Debunking The Top 10 Energy Myths
By Elizabeth Svoboda
http://www.popularmechanics.com/science/energy/debunking-myths-about-nuclear-fuel-coal-wind-solar?click=pp

Myth No. 1

Nuclear Power Isn't a Safe Solution

In a recent national poll, 72 percent of respondents expressed concern about potential accidents at nuclear power plants. Some opinion-makers have encouraged this trepidation: Steven Cohen, executive director of Columbia University's Earth Institute, has called nuclear power "dangerous, complicated and politically controversial."

During the first six decades of the nuclear age, however, fewer than 100 people have died as a result of nuclear power plant accidents. And comparing modern nuclear plants to Chernobyl—the Ukrainian reactor that directly caused 56 deaths after a 1986 meltdown—is like comparing World War I fighter planes to the F/A-18. Newer nuclear plants, including the fast reactor now being developed at Idaho National Laboratory (INL), contain multiple auto-shutoff mechanisms that reduce the odds of a meltdown exponentially—even in a worst-case scenario, like an industrial accident or a terrorist attack. And some also have the ability to burn spent fuel rods, a convenient way to reuse nuclear waste instead of burying it for thousands of years.

Power sources such as coal and petroleum might seem safer than nuclear, but statistically they're a lot deadlier. Coal mining kills several hundred people annually—mainly from heart damage and black lung disease, but also through devastating accidents like the April mine explosion in West Virginia. The sublethal effects of coal-power generation are also greater. "The amount of radiation put out by a coal plant far exceeds that of a nuclear power plant, even if you use scrubbers," says Gerald E. Marsh, a retired nuclear physicist who worked at Argonne National Laboratory. Particulate pollution from coal plants causes nearly 24,000 people a year to die prematurely from diseases such as lung cancer. Petroleum production also has safety and environmental risks, as demonstrated by the recent oil spill in the Gulf of Mexico.

INL nuclear lab's deputy associate director, Kathryn McCarthy, thinks the industry can overcome its stigma. "It's been a long time since Chernobyl and Three Mile Island," McCarthy says, "and people are willing to reconsider the benefits of nuclear energy." Nuclear plants emit only a tiny fraction of the carbon dioxide that coal plants do, and a few hundred nuclear facilities could potentially supply nearly all the energy the United States needs, reducing our dependence on fossil fuels.

Editor’s Note: The number of premature, radiation-related deaths caused by the Chernobyl meltdown are also great, ranging from an estimated 4000 (United Nations) to 93,000 (Greenpeace) to 985,000 (the authors of Chernobyl: Consequences of the Catastrophe for People and the Environment, published this winter). However, Chernobyl’s Soviet-designed RBMK reactor, which used a graphite moderator and had no containment structure, is not used in the United States, even in the older second-generation plants.

Myth No. 2

Sure, Corn Ethanol is Problematic—But Switchgrass Will Save the Day

The renewable energy movement's darling for years, corn-based ethanol has fallen out of favor for not making good on its promises of efficiency. Cellulosic ethanol—made from plant parts containing cellulose, such as grass and wood chips—seems poised to be the next star of the biofuel circuit. Its fuel crops require less fertilizer and use water more efficiently than corn. Plus, it can be created from waste products like lawn clippings and tree branches.

But the upstart fuel will have to surmount sizable environmental and financial challenges. For one, it takes a tremendous amount of cellulose to produce ethanol in industrial quantities, which means a lot of land would still have to be devoted to fuel production. "The low density of the supply is a problem," says Tad Patzek, a chemical engineer at the University of Texas at Austin. "To supply fuel to, say, the Bay Area, you would need an area of switchgrass that is larger than all the agricultural land in California."

And since cellulose is tough and fibrous, it requires heavy-duty enzymatic decomposition processes to convert the plant matter into simple sugars that can be fermented into ethanol. These processes consume large amounts of energy and are so pricey that a study in Bioresource Technology last year concluded that cellulosic ethanol won't be competitive with gasoline unless oil prices remain above $90 a barrel.

When that day comes, cellulosic could play a modest role in boosting supplies. And that's worth more research today. But hopes that grass clippings will end our oil habit are overblown.

Myth No. 3

Wind Power is Far Too Unreliable

First things first: Wind power is intermittent; it's just the nature of, well, nature. Due largely to the unpredictability of weather, turbines typically generate only about one-fifth of the energy they'd make if they actually ran 24/7. That said, energy planners have devised tactics to make wind power reliable.

One of the best ways to balance wind's now-it's-here-now-it's-not quality is to construct grid connections between different regions of the U.S. "We have monitoring systems that show us the winds as they proceed through different regions," says George Van Hoesen, a managing partner at Global Green Building, an environmental consulting firm in Missouri. "We understand the currents and the flows." Armed with this data and computer models, utilities can plan to shunt surplus power generated in one part of the country to areas that need it.

Science supports that strategy. A recent Stanford University study found that when many wind farms are interconnected through the grid, about one-third of the electricity they generate can be counted on as a reliable source of around-the-clock power. (Less reliable wind energy sources can still be put to profitable use—to charge batteries for electric vehicles or produce hydrogen transportation fuel, for example.) And a University of Delaware study published this spring concluded that an offshore grid, connecting wind generators along the East Coast, could provide relatively stable output. Over a simulated five-year period, power never petered out entirely.

"In the eastern United States, storms typically move along the coast," says Willett Kempton, a lead author. "Thus, if offshore wind farms are connected by a transmission line, the power from the whole set is more consistent."

Still, even the savviest grid connections have limits. The most optimistic projections calculate that wind can supply about 30 percent of the planet's electricity by 2030, so power sources like nuclear, hydropower and solar will be needed as supplements. It might not be a great idea to place all bets on wind, but with the latest turbines able to generate pollution-free electricity at less than 5 cents per kilowatt-hour, it wouldn't be smart to let wind go by the wayside while we invest in less sustainable fuels, either.

Myth No. 4

Algae Grows Anywhere, So Turning It Into Fuel Will Be Cheap

It grows in ponds. It grows in streambeds. It even grows in your sink if you forget to scrub it. Algae is so omnipresent that startups like Solix and Aurora Biofuels make it easy to envision the microscopic green organisms meeting all the transportation needs of the planet at pennies a gallon for eternity.

But in-depth experimentation suggests that algae-fuel supremacy isn't going to come easy. The strains of algae that work best for biodiesel are specialized lipid-producers that won't thrive in just any circumstances. Algae-fuel researchers have tried growing the organisms in open ponds for decades, but the water often becomes contaminated with native algae, which quickly outcompete lipid-rich strains.

Closed bioreactors come with their own set of issues. "Even relatively inexpensive ones are going to add dramatically to capital costs," says biochemical engineer John Sheehan, who worked on a stalled National Renewable Energy Laboratory algae-fuel project. Plus, as bioreactors scale up, decreased surface-area-to-volume ratios often make it difficult for all the algae to get the solar energy they need, making them subpar for fuel production. Algae fuel may eventually take off, but it's going to require a lot of testing, technical tweaking and expensive infrastructure to get there.

Myth No. 5

Tidal Power is a Lost Cause

As the sea level rises and falls, tides roll in and out twice a day, unfailingly. It's hard to imagine a more predictable source of power. Yet tidal power's showcase project in the United States, an array of underwater turbines anchored in the East River in New York City, hasn't exactly been an overnight success. Two initial turbine designs flopped over the course of several years; blades and hubs snapped off because they weren't strong enough to withstand the near-constant force of the water.

Still, it's too soon to give up on tidal power. The Rance tidal power plant in France has an installed capacity of 240 megawatts and has been in continuous operation for more than 40 years. Its axial-flow turbines are capable of operating as the water flows in both directions. And after several false starts, Verdant Power's array operated for more than 9000 hours in a 2008 trial, delivering 70 megawatt-hours of energy to two end-users. This summer, the startup Natural Currents Energy Services plans to install proprietary turbines in two projects that will power marinas in New Jersey. "We're talking about the entire ocean moving in one direction or another," says Global Green Building's Van Hoesen. "The sheer volume of energy makes it very attractive."

Myth No. 6

Clean Coal Can Clear the Skies of Emissions

The phrase "clean coal" has recently entered the argot of energy planners and political candidates, implying that coal—in addition to supplying cheap, reliable base-load power—can be an environmentally friendly energy source. Energy Secretary Steven Chu endorsed this viewpoint, announcing that the Department of Energy would spend more than $3 billion to fund facilities that capture carbon dioxide from coal and stash it underground, reducing air pollution.

Unfortunately, clean, cheap coal is still a pipe dream. According to the National Energy Technology Laboratory, the cost of capturing carbon dioxide from coal plants and storing it in underground locations will increase the price of electricity from 30 to 100 percent, depending on the method used. In addition, coal-fired power plants that perform sequestration burn one-quarter more coal than their unimproved counterparts to produce the same amount of electricity. That means more destructive mining operations, more CO2 emissions from transportation and more coal ash, the toxic byproduct of all coal-burning. "We have implemented some technologies that are cleaning the air," says Mary Fox, an environmental scientist at Johns Hopkins University, "but that has led to a displacement of some of those waste products into solid waste."

That displacement can lead to serious health consequences, as in the case of the coal-ash slurry that broke through a dike in Tennessee, sullying water supplies with mercury, lead and arsenic. Disposing of toxic ash responsibly could cost in excess of $5 billion annually, so efforts to pass more stringent federal controls on solid waste have stalled. For better or worse, coal produces roughly half of the nation's electricity, so technology for next-gen facilities is worth developing. But no breakthrough will cause the nearly 500 plants already operating in the U.S. to magically clean up their act.

Myth No. 7

The Risk of Earthquakes makes Deep Geothermal Unrealistic

Horror stories about deep geothermal drilling began circulating after a series of earthquakes shook the city of Basel, Switzerland, in 2006. And, in fact, a scientific analysis concluded that a geothermal system likely set off the quakes, causing a similar project in California to be scuttled.

But deep geothermal, also called enhanced geothermal, has distinct advantages too. Because it taps into the hot, dry bedrock miles below the surface, drilling could be widespread. A recent study led by MIT identified 200,000 exajoules of extractable deep geothermal energy, which could supply more than 2000 times the nation's annual energy use.

Odds are very low that enhanced geothermal power would ever cause a quake on the scale of, say, the recent shake-up in Chile, says Colin Williams, a geophysicist on the U.S. Geological Survey earthquake hazards team. Even the largest quake in Basel, a 3.4 on the Richter scale, caused only minimal damage. And experts say that if enhanced geothermal plants are constructed farther away from cities—in rural areas of Europe or the western U.S., for example—any induced seismicity would have even less effect on the human population. "Should we say the technology is dead?" says scientist Domenico Giardini, who analyzed Basel. "Absolutely not."

Myth No. 8

U.S. Shale can Provide Energy Independence

Shale oil hasn't gotten too much attention since the oil crisis of the 1970s. But today, proponents are once again pointing out that there are more than a trillion barrels of oil locked in the shale deposits of Colorado, Utah and Wyoming, more than all the proven crude-oil reserves on the planet. That would be enough to meet current U.S. oil demand for an entire century.

The problem, then and now, lies in the financial and ecological costs of extracting the oil. Shale oil naturally occurs in the form of kerogens, solid, waxy substances with a texture similar to that of ChapStick. Once the kerogens are heated to over 500 F, they exude hydrocarbons, which must be treated with hydrogen in order to be processed into usable fuel—a highly energy-intensive process that releases large amounts of CO2.

And just to get at these kerogens, energy companies would have to mine and process millions of tons of shale from the earth—leaving behind toxic heavy metals and sulfates that could seep into groundwater. "There's a water contamination issue," says Olayinka Ogunsola, an engineer at the Department of Energy. "There's also a land reclamation issue—[mining] would create a lot of disturbance in the area." Mining and processing shale also require vast amounts of water—producing 2.5 million barrels of shale oil per day would require 105 million to 315 million gallons of water daily. That might be the biggest deal breaker of all for parched western states.

So while extracting the oil from U.S. shale may be technically possible, the scale of such an enterprise, as measured in acres and natural resources, may never make it worthwhile.

Myth No. 9

Solar Energy Will Never Pay for Itself

Solar panels are certainly expensive—about $100 per square foot for a typical installation—but eventually, you're destined to end up on the positive side of the equation.

According to the California Solar Electric Company, it may take from eight to 12 years to recoup in saved energy costs the investment put into a basic residential photovoltaic (PV) solar array. But this estimate varies greatly depending on factors like the size of the array and the amount of sunlight that hits it, and advances in PV technology continue to shorten the payback period.

"The shortest payback with new thin-film cells is less than a year," says Burr Zimmerman, a chemical engineer and co-founder of the Kairos Institute, which ushers new technologies into the marketplace. Thanks to ramped-up production and cheaper materials, up-front costs continue to plummet as well; the price of solar cells has fallen fifteenfold since 1980.

After a solar array's initial payback period, you start to reap some serious financial benefits. Assuming solar cells have an average life expectancy of 30 years, more than 50 percent of the power solar cells generate ends up being free. "There are maintenance issues," Zimmerman says, but over time, "solar cells are definitely making you money."

Myth No. 10

We Have to Drill Our Way Out of the Energy Dilemma

Discussions of America's energy future tend to focus on increasing production. There's no question that more mining and drilling can modestly increase overall supply—but, as recent accidents have shown, at a steep human and environmental cost. Renewable sources show promise but will take time and money to implement. "I'm a big advocate of renewables, but I'm also an advocate of common sense," says David Hughes, a fellow at the Post Carbon Institute. "Radical conservation has to be number one."

The U.S. Energy Information Administration projects that, under existing policies, total energy consumption will grow by 14 percent by 2035. That doesn't have to be the case. A report published last year by McKinsey & Company calculates that widespread deployment of energy-efficiency measures can decrease consumption by 23 percent of projected demand by 2020. What's more, such measures would result in $1.2 trillion in savings, far more than the $520 billion investment required to implement them. The corresponding reduction of greenhouse gas emissions would be like taking an entire U.S. fleet of passenger vehicles off the road.

Personal actions certainly help: A 2008 trial by Baltimore Gas and Electric showed that customers who had smart meters reduced their energy use by up to 37 percent during peak periods. And semiconductor-powered light-emitting diodes (LEDs) have the potential to reduce lighting-related energy consumption to one-sixth of its current level. The DOE estimates we could be well on our way to that goal by 2025, cutting lighting energy use by 29 percent—and collectively saving $125 billion.

There's also ample room for industry to streamline its energy consumption. If plants like oil refineries and steel mills convert exhaust heat into electricity via cogeneration, they could reap an extra 100 gigawatts, reducing CO2 emissions by about 400 million metric tons. Energy saved, it turns out, is the cheapest new source.


Adventures in Very Recent Evolution
By Nicholas Wade
http://www.nytimes.com/2010/07/20/science/20adapt.html?_r=1&pagewanted=all

Ten thousand years ago, people in southern China began to cultivate rice and quickly made an all-too-tempting discovery — the cereal could be fermented into alcoholic liquors. Carousing and drunkenness must have started to pose a serious threat to survival because a variant gene that protects against alcohol became almost universal among southern Chinese and spread throughout the rest of China in the wake of rice cultivation.

The variant gene rapidly degrades alcohol to a chemical that is not intoxicating but makes people flush, leaving many people of Asian descent a legacy of turning red in the face when they drink alcohol.

The spread of the new gene, described in January by Bing Su of the Chinese Academy of Sciences, is just one instance of recent human evolution and in particular of a specific population’s changing genetically in response to local conditions.

Scientists from the Beijing Genomics Institute last month discovered another striking instance of human genetic change. Among Tibetans, they found, a set of genes evolved to cope with low oxygen levels as recently as 3,000 years ago. This, if confirmed, would be the most recent known instance of human evolution.

Many have assumed that humans ceased to evolve in the distant past, perhaps when people first learned to protect themselves against cold, famine and other harsh agents of natural selection. But in the last few years, biologists peering into the human genome sequences now available from around the world have found increasing evidence of natural selection at work in the last few thousand years, leading many to assume that human evolution is still in progress.

“I don’t think there is any reason to suppose that the rate has slowed down or decreased,” says Mark Stoneking, a population geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

So much natural selection has occurred in the recent past that geneticists have started to look for new ways in which evolution could occur very rapidly. Much of the new evidence for recent evolution has come from methods that allow the force of natural selection to be assessed across the whole human genome. This has been made possible by DNA data derived mostly from the Hap Map, a government project to help uncover the genetic roots of complex disease. The Hap Map contains samples from 11 populations around the world and consists of readings of the DNA at specific sites along the genome where variations are common.

One of the signatures of natural selection is that it disturbs the undergrowth of mutations that are always accumulating along the genome. As a favored version of a gene becomes more common in a population, genomes will look increasingly alike in and around the gene. Because variation is brushed away, the favored gene’s rise in popularity is called a sweep. Geneticists have developed several statistical methods for detecting sweeps, and hence of natural selection in action.

About 21 genome-wide scans for natural selection had been completed by last year, providing evidence that 4,243 genes — 23 percent of the human total — were under natural selection. This is a surprisingly high proportion, since the scans often miss various genes that are known for other reasons to be under selection. Also, the scans can see only recent episodes of selection — probably just those that occurred within the last 5,000 to 25,000 years or so. The reason is that after a favored version of a gene has swept through the population, mutations start building up in its DNA, eroding the uniformity that is evidence of a sweep.

Unfortunately, as Joshua M. Akey of the University of Washington in Seattle, pointed out last year in the journal Genome Research, most of the regions identified as under selection were found in only one scan and ignored by the 20 others. The lack of agreement is “sobering,” as Dr. Akey put it, not least because most of the scans are based on the same Hap Map data.

From this drunken riot of claims, however, Dr. Akey believes that it is reasonable to assume that any region identified in two or more scans is probably under natural selection. By this criterion, 2,465 genes, or 13 percent, have been actively shaped by recent evolution. The genes are involved in many different biological processes, like diet, skin color and the sense of smell.

A new approach to identifying selected genes has been developed by Anna Di Rienzo at the University of Chicago. Instead of looking at the genome and seeing what turns up, Dr. Di Rienzo and colleagues have started with genes that would be likely to change as people adopted different environments, modes of subsistence and diets, and then checked to see if different populations have responded accordingly.

She found particularly strong signals of selection in populations that live in polar regions, in people who live by foraging, and in people whose diets are rich in roots and tubers. In Eskimo populations, there are signals of selection in genes that help people adapt to cold. Among primitive farming tribes, big eaters of tubers, which contain little folic acid, selection has shaped the genes involved in synthesizing folic acid in the body, Dr. Di Rienzo and colleagues reported in May in the Proceedings of the National Academy of Sciences.

The fewest signals of selection were seen among people who live in the humid tropics, the ecoregion where the ancestral human population evolved. “One could argue that we are adapted to that and that most signals are seen when people adapt to new environments,” Dr. Di Rienzo said in an interview.

One of the most visible human adaptations is that of skin color. Primates have unpigmented skin beneath their fur. But when humans lost their fur, perhaps because they needed bare skin to sweat efficiently, they developed dark skin to protect against ultraviolet light.

Coloring the skin may sound simple, but nature requires at least 25 different genes to synthesize, package and distribute the melanin pigment that darkens the skin and hair. The system then had to be put into reverse when people penetrated the northern latitudes of Europe and Asia and acquired lighter skin, probably to admit more of the sunlight required to synthesize vitamin D.

Several of the 25 skin genes bear strong signatures of natural selection, but natural selection has taken different paths to lighten people’s skin in Europe and in Asia. A special version of the golden gene, so called because it turns zebrafish a rich yellow color, is found in more than 98 percent of Europeans but is very rare in East Asians. In them, a variant version of a gene called DCT may contribute to light skin. Presumably, different mutations were available in each population for natural selection to work on. The fact that the two populations took independent paths toward developing lighter skin suggests that there was not much gene flow between them.

East Asians have several genetic variants that are rare or absent in Europeans and Africans. Their hair has a thicker shaft. A version of a gene called EDAR is a major determinant of thicker hair, which may have evolved as protection against cold, say a team of geneticists led by Ryosuke Kimura of Tokai University School of Medicine in Japan.

Most East Asians also have a special form of a gene known as ABCC11, which makes the cells of the ear produce dry earwax. Most Africans and Europeans, on the other hand, possess the ancestral form of the gene, which makes wet earwax. It is hard to see why dry earwax would confer a big survival advantage, so the Asian version of the gene may have been selected for some other property, like making people sweat less, says a team led by Koh-ichiro Yoshiura of Nagasaki University.

Most variation in the human genome is neutral, meaning that it arose not by natural selection but by processes like harmless mutations and the random shuffling of the genome between generations. The amount of this genetic diversity is highest in African populations. Diversity decreases steadily the further a population has migrated from the African homeland, since each group that moved onward carried away only some of the diversity of its parent population. This steady decline in diversity shows no discontinuity between one population and the next, and has offered no clear explanation as to why one population should differ much from another. But selected genes show a different pattern: Evidence from the new genome-wide tests for selection show that most selective pressures are focused on specific populations.

One aspect of this pattern is that there seem to be more genes under recent selection in East Asians and Europeans than in Africans, possibly because the people who left Africa were then forced to adapt to different environments. “It’s a reasonable inference that non-Africans were becoming exposed to a wide variety of novel climates,” says Dr. Stoneking of the Max Planck Institute.

The cases of natural selection that have been tracked so far take the form of substantial sweeps, with a new version of a gene being present in a large percentage of the population. These hard sweeps are often assumed to start from a novel mutation. But it can take a long time for the right mutation to occur, especially if there is a very small target, like the region of DNA that controls a gene. In the worst case, the waiting time would be 300,000 generations, according to a calculation by Jonathan Pritchard, a population geneticist at the University of Chicago. And indeed, there are not many hard sweeps in the human genome.

But the new evidence that humans have adapted rapidly and extensively suggests that natural selection must have other options for changing a trait besides waiting for the right mutation to show up. In an article in Current Biology in February, Dr. Pritchard suggested that a lot of natural selection may take place through what he called soft sweeps.

Soft sweeps work on traits affected by many genes, like height. Suppose there are a hundred genes that affect height (about 50 are known already, and many more remain to be found). Each gene exists in a version that enhances height and a version that does not. The average person might inherit the height-enhancing version of 50 of these genes, say, and be of average height as a result.

Suppose this population migrates to a region, like the Upper Nile, where it is an advantage to be very tall. Natural selection need only make the height-enhancing versions of these 100 genes just a little more common in the population, and now the average person will be likely to inherit 55 of them, say, instead of 50, and be taller as a result. Since the height-enhancing versions of the genes already exist, natural selection can go to work right away and the population can adapt quickly to its new home.