

, the hydrogen is compressed to

700\,\mathrm{bar}

300\,\mathrm{K}

by a compressor taking twice the isothermal work, and its fuel cell runs at

0.75\,\mathrm{V}

. ((a)) Find the electricity the fuel cell delivers per kilogram of hydrogen, and the mass of hydrogen the town must store. ((b)) Find the summer electricity the chain needs and its round trip. ((c)) Better catalysts would let the electrolyser run at

1.6\,\mathrm{V}

and the fuel cell at

0.85\,\mathrm{V}

, with compression unchanged. Find the new round trip, and the largest round trip that better catalysts alone could ever give, with no compression and an electrolyser that takes no heat from outside.

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