A new study suggests that the intermittency problem associated with wind power can be overcome in part by building more wind power.
One of the drawbacks to wind turbines is that while they may provide a lot of energy at times, they can never be counted on to provide energy in a pinch, a characteristic called “capacity.”
As a result, if a larger proportion of windmills are deployed on the power grid, the system will also need a lot of conventional generation that will sit idle for most of the hours in a year, providing value only by being available for when the wind stops.
A new study of wind integration, however, argues that the capacity value of windmills could be improved by building even more of them, spreading them out geographically, and connecting them with a strong grid.
The reason is that the wind is always blowing somewhere, and if it can be averaged over a bigger area, the minimum amount of energy available will rise.
The study, ordered by the Energy Department’s National Renewable Energy Laboratory and performed by the EnerNex Corporation of Knoxville, calculated, for example, that if massive wind farms were built in the Great Plains states, with only weak grid connections to the eastern seaboard, they could be counted upon for only 19.9 percent of their capacity.
That is, while a single turbine might be capable of producing one megawatt, it would take five of them to assure a supply of one megawatt.
But with stronger transmission connections, grid planners could assume a minimum availability of 24.1 percent.
The percentage difference may seem small, but newly built power plants cost millions of dollars per megawatt of capacity, and the added capacity value would offset the cost of the transmission.
The study’s overall conclusion is that there is no technical barrier to supplying 20 percent or 30 percent of the energy on the Eastern Interconnection, the power grid that stretches form Halifax to New Orleans. It would take money, however, and a new way of planning for transmission lines.