Page 228 - Solar Power in Building Design The Engineer's Complete Design Resource

198 LEED—LEADERSHIP IN ENERGY AND ENVIRONMENTAL DESIGN

Figure 7.9 Water and Life Museum roof-mount solar power system.
Engineered by Vector Delta Design Group Inc. Photo courtesy of Fotoworks.

significant amounts of energy will not contribute to atmospheric pollution because it
will not be dumping millions of tons of carbon dioxide into the air.

Projected economic contribution Considering maximum performance degra-
dation over the life span of the solar power system, projected ac electric output power
throughout the system life span under worst-case performance conditions is expected
to be as follows:

Energy production

Daily energy production = 350 kWh (worst-case hourly energy output)
× 5.5 (hours of average daily insolation) = 1925 kWh

Yearly energy production = 1925 kWh × 365 days = 702,625 kWh

System lifetime (25 years) energy production = 702,625 kWh × 25 years
= 17,565,625 kWh or = 17.7 MWh

Assuming an optimistic rate of electric energy cost escalation over 25 years of sys-
tem life at a mean value of $0.75/kWh, the projected saving contributions by the solar
power system could be approximately $13,174,218.00. If we assume a rate of 1 percent