See the Tabbed Pages for links to video tutorials, and a linked list of post titles grouped by topic.

This blog is expressly directed to readers who do not have strong training or backgrounds in science, with the intent of helping them grasp the underpinnings of this important issue. I'm going to present an ongoing series of posts that will develop various aspects of the science of global warming, its causes and possible methods for minimizing its advance and overcoming at least partially its detrimental effects.

Each post will begin with a capsule summary. It will then proceed with captioned sections to amplify and justify the statements and conclusions of the summary. I'll present images and tables where helpful to develop a point, since "a picture is worth a thousand words".

Thursday, September 19, 2013

The Keystone XL Pipeline Would Significantly Worsen Global Warming

Summary.  President Obama is weighing a decision whether it is in the national interest to approve the Keystone XL pipeline.  It would carry bitumen from Alberta’s tar sands to refineries on the U. S. gulf coast.  He has said he would not approve the pipeline if it would make climate change “significantly” worse.

Tar sands oil, being very different from conventional petroleum, requires far more energy, derived by burning fossil fuels, to extract it for shipment and to refine it for final use.  The high capacity of the pipeline would transport so much bitumen that, once burned as refined fuel, it would add between 82.5 million tons and 181 million metric tons per year of carbon dioxide to the atmosphere, corresponding to at least 1.4% of all emissions from the U. S. The pipeline would commit the U. S. to these emissions for each year of its operational lifetime, perhaps 40 years or more. 

Officials of the Canadian government have visited Washington several times in recent months advocating assertively for approval of the pipeline.  Clearly the Keystone XL pipeline figures importantly in Canadian political and economic considerations.  Those interests do not necessarily overlap with those of the United States.

The energy economy may be considered as a zero sum undertaking, balancing new investments in fossil fuels with those in renewable energy.  It is estimated here that if the investment in the Keystone XL pipeline were instead directed toward investment in wind energy, it could result in installation of 1,420 high capacity wind turbines and construction of a high voltage transmission line 1,563 miles long.  This investment would provide many jobs during construction, making a positive contribution to economic activity in the U. S.

The President should not approve the XL pipeline.  Instead, his administration should promote development of renewable energy sources as avidly as possible.

Analysis and Conclusions

The extent of warming of the earth’s climate depends not on humanity’s annual rates of adding new greenhouse gases to the atmosphere, but rather on the total accumulated amount of such gases added since the industrial revolution began 150 years ago.  Carbon dioxide, the main greenhouse gas, remains in the atmosphere for a century or even longer (referring to the large portion not captured by photosynthesis or absorbed into the oceans).  Therefore, even if we reduce our annual emissions rate we can never lower the accumulated total, but rather only minimize the new higher accumulated total of greenhouse gases in the atmosphere.  For this reason it is imperative to migrate away from a fossil fuel-driven energy economy as soon as possible, and shift toward a renewable energy economy.

Approving the Keystone XL pipeline would commit the U. S. to additional accumulation of new greenhouse gases from burning this fuel throughout its operational lifetime, to the extent of at least 1.4% per year of all fossil fuel derived carbon dioxide emitted by the U. S.  Thus use of Canadian bitumen for the lifetime of the pipeline would add significantly to the world’s burden of new greenhouse gases.  Additionally, extracting and refining tar sands bitumen requires large amounts of energy, which itself is derived by burning fossil fuels and creating more greenhouse gas emissions.  Accordingly, the pipeline would significantly and adversely affect global warming if it were approved.  The urgings of Canadian government officials should be rejected.  It is not in the interests of the U. S. to grant approval.

Instead, the U. S. should take every opportunity to develop renewable sources of energy that have very low or zero rates of emission of new greenhouse gases.  Government and corporate policies should be encouraged that promote migration away from fossil fuel use and toward a renewable energy economy.


Introduction.  The Keystone XL pipeline (XL) is an international transport pipeline project intended to carry bitumen (Alberta tar sands oil) from the Canadian border to refineries on the U. S. Gulf Coast.  Since the project has an international aspect, involving oil transport across the Canada-U. S. border, it requires positive review by the U. S. Department of State and approval by the President.  The query to be resolved is whether this is in the national interest.

While the XL pipeline application has been pending, President Obama delivered a major speech on his energy policy on June 25, 2013.  He said he would not approve the application if the pipeline would make climate change “significantly” worse.  

Canada is aggressively promoting approval of the pipeline in numerous visits to Washington.  Alison Redford, the Provincial Premier of Alberta, visited Washington, D.C. for the fourth time in 18 months during the week of April 8, 2013 to press the case for favorable action on the XL pipeline.

On September 9, 2013 Canadian Minister of Natural Resources Joe Oliver met with U. S. Secretary of Energy Ernest Moniz.   Minister Oliver has visited Washington on numerous occasions to promote approval of the pipeline application.  In addition, Canadian Prime Minister Stephen Harper is reported to have sent a letter to President Obama in August 2013 in which Mr. Harper proposed "joint action to reduce greenhouse gas emissions in the oil and gas sector."  By this gesture he seeks to further approval of the pipeline application.  This offer is a concession to U. S. concerns about greenhouse gases that Canada has not previously made.

The New York Times reported on August 25, 2013 that Canada would find other modes of transporting the bitumen to the U. S. market and/or other destinations for the bitumen if the XL pipeline application is rejected.   Nevertheless, internal Canadian government documents released to the Canadian Pembina Institute reveal that Canada has been relying on approval to expand production of bitumen from the tar sands.

[Update September 22, 2013]  An editorial contributor to the New York Times reports that the Canadian government is restraining government scientists from free and open communication of their findings, especially in the fields of climate change, the Alberta tar sands, and fisheries.  The writer concludes “the Harper [Canada’s prime minister] policy seems designed to make sure that the tar sands project proceeds quietly, with no surprises, no bad news, no alarms from government scientists.”

It is clear that approval of the Keystone XL pipeline is a major issue in Canada, both politically and economically.

Characteristics of bitumen.  Bitumen occurs as a highly viscous fluid or a soft solid, mixed with sand.  Extracting tar sands bitumen deposited near the surface requires expending about 20% of the energy content of the bitumen.  Deeper reservoirs require about 30% of the energy contained in it.  Obtaining conventional oil, on the other hand, needs only about 4%. Bringing the bitumen to the surface and freeing it from the sand mixture requires heating the raw material to temperatures hot enough that the bitumen flows more freely.  The process produces waste water that now includes toxic heavy metals and bitumen components that have to be stored to keep the waste from contaminating running streams. 

Refining tar sands bitumen takes extra processing compared to refining conventional petroleum.  The additional steps require additional large amounts of energy and use large amounts of water.

In summary, extracting and refining tar sands bitumen is far more energy intensive than recovering and refining conventional petroleum.

The Keystone XL pipeline is expected to transport 830,000 barrels of fuel a day.  Refining petroleum yields about 75% of carbon-containing fractions that are suitable for use as fuels.  Although bitumen is different than petroleum, If bitumen provides the same yield, this writer estimates conservatively that the annual amount of fuel transported would emit 82.5 million tons of carbon dioxide (CO2) a year when burned.  (This figure does not include the extra emissions arising from the energy used in extraction and refining.) This works out to this pipeline alone transporting fuel that would emit 1.4% of all CO2 produced by burning fossil fuels in the U. S. (fossil fuel data).  Another report estimates annual emissions to be 181 million metric tons per year, or more than twice as much as the lower estimate.  These emissions would continue for the useful service lifetime of the pipeline, perhaps 40 years or more.  Not approving the pipeline and not extracting this amount of bitumen would prevent this amount of emissions indefinitely into the future.

Continuing fossil fuel use, such as by building the XL pipeline, is but one arm of the energy economy’s zero sum undertaking.  In weighing whether to approve the Keystone XL pipeline, the choice is not whether to approve it or simply to reject it.  Rather the correct decision to consider is whether to use the funds foreseen for the Keystone XL investment, prolonging the fossil fuel energy economy, or to shift such investment to expand renewable energy.  A current estimate of the cost of constructing the XL portion of the Keystone system is US$7 billion.  Earlier phases of the Keystone system experienced cost overruns of as much as 100%; if so, the XL portion under consideration could cost as much as US$14 billion.

As noted above, the pipeline, if built, commits us to continued atmospheric emissions of CO2 over its full service lifetime, perhaps 40 years or more.  If the pipeline were not built and its intended capacity for bitumen remained in the ground, emissions equal to about 1.4%/yr of the U. S. total would be avoided.  The longer we delay the abatement of emissions, the more intensive and more expensive mitigation efforts would need to be.

Renewable energy is a second arm in a zero sum energy economy.  An alternative strategy is to shift the US$7-14 billion investment envisioned for the pipeline into developing industrial scale, renewable energy sources and energy transmission infrastructure. We should stop harvesting tar sands oil and build wind farms and solar farms instead.  We should reject new oil pipelines in favor of new transmission lines to deliver electricity from those farms to energy consumers.

The cost of wind energy generation is falling dramatically each year.  A report from the Lawrence Berkeley National Laboratory, a facility of the U. S. Department of Energy, reports that the levelized cost of electricity from wind (a measure of the expense incorporating all costs  throughout the lifetime of a project) ranges from US$20 to US$40 per MWh (megawatt-hour, a unit measuring the amount of energy).  It is lowest in the windy portion of the U. S., the Midwest interior. Broadly, this is the region that the projected Keystone XL pipeline would traverse.  

Construction costs for wind energy based on generation capacity are as low as about US$1,760/kW (kilowatt, a unit of power, or the rate of generating energy in a fixed time).  The average capacity of installed individual turbines was almost 2 MW in 2012.  Wind power provides an important source of jobs in the U. S. economy, since the domestic content of turbines increased from 25% in 2006-2007 to 72% in 2012.

We need new high voltage transmission lines to carry power from a renewable facility to consumers.  The American Electric Power Company estimates costs for constructing a lower-voltage line (345 kV) at about US$1.1-2.0 million (2008 dollars) per mile, and for the highest voltage listed (765 kV), a cost of US$2.6-4.0 million per mile.  Most of this expense comes from direct labor costs (construction, 41%; siting and management, 8%) and in labor involved in providing the materials (the materials cost is given as 41% of the total).  Thus it is seen that constructing a high voltage transmission line provides a large number of high-skilled jobs during the project.

Substituting investment in wind energy for the Keystone XL pipeline provides a high amount of installed capacity.  This writer has estimated investing in wind energy for a cost, US$10 billion, intermediate between the stated cost of the XL pipeline, US$7 billion, and a 100% cost overrun.  The sum is divided evenly between wind turbines and a transmission line.  Using the information above it is calculated that

investing in 2MW turbines would provide 1,420 turbines; and

investing in a 765 kV transmission line would provide 1,563 miles.

Turbines with even larger power capacities are currently becoming available.  Turbines that can operate at low wind speeds with high efficiency are available.  Wind turbines have to be installed with wide separations, so that original use is retained for a large fraction of the land that the wind farm occupies.

It is concluded that investing in the Keystone XL pipeline is not in the national interest of the U. S., as it contributes significantly to worsening the problem of global warming.  Investment should be directed instead to renewable energy sources, such as industrial wind farms described here, solar farms and the like.
© 2013 Henry Auer

No comments:

Post a Comment