intermittence, the supply curve for photovoltaics makes it a potentially valuable contributor to
peak shaving. In addition, distributed power offers the prospect of increased security and grid reliability.
The relationship between the building owner and the utility is important to the success of
grid integrated systems. Most owners want to maximize the output of their system, and they normally
have little concern about the utility's peak load. One way to benefit both the owner and the utility is by
providing time of use net metering, which values the electricity produced during the peak period higher
than that produced during off peak times. This more sensitive metering would encourage owners to orient
their systems to provide the highest value electricity and would help the utility address its peak
Utilities continue to have concerns about the safety, reliability and costs of net metering.
Addressing barriers to metering should be feasible with accelerated development of low cost metering
devices, along with education and demonstration activities such as DOE's Million Solar Roofs Program.
Thin film photovoltaic technology is the focus of current federal R&D efforts because it holds
considerable promise for cost reductions due to its need for less semiconductor material. In the long
term, research into nanocomposites offers the promise of an inexpensive and high efficiency solar energy
Currently, grid connected photovoltaic systems cost an order of magnitude more per kilowatt hour
than do fossil, nuclear, and wind generation energy sources. However, a more appropriate comparison with
end user prices (which include transmission and distribution costs, taxes, profits, and other fees, and are
therefore much higher than generation costs) suggests that solar power is more closely competitive with
these other sources. The market for solar power is expected to grow rapidly over the next decade, due to
production tax credits, renewable portfolio standards, and buy down programs (such as California's subsi
dies for residential and commercial photovoltaic systems), combined with anticipated cost reductions of
at least 5 percent per year.
Integrated Building Systems. By 2010, advances in building envelopes, equipment, and systems
integration, may lead to 50 percent reductions in the energy requirements of new buildings relative to
2000. Incremental cost estimates for these advanced building systems run from 0 to 2 percent of the
total building cost, because most of the additional building envelope cost is offset by cost savings on the
downsized HVAC system.
If augmented by on site power, buildings could reduce their net energy
Towards a Climate Friendly