Dear EarthTalk: I heard that some wind farms use fossil fuels to power their generators when the wind won"t. Doesn't that defeat their whole renewable energy purpose? Why not let the wind power it or not? Also, I've heard that the low-frequency sounds generated by these turbines can harm people and animals. Is this true?
—Ryan Lewis, Plainwell, MI
Indeed, one of the major drawbacks to wind power is the fact that, even in windy locations, the wind doesn't always blow. So the ability of turbines to generate power is intermittent at best. Many turbines can generate power only about 30 percent of the time, thanks to the inconsistency of their feedstock.
In order to overcome this Achilles" heel of intermittent production, some wind companies have developed back-up systems that can spin turbines even when the wind isn't blowing, thus optimizing and keeping consistent the power output. For example, Colorado-based Hybrid Turbines Inc. is selling wind farms systems that marry a natural gas-based generator to a wind turbine. "Even if natural gas is used, the electricity produced
is twice as environmentally clean as burning coal," reports the company. Better yet, if a user can power them with plant-derived biofuels, they can remain 100 percent renewable energy-based.
While some wind energy companies may want to invest in such technologies to wring the most production out of their big investments, utilities aren't likely to suffer much from the intermittent output if they don"t. Even the utilities that are most bullish on wind power still generate most of their electricity from other more traditional sources at the present time. So, when wind energy output decreases, utilities simply draw more power from other sources—such as solar arrays, hydroelectric dams, nuclear reactors and coal-fired power plants—to maintain consistent electrical service. As such, reports the American Wind Energy Association, utilities act as "system operators" drawing power from where it's available and dispatching it to where it is needed in tune with rising and falling power needs.
But just because generating wind power all day long isn't imperative doesn't mean that suppliers aren't doing all they can to maximize output. To wit, turbine manufacturers are beginning to incorporate so-called Active Flow Control (AFC) technology, which delays the occurrence of partial or complete stalls when the wind dies down, and also enables start-up and power generation at lower wind speeds than conventional turbines. The non-profit Union of Concerned Scientists lauds AFC for these capabilities, which in turn can help system operators create a more reliable electric grid less dependent on fossil fuels.
As to whether or not noise from wind farms can harm people and wildlife, the jury is still out. New York-based pediatrician Nina Pierpont argues in her book, Wind Turbine Syndrome, that turbines may produce sounds that can affect the mood of people nearby or cause physiological problems like insomnia, vertigo, headaches and nausea. On the flip side, Renewable UK, a British wind energy trade group, says that the noise measured 1,000 feet away from a wind farm is less than that of normal road traffic. Here in the U.S., a Texas jury denied a 2006 noise pollution suit against FPL Energy after FPL showed that noise readings from its wind farm maxed out at 44 decibels, roughly the same generated by a 10 mile-per-hour wind.
Dear EarthTalk: My neighbor told me to pour bleach down my drains every week to keep them clear. Is this safe to do?
—Trish Osterling, via e-mail
Bleach is a useful cleaner and disinfectant, but pouring it down the drain will not do anything to help keep the drains clear. In addition, you could cause a dangerous chemical reaction if it comes into contact with other household products you might be using.
Common household bleach, also known as chlorine bleach, is a liquid compound of sodium hypochlorite, which is a combination of sodium chloride (a salt) with water and chlorine. It's often used to whiten laundry or to disinfect kitchen surfaces. Bleach is also an ingredient in other household cleaners, like those used for bath and toilet cleaning. (A different sort of bleach, known as oxygen bleach, is used for laundry stain removal and does not have the same disinfecting/cleaning properties as chlorine bleach.)
According to the Household Products Database at the U.S. Department of Health and Human Services (DHHS), chlorine bleach is corrosive to the eyes; injures skin and mucous membranes on contact; and is harmful if swallowed. Bleach is "a lung and eye irritant," warns the Washington Toxics Coalition (WTC), a Seattle non-profit that advocates for green friendly household products. Even used alone, fumes from chlorine bleach can irritate the lungs, so it should not be used by people with asthma or lung or heart problems, says the group. It is also "reactive" with ammonia and acids, forming more harmful fumes.
"One of the most common home accidents is the mixing of products containing chlorine bleach with those containing ammonia," says WTC. The combination creates chloramine gas, which is highly irritating to the lungs. Since many cleaning products contain ammonia, the inadvertent mixing must be avoided. Mixing bleach and acids results in the release of chlorine gas, according to the New Jersey Department of Health and Senior Services, exposure to which can cause coughing and breathing problems, burning eyes and, at high levels, vomiting, pneumonia and even death. Products containing acids include vinegar, some glass and window cleaners, toilet bowl cleaners, drain cleaners and rust removers. An "incompatibility chart" listing many chemicals that will react with bleach is available at the Chlorine Institute's cl2.com website.
Bleach alone is not necessarily hard on the environment. When use as directed, it will break down mostly into salt water in wastewater treatment or septic systems, says WTC. A dilution of bleach in water is effective as a disinfectant, and can be scrubbed onto non-porous food-contact surfaces like plastic cutting boards or refrigerator shelves and left to air dry. The Clorox Company recommends a solution of one tablespoon bleach per gallon of water for sanitizing.
So, what are the better ways to keep drains clear? Home drains in the kitchen and bath generally get clogged by grease, food waste and hair, none of which will be effectively dispersed by bleach. WTC recommends carefully pouring a kettleful of boiling water down the drain to free up a slow drain, or using mechanical methods such as a plumber's snake, plunger or hose-end bladder to clean a clogged drain.
EarthTalk is now a book! Details and order information at: www.emagazine.com/earthtalkbook.