“By 2042, residential photovoltaic (PV) electricity systems will cost less than $0.90/watt, installed and commissioned, supplying AC electricity for $0.02/kwh to $0.05/kwh, depending on geographic location.”

All per-watt prices expressed as DC nameplate rating of panel or inverter. All “kwh” expressed as AC at the meter, after 0.73 derating from DC nameplate rating, shown as an annual average from a fixed-tilt pointing south. Assuming 25-year warranted system life with 20% end-of-life PV panel derating. . . . Over the last 30 years, solar cell technology has halved its price-per-watt roughly every 7-8 years. Today, more capital than ever is being poured into PV research on all levels – academia, industry, government. Affordability should accelerate. To keep a conservative forecast, let's assume that PV panel price will halve every 12 years (not the historical 7 years) for the next 30 years. This gives us commodity solar panels at $0.20/watt by 2042. Today (2012), DC-AC central inversion is roughly 50 cents-per-watt. The preferred DC-AC micro inversion technology is around 80 cents-per-watt with 25 year warranty. Being very familiar with power supply design, economy of scale, offshore integration, and manufacturing, I have a high confidence that micro inversion will be under $0.20/watt by 2042 (if not far sooner, perhaps 2025-2030). Commodity crystalline PV efficiency is around 15-16% today. Historical 30-year PV efficiency has improved roughly 3% per year. To remain conservative, let’s assume that PV efficiencies will improve at just 2% per year over the next 30 years. A 2% per-year PV efficiency improvement gives us 30% efficient panels by 2042, effectively halving the number of physical panels and mounting structures required per site — lowering freight, installation, and job management costs to roughly $0.50/watt. By 2042, this conservative forecast gives us: Panels: $0.20/watt Inversion: $0.20/watt Install & Mgmt: $0.50/watt Installed grid-tied PV systems at $0.90/watt puts us around $0.02/kwh in high sun areas (Las Vegas-Phoenix) and $0.05/kwh in weak solar areas (Seattle-Fairbanks) — without rebates or other incentives. By 2042, the median U.S. cost to generate PV electricity becomes $0.035/kwh, which is roughly 1/3 the median U.S. rate of utility-delivered power. Most “25 year” systems will remain in operation much longer, making PV even less expensive than this forecast, approaching $0.01/kwh in some locations. But all the news is not good. For a more detailed and comprehensive analysis of PV trajectory and its possible impact on global energy, please see: http://www.microclesia.com/?p=2990