Wind farms reduce CO2e emissions in the overall electrical grid by substantial amounts. Typical grids produce 800 g of CO2e per KWh generated by their mixes and wind energy displaces virtually all of that. Claims related to concrete use are pure disinformation as is shown by apples-to-apples comparison of full-lifecycle comparisons of wind energy to other forms of generation. Implications that wind farms change weather and cause global warming are massive exaggerations from minute local effects.
There are four overlapping places where people attack wind power with incorrect information:
- Wind turbines full-lifecycle CO2 emissions including the concrete bases is very low
- Wind turbines don’t require extra backup running so it doesn’t get added in
- Cycling of fossil fuel plants to support variability of renewables barely adds any CO2
- Wind turbines don’t change the climate by mixing layers of air
Wind turbines including concrete bases have the lowest CO2e emissions of any form of generation
Concrete use is factored into the full lifecycle cost analyses (LCA) comparing various forms of generation. Manufacturing LCAs follow ISO standards, must be published and must be subjected to external independent auditing. Every manufacturer of anything bigger than a breadbox follows the same standard, regardless of what form of generation they are building and maintaining. The best available meta-analyses of all forms of generations’ lifecycle costs of energy show that wind energy has a full-lifecycle, CO2e emission lower than any other form of generation, lower even than nuclear, 1 / 50th of natural gas and 1 / 100th of coal.
Wind turbines not use unusual amounts of concrete, and it is included in the apples-to-apples comparisons that show that with the concrete bases, wind energy is still much better than the alternatives.
Wind farms on the grid require a fraction of their capacity as backup, and the backup is often non-CO2e producing
Before we get into the details, what does actual grid management data show? Pretty much one-for-one replacement of fossil fuel generation with wind energy, meaning that CO2e is also displaced on a one-for-one basis.
According to major grid management studies in the UK and Finland, renewables at penetrations of up to 20% of demand will require only 20% of their capacity as backup and that backup can and will be from neighbouring jurisdictions’ excess capacity, whether from unused hydro capacity within jurisdictions and from already existing fossil fuel generation capacity that is maintained as backup instead of being decommissioned.
Picking apart the disinformation, no one suggests that wind energy provide 100% of grid demand, but that it makes sense in the range of 10-20% of grid demand for the majority of jurisdictions (outliers including Spain, Holland and one state in Australia). In that range, it requires about 4% maximum of demand as backup.
The second piece of disinformation is the assertion that coal or natural gas capacity has to be built to provide this backup capacity. As backup will come from existing nearby jurisdictions, unused hydro and existing generation capacity that is no longer used full-time, no new backup must be built in the vast majority of cases. Natural gas plants are typically used for peaking supply now, which is exactly the same usage model needed for renewables backup; they often have capacity factors of 10% already. This doesn’t change anything about use of natural gas. Coal plants are never used for backup because it takes hours to turn them up or down.
Empirical evidence from the UK National Grid and the US NREL shows almost no impact on fossil fuel plant efficiency
These are the results of the “high” penetration scenario of the Sept 2013 released study from the US National Renewal Energy Lab where 16.5% each of wind and solar were providing total demand. Note that when 33% of energy is provided by renewables, total carbon savings are from 39-34% and other savings are equally significant. Total fuel costs savings for supply were $7 billion compared to <$35 million for increased operating costs for fossil fuel generators, a net savings in costs of generation of about $7 BILLION DOLLARS. This study was based on emissions data from almost every generation facility in the USA, and reviewed by over 50 grid management and energy experts from utilities, research institutes, universities, manufacturers and generation firms across the USA.
A direct quote from the head of Energy Strategy for UK’s National Grid is persuasive:
Dismissing this as one of the “flakier arguments” in the renewables debate, Smith points to arecent analysis National Grid undertook for the Scottish Parliament. It concluded that over an 18 month period, the expected emissions benefit of using wind power – that is the amount of carbon dioxide saved by using wind to produce power – was reduced by just 0.1 per cent as a result of the need to use fossil fuel power stations as backup.
So wind energy requires a fraction of its capacity as backup and that backup won’t be creating nearly as much CO2e as critics claim.
Wind turbines can make minor changes to local weather, not the climate
Liming Zhou, associate professor at the State University of New York, Albany published a paper on February 2012 in Nature Climate Change which found that ground temperatures directly beneath three wind farms in Texas were an average of 0.72 degrees warmer. The diagram below is from his paper showing an enhanced view of this increase in ground temperature.
First, the facts.
- Mr. Zhou did publish a paper which found localized warming under wind farms in Texas at night. This was an average of 0.72 degrees.
- It is highly localized. There is no spread of this warming beyond the immediate locales of the wind farm.
- There is no observable impact on local flora or fauna.
- There is no connection to drought in Texas.
- The study only looked at “satellite data for the period of 2003–2011 over a region in west-central Texas”.
Now the spin, which Mr. Zhou backed into and then backed away from:
- Mr. Zhou stated in his paper that: “Our results show a significant warming trend of up to 0.72 °C per decade.” As his data only covers 9 years, it is impossible for him to assert a warming trend per decade.
- Mr. Zhou also says “These changes, if spatially large enough, may have noticeable impacts on local to regional weather and climate.” What he doesn’t say is that this would require wind turbines everywhere. And what he also doesn’t say is that this degree of wind energy would supplant all fossil fuel generation within a radius of about a 1000 miles with its attendant waste-heat and warming C02 emissions. The net impact would undoubtedly be highly positive. While AGW is strongly supported by evidence, Mr. Zhou is speculating.
To his credit, at no time did Mr. Zhou say wind turbines would have a larger climatic impact. This was left to Fox News and various other news sources that should have known better, but couldn’t resist the headline.
This has become fodder for a long-running myth that has been dismissed by everybody who doesn’t hate wind energy. Only global-warming denying news outlets and anti-wind lobbyists still pretend this is true. It’s part of their habit of throwing everything and the kitchen sink at wind turbines instead of having a rational conversation about siting and intelligent setbacks.
So what does this all mean?
Wind farms are a key wedge in the fight against global warming. They produce less CO2 full lifecycle than any other utility-scale form of generation when all factors are added in. And since they eliminate fossil fuel generation pretty much one-for-one, every hour they are spinning they are reducing carbon emissions from the grid.