2. Nuclear Fissionary, April 2, 2010

4. Why are prices declining?  Generally, solar panels make up about 50% of the cost of a system (40% for thin film), the inverter is 10%, and the balance of system is 40%.  Decline in price is being driven by:  Increased solar cell efficiency  manufacturing technology improvements  Economies of scale  Intense competition (particularly from China)

5. Installed Solar - Example

6. Monthly Savings Calculation: A south facing roof top solar system with no shading, and with a normal yearly dessert sunlight radiance of 2,400 per square meter would produce 1,840 kWh of electricity per year per nameplate kW capacity (assuming 23.3% losses for DC to AC conversion and other system losses). With a 5 kW system installed, the first year production would be 9,200 kWh (5 x 1,840). Assuming a system degradation of 0.5% per year times 25 years yields a net 8,050 kWh yearly average electricity savings (9,200 x.875). Assuming an average 2010 residential electricity price in AZ of $0.11 per kWh yields a yearly savings of $886 (8,050 x $0.11 not counting future inflation). The monthly savings would then be $73.79 ($886 divided by 12). This was then rounded to $74.00 even.