Oversimplifying a complex topic – measuring the "sustainability" of renewable energy

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Cai Steger, Energy Policy Analyst, New York, Center for Market Innovation

The environmental impact of electricity generation is an incredibly complicated issue.  Each electricity generation option, be it fossil fuel, nuclear or renewable, brings with it environmental costs and challenges.  Some of these same energy technologies (such as renewables) also have environmental benefits when compared to others (such as coal power).  It’s impossible to do the topic justice in one (or many) blog post(s).

Which is what makes yesterday’s NY Times op-ed by Robert Bryce so unfortunate.  In it he raises questions about the environmental impacts of wind and solar generation, but does so by relying on incomplete and inaccurate data and extensive oversimplification, leaving information gaps large enough to ride a coal-laden train through (each one is over a mile long – so these are big gaps). 

NRDC welcomes an intelligent and nuanced conversation about this extremely complex topic.  We recognize both the critical need for utility-scale renewables projects, as well as the significant environmental damage that poorly sited projects can cause.  It’s a difficult line to straddle, but as demonstrated by our engagement in multiple multi-stakeholder efforts across the country, and our support of important renewable policies and funding we are trying to find a balance between the two.    

But before we can have that conversation, we need to have a common ground for discussion.  And in that sense, fact checking Mr. Bryce’s column is a helpful exercise in laying out some key parameters. 

  • Using “land use” and “steel use” is an incomplete measure of environmental impact.  When analyzing environmental impact, a full lifecycle analysis of a specific energy technology is critical to understanding the many, varied impacts from each aspects of the entire production cycle.  Among other things, this requires understanding water use and pollution, air pollution, habitat fragmentation and destruction, animal and/or plant mortality, soil degradation, noise, light and heat pollution, and waste disposal from not just the energy production process itself (i.e. generating electricity) but critically the full lifecycle of generation – the construction of the generation facility, the extraction and transportation of all inputs (e.g. fuel) and the decommissioning of the facility.   In determining “demand on natural resources”, Mr. Bryce looks only at wind and solar and stops at a back-of-the-envelope quantification of land use and steel use in only one segment of the full production cycle.  This paints a highly limited and inaccurate picture of total environmental impact from all energy technologies. 
  • “Land use” is not simply a measure of acreage of the production facility. Even if we just focus on “land use”, not all land use is the same.  Land intensity on a lifecycle basis is the critical metric – how the land is being disturbed, and whether it can be restored after use, and throughout the entire production cycle (i.e. extraction to generation to decommissioning).  It is unreasonable and inconsistent with existing reality to consider wind project developments with livestock grazing underneath turbines or farmers harvesting crops alongside turbines, more damaged than land around a coal mine or natural gas field, or fuel transport infrastructure (e.g. pipelines, railroads), or surrounding fossil fuel generation facilities. 
  • Specific to wind, calculating the land use of wind is more complicated than a simple “array spacing” measurement method.  Mr. Bryce uses “array spacing” for his wind calculations (i.e. all land between the turbines) as opposed to “turbine footprint” (turbine structures themselves, plus permanent structures).  Neither position fully reflects the environmental impact of wind power. Array spacing does not accurately account for the land impacts of wind energy because of the multiple complementary uses of the land and the relatively low intensity of the land usage. The footprint calculation does not fully account for the environmental effects of altering the flight space above the earth, causing avian habitat disturbance, and bird and bat mortality or habitat fragmentation due to road construction and transmission connection. To some extent, the same is true of solar facilities.  Mr. Bryce’s method of determining land use is certainly defensible in some viewpoints, but others would consider this too expansive a definition.  And to reiterate, either calculation remains a poor substitute for a more complete lifecycle environmental analysis.
  • Options to reduce the environmental impact of wind and solar are much greater than for fossil fuel and nuclear plants.  Simply put, and as demonstrated by a number of the “fast track” solar projects permitted last year by the Department of the Interior, renewable projects can be resized and re-engineered to reduce environmental effects from water and land use, habitat fragmentation and other pollution.  Decades of experience have shown this to be untrue in the case of surface coal mines, uranium mines, or natural gas fields, or extremely difficult to address in the case of toxic chemicals emitted into the air, soil and water from using that fuel.  Given the great need for new generation resources in the future, and the need to meet the priorities of many stakeholders, this ability to reduce environmental impact has real value.
  • The diversity of less environmentally impactful renewable energy resources must also be incorporated in this type of analysis.  Undoubtedly utility-scale wind and solar will account for significant portions of many state renewable portfolio standards, and with it the need for transmission.  But so too will zero-impact energy efficiency (which will reduce the overall electricity load and therefore the amount of renewables required), and distributed generation that can be built on brownfields, previously disturbed lands, or buildings.  Modeling for California’s 33% RPS is a good example of this concept. The either/or metric laid out by Mr. Bryce is too limiting and incomplete, and therefore flawed.

There are many other factors to be taken into account in analyzing the footprint and impacts of different energy technologies – we have highlighted just a few in this limited space. As multiple analyses have shown in recent years, there is a huge disparity between just land use calculations, where depending upon your assumptions, each technology can be favorably or unfavorably compared to the other.  We do ourselves and all interested stakeholders a great disservice if we don’t paint a full picture of the impacts of all our energy choices, especially at such a critical juncture in building our clean energy future.

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