Power Production
The Corps has 375 main generating units, plus a number of "house units" that only provide power to run the internal systems of our powerhouses (these are called "Station service Units"). Our smallest units are 1 megawatt or less, but most of our units are very much larger, up to our largest unit which can produce 220 megawatts. Our powerhouses range from having a single small generating unit, up to having to 27 huge units (the powerhouse at that plant is nearly a half mile long!). All together our units have the capability to generate 21,000 megawatts--making the Corps of Engineers the largest producer of hydroelectric power in the US. If 21,000 megawatts sounds like a lot of power, it is! Read on to see just how much.
A Relative Example
The basic unit of measure for electrical POWER is the watt. Everyone is familiar with what a 100 watt light bulb looks like. A 100 watt bulb consumes 100 watts of electrical power when operating; 10 bulbs consume a total of 1000 watts to operate. 1000 watts is the same as 1 kilowatt (kilo is the metric word for 1000), which is abbreviated as 1 kW.
The basic unit of measure for electrical ENERGY is the kilowatt-hour (abbreviated as kW-hour). The 10 light bulbs, when left on for 1 hour, use 1 kW-hour of electrical energy. If you look on your monthly electrical bill, you will see how many kW-hours of electricity you used in your home. Electrical energy costs vary significantly in different parts of the country, but for this example we will use a value of 8 cents per kW-hour. If you used 500 kW-hours hours and were charged 8 cents per kW-hour, your monthly bill would be $40 (500 kW-hours x $0.08).
Back to the light bulb example. How many 100 watt light bulbs could the Corps' 21,000 megawatts run? Well, 1 megawatt is the same as a thousand kilowatts. Remembering that 1 kW can light 10 bulbs, and that 1 megawatt is the same as 1000 kW, you find that 1 megawatt will run 10,000 light bulbs (1000 kW x 10 bulbs/kW). Since 1 megawatt can run 10,000 bulbs, 21,000 megawatts can run 210 million light bulbs (21,000 x 10,000 bulbs)!
If an average value of 8 cents per kW-Hour is used, and if all of the Corps generating units were run at full capacity for one day, the value of the electricity generated would be: (21,000 megawatts) x (1000 kW/megawatt) x ($0.08/kW-Hour) x (24 hours/day) = $40,320,000.
That would be $40 million per day if all units were running at full capacity! However, all of the Corps' generating units cannot be operated 100% of the time for a number of reasons: The need for power varies hourly, daily, and seasonally. Large quantities of electric energy cannot be stored, so electricity is only generated when needed. The amount of water flowing in rivers varies depending on the season and the weather (at times there is insufficient water available to run all units). Maintenance needs make some units unavailable. Environmental factors often require specialized or restricted operations.
But even with all of these factors, the sale of hydroelectric power generated from units operated by the Corps of Engineers returns an amazing amount of revenue to the US Treasury each year.