As the cost of solar thermal technology is sliding down due to technological advancements, its integration in to building systems is becoming more meaning ful and home owners are integrating the solar PV in to the building architecture. Use of solar energy in buildings can be done in three possible ways.
(1) generating daytime electricity for the building,
(2) providing power to the electrolyzer to produce the hydrogen (and oxygen) for the fuel cell and storage
(3) supplying excess electricity to the grid.
The stored hydrogen could even be used to fuel the “family Freedom Car,” in addition to providing the hydrogen for the fuel cell (24-hour power). Thus, this concept could fulfill the “zero-energy home” objective, but could also result in the “energy-plus” residence—providing more energy than it needs. The excess could be shared with the utility, as well as with neighbors.
As per one of the NREL study conducted on solar PV hydrogen systems, the hydrogen production from PV electrolysis process costs about 1.6$/kg (at a PV panel price of 3$/Wp). While the PV modules cost have come down to about 0.8$/Wp, the cost of hydrogen production at large scale can be expected at a price of less than Dollar per kg, which is at par with the conventional fuel prices.