Week of 6/22/2008

Dear EarthTalk: In renovating a vacation cabin, I discovered carpenter ants working their way through the walls. Is there any way to responsibly get rid of the pests without using noxious chemicals that could potentially harm my family?

—Curran Clark, Lummi Island, WA

Carpenter ants may seem small and look harmless, but they can do serious damage to anything wooden in your home, including not only furniture but also the very framing and walls that hold up the house. If you are seeing a lot of ants or small piles of sawdust-like material in random spots in or around your home, you are most likely suffering from a carpenter ant infestation.

Ants are very social beings and form large colonies before spreading out to find additional nest sites. They thrive by hollowing out wood, especially in moist or rotten spots, to build their nests and then use their new home in your walls and chairs as a base camp from which to forage for food and water in their nearby surroundings. Indeed, their very presence is a good indication of moisture or rot problems in the wood, so homeowners may have more work on their hands than simply exterminating carpenter ants.

In the northern latitudes of the continental U.S. and in much of Canada, carpenter ants are the most common insect wood destroyer, surpassing even the mighty termite. But while many commercially available chemical pesticides will rid a structure of carpenter ants, homeowners are increasingly steering away from such toxins proven to impact the human nervous, respiratory and reproductive systems.

In dealing with carpenter ants, which can do serious damage to anything wooden in your home, avoid pesticides that are toxic to people by looking for those with boric acid or borax as the active ingredient.© Dalantech, courtesy Flickr

Perhaps the most economical and effective way to get rid of carpenter ants is by applying boric acid (also known as borax) to their nest sites and surroundings. This natural non-toxic element, mined from below the Mojave Desert in southern California, has a long history of use in exterminating brazen populations of cockroaches, palmetto bugs, waterbugs, silverfish, termites, and, you guessed it, carpenter ants.

Al Abruzzese, owner of the website Al’s Home Improvement Center, swears by boric acid to get rid of wood-boring pests. "This simple inexpensive, household chemical is deadly to all insects," he says. "It has been shown to attack their nervous systems, as well as being a drying agent to their bodies."

Beyond just being effective as an all-natural insecticide, boric acid is non-toxic to humans. Abruzzese says it is safe enough to use around children—it has been used in ointments and salves for diaper rash on babies in the past—and can be an important part of eyewash solutions as well, albeit in very diluted form (don’t try it at home). One common brand name to look for is Nisus Bora-Care, but any pesticide with boric acid or borax listed as an active ingredient will do just fine.

For those not into do-it-yourself pest control, calling in an exterminator that uses all natural products is a good option. Oregon’s All Natural Pest Elimination, for instance, services the entire four state region of the Pacific Northwest with products from Natureline—crafted from safe botanical extracts and essential oils, not synthetic chemicals—on all of its extermination jobs. Look in the yellow pages for exterminators in your area, and call each one you are considering to make sure they stay away from noxious chemicals.

CONTACTS: Al’s Home Improvement Center; Nisus Bora-Care; All Natural Pest Elimination

Dear EarthTalk: What is "cogeneration" as a means of providing heat and power?

—Jerry Schleup, Andover, MA

A look inside the workings of a cogeneration power plant at Yale University.© Sweet lil' Bunny, courtesy Flickr

Cogeneration—also known as combined heat and power, distributed generation, or recycled energy—is the simultaneous production of two or more forms of energy from a single fuel source. Cogeneration power plants often operate at 50 to 70 percent higher efficiency rates than single-generation facilities.

In practical terms, what cogeneration usually entails is the use of what would otherwise be wasted heat (such as a manufacturing plant’s exhaust) to produce additional energy benefit, such as to provide heat or electricity for the building in which it is operating. Cogeneration is great for the bottom line and also for the environment, as recycling the waste heat saves other pollutant-spewing fossil fuels from being burned.

Most of the thousands of cogeneration plants operating across the United States and Canada are small facilities operated by non-utility companies and by institutions like universities and the military. For small cogeneration plants—those that generate anywhere from one to 20 megawatts of power—biomass or even methane from garbage dumps can be used as a front-end fuel source, but natural gas is far more common as the primary input.

For instance, Sunnyvale, California-based Network Appliance Inc., a computer networking company, relies on a one megawatt natural gas-powered cogeneration system to power the building’s extensive air conditioning needs, and for back-up power for use during peak demand times. The company estimates it saves around $300,000 a year in energy costs thanks to the cogeneration system.

In another example, Illinois-based Epcor USA Ventures operates three mid-sized (25 megawatts and up) cogeneration power plants in San Diego to power U.S. Marine Corps and Navy bases there. All three plants work in the same way: Natural gas turbines drive electrical generators that in turn exhaust hot gases. These are then captured to drive a steam generator hooked into the bases centralized heating and cooling systems. Since the systems generate power to spare, Epcor is talking with area companies about kicking in for a share of the steam to keep their energy bills and carbon footprints in check.

Cogeneration is not limited to stationary power plants. Honda is exploring the use of a specialized automotive cogeneration generator designed to improve the overall efficiency of hybrid vehicles by recapturing waste exhaust heat from the internal combustion engine and converting it to electricity to recharge the battery pack. The idea is still in the research and development phase, it could make its way into new cars within a few years, further improving on the already impressive efficiency of hybrid cars.

CONTACTS: Network Appliance Inc.; Epcor USA Ventures; Honda Motor Company