By Fred Porter
Special to The Sopris Sun
Wind power continues to be Colorado’s largest source of electricity with near-zero greenhouse gas (GHG) emissions, accounting for 28% of generation in 2022. Xcel Energy reported its fraction of electricity generated by wind was 35%, and Holy Cross Energy (HCE) reported 36%. HCE’s new windfarm was only operational in June 2022, so their fraction will be significantly higher this year. Further wind power expansion is important for decarbonizing heating, as wind power production is 30% greater in winter than in summer, contrasted with solar power production which is 50% less.
In eastern Colorado, there are about 2,900 wind turbines. Enough electricity for 1,000 households is generated by each new turbine, about half of this by the older ones. Many of these are visible from I-70 and I-76, leading some to conclude that the Colorado prairie is filled with turbines, though that’s not the case. Property agreements are in place for more windfarms, though the power lines from the plains are occasionally congested.
Power line capacity can be increased by allowing more current to flow in existing power lines during cold, breezy weather and Xcel has run a pilot project. Replacement of inflexible coal plants with quick-acting gas plants will free up capacity on a few existing lines. Xcel’s “Power Pathway” will build new power lines in the southeast and south-central plains. Locally, Xcel is replacing the 100-year-old Hopkins-to-Basalt line. The new poles will be able to carry another circuit, eventually doubling its capacity to supply the Valley with wind power from the plains.
On the West Slope, wind conditions are less favorable. The best potential is north of Craig, but most of that land is off-limits to protect sage-grouse habitat. Just over the Wyoming border the largest windfarm in the country is finally under construction by a subsidiary of Anschutz Corporation. Two huge power lines are also under construction to carry that wind power and more from Wyoming to Utah, at one point paralleling existing lines west from Craig, yet with no connections in Colorado.
Wind power installations slowed significantly in the last two years nationwide. If the U.S. is in a clean energy rush, why? Is this also happening in Colorado? Yes, for the time being. But no, in the near future.
During 15 years of wind power expansion, the cost of competing power fell; first due to cheaper fossil gas, and then due to cheaper solar panels. Also, “the grid” is congested in some windy areas which increases the cost of wind power connection. Some material supplies were disrupted, due to COVID, trade restrictions, natural gas price spikes and the Ukraine war. More recently, interest rate increases have raised the cost of power from all new generators.
With assistance from fossil fuel interests, opposition to windfarm development has increased. Support from some progressives and climate activists has been tepid. This is usually based on environmental concerns, some real but some exaggerated, outdated, or imaginary.
The inputs of energy and materials are often cited first by opponents of windfarms. Why put up with their impacts if they don’t actually reduce GHGs? The supply chain for wind turbine components clearly causes GHG emissions. Comparing inputs and outputs can be confusing because wind turbines generate electricity, and fossil fuel is burned directly to produce some of the components. However, multiple studies and measurements conclude that fossil fuel-based electricity emits 40-80 times more GHGs than wind-generated electricity.
Some environmental effects have been reduced by recent improvements. Probably the most well-known effect is the killing of birds, particularly raptors. Over time, developers and regulators have become better at avoiding prime habitat. Towers for the first wind turbines were built with struts which provided raptor perches, but now cylindrical towers are universal. Although 60,000 wind turbines were installed in the U.S. over the last 15 years, the bald eagle population has increased by a factor of four.
To avoid clobbering birds, automated cameras and sensor arrays are also being deployed. These scan the sky, determine the path and species of detected birds, and signal the turbine to apply the brakes when required.
The same can be done for bats with sensors that listen for their echolocation.
Four-legged wildlife like antelope continue to use habitat that intersects with windfarms, though avoiding some areas at some times. Maintenance traffic in operational windfarms is only intermittent.
Some of the visual impact can be mitigated, but obviously not all. The blinking lights can stay off until radar detects approaching low-flying aircraft. These Aircraft Detection Lighting Systems are already mandated in three states. At times, shadows from spinning blades may flicker annoyingly across home sites, but simple software can know when to stop the rotation to avoid this.
Rotating blades make noise, though the wind itself often drowns this out. Newer blades reduce noise using serrated trailing edges and newer turbines have quieter gearboxes and generators. I stopped below a spinning wind turbine in Iowa recently and the cicadas completely drowned it out.
Defunct towers and generators are usually recycled, but the composite blades less so. Recently, blade recycling facilities have opened. When the oldest windfarms have worn out, most have been “repowered,” meaning the turbines are replaced, typically with fewer but larger new ones. And while fossil fuel wells and mines are eventually depleted, the wind is not.
On the internet, pictures are readily available of collapsed towers, broken blades and burning generators. These failures are very rare (1 in 5,000 or 10,000 per year), and the impacts are localized and quickly mitigated. Concerns about EMFs and infrasound seem to exaggerate small increases in background exposures. Relative to the exposures and effects from fossil fuels, these seem minor.
A follow-on article will discuss the costs and prices of wind power, and the integration of high fractions of variable power into a reliable, affordable electric grid.
This map shows the location of windfarms in Eastern Colorado — about 2,900 total wind turbines. Map services and data are available from U.S. Wind Turbine Database, provided by the U.S. Geological Survey, American Clean Power Association and Lawrence Berkeley National Laboratory via eerscmap.usgs.gov/uswtdb