Tuesday, June 26, 2007

Global Exergy and the Asian Economies

At this year's Foo Camp, I went to an interesting discussion on Global Energy led by Saul Griffith and Jim McBride. Using the work of Wes Hermann, they presented a first draft of a pretty compelling slide show, which one member of the audience suggested they call "A Convenient Truth". Wes Hermann has done extensive research on Exergy and how much of it is physically available. Saul and Jim want to make his work more accessible in the hope that it might shape energy policy.

What is Exergy? We refer to the following definition from a paper of Wes Hermann:
Exergy is used as a common currency to assess and compare the reservoirs of theoretically extractable work we call energy resources. Resources consist of matter or energy with properties different from the predominant conditions in the environment. These differences can be classified as physical, chemical, or nuclear exergy. This paper identifies the primary exergy reservoirs that supply exergy to the biosphere and quantifies the intensive and extensive exergy of their derivative secondary reservoirs, or resources.
Wes Hermann not only calculates the available Exergy from most energy sources, he also determines where particular energy resources are most plentiful. ("How much solar energy can one generate if one blanketed the earth's ENTIRE surface with the most efficient solar panels?") In essence, Wes Hermann sets out to calculate the terrestrial potential from all possible energy sources. He concludes that Solar, Wind, and Nuclear (in that order) are the most plentiful. In addition, Hermann locates the best places to harvest each possible energy source. In the sample graph below, we have the Tidal Power available (in watts per sq. meter) across the planet:

Similar maps can be constructed for other energy sources. In an ideal world, precious materials (e.g. silicon for solar panels) would be deployed in areas with the most potential (solar) Exergy.

Starting from the current global Exergy consumption of 18TW, Exergy calculations should inform energy policy. The 18TW is set to grow as the India, China, and the Southeast Asian economies continue to develop. Using the U.S. as an example, economic growth is positively correlated to energy consumption:

India and China's economies are growing at a steady pace, so the 18TW total Exergy consumed is sure to rise sharply:

Just like energy consumption, Ecological footprints rise as countries (see Human Development Index) develop:

The size of the populations of the fast-growing Asian countries means we need to pay attention to Exergy now!

Of course the Indian, Chinese, and ASEAN economies may hit obstacles along the way, but sound energy policy suggests that we assume that they will continue to develop in a modest pace.

Actually in another interesting discussion at FOO camp, Steve Hsu pointed out an interesting fact: historically, China's share of the world's GDP was quite high.

Using PPP (purchasing power parity), China's share of the world's GDP may actually just be reverting to its historical values. Look for China's ecological footprint, and Exegy consumption, to keep rising. Unless we act soon, the current 18 TW global Exegy consumption will surely look small in a few decades.

Tuesday, June 19, 2007

The True Cost of Coal

As far as electricity generation is concerned, Coal is the benchmark against which all renewable energy sources are compared with. In a previous post, I compared the cost per kilowatt hour (KWH) from a variety of renewables and concluded that coal is still much cheaper. In this post we will evaluate coal using the Triple Bottom Line and conclude that it is clearly a lot more expensive than it seems. It is important to evaluate the cost of coal more realistically before the developing world builds even more coal-powered generation plants.

In thinking about coal, it is useful to separate the problem into two pieces: mining and extraction, and electricity generation. In a previous post, I examined technologies for coal-powered electric plants that use sequestration to ensure that emissions are captured and stored underground. None of the touted "carbon sequestration" or "clean coal" technologies have been deployed in a commercial plant and doing so would naturally add to the cost per KWH.

The cost of mining and extraction is where traditional accounting falls short. First off, how is coal extracted?
... Early coal mining was almost exclusively done in deep shafts that led to thick (5-10 feet) coal seams, which were blasted and picked out and loaded on rail cars to be drawn out of the mine by mules. Miners worked in dark, dusty conditions always at the risk of fatal roof falls and methane gas explosions. Beyond the risk of sudden death or serious injury, miners also faced the prospect of black-lung disease if they spent years in the profession.

Deep mining has indeed come a long way. Today, miners use a technique called long-wall mining, which involves a long (up to a mile) face of an underground coal seam which is dislodged by a saw that runs on tracks along the face. This method is much more efficient at removing thick coal seams than the old blast-and-pick method, and accounts for half to two-thirds of current Appalachian coal production. While some dangers are now less, current underground mining still results in fatal roof fall and explosion accidents.

Surface mining, or strip mining, has become more and more popular in recent decades, especially in removing thinner seams of coal (as little as a foot thick). The most recent innovation in strip mining is known as mountaintop removal. It peels back a mountain, layer by layer, by alternately blasting the thick layers of rock away from the coal seams and then scraping the coal seam out and hauling it away in huge dump trucks. Much of the “overburden” rock (the non-coal layers) is pushed off into adjacent valleys. As much as 500- to 1,000-vertical feet of a mountain may be removed in the process and valleys are filled in to depths of as much as 500 feet by the rubble.
The current approaches involve either removing entire mountain tops or dislodging mile-long underground seams! Unless the mining companies are voluntarily estimating the cost of these forms of environmental degradation, the cost of electricity from coal as quoted in media reports, is not accurate. The list of environmental problems associated with coal mining is depressing. Here is one I ran across from the Union of Concerned Scientists:
Altered landscapes. Surface mining in Appalachia often removes entire mountaintops and dumps the wastes into valleys and streams; between 1985 and 2001, more than seven percent of the region's forests were cut down and more than 1,200 miles of its streams buried or polluted. In addition, waste materials from underground mining are placed in large piles above ground, which can also scar the landscape and alter stream flow.

Water contamination. Acids and toxic metals can contaminate surface and groundwater, harming aquatic life and rendering water supplies undrinkable.

Safety hazards. Underground mining accidents result in many deaths and injuries, and coal dust inhalation causes chronic health problems. Black lung disease still kills about 1,000 former coal miners in the United States each year.

Water contamination. Impurities such as acids and heavy metals removed from coal and stored in slurry reservoirs canleach into surface and groundwater.

Safety hazards. Slurry reservoir dams can fail, flooding local waterways and putting both wildlife and downstream communities at risk.
The main problem with both mountain top removal and long-wall mining is that landscapes are permanently altered as a result of coal mining:
... The coal in the Appalachian Mountains is hard to extract because it is buried under layers of shale and sandstone hundreds of feet thick. A few decades ago, strip miners would cut along the edge of a ridge side, then auger into a coal seam. But today, with bigger machines and little moral or regulatory constraint, coal operators simply blast away the entire mountaintop -- its forests, capstones, and topsoil -- so they can scrape out thin seams of low-sulfur coal. Nearly everything else is dumped into the valleys below, often burying pristine headwater streams. The resulting "valley fills" create the largest man-made earthen structures in the country -- huge treeless funnels that let mud and rainwater wash unimpeded through low-lying communities all across central Appalachia. The town of McRoberts, Kentucky, recently endured three "100-year floods" in 10 days. The water filled homes and carried away carports. When TECO Energy of Tampa, Florida, had leveled every peak around the community, it took the coal, took the profits, and left the people of McRoberts with crumbling homes, terrible roads, and a constant fear of being washed away in one’s sleep.

According to the Environmental Protection Agency, in addition to the more than 700 miles of streams buried by valley fills, thousands more miles have been contaminated with sediment, heavy metals, and acid mine drainage, a toxic orange syrup that kills everything in its path. And these are headwaters, so their contamination affects all life downstream. In Letcher County, Kentucky, children suffer extremely high rates of diarrhea, vomiting, nausea, and shortness of breath, all of which can be tied to dissolved minerals in nearby streams. Presumably the Clean Water Act was established to prevent such degradation. But early in the Bush administration, coal lobbyist Steven Griles was named a deputy secretary at the Department of Interior. Officials changed one word of the act -- replacing "waste" with "fill" -- so that toxic mining debris could be dumped into rivers as benign fill material.

There will soon be enough flattened mountaintops in Appalachia -- 1.4 million acres -- to set down the state of Delaware on former summits. Try driving across the 10,000-acre wasteland that surrounds Larry Gibson’s home on Kayford Mountain, West Virginia. Hundreds of people, like the photographer J. Henry Fair, make that trip every year to see, in Gibson’s words, "what hell looks like." Kayford Mountain, more than any place I know, illustrates the power and the willingness of some human beings to convert the natural world into money and "cheap energy" as quickly as possible. If that means the total destruction of an entire region, its people, and its culture, so be it.

And yet the majority of Americans have never heard of mountaintop removal.
One may be able to clean up coal-powered plants, but can one mine for coal without destroying the environment? Coal isn't as cheap as it appears, if anything the true cost of mining it probably makes it one of the most expensive energy sources. Using the Triple Bottom Line (People, Planet, Profits), coal costs a heck of a lot more than renewable energy sources.

Coal is touted as the cheapest source of (abundant) energy around, and in this post I argue that coal is actually quite expensive. From a power generation and emissions perspective, will "clean coal" and "carbon sequestration" be as cost-effective as current renewable energy sources? No commercial plants have been deployed so cost estimates are mere guesses at this point. Given the growth in coal usage in China and India, developing "clean coal" power plants is extremely important.

More importantly, Coal is cheap because the environmental costs of mining and extraction are more or less ignored. How cheap would coal mining be if it were held to the standard that it should be?

Hopefully the current excitement surrounding renewable energy, plus a heavy dose of energy efficiency and conservation will lead to less coal in the future.

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Wednesday, June 13, 2007

No Longer A Waste: Energy and Recycling

The Economist had a recent article on municipal curbside recycling which laid to rest the question of whether recycling is good for the environment. Recycling involves trucks, other machinery and energy inputs, so a valid question is whether or not the amount of materials extracted justifies the amount of energy used in the process. Using the results from a recent study sponsored by the UK-based Waste & Resources Action Programme, the answer is recycling DEFINITELY pays off. The study is essentially a meta-analysis of about 55 respected Life Cycle Analyses from several countries.
The UK’s current recycling of those materials saves between 10-15 million tonnes of CO2 equivalents per year compared to applying the current mix of landfill and incineration with energy recovery to the same materials. This is equivalent to about 10% of the annual CO2 emissions from the transport sector, and equates to taking 3.5 million cars off UK roads. ... The message for policy makers and practitioners is unequivocal. Recycling is good for the environment, saves energy, reduces raw material extraction and combats climate change.
The article also includes interesting factoids, along with several graphs and metrics.

The above graph is based on data from the OECD. Recycling Rates are defined to be the total (weight in tons) of all Recycled Municipal Solid Waste (MSW) as a percentage of Total MSW. In recent years, single-stream or co-mingled recycling has been used successfully to boost recycling rates. In single-stream recycling, a single recycling bin is provided and materials are separated by the recycling facilities. With an extremely high recycling rate of 69%, San Francisco is one of the most successful single-stream recyclers around. Through a combination of human and machine-automated separation techniques (Eddy-current separators), SF "... processes an average of 750 tons of paper, plastic, glass and metals a day."

I used the colorfully titled 2006 State of Garbage in America to get a snapshot of the recycling rates by state. As a secondary metric, I will also look at the percentage of total MSW (municipal solid waste) which ends up in landfills. Using this metric, the Rocky Mountain Region performed horribly, with 86% of all MSW ending up in landfills:

In New England, 36% of MSW is converted to energy thus only 35% of total MSW ends up in landfills. After recyclable materials are separated, the remaining suitable MSW are combusted and the heat generated is used to power steam turbines that generate electricity. In a previous post, I compared sources of electricity for a few key countries and noted that Denmark generates 3.6% of its electricity using MSW. These Waste-to-Energy facilities do create emissions, but the EPA considers the emissions from these primarily biomass derived materials, to be part of the "Earth's natural carbon cycle". Because of the variation in Waste-to-Energy facilities, there are possibly other environmental problems that accompany such facilities.

I loaded the data and mapped the results at the State level. For recycling rates, higher rates are desirable. The West Coast states (CA, OR, WA) all recycled at least 40% of their total MSW:

I'm astounded that in the year 2006, there are still states with single-digit recycling rates!

For the percentage of total of MSW which ends up in landfills, lower rates are desirable. The New England States convert a large percentage of their MSW to energy so they have lower percentages ending up in landfills:

CT converted a whopping 65% of its MSW to energy! To the extent that the low Landfill rates are driven by high Waste-to-Energy conversion rates, further studies on the environmental impact of such facilities should be conducted.

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Monday, June 11, 2007

Occasional Dimes

  • The Strange Rise of Modern India: This is a must-read book on the world's largest democracy, incredibly well-written. Here is a recent interview with the author.

  • Danish Wind Sector runs into problems: "A conservative government has changed the rules of the game: Subsidies for wind-generated electricity have been reduced and planning rules for new turbines tightened. As a consequence, the flourishing market is stalling. In 2006, Denmark installed only 11 megawatts of new turbines, compared with the 2,200 megawatts installed in its big southern neighbor, Germany."

  • Large-scale production of Hydrogen using an Aluminum alloy: From Science Friday.

  • Going Green: A special broadcast from the Peabody award-winning program To The Best of Our Knowledge.

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    Tuesday, June 05, 2007

    Clean Technology Venture Capitals

    A few months ago I reviewed data on VC and Federal investments in Clean/Renewable energy. Since then I have been on the lookout for similar data by geography. Luckily The Economist just published an article comparing different regions in the U.S. in terms of the amount of Clean Technology VC investments.

    Based on my previous post, Clean Energy accounted for about 10% in 2006 VC investments. The U.S. Clean Technology total for 2006 was $2.9B with Silicon Valley garnering the largest share:

    If one adds up total investments in the State of California, I suspect that the Golden State took in close to 30% of the total. The regions that attract technology (VC) investments are the leaders in Clean Technology start-ups as well. The combination of entrepreneurs, engineers, great Universities, research labs, and environmentalists will make Silicon Valley hard to dislodge. Surprisingly, Denver which has the National Renewable Energy Laboratory attracted less investments than Texas.

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