“It is time to stop referring to solar power as ‘renewable’ or ‘free.’ The reality is that these descriptions have no practical meaning and only serve to obfuscate the true nature of solar energy as a source of electricity. Ultimately these are propaganda words invoked by special interests in the renewable energy industry whose purpose is to color the political debate about energy policy in favor of subsidies and special privileges foisted upon taxpayers and utility customers.”
“… it is solar power’s lack of renewability when actually needed that makes it so expensive as compared to [fossil fuels].”
The answers to the two title questions are, except in the most trivial sense, no and no.
Solar energy is said to be renewable because, as one source puts it, it is “naturally replenished.” Or as another source states slightly differently, solar power is renewable because “there is an endless supply.” But the truth of the matter is that in any meaningful technological, economic, or practical sense, solar is anything but renewable.
For any BTU of usable energy generated by the sun, it is highly unlikely that, as it is used, it will be, or even can be renewed by another BTU of energy also generated by the sun. This is because (unlike the claim above that “there is an endless supply” of solar power), on any given day there is a very finite supply and, on some days, no supply at all of sunlight that is usable for conversion to electricity.
The extent to which a megawatt of electricity that is generated by solar power can be actually renewed by another megawatt of electricity that is also generated by solar power is completely dependent on the time of day that the electricity is used to light a lamp, run an air conditioner, or heat a hot water tank. If I generate electricity from the solar panels on the roof of my house at 2:00 in the afternoon to run my air conditioner, to renew that used electricity at 6:00 PM to cook my dinner would be impossible.
In fact, I would have to turn to an entirely different source of energy, one whose renewability does not depend on whether or not the sun is shining, like coal, natural gas, or nuclear power. It is meaningless to refer to an energy source as “renewable” if it can’t be renewed as needed. If my solar energy does not allow me to renew the electricity that I use at 4:00 pm until 10:00 am the following morning, in what practical sense can that energy source be called renewable? The answer is none.
Of course this is not only true for the household with panels on its roof but also of solar generated electricity being put onto the electrical grid, and for all the same reasons. It seems to be a dead give away that there is not “an endless supply” of an energy source or that it is not “naturally replenished” if for most hours of any given day it needs back up generation from a supposedly non-renewable conventional energy source.
Indeed, in a practical or even meaningful technological sense, which is the truly renewable energy source (i.e. that which is renewable on command for the purpose of generating electricity) the sun or coal or natural gas? Clearly it must be the latter two. In fact it is solar power’s lack of renewability when actually needed that makes it so expensive as compared to these other sources.
A “Free” Source of Electricity?
So what does this imply for the claim that the sun is a “free” source of energy? If the word free refers to price in the economic sense then the claim is misleading at best. The price of the sun as an energy source is completely bifurcated. Energy from the sun has two prices, zero and infinity. On a clear day at noon it’s free, and on that same day at midnight it’s infinite.
That is, it cannot be obtained at any price. The same is true for sunny vs cloudy days. It is typically argued that on average, given that many days will be cloudy with no “usable sun” at all, a solar-based power plant can generate electricity for about five hours. This means that for an average of 19 hours out of every day the price of solar as a usable energy source is infinity.
Of course it’s also important to note that we’re only talking about the price of the fuel source, i.e. sunlight as opposed to “non renewables” like coal or gas. But the entire apparatus that gets us to the point where we can use sunlight as a fuel source to generate electricity is itself quite expensive.
The fact that the sun isn’t around a whole lot to take advantage of that apparatus means that the very high fixed costs of solar installations can be considered productive over a relatively small percentage of any given day and therefore have to be “levelized” over an equally small amount of actual electricity output. This is why there is a very high levelized cost of electricity from solar power compared to other sources. Usable solar power is never “free” even during the short periods when the fuel source is.
It is time to stop referring to solar power as “renewable” or “free.” The reality is that these descriptions have no practical meaning and only serve to obfuscate the true nature of solar energy as a source of electricity. Ultimately these are propaganda words invoked by special interests in the renewable energy industry whose purpose is to color the political debate about energy policy in favor of subsidies and special privileges are foisted upon tax payers and utility customers.