And other forms of clean and renewable energy. It's fine to say, "Solar currently costs more than grid power in $/kwh, but we're using it anyway to be cleaner." That's a good message. Saying that solar for more than $3.50/watt "pays for itself" in some number of years compared to grid power is, to the best of our knowledge today, a lie.

Doing solar to be cleaner, and promote demand so that the total cost falls to compete with the grid -- these are good things. Pretending it's what it's not is bad.

Now, I can see arguments to bump the number. For example, the "total cost to society" of grid power is higher than its market cost, because of how it competes. It's hard to decide an exact number for the total cost of grid power -- there will always be debate. Solar itself also has extra costs, since manufacturing it takes grid power and creates pollution as well, though these are comparatively low.

But none of the "pays for itself in N years" statements are using this sort of analysis. They're mostly using bad math.

Another issue for debate is the rebates. Typical solar today can be put in for about $8/watt, and the cost can get near the $3.50 price with rebates and tax breaks. However, this is not solar being cost-effective, this is taxpayer money doing the work. Which may be a wise decision, but again we should be clear about what it is, and ask if this is the best way to use taxpayer money and government power to create greener energy. It may be, but we don't discuss it in those terms.