California Copes with Solar Energy
First let’s start with the concept of “energy density.” Nuclear converts matter to energy according to Einstein’s formula of E = mc2. This is a very large number, on the order of one quadrillion, which is why nuclear can power a city the size of San Francisco on a facility of one square mile.
Wind and solar – the “renewables” that are supposed to take the place of nuclear and fossil fuels – are far less dense. We can judge their density by using the very similar equation for kinetic energy – E = ½ mv2 – where m is the mass of the wind and v is its velocity. The strongest winds can blow at about 60 miles per hour. In order to get a comparison with nuclear we must match this up against the speed of light (c), which is seven-and-and-half times around the world per second. The result is that it takes about 40 square miles of windmills to equal the output of one nuclear plant.
Sunlight falling on the earth produces energy of about the same density as windmills. Sunlight reaches the earth at about 400 watts per square meter, which means the sunlight falling on a card table can power four 100-watt bulbs. When all this energy is converted to usable electricity, the figure is closer to one 100-watt bulb per card table or once again the same 40 square miles to match the 1000-megawatt output of the average nuclear or coal plant.* This is what California is dealing with in trying to generate 33 percent of its energy from renewable sources by 2020 and 50 percent by 2030.
You’re going to have to find a place to put these facilities. Now fortunately for California, the state has a lot of scrub and desert land. What a perfect place to locate 10- and 20-square-mile facilities! Much of this land is still owned by the federal government through the Bureau of Land Management. In order to push the state toward these goals, President Obama has instructed the Department of Interior to make these lands available for renewable energy projects.
Thus, the Ivanpah Solar Power Station, constructed on BLM desert land and the crown jewel of California’s renewable efforts so far. Ivanpah uses “concentrated solar power,” which involves deploying 173,000 heliostats, each with two mirrors, to focus the sunlight on three boilers that produce steam that drive an electric turbine. The facility occupies 5.6 square miles and was built for $2.2 billion, including $300 million NRG, $168 billion from Google, and a $1.6 billion loan guarantee from the federal government. Originally aimed at a nameplate capacity of 440 MW, it was scaled back to 392 MW because of problems with the desert tortoise.
Now it is important to remember that when wind and solar facilities talk about “nameplate capacity,” they are referring to a maximum output that probably only occurs for a few hours a day. In practice, solar facilities run at about 25 percent of their nameplate capacity on a 24-hour basis while wind farms may hit 30 percent. Thus the “392 MW” Ivanpah facility is actually only producing about 100 MW on a round-the-clock basis. Fortunately, solar output peaks in the middle of the day when electrical demand is highest so the 392 MW makes a decent contribution to the grid.
However, there are problems. Last week it was revealed that Ivanpah is burning enough natural gas each year to put 46,000 metric tons of carbon dioxide into the air. This qualifies it as a major emissions facility that must participate in California’s cap-and-trade program. The operators say they need to burn the gas to keep the boilers at a minimum temperature overnight and during cloudy spells so they can be quickly started to produce steam when the sun comes out again.
Equally condemning was a report published in Proceedings of the National Academy of Sciences which said that solar facilities are being planned for land that is “incompatible” because of biological considerations and because they are not located near suitable transmission lines. Said the report:
In examining the type of land cover impacted by California’s solar installations, we found that a large percentage of installed and planned solar photovoltaic and concentrating solar power capacity (36% and 48%, respectively) are sited in biologically rich shrubland and scrubland environments. Additionally, 28% of solar installations are located in croplands and pastures, creating potential conflicts between using the land for food and energy production. . . . We found that fewer than 15% of solar installations are sited in “Compatible” areas. The most common reason for incompatibility was the need for extending transmission lines to bring power from remote areas to populated areas.
The authors recommended that solar facilities be located in the “built environment” – on rooftops, parking structures and buildings in urban areas where they will not cause ecological damage. But they admit that this adds considerable costs and property-rights problems. “We recognize that siting solar power plants in remote areas is less expensive than smaller-scale development in built environments due to economies of scale.”
Now all this applies only to California, which has plenty of shrubland and scrubland to spare for this sort of thing. Probably most states west of the Rockies have the same deserts and high plains to spare. But what happens when we move east of the Rockies into the fertile farmlands of the Mississippi Valley? The mountains of the Shenandoah Valley and New England? Are we going to cover the Green Mountains or the White Mountains or the Blue Ridge Mountains with 60-story windmills or 10-square-mile solar installations?
The tremendously low energy density of “renewable” resources means they must consume vast amounts of land in order to be productive. Are we really prepared to sacrifice that much landscape just to avoid the almost infinitely greater energy density of nuclear power?