HYDROGEN AND ELECTRICITY AS CARRIERS OF SOLAR AND WIND ENERGY FOR THE 1990S AND BEYOND

This study compares the costs of possible future large-scale and long-distance solar and wind energy delivery systems for electric, thermal, and automotive end-uses. Solar and wind resources are intermittent, and the best sites are often remote from the energy end-use. Electricity is presently the dominant secondary carrier of renewable energy to end-use markets. However, electricity is relatively expensive to store in large quantities and to deliver over long distances. Hydrogen systems potentially offer storage and long-distance delivery advantages. The analysis indicated that hydrogen systems could be competitive with electricity as an energy carrier for thermal end-uses, particularly over longer distances. Development of cheaper bulk electric storage technologies, e.g. superconducting magnetic energy storage, could erode this advantage. Hydrogen energy systems do not appear to be competitive when the end-use is electric or automotive. The increased cost of the larger solar and wind capture and generation requirements, due to the overall lower efficiency of the hydrogen systems, more than offsets the energy storage and delivery savings. The economics of hydrogen as an energy carrier would significantly improve in electric end-use applications if cogeneration value were considered or if fuel cell and other efficiencies were improved beyond expected levels. The wind energy systems examined had overall lower cost than solar energy systems for hydrogen production. Further comparisons of hydrogen and electric systems would benefit from site-specific analyses. Sensitivity studies for transportation distance, electric transmission costs, capacity factor, storage time, cogeneration, time-dependent end-use value, hydrogen water requirements and costs, and aerospace applications would be valuable areas for further investigation.