The Damage Done, Part 10 — Are Renewables Really Better for the Environment Than Fossil Fuels?

Over the past two months, I’ve written a series of articles on “The Damage Done” by various energy sources used for the generation of electric power. Each week, I’ve examined one of the primary energy sources, whether “green” or conventional, trying to understand the environmental effects of each method of generating power — pollution, greenhouse gas emissions, health effects, or other externalities. Having written nine articles in the series, I’m now ready to do a comparison and try to answer the question, “Is green energy really any better for the environment than conventional power generation from such sources as coal, natural gas, and nuclear?”

In case you want to get caught up on the previous installments of this series, here’s where to find them:

The Damage Done, Part 1 — Is Green Energy Really Better for the Environment?

The Damage Done, Part 2 — How Do You Measure the Environmental Effects of Energy?

The Damage Done, Part 3 — Is Coal Really So Bad for the Environment?

The Damage Done, Part 4 — Natural Gas, Green or Dirty?

The Damage Done, Part 5 — Nuclear Power, the Green That Glows?

The Damage Done, Part 6 — How Green Is Hydro Power?

The Damage Done, Part 7 — Wind Power — Really Green, or Is It Just Spin?

The Damage Done, Part 8 — Does Solar Power Have Its Environmental Dark Side?

The Damage Done, Part 9 — Geothermal Is Hot Stuff, but Is It Really Green?

Pie chart showing global sources for electricity generation

I’ve been able to find several studies that put numbers to the environmental impacts of electrical power sources. These studies vary in the range of energy sources they cover, in what they measure, and in the metrics they use. By examining a number of them, we can start to get a reasonable idea of how the various energy technologies stack up against one another.

Power Production and Greenhouse Gases

Gas power plant in New Hampshire, US

Gas power plant, New Hampshire, U.S. Credit: Flickr/Jim Richmond, CC BY-SA 2.0

Researchers have devoted the most effort to identifying the climate-change impacts of electric power generation, or “carbon footprint.” Carbon footprint is a measure of greenhouse gas (GHG) emissions, usually expressed in carbon dioxide (CO2) equivalents, or “gCO2eq,” (grams of carbon-dioxide equivalent). The term “equivalent” enters in because CO2 is not the only GHG — water vapor, methane, nitrous oxide, and ozone are also GHGs. But for convenience, the greenhouse effects of all of the GHGs are wrapped up together into the one CO2-equivalent metric.

The following chart shows various electrical generation sources and their climate-change impacts, according to three different sources:

  1. NEEDS (New Energy Externalities Developments for Sustainability), Project no. 502687, “External costs from emerging electricity generation technologies,” March 24, 2009
  2. Dynamic life cycle assessment (LCA) of renewable energy technologies,” Martin Pehnt, Institute for Energy and Environmental Research, Germany, Renewable Energy, 2006;
  3. Valuing the greenhouse gas emissions from nuclear power: A critical survey,” Benjamin J. Sovacool , Vermont Law School, Energy Policy, 2008

 

Climate Change Impacts of Electricity Generation Sources

Energy Source NEEDS Climate Change Damage in Year-2000 Euro-cents (€c) /kWh NEEDS Climate Change Abatement Costs in Year-2000 Euro-cents (€c) /kWh Pehnt — gCO2eq/kWh Sovacool — gCO2eq/kWh
Conventional Energy Mix (Coal, Gas, Nuclear, etc.)

566.000

Coal

.66 – 9.40

1.82 – 2.16

960 – 1,050

Natural Gas

.32 – 4.35

0.94

443.000

Nuclear

.01 – .07

0.01

66.000

Hydro

10.000

10.0 – 13.0

Wind

.01 – .08

0.02

11.000

9.000

Solar PV

.05 – .62

0.13

104.000

32.000

Geothermal

41.000

38.000

 

These figures demonstrate a dramatic difference in the GHG-related impacts of the various energy sources. Fossil fuels, that is, coal and natural gas, are much higher emitters than nuclear and the renewables. Just to try to put some scale on it, let’s give the seemingly most-innocuous energy source, wind power, a score of 1 and show how the other energy sources compare as GHG emitters:

 

Energy Source Climate-Change Impact as a Multiple of 1
Wind

1.00

Hydro

.91 – 1.44

Geothermal

3.73 – 4.22

Solar PV

3.55 – 9.45

Nuclear

.50 – 7.33

Natural Gas

32.00 – 49.22

Coal

66.00 – 117.50

 

This means that, when it comes to GHG-related environmental impacts, wind and hydro have the lowest impacts; geothermal, solar, and nuclear have quite-low impacts; and fossil fuels have very large impacts. Natural gas’s emissions per kilowatt hour are at least 32 times as high as wind’s, and coal’s are at least 66 times as high.

 

Aerial view of Isar II nuclear plant in Germany

Isar II nuclear power plant, Germany. Credit: Flickr/J Brew, CC BY-SA 2.0

 

Not all readers will agree that greenhouse gas emissions really cause dangerous global warming, but the fact that the fossil-fuel technologies result in much higher GHG emissions should make us suspicious that they might cause other emissions and other environmental damages as well.

Let’s see whether that’s the case.

Environmental Effects of All Those Kilowatt Hours

The NEEDS study mentioned previously estimated damages across a number of energy sources, considering other areas besides climate change: health impacts, biodiversity loss, crop yield losses, material damage, and land use. The following chart consolidates some of the NEEDS findings:

 

Quantifiable External Costs From Electricity Generation Technologies in Year-2000 Euro-cents (€) per kWh
Technology Health Impacts Biodiversity Crop Yield Losses Material Damage Land Use Total Non-Climate Cost
Coal – Lignite

0.720

0.070

0.020

0.010

0.010

0.840

Hard-Coal

1.050

0.090

0.020

0.020

0.050

1.240

Natural Gas Combined Cycle

0.310

0.030

0.010

0.010

0.010

0.370

Nuclear

0.060

0.004

0.001

0.001

0.010

0.080

Offshore Wind

0.060

0.000

0.000

0.000

N/A

0.070

Solar PV

0.470

0.020

0.000

0.010

N/A

0.500

Concentrating Solar

0.120

0.010

0.000

0.000

N/A

0.13

 

You can see from these results that nuclear power and the renewables compare favorably in most categories with the fossil fuels. The one exception is photovoltaic solar, in the category of health impacts. In the short-term, PV solar’s health impacts are rated worse than those of natural gas. The longer-term projections of the NEEDS report show PV’s health impacts declining to .07 cents/kWh for 2025, and .04 cents/kWh for 2050.

One current concern about solar PV is the manufacturing process required to produce solar panels. In its report “Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use,” the U.S. National Academy of Sciences writes:

Solar panels are made of semi-conducting materials similar to those used in the electronics industry. “Solar grade” silicon, derived from quartz sand, is the most commonly used material to make solar panels. However, emerging thin-film technology, which allow use of solar panels as roof tiles and other building features, can be made of a variety of materials, including amorphous silicon, gallium arsenide (GaAs), cadmium-telluride (CdTe), and copper indium gallium selinide (CIGS)…

Manufacturing these panels is a very high-technology, material- and energy-intensive process. A number of the metals for thin-film PV technology are toxic (for example, arsenic and cadmium), thus raise environmental and public health concerns about metal emissions during the extraction, material upgrading, and manufacturing activities associated with PV systems.

End-of life disposal of solar panels is another concern highlighted by NAS:

Worn-out solar panels have potential to create large amounts of waste, a concern exacerbated by the potential for toxic chemicals in solar panels to leach into soil and water. Many components of solar panels can be recycled, but the United States currently does not have or require a solar PV recycling system.

Nurek Hydropower plant, Kyrgyzstan

Nurek Hydropower plant, Kyrgyzstan. Credit: Flickr/Oleg1975, CC BY 2.0

Martin Pehnt’s life cycle analysis (LCA) study, mentioned above, evaluates the environmental impacts of electrical generation technologies in a different set of categories, including:

  • The amount of non-renewable energy they require — even hydro, wind, and solar involve some use of conventional energy somewhere in their life cycles;
  • Their resource consumption — that is, non-energy resources, such as construction materials to build plants. Pehnt uses iron ore as a proxy for resource consumption in general;
  • Their contributions to acidification (decrease in pH and increase in formation of acid, particularly in seawater) and eutrophication (excess algae growth in water, or blooms, due to deposition of chemicals); and
  • GHG emissions, as discussed previously.

LCA involves investigating the “environmental impacts of … systems or products from cradle to grave throughout the full life cycle, from the exploration and supply of materials and fuels, to the production and operation of the investigated objects, to their disposal/recycling,” Pehnt explains.

Pehnt’s analysis compares renewables with a conventional energy mix of such sources as coal, gas, and nuclear. The following chart lays out some of the key measures from his study:

 

Environmental Impact

Conventional Energy Mix impact
/kWh

Hydro impact
/kWh (large facility)

Wind (on-shore) impact
/kWh

PV Solar impact
/kWh

Geothermal impact
/kWh

Non-Renewable Energy Demand in megajoules (MJ)

8.91

0.10

0.12

1.50

0.54

Iron Ore in grams (Proxy for non-energy resource consumption)

2.60

1.70

3.30

3.30

3.20

Global Warming (g CO2 equiv.)

566.00

10.00

11.00

104.00

41.00

Acidification (mg SO2 equiv., or sulfur dioxide equivalents)

1,083.00

42.00

61.00

528.00

190.00

Eutrophication (mg PO43- equiv., or phosphate equivalents)

59.90

5.00

4.00

44.00

24.80

 

As you can see from these results, renewables compare favorably with the conventional energy mix in most categories. Since all electrical generation requires the construction of physical facilities, renewables and conventional energy score about the same when it comes to resource consumption.

Wind farm in Spain

Wind farm in Spain. Credit: Flick/Chris Barber, CC BY 2.0

PV solar’s impacts tend to be higher than the other renewables, especially hydro and wind — again, the manufacture and end-of-life disposal of photovoltaic panels have significant environmental effects, although not to the extent of fossil fuels.

So, it’s safe to say that the research points to greater environmental damage caused by fossil-fuel power generation. Renewables such as hydro, wind, solar, and geothermal do less environmental damage per kilowatt hour, considering such areas as health impacts, loss of biodiversity, loss of crop yields, acidification, eutrophication, and climate-change impacts.

Nonetheless, each source of electrical power generation comes with its own environmental baggage, such as:

  • Coal‘s production of toxic ash, and the environmental destruction involved in coal mining;
  • Concerns over the use of hydraulic fracturing (fracking) to extract natural gas;
  • The dilemma over what to do with the radioactive waste produced by nuclear power;
  • The environmental effects of damming rivers and creating large new bodies of water for developing hydro power;
  • Environmental damage from solar power’s technology-intensive manufacturing process and disposal issues (discussed above);
  • Wind power’s danger to flying creatures; and
  • Geothermal‘s issues, thought admittedly minor, with subsidence and seismic events.
Solar farm

Solar farm. Credit: Flickr/Michael Mees, CC BY 2.0

This article wraps up our consideration of the environmental externalities of electrical generation technologies. However, I intend to devote a few articles to a similar consideration of energy sources for transportation — the environmental impacts of petroleum, natural gas, biofuels, electricity, and possibly hydrogen.

As always, please feel free to use the comment space below to express your musings, insights, analysis, or foaming ideological rant.

 

Geothermal plant in Iceland

Geothermal power plant in Iceland. Credit: Flickr/ThinkGeoEnergy, CC BY 2.0

 

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