Sunday, April 20, 2008
News
Eight Questions for Earth Day
Longtime Sunday Paper contributor and HowStuffWorks “Question of the Day” guy Josh Clark answers some questions that are bound to come up during your Earth Day celebration.
Is it possible to power our homes with our poop?
Yes. Yes it is. The biomass that is feces is actually a great energy source. The aid group Heifer International has been spreading the word around the globe that a reliable natural gas can be produced from animal fecal matter. The methane present in poop can be purified when allowed to ferment in an airtight container. The biogas that’s produced can be burned and used to provide both power and heat. Even better, mini poop power plants are scalable and fairly easy to build. Which means that they can be set up in poor rural areas, where some of the worst deforestation occurs. Poop gas can save trees that would have been cut down to provide fuel.
And feces can simply be burned, too. Cultures around the world have used dried poop cakes as fuel for heating and food preparation for about as long as domesticated animals have been around. Georgia’s got its fair share of chicken poop, and much of that will be trucked into a 20 megawatt power plant in Carnesville soon. Earth Resources Incorporated has secured a $29 million pledge from the Department of Agriculture to help underwrite the project. Feces as fuel has an added benefit: When it’s applied as fertilizer, or simply dumped, feces releases methane, a powerful greenhouse gas about 20 times stronger than CO2. Since it was going to release methane regardless, it has no net greenhouse gas generation. Warming a chicken house using heat from burned chicken litter, for example, means no extra fossil fuels have to be added to the equation. And the ash left over from the burned poop can still be used as fertilizer for crops. The circle of life is complete.
If we want to save the planet, does it matter what we eat?
As a ravenous meat-eater, I hesitate to say it (forgive me, Morton’s), but yes, what we eat does make a difference. Meat is the hallmark of a wealthy society. It’s simply far more expensive to raise cattle than food without a face. Livestock not only take up more land, but the land they require for food and grazing would just as easily feed humans. And their water needs pack another staggering wallop. Depending on who you talk to, it takes anywhere from 441 to 2,500 gallons of water to produce one pound of beef. The grain eaten by the average meat cow in a day—about 25 pounds of corn—could feed about 10 hungry humans.
That corn, too, comes at a cost. The fertilizer used for every bushel of corn requires an average of 1.2 gallons of oil to produce. This includes fossil fuel that’s actually used in the fertilizer, as well as the oil used to produce and transport the fertilizer. Of course, if you ate that corn, oil would still be part of the fertilizer equation, but when fed to a cow, there’s the transportation oil factor, too. Chauffeuring livestock to slaughter, and then the meat that livestock becomes to stores and restaurants, also burns plenty of oil. In total, a person who eats meat is responsible for about 1.5 tons more of CO2 emissions each year than his vegan counterparts.
What's the point of using those cloth bags at the supermarket? Doesn’t it take energy to make them, too?
It does, sure, but the point is the second “R” in the recycling triumvirate: Reduce, reuse, recycle. Plastic bags do have their secondary uses—using them to pick up dog poop is an excellent example, but rare is the granola-cruncher who’s devoted enough to rinse it out afterward and use it again. Instead, Americans throw out about 100 billion polyethylene bags each year, recycling only 0.6 percent of them.
Some cities around the globe are trying to put a tax on disposable grocery bags or banning them altogether. Seattle’s introduced a “green tax” of 20 cents for every paper or plastic bag used in the transaction, based on a similar system in Ireland. San Francisco is taking steps to ban the use of plastic grocery bags within the city. Countries like South Africa and Bangladesh already have bans underway. And beginning on Earth Day, the Whole Foods grocery chain is discontinuing polyethylene bags in its stores.
Beginning on Earth Day, the Whole Foods grocery chain is discontinuing polyethylene bags in its stores.
There can be drawbacks to cloth bags, too. Cotton bags may be produced from fibers grown with pesticides and fertilizers. Blood drippings from meat or a broken egg can make the bags a bit gamey. So they need to be washed, which requires energy. Still, in this damned if you do, damned if you don’t scenario, cloth beats plastic or paper.
Do those twirly-looking light bulbs really save energy in the general scheme of things?
This is one of those one-person-can’t-really-make-a-difference-but-300-million-people-can things. When everyone in the United States changes just one light bulb to a compact fluorescent lightbulb (CFL—those “twirly-looking light bulbs”), the effects are staggering. Enough energy to power 3 million homes, almost the entire number of households in Georgia, would be saved. The reduction of greenhouse gas emissions would be equal to 800,000 cars suddenly vanishing into thin air.
CFLs last about 10 times longer than the average incandescent bulb. The problem is, CFLs contain about 5 milligrams of mercury, a neurotoxin that can cause kidney and brain damage. According to research by Stanford University, even such a small amount of mercury is enough to contaminate up to 6,000 gallons of water beyond safe drinking levels. So when a CFL breaks, the cleanup is a hassle. The EPA offers 12-step instructions for safely cleaning up such CFL disasters at www.epa.gov/mercury/spills.
Whatever happened to solar power?
Like wedge-heels, those solar panels on the roof of your weird friend’s parents’ house in the ’70s are back in a big, fashionable way. One of the bigger hurdles of the solar panels of yore was the monumental price of installation. The first silicon solar cells created in 1953 by Bell Laboratory researchers produced electricity from solar power at about $300 per watt. By contrast, this past winter, Georgia Power sold an hour of electricity for about 10 cents per 1000 watts.
Solar power’s gotten decidedly cheaper in the last few decades, but it’s still fairly expensive. Currently—taking into account equipment and installation—it goes for about $5 per watt. The vast majority of the juice you use in your house is produced by nuclear energy, petroleum, natural gas and coal, which produce huge amounts of electricity super-cheap. And “cheap” has traditionally beaten “environmentally friendly.”
Still, there’s much to be said for installing solar panels on your roof these days. Next-generation set-ups can run to the tens of thousands of dollars, but most banks view solar panel installations as a home upgrade and offer improvement and equity loans. So consider the panels an investment. In roughly 10 years, the panels will pay for themselves. During the interim, you’ll be paying off the loan, not paying power bills. Once the loan’s paid off, no more monthly payments. What’s more, some Georgia utility companies offer rebates to customers who install solar cells. And a good system connects to the electrical grid. You can actually sell the excess electricity you don’t use to the power company you once paid.
Is nuclear energy really safer now than it was when Three Mile Island melted down?
When the Three Mile Island nuclear power plant in Pennsylvania experienced an overheated cooling tower on March 28, 1979, it was the worst accident in the history of nuclear power up until that time (it would be horrifically eclipsed in 1986 when Reactor No. 4 at Russia’s Chernobyl nuclear plant melted down, killing 56 people and contaminating many more).
It took 14 years before the Three Mile Island site was officially decontaminated. On March 28, a release valve that had opened to depressurize a cooling tower didn’t close once the pressure was alleviated. As it sat open, coolant spilled out of the tower, but failed to register on any gauges. It’s like your car spilling antifreeze and the warning light not showing up on your dashboard. Except much, much worse.
Without coolant, the reactor overheated and the fuel pellets melted down. This would have been as bad it gets as far as nuclear accidents go, but Three Mile Island lucked out: The vast majority of the radiation from the melted fuel was contained. Most of the 2 million residents around the plant were exposed to radiation equal to only one-sixth that of a chest X-ray. And reams of studies found few lasting effects from the meltdown in the surrounding area.
Still, the accident scared the hell out of regulators. And America suddenly realized that those nuclear power plants dotting the countryside pose a real threat. The backlash against nuclear power after Three Mile Island created a legacy. It made the energy source safer; regulations covering nuclear power in the U.S. grew decidedly tighter as a direct result of the accident. Prior to 1979, it was assumed that humans were largely a redundancy; the computer—like the one at the nuclear power plant where Homer Simpson sleeps and eats his way through his job—can handle anything.
When Three Mile Island’s alert system failed to work properly, though, nuclear authorities decided maybe humans weren’t such a bad idea, and made sure they got better training and drug tests. Oversight by the Nuclear Regulatory Commission vastly increased, establishing rules that require two or more NRC inspectors to live near the plant they inspect to oversee it day to day. And new tech has emerged: Pebble bed reactors use balls of fuel that require higher temperatures to melt. Even the worst coolant-loss scenario won’t produce temperatures that will melt the fuel.
Nuclear power contributes slightly more than a fourth of Georgia’s electricity output.
According to the Energy Information Administration, nuclear power contributes slightly more than a fourth of Georgia’s electricity output. If the Vogtle and Hatch nuclear plants, located in southeast and south central Georgia, had not been built, coal-fired power would have been the most likely alternative, adding to the emissions problem. (The Southern Nuclear Operating Company has presented a plan to the U.S. Nuclear Regulatory Commission to bring a new reactor on line at the Vogtle site by 2015.)
One thing about nuclear energy that remains dangerous, though, is the mining of the radioactive materials used to create energy in the reactors. And no one has yet to come up with an acceptable means of disposing of spent nuclear fuel. An MIT study from 2004 concluded that if the problems of cost, waste and safety in nuclear power are not addressed, there won’t be any nuclear power 50 years from now.
I've heard that ethanol use is as bad for the planet as fossil fuel use. Is that true?
That really depends on who you ask. When it comes to the future of energy resources, there’s a lot of money up for grabs.
Most studies of the net energy ratio of ethanol (the amount of energy required to produce it compared to how much energy it produces) depict it murdering that of fossil fuels. There are some, however, that tell a different story. One study, by researchers from Cornell and Berkeley, found that ethanol derived from corn requires 29 percent more fossil fuel energy to produce than it will, itself, produce. What we’re looking for is the opposite, where the output exceeds the input. Instead, the Cornell/Berkeley researchers found that for every one unit of petroleum used in the production, refining and transportation of ethanol, it produced only 0.89 units of energy. You’re reading that right; it’s actually a loss of energy.
Of course, this study is buried amid a mountain of competing studies that say quite the opposite. One found that ethanol can have a 343 percent energy yield, meaning it puts out almost 3.5 times the amount of energy it requires. And some types of ethanol have been shown to produce 88 percent less greenhouse gas emissions than regular gasoline.
Ethanol production does have some real impact on the planet. Corn ethanol production uses a plant that might be better used for food, which is currently very scarce in some parts of the world, and much more necessary than car fuel. It also requires fertilizer and water. Even switch grass, a non-edible prairie grass that looks pretty fit for the ethanol feedstock front-runner these days, could edge out food production: Both food and ethanol require land—something of which there is most definitely a finite amount—and whichever one pays the most gets planted.
Do those carbon offsets I can buy really do anything?
Everyone from car insurance companies to airlines is chiding us to spend an extra few bucks to offset our carbon footprints these days. By entering a few pieces of data into a carbon calculator, you can receive a quantified measure of how guilty you should feel about your CO2 emissions. But wait—you can pay money to alleviate that guilt! Does that money do anything to actually help the environment, though? It depends on where it goes.
These credits are like stocks, but instead of shares in a company, each represents a metric ton of CO2 not emitted.
You should be discriminating about which organizations get your money. Established groups like the Clean Air Conservancy use it to buy carbon offsets on the Chicago Carbon Exchange. These credits are like stocks, but instead of shares in a company, each represents a metric ton of CO2 not emitted. These credits can be traded, but the Clean Air Conservancy buys blocks of credits and takes them out of circulation. The Chicago Exchange is voluntary, but if Sen. Barack Obama takes office, rumor has it that a mandatory exchange will be established and the credits could be worth a lot of dough.
Your carbon offset money might also go to projects around the world. Some are better than others: Planting trees seems like a reasonable way to alleviate the strain you put on the globe. The problem is, while trees lock up carbon dioxide, they also die. And when they do, that CO2 is once again released into the atmosphere. SP