San Francisco Solar Power Home Save money while you do the right thing for your community's environment A solar energy system was designed for a residence in San Francisco. This system included 18 Sharp 185 solar modules and 1 SMA 2500 UL-SBD inverter. A total of 2,970 watts of peak power generating capability is provided (based on manufacturer output ratings). This solar energy system provides about 3,785 kwh per year -- after taking into account various real-world efficiency losses.  Total costs of the solar energy system were $26,424, including all engineering, equipment, permits and installation on this flat roof. The customer received a $9,842 rebate from PG&E as part of the State-mandated Self Generation Incentive Program, an $2,487 California State Tax Credit. Net costs to the business (not including the accelerated depreciation as described below) were $13,996. Based on current A-10 commerciall electric rates, a 7% discount rate, 30 year system lifetime, 5% annual electrical rate increases, 6% borrowing rates, and 42% combined State and Federal tax rates, this system will save the business $443 per year with a Net Present Value of $4,424. On a cash basis, this business' electric bill went down by $37 per month. Moreover, because of the MACRS depreciation schedule used for PV systems, 50% of the system is depreciated in the first year with the remainder depreciated over the subsequent four years. The table below shows the magnitude of the positive cash flows for the solar energy system over the first ten years. Energy Analysis Our recommendation to install this particular solar energy system was based on a detailed analysis of the business' energy bills, roof condition, shading and orientation, electrical system, local weather conditions, environmental interests, financial goals, economic parameters and aesthetic preferences. This analysis was summarized in a detailed, 50 page report that we presented to the business. The two bar charts below highlight the results of our before and after energy bill analysis. Note that the solar energy system dramatically reduces energy charges and surcharges (per kwh) in the summer months -- when the rates are highest). There is also a reduction in demand charges (per kw). For businesses that are on complicated demand and seasonal rates, the only way to accurately model your savings is to compare your before and after consumption on a monthly basis using actual, on-site conditions coupled with current utility rates.   These savings do not take into account several important factors: Distributed solar energy power is a renewable energy resource and very kind to the environment. Renewable solar energy system improvements add significantly to the value of your property without any increase in the assessed value in most municipalities. Cash flow savings are likely to be hundreds of dollars per month if you were to install a solar energy system in conjunction with other energy saving devices - and then refinance the entire package at a lower interest rate.