Solar has become so efficient that solar versus stock arguments are possible
With the price of grid electricity going up, and the cost of home-generated solar power going down, the case for investing in solar panels has never been better. In fact, it’s so good that the savings may be higher than you could make with a typical portfolio of stocks, a report called Going Solar in America finds. The NC Clean Energy Technology Center at North Carolina State University compared 25-year returns from Standard & Poor’s 500 stock index with projected returns from a home solar system. In 46 of 50 cities, it found that solar came out ahead.
The analysis says solar power is frequently cheaper than grid electricity. “Of the single-family homeowners in America’s 50 largest cities, we estimate that 9.1 million already live in a city where solar costs less than their current utility rates if they bought a PV system outright– and nearly 21 million (93% of all estimated single-family homeowners in those cities) do if low-cost financing is available,” the report says. (Low-cost financing means interest rates of 5% on a 25-year lease.)
The Lawrence Berkeley National Laboratory estimates that the median cost of residential solar has gone from about $12 a watt in 1998 to about $4.70 a watt in 2013. The calculation is based on the cost of a solar system over its lifetime, adjusted for inflation, and a typical household’s power usage.
“When the declining cost of solar is coupled with the rising cost of grid electricity, the financial case for solar (given the strong odds of future rate increases) can be quite persuasive, particularly for locales with higher than average electricity rates, such as California and the Northeast,” the report says.
Cities with the greatest monthly savings, according to the study, are all in California: Oakland ($187), San Francisco ($187), San Jose ($186), San Diego ($137), and Long Beach ($131).
The NC Clean Energy Technology Center ranked cities by where the overall benefits are greatest, finding that New York, Boston, and Albuquerque, New Mexico, come top. The index is based on three sets of numbers: first year savings from installing solar, the relative value of an investment compared to the S&P 500, and the overall cost of solar compared to grid electricity.
The study finds that financing a five kilowatt rooftop solar PV system at 5% interest is a better investment than paying upfront. That’s because the projected costs of solar are based on “net present value”—a way of calculating the future value of an investment in present-day dollars. Financing allows customers to keep more of their income in the short term (and take advantage of federal subsidies), while avoiding a large upfront payment. Paying outright is a better investment than the S&P 500 in only 20 of 50 cities, the report says.