The question keeps coming up: Is wind/solar cost-competitive yet? Is nuclear? The answers shift depending on fuel prices and location. In Morocco when I researched this in 2001, for example, they had no fossil fuels at all, so imported coal was going to cost 6c/kWh in hard currency whereas the steady tradewinds along the Atlantic coast generated wind energy at 4.5c/kWh at the one wind park that had been up for a year. In the rest of the world, newly built natural gas facilities are usually cheapest at about 3.5c per kWh, and wind at around 5.5c for good locations, but obviously this depends on the price of gas. Solar used to be absolutely non-competitive (in the double digits), but new “thermal solar” (where parabolic mirrors heat a liquid that turns a turbine) are now being built on a utility scale. Handily for solar, the sun shines during the day’s peak demand hours.
The breakdown goes something like this:
1. Construction Cost:
– Gas is cheapest, coal second-cheapest. New “clean coal” technologies cost a bit more than renewables.
– Renewables are costly to construct since fuel is free. The entire per-kilowatt price for windpower is the construction cost divided by 20 years.
– Nuclear is basically ludicrous. When on budget, it costs the same as wind. When off budget, it’s out of the ballpark. The last nuclear plant to come online in the US took 23 years to build at a cost of $6.9 billion. The history of nuclear is a history of government bail-outs, and McCain’s nuclear energy plan is yet another example of faith-based economics.
– Gas prices depend on whether you are piping it within North America or getting liquified natural gas (LNG) from other continents. The US has some gas in Alaska and the Gulf of Mexico, but most of the world’s gas is in Russia, Iran, and Qatar. Gas costs more than coal and prices are expected to rise.
– Coal prices are low, and we (and China) have unlimited amounts of it if we choose to mine it. People are working on how to turn coal into natural gas.
– Renewables cost $0 and will always stay at $0 no matter how other prices move.
– Nuclear: mining, refining, using, decommissioning, and storing the fuel costs some unspecified amount. Uranium comes from Australia and Canada. Some say the marginal dispatch price is only 1.7c/kWh for nuclear after the plant is built, but Britain paid $90 billion in liabilities for its inept and now-bankrupt waste re-processor, according to the Economist.
– Gas and coal turbines have to be shut down for cleaning (coal more than gas) on a regular rotating schedule. The average plant has 2-6 turbines.
– Wind just has air blowing through its turbines, so maintenance is less intensive. The average utility-scale plant has 80-200 towers. Solar’s surfaces have to be cleaned to maintain efficiency.
– Nuclear sometimes gets less maintenance than it should, leading to scary stories of cracked concrete. All power plants have security, but nuclear has super-security.
4. Public Costs:
– Coal is dirty, causes cancer, etc.
– Gas is pretty clean but still has global warming problems.
– Nuclear has no global warming, but the nuclear waste sticks around. A Chernobyl-style disaster isn’t a real likelihood, though.
– Importing fuel adds to the trade deficit, whereas high construction dollars tend to stay in the country in the form of construction jobs.
– Price insecurity can also have geopolitical consequences, such as wars for Kuwaiti/Iraqi oil or Iranian natural gas. See where 2/3 of the world’s gas is located: http://en.wikipedia.org/wiki/List_of_countries_by_natural_gas_proven_reserves.
– Nuclear waste leads to dirty bomb risk.
– A network of 200 wind turbines is harder to bomb, though the transmission nodes could still be targets. Flammable things like gas pipelines, LNG terminals, and coalyards are all obvious targets.
You can see that I think wind and solar are the most sensible choice. For a case study with real numbers, here’s a Swarthmore engineering prof’s analysis of the market in Pennsylvania.