Solar electricity comes straight from the source – by which I mean that most electricity is some form of converted sunshine. I bet when you plug something into your wall you don’t think about the fact that you’re plugging into the sun. Unless, of course, you already have a PV system.
The electricity that comes out of your outlets is about 50% coal-based in the US, but coal is really just sunshine that was stored underground for a couple of hundred million years. After the coal is unearthed it is burnt in a box somewhere far away to boil water, generate steam and spin a turbine. Pretty inefficient, right?
Increasingly gas is being used instead of coal as a slightly more efficient form of stored sunshine. In some markets gas-fired power is coming to dominate due to the fact it burns a little bit cleaner – although nowhere close to the cleanliness of direct solar. Gas-fired plants are also easier to turn on and off than coal plants, so they are used for peak load, which is when the demand for electricity is at its max and generation must be increased to meet that need. Peak load typically occurs in the late afternoon/early evening when businesses are still open, but many people have already gone home and turned on their air conditioning while they cook dinner, do laundry, watch TV, etc.
Solar is a great replacement for this load, since it’s clean power AND the peak hours of solar power generation line up pretty well with peak demand. For people with PV systems who are on a Time of Use rate schedule then it works out perfectly because they’re producing electricity and selling it back to the grid when it’s more expensive and buying it back at night when it’s cheaper.
Speaking of cost, let’s look at what happened at Southern California Edison (SCE) earlier this year. SCE, a big conventional utility, asked regulators to approve 20-year contracts to buy 250 megawatts of electricity from 20 small-scale photovoltaic farm. According to Todd Woody of Forbes, the 20 projects — which will generate between 5 and 20 megawatts — will produce electricity at a cost below what utility industry wonks call the “market price referent.” The MPR, as they call it, represents the levelized cost of electricity over 20 years of a combined cycle gas turbine like those typically found in natural gas power plants in the Golden State. Translated into plain English, solar power is fast becoming cheaper than gas-fired power.
So in the real world marketplace of California gas is getting too expensive, when it compares to solar direct. Here’s a graph to show you the same points (tip of the hat to VoteSolar for all these facts & graphs):
My third installment of The Solar Ascent is going to focus on coal. Here’s a question for you to answer in the comments: Only two states don’t have any coal-fired generating capacity. Which ones are they? No cheating! :-) The first person to guess both states correctly wins a Sungevity t-shirt.
Next week: The Ascent of the Sun: Say Good-bye to Ol’ King Coal (Part 3 of 3)