Wind farm argument misapplies load factor
In particular, it repeated the incorrect ‘fact’ that wind farms only produce power a third of the time. Wind farm opponents often assert this misunderstanding.
To quote the link: ‘But the proportion of time a wind turbine operates is called its load factor. And the load factors achieved by commercial wind farms are low.’ This is a misunderstanding of the concept of ‘load factor’ or ‘capacity factor’ as it applies to wind turbines. It is not ‘availability’. Wind turbines typically are available at near 100%.
A nuclear plant, for example, is essentially an on or off device. It is either producing 100% of its capacity or zero. A reactor running at, say, 50% is a sick reactor. What this means is that a reactor with a 80% load factor (British average) is cold and dead - unavailable - for more than two and a half months per year, often requiring 1,000 megawatts of backup power.
A wind turbine is different. Here is an analogy: an automobile engine is ‘nameplate’ rated at 100 horsepower. The actual typical demand on the engine may be only 10 horsepower. Only for passing or large accelerations does it reach near 100 HP. Running at a 10% capacity factor does not imply that it is unavailable 90% of the time.
A wind turbine is the same. Its ‘nameplate’ rating is sized for the occasional gusts of high winds that carry lots of valuable energy. Ordinarily, the winds generate at 30%-40% of maximum capacity. The turbine, if downsized to produce 100% at average wind speeds, would waste the power of the gusts.
The key point is that a wind farm operating at 35% capacity factor may, in principle, be available 100% of the time producing a steady 35% of rated capacity. Or it may fluctuate widely. That is not an inherent feature of wind turbines, but of individual sites. Off-shore farms may be very consistent, while desert sites may be quite variable. Do not misapply the concept of load factor.
Yale Simkin
Bolingbrook
Illinois 60490
United States
