Wind energy is now, in regards to energy production, very competitive with conventional electricity sources. There are several fiscal concerns regarding dependability when considering wind turbines, including back-up generation, operation consistency, efficiency, and cost. However, these too, are very competitive with conventional power plants.

Because of the electric grid’s innate design, every megawatt of wind energy does not need to be backed up with a megawatt of fossil fuel. The Utility Wind Interest Group reported that “…even at moderate wind penetrations, the need for additional generation to compensate for wind variations is substantially less than one-for-one and is often closer to zero.” (2003) Furthermore, research conducted in 2004 for the Minnesota Department of Commerce determined that adding 1,500 MW to the system of Xcel Energy in Minnesota would need only an additional 8 MW of conventional generation to deal with the new variability. This addition would generate enough electricity from wind energy to power more than 400,000 homes!

Several sources of electricity considered extremely reliable, coal, nuclear power, or natural gas, for example, undergo unpredicted outages. They are also not backed-up with a comparable amount of generation from a different plant. Wind farms are built in windy areas where seasonal and daily wind patterns can be estimated. Because of this, wind is indeed a variable source of energy but it is not unreliable. How can we measure the productivity of a wind turbine or any other power production facility? It is done by comparing the plant’s actual production over a specific period of time with the amount of power the plan would have produced if it had run at full capacity for the same amount of time. It looks like this:

Capacity Factor =

Actual amount of power produced over time
_______________________________________________

Power that would have been produced if turbine
operated at maximum output 100% of the time

Wind turbines generate electricity most of the time (65-80%) but the output amount is variable. However, a power plant that operates at 100% of its maximum generation potential 100% of the time, doesn’t exist. Wind farms are built in locations where the wind blows at a constant rate, yet variations occur due to seasonal changes, so a wind farm will generate power at full rated capacity about 10% of the time. On average, a wind plant will generate at 30-40% of its rated capacity throughout the year. As more utility-scale wind energy projects are developed across the US, the number of wind turbines operating in a given area will increase. This has been shown to inherently reduce wind’s aggregate production variability, making it more predictable and reliable.

To date, a backup capacity for wind energy does not exist. Surplus wind energy can grow substantially during times that do not match customer use patterns. Therefore, there is a strong need to find ways we can store this “surplus” energy. Two proposed off-peak electricity uses of this “surplus” energy, include the deployment of plug-in hybrid vehicles with off peak charging and production of hydrogen to power vehicles.

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