In a prior life, I worked as a Nuclear Engineer doing reactor physics calculations for some of the nuclear power plants in the New England area. In those days, the plants I "got close to" were Maine Yankee (Wiscasset ME, Closed), Yankee Rowe (Rowe MA, Closed), and Vermont Yankee (Vernon VT, pending license extension). I also spent a few weeks at Vermont Yankee and Maine Yankee during one of their refueling outages and was given a great tour of Seabrook Nuclear Power Station (Seabrook NH, operating) before it went on-line.
In my present life, I install solar electric and solar hot water systems (NewEnglandBreeze.com). The only nuclear reaction I care deeply about now is 93 million miles away and is fusion not fission.
In my current role, I often hear that we should "go solar." And while I'm all for this, there is one big issue - Scale.
If you've ever been on-site at a nuclear power station, the thing that is most likely to impress you is the size. Just about every component used for or to support power generation is massive. For example:
* Inside each reactor building (the domes at Seabrook, Maine Yankee and, Yankee Rowe, the "box" at Vermont Yankee), is/was a crane capable of lifting the reactor core into place. The crane sat idle most of the time yet had the capacity to lift hundreds of tons.
* The Reactor Vessel head is held on with bolts as big around as a 5-gallon bucket. Ten men couldn't turn the wrench for the nuts so it is crane operated.
* The backup diesel generators at Seabrook Station are enormous. 40 feet high, 50 feet wide and more than 100 feet long. If you are in the room without hearing protection when they start, you'll likely go deaf.
Everything about these facilities is huge. And there is a reason for this. These units generate/ed staggering amounts of thermal and electrical energy. To put these numbers in perspective, here is what it would take to replace one year's worth of energy generated by Seabrook Station with solar panels (photovoltaics).
Seabrook Station is a Westinghouse designed pressurized water reactor (PWR). It is rated at 1,244 megawatts-electric. That means that its peak power output is 1,244 Megawatts (1). Seabrook's capacity factor for the past three years was, on average, 88%. That means it operated at peak power for 88% of the 8,760 hours in the year (or some combination of below peak and peak such that the total annual production was 88% of the plant operating at 100% power for 8,760 hours). Thus, the average energy output of the plant for each of the past three years was 1,244 MW x 8,760 hours x 88% = 9,622,439 Megawatt-hours.
A typical solar panel is around 200 watts of peak power (they range from tiny 10 watt panels to 300+ watts, but most "grid tied" applications use 180 to 240 watt panels). In MA, the solar capacity factor for an unshaded solar array is about 13%. That means for every 1,000 watts of solar panels, you'll get about 1,200 kilowatt-hours per year. When installing solar panels on "ground mounted" or "flat roof" arrays, we can fit, on average, about 7 watts per square foot (we have to space panels out so they don't shade each other).
If we want to generate 9.6 million Megawatt-hours in a year using solar, we need more than 40 million 200-watt solar panels. At 7 watts per square foot, those 40 million panels require more than 41 square miles (assuming no space for roads). And that only replaces Seabrook Station! (And worst of all, you'd only get that energy on sunny days. As my friends who are still in the Nuke business say, "Solar's all right, but Nukes do it all night.")
We (humans) use an enormous amount of energy (particularly in the US) and until we dramatically change our energy use habits, we are stuck with Nukes and all the other undesirable energy generating plants.
-The Energy Miser
P.S. As I finished this write-up, I realized I have the numbers for wind generation as well. The Hull Massachusetts Unit 2 Wind Turbine is a land based turbine rated at 1.8 Megawatts. It has a 200-foot tall tower and 130-foot blades. Its first year's capacity factor was about 26%. How many turbines do we need to replace Seabrook? Assuming a 26% capacity factor, a Hull-2-sized turbine will generate 1.8Mw x 8,760 hours per year x 26% = 4,100 Megawatt-hours per year. Therefore, Seabrook's 9.6 million MWh/year divided by Hull-2's 4,100 MWh/year = 2,353 Hull-2-sized wind turbines.
Cape Wind better get moving...
-TEM
(1) The unit "Megawatts" is a measure of power and is an "instantaneous" measurement. The unit "Megawatt-Hours" is a measure of energy or power over time. Your electric company bills you for energy. However some commercial/industrial sites also pay "demand" charges which are based on peak power usage.