Induced Earthquakes A Potential Hazard for Geological Storage of Carbon Dioxide

Summary.  The world is burning fossil fuels at an ever-increasing rate, resulting in increased release of the greenhouse gas carbon dioxide into the atmosphere.  This results in an increase in the long-term globally averaged temperature.  Consequently there is great interest in developing carbon capture and storage in geological repositories to help abate the increase in atmospheric carbon dioxide.

Zoback and Gorelick have just published a paper that a) emphasizes the vast amounts of carbon dioxide that need to be captured and stored, and b) analyzes in detail the likelihood that small-scale earthquakes may be induced at the injection sites because of the increased fluids introduced into the storage sites.  Their concern is that even small to medium scale earthquakes may destroy the integrity of the sites, leading to significant leakage of carbon dioxide back into the atmosphere.  They conclude that extensive deployment of carbon storage involves considerable risk.

Background.  Zoback and Gorelick have analyzed the long-term geological storage of carbon dioxide (CO₂) as a means of permanently removing this greenhouse gas from the atmosphere by carbon capture and storage (CCS; see the next section).  First we present some introductory information on CCS. (Background on CCS may be found in this earlier post.)

The European Union (EU) has embarked on the only multinational program in the world, based on binding enacted policies, to reduce emissions below the emissions levels of 1990 by 20% by 2020, and by 80-95% by 2050 (the EU Roadmap; see this post).  Achieving such goals requires decarbonization of most energy sources.  The EU recognizes that a major portion of this reduction should come from use of CCS for large scale fixed sources involved in generating electricity. 

To begin research and development of CCS technology, the EU has selected six demonstration projects in six member countries, using differing capture and sequestration technologies.  The EU has committed EUR1 billion (US$1.25 billion) to them.  Variously, they range in size from one at 30 MW (to be scaled up to over 300 MW) to 900 MW, with most projects expected to capture about 90% of the emitted CO₂.  Storage will be in land-based or offshore saline aquifers, and depleted land-based or offshore gas fields.

In the U. S. the state of California is implementing a plan very similar to the EU’s Roadmap.  In a non-official report detailing how California might attain these goals, the California Science and Technology Council (CSTC) relies heavily on decarbonizing energy sources to the greatest extent possible (see this earlier post).  Electricity generation is to be decarbonized, to the extent that use of fossil fuels is maintained, by use of industrial-scale CCS, even though the report recognizes that this technology remains unproven.  Decarbonization of electricity generation is especially important because CSTC envisions use of electric vehicles to decarbonize transportation.

The U. S. Department of Energy (DOE) is sponsoring research on CCS, as reported in the Carbon SequestrationProgram: Technology Program Plan of the National Energy Technology Laboratory.  Its budget request for Fiscal Year 2011 was about US$140 million, with anticipated sharing by an equal amount from Regional Carbon Sequestration Partnerships with universities and corporations.  This budget has grown from about US$10 million in 2000.  Recent support from the American Recovery and Reinvestment Act of 2009 (the fiscal “stimulus”), included in the recent growth of this funding, is essentially exhausted at this time. All aspects of the various stages in capture, release and concentration, transportation and geological storage, as well as monitoring, verification and accounting, are being investigated at laboratory and small pilot scale.

Similar programs are also supported in the DOE Fossil Energy program.  Their requested budget for Fiscal Year 2013 is about US$276 million for CCS and Power Systems, which supports projects as large as industrial scale pilot projects.

Cautionary Analysis of CCS.  Zoback and Gorelick analyzed the dangers to maintenance of reservoir integrity in geological sequestration of CO₂, in a paper published in the Proceedings of the National Academy of Sciences, June 26, 2012, vol. 109, pp. 10164-10168 .  As background, the authors note:

·        CCS will be very costly;

·        in the U. S. use of coal for generating electricity produces about 2.1 billion metric tons of CO₂ a year, or about 36% of all U. S. emissions;

·        China’s emissions are about 3 times more than this from coal-fired generation, corresponding to about 80% of its emission rate;

·        annually, on a worldwide basis, CCS has to contend with 3.5 billion tons of CO₂, which requires injecting an amount of CO₂ underground roughly equal to the volume of all the oil extracted from oil wells worldwide;

·        this amount of injected CO₂ requires that worldwide about 3,500 functional industrial-scale injection facilities be operational by mid-century, averaged to about 85 facilities added per year; and

·        geological storage must remain faultlessly leak-tight in order to compare with freedom from emissions of renewable energy sources.

The authors include the following analyses:

o       The paper itemizes several instances of earthquakes apparently triggered by underground injection of liquids.  This can arise because many geological formations are already in states of unresolved stress, so that the relatively minor perturbation arising from fluid injection releases the stress in an earthquake.  The fluid in essence makes it easier for the stressed surfaces to slide over one another, which is the hallmark of an earthquake.  Zoback and Gorelick emphasize that it is not any land-based earthquake damage to human wellbeing that concerns them, but rather that even small earthquakes, likely not to produce damage to structures, are likely to damage the geological structures holding the pressurized CO₂.  CO₂ could then readily permeate to or near the surface, permitting release into the atmosphere and defeating the intent of the storage in the first place.  They present the results of calculations that even a small earthquake of Magnitude 4 could induce slippage of several cm. along a fault of about 1-4 km (0.6-2.4 mi).

o       In stressed geological formations, it is not only the pressure of injected CO₂ that is potentially hazardous, but also the rate of injection.  More rapid pressure buildup is more likely to trigger an earthquake event; the need to dispose of large volumes of CO₂ would be an incentive for high injection rates.

o       A widely known injection site is the Utsira formation of the Sleipner gas field in the North Sea.  About 1 million tons of CO₂ has been separated from natural gas and reinjected below ground every year, for the past 15 years.  There has been no earthquake activity to date.  The authors calculate that about 3,500 such sites would have to be identified and put into service to accommodate storage needs projected for 2050 (most of which would be needed right now, in fact).  The authors conclude “Clearly this is an extraordinarily difficult, if not impossible task” if only geologically suitable sites are to be used.

o       Depleted oil and gas wells, while seemingly attractive as potential injection sites, are not numerous enough to satisfy the need, and are not necessarily located conveniently for the need.

The authors conclude “multiple lines of evidence indicate that preexisting faults found in brittle rocks almost everywhere in the earth’s crust are subject to failure, often in response to very small increases in pore pressure. In light of the risk posed to a CO₂ repository by even small- to moderate-sized earthquakes, formations suitable for large-scale injection of CO₂ must be carefully chosen.”  Because of the extremely large volumes of CO₂ needing to be disposed of, the industrial-scale CCS needed will be “extremely expensive and risky for achieving significant reductions in greenhouse gas emissions”.

Certain CCS projects have been abandoned due to risk and lack of financing.  The very factors identified by Zoback and Gorelick are echoed in these two recent news reports. 

The Guardian on June 17, 2012 reported that Ian Marchant, chief executive of Scottish and Southern Energy, while still favoring CCS development, warned the British Parliament that a CCS project his company is undertaking is “the most risky project I’ll ever invest in….CCS is…at the demonstration stage….We do not know that this technology will work”.  He called for UK government support at this demonstration phase of the project.

The same article noted that another company, Scottish Power, abandoned CCS technology last year.  Together with Shell, the company evaluated it would need at least £1.5 billion (US$2.3 billion), and the UK government could not support such a funding level.

Similarly, theGuardian reported on June 26, 2012 that Ayrshire Power (Scotland) abandoned its planned new CCS-fitted 1852 MW power plant because it feared it could not obtain funding from the UK and the European Commission.  Nevertheless, the Scottish energy minister still strongly supports CCS development since it borders North Sea offshore CO₂ storage sites.

Rebuttals of Zoback and Gorelick’s warnings.  There has been response from the CCS community rebutting the serious concerns expressed by Zoback and Gorelick.  For example, two scientists were featured in the internet-based Carbon CaptureJournal (accessed June 27, 2012).

Dr. Malcolm Wilson, Chief Executive Officer, The Petroleum Technology Research Centre (PTRC), provided a detailed accounting of the experience gained at the Weyburn-Midale Project, an oil field storage development project in Saskatchewan, Canada, which it seems is an extended oil recovery project as well.  Storage has been under way there for 11 years, with a total of 21 million tonnes (metric tons) of CO₂ stored in that time.  Detailed research and characterization of the site has been undertaken throughout this time; indeed, seismic events with Magnitudes of -1 (extremely small) have been recorded.  Dr. Wilson considers this site now to be industrial scale, as 2.8 million tonnes of new CO₂, and more than 5 million tonnes when recycled CO₂ are included, have been injected; no earthquake activity or leakage has been identified.

PTRC is also conducting research on their Aquistore Project, for storage in saline aquifers.  Noting with approval that Zoback and Gorelick cite aquifers favorably because of their very large storage capacities, Dr. Wilson notes that the Aquistore Project will be the first industrial scale storage project, since it will receive CO₂ from a coal-fired power plant.

Dr. Bruce Hill, senior staff geologist at Clean Air Task Force (CATF) rebuts the concern over lack of integrity of storage sites due to earthquake activity by emphasizing the rate of CO₂ migration toward the surface, rather than the total amounts potentially released.  Dr. Hill emphasizes that there are many layers of rock structures, extending thousands of feet, overlaying injection sites, seeming to belittle the concerns of Zoback and Gorelick.  Dr. Hill feels that the examples cited by the authors are not representative.  He points out that “approximately 1 billion tons of CO₂ have been safely injected (and stored) in the process of enhanced oil recovery in the U.S. since the late 1970s, with no reported seismic incidents. In fact, there have been no earthquakes reported anywhere from saline CO₂ injections either”.

Dr. Hill concludes that CCS technology is “viable” and should play a significant role in potentially storing the very large amounts of CO₂ that need to be recovered to reduce atmospheric CO₂ accumulation.

George Peridas responded to the paper on the Natural Resources Defense Council Blog on June 22, 2012.  Mr. Peridas believes that Zoback and Gorelick raise valid issues, including whether CCS can cause earthquakes and whether such earthquakes could lead to leakage of the injected CO₂.  But in his opinion, the conclusions reached by the authors are more extensive than warranted by the evidence, for example with respect to the second issue, leakage.  He does not agree that an earthquake event would lead to migration of CO₂ all the way to the surface.  He believes that an experiment cited by the authors, performed on granite, a brittle mineral, is not representative of capstone layers anticipated in CCS, which would be more compliant, yet impermeable, shales.  In the case of existing fossil fuel geological reservoirs, large earthquakes have been known to occur without loss of the materials.  Mr. Peridas additionally cites Sally Benson (Stanford University and Lead Coordinating Author of the Underground Geological Storage Chapter in the Intergovernmental Panel on Climate Change Special Report on CCS) as stating that naturally care must be taken in choosing CCS injection sites, but that finding such sites should be feasible.

Discussion

Our earlier post, “Carbon Capture and Storage: A Needed yet Unproven Technology”, presented background information on the various technologies that may be employed in each phase of capturing CO₂, from the burning of fossil fuels for energy, to transporting the CO₂ to a storage site, and finally the actual storage process.   Many problems remain to make CCS industrially viable for utility-scale facilities.  Resolving these problems requires investment of large sums of money, worldwide, to arrive at practical CCS by about 2020.  Currently a relatively small number of demonstration and pilot projects are under way around the world.

The use of fossil fuels is projected to grow considerably in the coming decades around the globe, primarily in developing countries which will power their rapidly expanding economies with energy derived from burning fossil fuels.  This means that the annual rate of CO₂ emissions will continue expanding, and that the total accumulated concentration of atmospheric CO₂ likewise will continue increasing.  Even in developed countries having programs to abate CO₂ emissions at various stages of maturity, a major aspect of such abatement involves shifting transportation to electric power.  Thus the total demand for electricity is projected to grow in developed countries as well; to the extent that this demand is not met by renewable sources the need for contending with abatement of CO₂ emissions likewise will grow.  For this reason emission abatement programs will rely ever more heavily on technologies such as CCS.

The paper by Zoback and Gorelick serves at least three useful functions.  First, by arithmetic analysis, it underscores the vast, unprecedented need for functional and effective injection sites projected by 2050.  Some of this information has been summarized above.

Second, its geophysical modeling emphasizes the many unknown factors remaining in choosing and developing new CO₂ injection sites.  The seals installed surrounding well bores, and the many geological factors involved in retaining the injected CO₂ out of contact with the atmosphere for hundreds or thousands of years must be essentially fail-safe.  Yet this work emphasizes that the very act of injecting pressurized fluid facilitates potential small-scale earthquakes that, according to the modeling, have the potential of opening fissures in these seals that could lead CO₂ back to the surface.

Third, it has engendered fruitful debate in the CCS community about the integrity of proposed injection sites.  Although these issues were already known among workers in the community, they have now been aired among a wider public.  This has the effect of ensuring that research and data gathering, involved in characterizing new injection sites, will be carried out diligently and effectively so that wise siting choices may be made.

The critics of Zoback and Gorelick, such as those cited above, include examples in their rebuttals of injection sites taking advantage of pre-existing wells used in the extraction of oil and gas from their geological repositories.  These have kept the fuels underground for millions of years, and so are cited as justifying CO₂ injection for the same reasons.  These are likely not representative of the thousands of new storage injection projects that will be needed to accommodate the demand.  Overall the number of pilot injection sites worldwide is small, and many are new experimental projects.  The concerns raised by Zoback and Gorelick merit careful attention going forward as CCS technology is developed further and deployed in number.

© 2012 Henry Auer

Wind Energy: A Growing Source of Renewable Energy

Summary.  Wind energy plays a small but growing role in the world’s energy economy.  The European Union has the objective of reducing greenhouse gas emission by 80-95% by 2050.  China’s 12^th Five Year Plan, covering 2011-2015, includes the goal of rapidly expanding its presently small wind generating capacity.  The United States, with no national energy policy currently in place, has several short term fiscal incentives to stimulate private development of renewable energy including wind energy.

Introduction.

The burning of fossil fuels is recognized as being a major contributor to the increase in man-made greenhouse gases accumulating in Earth’s atmosphere.  The United Nations-sponsored Intergovernmental Program on Climate Change and other organizations conclude that the increase in greenhouse gases leads to warming of the average global temperature, which is predicted to produce several adverse consequences impacting our life on the planet.

The world’s nations have gathered in conference to attempt unified responses to the threats posed by global warming.  The most recent was the Cancun conference in November 2010.  In response to the perceived problem, most nations have undertaken to slow the growth of atmospheric greenhouse gases, and even to achieve a leveling off of their concentration at a new, elevated, level.  This involves ambitious programs to reduce burning fossil fuels, and to substitute alternative sources of energy in their place.  One contribution to this endeavor is large scale development of wind power for generation of electricity.  Aside from the energy required to manufacture the wind turbines used and the transmission lines that carry the resulting electricity, wind power is deemed to have no emissions of greenhouse gases when operating.

In this post development of wind power is described in Europe, China and the U. S.

Wind World-wide

According to the Global Wind Energy Council, world-wide wind generating capacity for electricity is predicted to grow to a total of about 450 gigawatts (billion watts, GW; see Note 1) within 5 years, and to about 1,000 GW in 10 years (reported by BTM Consult ApS).   At present the world-wide generating capacity is almost 200 GW, which is 22.5% higher than in 2009.

Europe

The European Union (EU) has 27 member nations.  The European Commission, its executive body, issued its Roadmap for moving to a low carbon economy in 2050 (see the post) on March 8, 2011.  The goal set forth in the Roadmap is to reduce greenhouse gas emissions by 80 to 95% from the emission level of 1990, by 2050.  The Roadmap builds on an earlier EU initiative to reduce greenhouse gas emissions by 20% by 2020.  Achieving these objectives requires concrete policy decisions to be implemented in each of the member nations.  It envisions reductions in emissions of 1% per year until 2020, then 1.5% per year from 2020 to 2030, and finally 2% per year until 2050.  These should provide about 25% reduction in emissions by 2020, about 40% by 2030, and about 60% reduction by 2040.  This is shown in the following graphic.

Relative greenhouse gas emissions charted at 5 year intervals by economic sector.  Actual results shown through 2010; projected results thereafter.  The red line shows projected results using policies in place prior to the Roadmap.  The remaining projections include technologies and policies to be implemented under the Roadmap.  Source: European Commission, “A Roadmap for moving to a competitive low carbon economy in 2050” March 8, 2011  http://ec.europa.eu/clima/documentation/roadmap/docs/com_2011_112_en.pdf

The Roadmap envisions major reductions in emissions coming from the electric power sector, by developing renewable sources including wind power.  Today all renewable sources for power generation in the European Union are already 45% of the total; the Roadmap envisions virtually 100% renewable power by 2050.

In the near term, the members of the EU have the goal of generating 21% of their electricity from renewable sources by 2010.  As seen in the graphic below, slightly less than half of non-hydro renewable electricity generation in 2005 was from wind energy.

Historical renewable electricity energy provided by sector in Europe, 1990-2005, Twh/yr (billion Kwh).

Purple, cross striped (narrow band at top): Offshore wind.

Purple, vertical stripes: On-shore wind.              Yellow: Solar photovoltaic cells.

Orange-brown cross striped: Geothermal electricity.

Gray cross striped: Biowaste.                 Green, dotted: Solid biomass.                Pink: Biogas.

Source: European Commission, Renewable Energy Road Map, 2007 http://ec.europa.eu/energy/energy_policy/doc/03_renewable_energy_roadmap_en.pdf

Although most wind energy in Europe is land-based, off-shore wind energy projects are also being developed, mostly in the North and Baltic Seas.  A European transnational grid is being developed to connect these resources.

China

China recently released its 12^th Five Year Plan, covering the years 2011-2015, including its plans for expanded energy production and use.   The five year plans are determined by the central government, and their implementation likewise is administered centrally. 

From 2010 to 2015, overall electric generating capacity will increase from about 1000 GW to about 1400 GW (see Note 1).  This increase includes a major and growing amount of generating capacity from coal, a very slight increase in hydroelectric generating capacity, and increases totaling about 1% of total capacity in 2010 to about 3% of total capacity in 2015, for renewable energy. 

According to a cited report from the Chinese Wind Energy Association, China is adding wind-generated electric power to its energy mix at a rapidly expanding pace, even as the share that wind generation contributes remains quite small.  At the present time, China’s total wind generating capacity is 45 GW.  It added 18.9 GW of new capacity in 2010, representing a 73% increase over the previous year.  Under the 12^th five Year Plan covering 2011-2015, China plans to install 70 GW of new wind generating capacity by 2015, and for the following five year plan, 150 GW by 2020. 

Much of this new wind capacity is manufactured within the country.  Sinovel Wind Group Co. is a specialized enterprise that manufactures on-shore, off-shore and intertidal wind generators.  In 2010 it provided 4.4 GW of capacity, making it the largest wind manufacturer in China, and No. 2 in the world.  The company has subsidiaries placed in Spain, Australia, Canada, the U.S.A. and Brazil.

According to the International Energy Agency’s World Energy Outlook 2010, during the period 2008-2035 about 9% of newly added energy demand in China will be delivered by renewable sources other than hydroelectric, including wind.  However, as noted above, the majority of the increases remain fossil fuel-derived energy.

United States

The U. S. is the only major emitter of greenhouses in the world without a national energy policy in place.  The U. S. Environmental Protection Agency is in the process of preparing administrative rules governing emissions in an atmosphere of active political debate and concerted opposition from affected interests.   As of 2010 35 states and the District of Columbia have put renewable portfolio standards, mandates or goals in place, which would govern the role of renewable energy sources within their respective boundaries.  Since the various programs differ, and 15 states have no policy in place, this creates a disparate and confusing regulatory framework across the country.

As of 2009, the role of wind power in the generation of electricity (excluding transportation and building heating) is shown in the following graphic



Source: U. S. Energy Information Agency http://www.eia.gov/energy_in_brief/slideshows/renewable_energy.html

It is seen that wind generation accounted for 1.7% of all electricity generation in the U. S., as of 2009.  (It is worth noting in passing that solar energy contributed a very small amount to electricity generation.)

According to the American Wind Energy Association, 35% of newly added generating capacity in the U. S. since 2007 is wind power.  The annual rate of increase in wind-based electricity generating capacity was 61% in 2008 and 28% in 2009.  The net summer electricity generating capacity in the U. S. is shown in blue in the following graphic.

Total wind energy generation (green line, left scale) and net summer generation capacity (blue bars, right scale) in the U. S. 1999-2009. Source: U. S. Energy Information Agency http://www.eia.gov/cneaf/solar.renewables/page/wind/wind.html  

It is seen that installed power generating capacity (blue) and total energy generated from wind (green; see Note 1) are increasing rapidly.  Nevertheless, according to the U. S. Energy Information Agency (USEIA), wind generation constituted less than 1% of the total energy consumed in the U. S. in 2009.  Based on the average electricity usage per household in 2008, the total energy generated by wind in 2009, 73,700 million Kwh, would have been sufficient to supply the electricity needs of 6,700,000 households (see Note 2).  The wind energy generated in 2009 represents 5.4% of all residential electricity used http://www.eia.doe.gov/tools/faqs/faq.cfm?id=96&t=3

in the U.S. in 2009.

A projection by USEIA of generating capacity that may be installed in the coming years is shown below. 

Source: U. S. Energy Information Administration http://www.eia.gov/cneaf/solar.renewables/page/wind/wind.html

Planned wind energy installations are shown in lavender.  It is seen that as of the date of preparation, 2009, wind facilities decrease significantly after 2011.  This may reflect the expiration of tax incentives explained below.  From the point of view of combating the emission of greenhouse gases, projected new installations fueled by fossil fuels (coal, red; and natural gas, orange) are much larger and highly significant.  Newly commissioned fossil fuel plants will continue in operation for several decades, making continued additions to the atmospheric burden of greenhouse gases each year.

The USEIA projects an increased role for renewable sources in the generation of electricity over the coming decades, increasing to 17% of overall electricity production by 2035 , up from 9% in 2008; wind power will be a major contributor to this growth.  A strong impetus for use of renewable sources is to contribute to the decarbonization of our energy economy.  This is viewed as a significant factor for minimizing the effects of global warming.  In general, the capital costs for installing renewable sources, including wind, are evaluated as being more costly than fossil fuel-driven sources.  Much of this cost comes from the fact that land areas in the U. S. that provide abundant sources of renewable energy, such as wind and solar power, are distant from the ultimate consumers, so that costly transmission lines must be built.  But balancing this initial outlay, the cost of operating the facilities is much lower once built, since no fuels need to be purchased.

These effects may be overcome by continuing to offer favorable tax credits for installing new renewable energy facilities.  The Federal Renewable Electricity Production Tax Credit has contributed to an eight-fold increase in wind energy production in the years  since 2001.  The Federal Energy Policy Act of 2005 provides interest-free financing to government entities intended for wind energy.  The USEIA projects that extending this credit beyond its expiry would have a significant favorable effect going forward.  Additional factors guiding installation of new renewable generation facilities are the Renewable Portfolio Standards or goals that many states have put in place, as well as marketable certificates for renewable energy that may be traded among providers.

The U. S. Energy Information Agency’s Annual Energy Outlook 2011 issued April 2011 presents a comprehensive analysis of U. S. Energy production and consumption foreseen through 2035.  Its Reference case is based on current policies and laws without assuming extension of provisions that expire at various points in time.  Its No Sunset case builds on the Reference case by assuming extension of favorable tax and other fiscal policies during the period of the analysis.  Its Extended Policies case includes the assumptions of the No Sunset case and adds to it the extension of current federal energy efficiency policies.

The following graphic presents historical and projected contributions to all forms of renewable energy other than hydroelectric power through 2035 under the Reference case.

Electricity generation from all renewable sources projected for the Reference case beyond 2009.

Source: U. S. Energy Information Agency: Annual Energy Outlook 2011 http://www.eia.gov/forecasts/aeo/pdf/0383(2011).pdf

In the years immediately preceding and following the cutoff year 2009 the most significant increase occurs with wind-derived electricity generation (blue).  This sector then shows a sharp break at about 2012 and remains essentially constant thereafter.  This stark behavior is due to the fact that under the Reference case favorable tax credits expire at that time, as discussed above.

The following graphic shows projections for the total amount of renewable electricity generated under the Reference, No Sunset, and Extended Policies cases.  Beyond about

Total renewable electricity generation per year over 2005-2009 (historical data) and 2010-2035 (projection) under three cases.  The kilowatt-hours generated are higher than in the preceding graphic, presumably because hydroelectric power is included here.

Source: U. S. Energy Information Agency: Annual Energy Outlook 2011 http://www.eia.gov/forecasts/aeo/pdf/0383(2011).pdf

2023 the No Sunset case, which includes extensions of favorable tax credits, leads to a significant increase in generation compared to the Reference case.  By 2035, considering electricity generation from all sources, the Reference case provides 14% whereas the No Sunset case provides 16%, displacing generation from fossil fuel-derived generation.  (The Extended Policies case falls below the No Sunset case because, it is proposed, its increased efficiencies lower the demand for electricity so that less needs to be  generated.)

On April 19, 2011 the U. S. Secretary of the Interior, Ken Salazar, approved construction of the first off-shore wind energy project in the U. S.  The project, by Cape Wind Associates, is to be installed in Nantucket Sound off the south coast of Massachusetts, and envisions 130 turbines arrayed across 25 square miles in the shallow waters of the Sound, generating up to 420 MW (0.42 GW) of power.  This should supply about 75% of the immediate region’s electricity needs. This project had previously gone through many years of environmental and permitting review at various levels of government.

Conclusion.  The perceived dangers accompanying increased atmospheric concentrations of greenhouse gases provide an impetus for the nations of the world to work toward an emissions-free energy economy.  The European Union, striving to attain 80-95% reductions by 2050, has significant wind energy installed, with plans to expand.  China, with a centralized economy, building on an initial small base, intends drastically to expand its wind energy generating capacity, while also expanding its fossil fuel-driven electricity generation.  The U. S., with no central energy policy in place, has short-term fiscal incentives to stimulate private development of wind energy; these incentives are not considered secure in the long term.  The disparate array of state renewable portfolio standards currently in place make it difficult for enterprises to plan and install new wind energy facilities.

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Note 1.  A watt is a unit of power, quantifying the rate at which energy is provided or consumed.  It is a small unit. 

A kilowatt (1,000 watts, Kw) is a more manageable unit of power.  10 100-watt light bulbs represent 1 Kw; an electric toaster would be 1-2 Kw.

Generating capacity is the rate at which an installation provides power, such as in millions of watts (megawatts, MW) or billions of watts (gigawatts, GW); please note these are watts, not kilowatts.

Energy is a measure of total work done, given by power x time and for electricity is watt-hours.  Again this is usually given in terms of kilowatt-hours, Kwh.  10 light bulbs burning for 1 hour would be 1 Kwh.

Note 2. According to the USEIA, in 2008 the average annual usage of electricity for a U. S. household was 11,040 kWh, with a state-by-state range of 6,200 (lowest) to 15,600 (highest).  The total residential electricity consumption in the U. S. in 2009 was 1,363 billion Kwh.  Commercial and industrial electricity usage is in addition to this amount.

© 2011 Henry Auer