Solar is good for powering equipment in remote locations. It is excellent for powering spacecraft. It is good for direct heating of swimming pools. Passive solar in the form of buildings designed to utilize sunshine for warmth and light can save energy.

Solar energy is not always a fraud. If you live off the electric grid, and you have a reasonable amount of sunshine, solar power, backed up by batteries, can be a good option for getting a modest amount of electricity. It will not be cheap electricity.

But, do not think that it is advisable to put solar electricity panels on your roof. Do not think that it is a good idea for your local utility to build large solar generating farms. Political influence has created subsidies and mandates that prop up the solar industry. The money is extracted from taxpayers and utility customers. The solar industry positions itself as doing a public service by preventing climate change. Even if you believe the climate change theories, the solar industry is a negligible force against climate change.

Utility scale solar in the sunniest climates can generate electricity for about 7 cents per kilowatt hour (KWh). Outside of the sunny south the cost is about 9 cents per KWh. Most of the cost is capital cost, amortized over the life of the plant. Government subsides often cut the price in half for users of solar electricity.

Residential rooftop solar, under the best conditions, may generate electricity for about 15 cents per KWh. Usually the cost will be considerably higher. Not everyone’s roof faces south and not everyone lives in a sunny climate.

A fundamental error is to suppose that if solar could generate electricity at a cost equal to conventional generators it would be competitive. The leading type of conventional generator is combined cycle natural gas. These plants can generate electricity at a cost approaching 3.6 cents per KWh, or 2 to 3 times cheaper than solar. In order to be competitive, solar has to generate power not just cheaper than the alternative, but, as will be explained, cheaper than the fuel consumed by the alternative.

Solar is undependable. It does not work on cloudy days or at night. It stops working if a cloud passes in front of the sun. Yuma, Arizona, is the sunniest city in the U.S. Even in Yuma, there are 50 cloudy days and 365 dark nights a year.

Adding solar to the electric grid does not displace conventional generating plants. Those plants are still there. They just work a little less, sitting idle when solar is working. The only money solar saves is the fuel that would have been consumed by the plants that are idle because solar is generating electricity. Natural gas plants, or coal plants, consume 2-3 cents worth of fuel per KWh. Nuclear plants consume 0.4 cent per KWh and hydro plants don’t use fuel. As a practical matter, to be competitive, solar has to compete with natural gas plants, the dominant alternative to solar. Unless the total cost of utility-scale solar is about 3 cents per KWh, instead of 7 to 9 cents, it is not going to be competitive with gas. The less-efficient gas plants consume about 3 cents worth of fuel per KWh of electricity produced.

Residential rooftop solar electricity costs 15 cents, and usually considerably more, per KWh. The electricity generated displaces power from the grid. If the solar power generated exceeds household consumption, the electricity is exported into the grid. Some electric meters may actually run backwards if electricity is being exported. In other cases the metering will measure both grid and solar electricity and payments will be made according to a prearranged formula.

If markets were not distorted by political influence, rooftop solar would hardly ever be competitive. But political subsidies and artificially high electricity prices make rooftop solar competitive in many places. For example, in California, many owners of large homes are charged over 40 cents per KWh in certain “tiers.”. These politically inspired rates make solar competitive for those owners of large houses.

Just as in utility scale installations, the true value of rooftop solar electricity is the cost of fuel consumption avoided when the solar is operating. The result is that the utility is often effectively forced to pay retail rates, typically about 13 cents per KWh, for electricity whose true value is about 3 cents per KWh. The owner of the rooftop solar also loses money unless his retail rate is in excess of the 15-cent, or more, cost per KWh.

The organization, Environment America, has published a report: Shining Rewards The Value of Rooftop Solar Power for Consumers and Society. This report reviews 11 other reports by solar advocates and utilities that attempt to calculate the value of rooftop solar to society. The 11 reports assign a value from a low of 3.5 cents per KWh to a high of 33 cents per KWh. This wide variation in the value of solar surely indicates that solid accounting methodology is absent. All the reports by advocates of rooftop solar found that the value of the electricity to society was greater than the current retail price of electricity. The three reports from utilities found the opposite.

How do the advocates of solar assign a value to society? It is a rather nebulous idea that rooftop solar has a value separate and greater than its actual economic value. A favorite trick is assigning a social value to CO2 emissions avoided. This is a highly speculative and subjective benefit. Another trick is to assume that new grid investment can be avoided or deferred because the solar is present. But on cloudy days, to say nothing of night, solar is not present, so how can investment in grid infrastructure be avoided?

The point of these studies is to make a case that the economic waste of solar is justified. Once one starts claiming that a dubious climate disaster awaits us 100 years in the future if we don’t follow the dictates of green ideology, the door is opened to justifying any green foolishness one can imagine.

There is a cult, inspired by computer models of the Earth’s atmosphere, that believes that if we don’t swear off CO2, we will be struck down by a climate disaster. The exact nature of the climate disaster keeps shifting. It was global warming and that morphed into extreme weather. Global warming did not work out because the globe stopped warming 18 years ago. Extreme weather is a better disaster, because nature is always providing extreme weather that can be blamed on CO2. The recent California drought that turned into the California flood is a perfect example.

If the believers in the climate cult were logical, they would be promoting nuclear power. Nuclear power is reliable, does not emit CO2, and has great prospects for technological advance. Some of the cultists are promoting nuclear power, but most have an anti-nuclear phobia left over from the anti-nuclear power movement of the 1970s and '80s. Most of the cultists are promoting solar and wind power, even though these forms of power can never dominate the power grid and provide reliable and economic electricity.

Norman Rogers writes often about environmental and energy issues. He has a website. For a more detailed and technical analysis of solar electricity see this article.