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Sunday, March 24, 2013

A(nother) reason to be skeptical about wind energy reducing emissions

A recent article on Treehugger related very closely to analysis I've been performing on 2011 U.S. Energy Information Administration data.

Iowa and South Dakota Approach 25 Percent Electricity from Wind in 2012: Unprecedented Contribution of Wind Power in U.S. Midwest | Treehugger
Graph from Treehugger

Defying conventional wisdom about the limits of wind power, in 2012 both Iowa and South Dakota generated close to one quarter of their electricity from wind farms. Wind power accounted for at least 10 percent of electricity generation in seven other states. Across the United States, wind power continues to strengthen its case as a serious energy source.
The entire article can be read at Treehugger
It looks great.

But, "seriously", here's the thing ....

The top 10 states in Treehugger's 2012 list are also the top 10 from the 2011 U.S. data I've been reviewing (here - 2011's data set includes emissions data only provided early in 2013).

75% of the top 12 wind states have higher CO2 emissions, per MWh of generation, than the US average.  The 3 exceptions, SD-South Dakota, ID-Idaho and OR-Oregon, all generated the majority of their electricity, in 2011, with hyrdo ( 51%, 71% and 81% respectively).

This may not be particularly meaningful in the negative sense either.  I've looked at CO2 emissions intensity for 2005 (when total US wind production was ~17TWh) as well as 2011 (when it had risen to ~120TWh).  At first glance this appears very positive for wind proponents, with the average reduction in CO2 emissions intensity, for  the 12 states noted above, being 21%, while the national average was only 11%.

However, the largest reductions in emissions are in the 3 states noted above as getting over half their generation from hydroelectric generation - and 2011 was a good year for hydroelectric production in those 3 states.  Filtering out those states, the average reduction in emissions intensity of the other 9 states was 11% ~ neither notably better or worse than the national average.

Wind energy's impact on emissions remains questionable - leaving the question to how it is a "serious energy source."

Looking at a couple of maps will indicate why the top wind states are the top wind sites - average wind speed aligns fairly well with wind generation as a percentage of total generation.

The darker the blue, the higher the % of wind



The growth of wind power in the USA has been fueled, in part, by federal programs that provide incentive to have more productive projects - and the turbines have settled accordingly.   Wind has a characteristic of  "a serious energy source" when it's located affordably in a windy region with a populace welcoming it.

A map indicating the emissions intensity in each state doesn't indicate good states and bad states - and it does not indicate wind states as low emissions states - but it does seem to indicate states that either mine coal or are close to coal mining states.  In those states, which feature Wyoming, coal remains the serious energy source.

I previously noted the CO2 emissions intensity dropped 11% from 2005 to 2011; as total generation changed only 1% over that time that equates to a 257 million metric ton reduction in emissions of CO2.
15 states each reduced emissions over 10 million metric tons.
None of those 15 states was in the top 10 (12) wind states as Treehugger, and I , calculated them above.

The greatest reduction in annual CO2 emissions came in New York, followed by Ohio - both of which produced less than they consumed; both were not simply net importers, but their levels of net imports grew from 2005 to 2011.

It's been a good period to live close to Ontario and Quebec (see Cheap Canadian Imports contribute to historic low New York electricity prices)