The Vermont Yankee nuclear power plant has a capacity of 605 megawatts (MW). These calculations show how much land would be required to replace the plant with electricity generated with wind turbines or solar panels.

To begin with, we have to take into account the actual production of each of these types of power sources in comparison to their capacity. (This is a bit like comparing the gas mileage on the sticker of a new car to the performance you get under real-life conditions.) Energy specialists use "capacity factors" to express this difference as the ratio of actual production to capacity. Expressed as percentages, these factors are often assumed to be about 90 percent for nuclear, 30 percent for wind and 20 percent for solar. The latter two are low because neither wind nor solar radiation are available all the time.

To match Vermont Yankee's output, here's how much land would be needed for wind or solar power. We start by multiplying Vermont Yankee's capacity of 605 MW by 90 percent, for an actual production level of 544.5 MW. To scale up wind or solar generation to that equivalent, we divide that number by each source's capacity factor, then multiply by the land area needed per megawatt. A reasonable estimate of land area for solar is 6.3 acres for each MW of production. For wind, the total land area accounts for the spacing of wind turbines in an array. Depending on spacing and other factors, a wind farm may occupy a total area of 30 or more acres per MW. The result of these calculations indicates a land area of approximately 17,000 acres for solar power and at least 54,000 acres for wind generation to replace Vermont Yankee.