The use of boron for thermochemical storage and distribution of solar energy

Boron has been proposed as a candidate for hydrogen production. In this study a process is described in which boron is used as a means to store and transport solar energy from a production site to motor vehicles, where it is used to generate hydrogen and heat. The proposed multi-step fuel cycle includes no carbon as a reducing agent and, therefore, no release of CO2 to the atmosphere. This process is safe, mostly involving harmless materials and well-understood technologies. It eliminates the distribution, storage, and pumping of hydrogen at the refueling station, and diminishes the amount of hydrogen stored on the vehicle to a minimum. It is shown that the boron reaction with water, performed on-board of a vehicle, has high hydrogen storage capacity based on both volume and mass, compared with other candidate technologies. An energy balance of the entire process predicts that the overall efficiency of converting solar energy to work by the vehicle engine can be about 11%. 2006 Elsevier Ltd. All rights reserved.