Long, boring road trips allow lots of time for pondering. Lots of wind farms allow for lots of comparison.
Why were some turning while others were not? It sure seemed like the closer to the road they were, the more they turned. Like stage dressing for eager Sierra Club motorists, puttering along in their polluting conveyances. Or perhaps the ones encroaching on highways were newer and earning the $0.023/kWh production tax credit, while the ones farther away had been abandoned or were simply priced out of the market at the time? Why was a wind farm on the right hand side of the road turning away, while one on the left hand side sat idle? I did see more turning than not, which probably means there's adequate wind transmission capacity for what's been built.
This report says that wind is curtailed for 3 main reasons:
1. Transmission constraints. Not enough transmission for peak periods. Since the capacity factor for wind averages 35%, is it economic to build additional transmission for the odd times when wind is producing at a higher rate? Probably not.
2. System balancing. High wind penetrations make it hard to keep the system in balance because they require curtailment of base load generators during periods of low load. That's not economic either. "Some utilities or grid operators have curtailed generation from wind plants when minimum generation levels on fossil-fuel plants are reached, because stopping and restarting fossil units within a few hours can be significantly more expensive than paying for a few hours of wind curtailment."
3. Other reasons: voltage issues, interconnection issues, frequency and stability issues. Too much intermittent wind can make the grid unstable. Wind generators also "self-curtail" to protect bats and enable de-icing. Probably not a problem, since it was well over 100 degrees when clusters of wind turbines sat idle.
The expired production tax credit pays wind farm owners $.023/kWH generated. How much is that on an annual basis? Not information easily found. Why not? This article says that the PTC has cost American taxpayers $30B over the past 35 years. Of course, the Koch monster gets blamed for spreading "misinformation," but nobody offers a corrected figure.
Warren Buffet has bragged that the production tax credit is the only reason to build wind farms, "they don't make sense without the credit."
The PTC allows wind generators to bid into energy markets at low, or even negative, prices. This makes it harder for unsubsidized base load generators to stay afloat. As a result, these generators beg for ratepayer subsidies and foist the cost of their failing generators off onto ratepayers.
Who thinks that we can replace all fossil fueled electric generation with intermittent renewables like wind?
Not PJM, whose recent capacity auction provides additional money to generators who can produce when called upon (you know, those baseload fossil fueled generators). This is going to cost consumers an additional $3.4B in yearly capacity charges.
And there we are. New intermittent wind capacity is being built at an alarming rate because it is profitable. New wind transmission capacity is being overbuilt at an alarming rate because it is profitable. All this intermittent generation is causing increased costs for consumers.
But the industry is raking it in. Thoughts to ponder...