Dear EarthTalk: With plug-in hybrid and electric cars due to hit the roads sometime soon, will there be places to plug them in besides at home? And if so, how much will it cost to re-charge?

– Nicole Koslowsky, Pompano Beach, FL

Gasoline-electric hybrids, like the Toyota Prius, are all the rage due to their fuel efficiency, and consumers have been clamoring for carmakers to up the ante and give these vehicles a plug. This way the batteries can be charged at home and not just by the gas engine and other on-board features, thus greatly reducing the need for gas except for long trips. And purely electric cars, like the Tesla Roadster already on the market, will be making more appearances on the streets as greater production brings the costs down.

So what’s an electric or plug-in hybrid driver to do when they need a charge and they’re nowhere near home? Plug-ins are expected to reach up to 60 miles on a charge (great for a commute but not for a longer trip); and though the Tesla reportedly went 241 miles on a charge in a recent European road rally, its everyday stop-and-go efficiency will likely be less and drivers will need “pit stops” far from home.

A few forward-thinking large companies have installed electric outlets accessible to employee parking, but most plug-in hybrid and electric car drivers will be looking for help well beyond the scope of their commutes. In the U.S., several cities in California, as well as Seattle, Chicago, Phoenix and others are now setting up recharging infrastructures. Paris, where Toyota is testing plug-in hybrids, already has over 80 recharging stations throughout the city and suburbs. Across the channel, London is working with the nonprofit Environmental Defense to install upwards of 40 electric recharging stations around town.

According to the California Cars Initiative (CalCars), which promotes plug-in hybrids, Americans recharging their plug-ins via a regular 120V outlet should expect to pay about $1 per gallon equivalent. “Using the average U.S. electricity rate of nine cents per kilowatt-hour (kWh), 30 miles of electric driving will cost 81 cents,” the group maintains. “If we optimistically assume the average U.S. fuel economy is 25 miles per gallon, at $3.00 gasoline this equates to 75 cents a gallon for equivalent electricity.”

For its part, Toyota has already released a few hundred plug-in Priuses in the U.S. to university and commercial fleet customers. The company will monitor the vehicles’ performance and use the data to tweak the design for a consumer-friendly version sometime after 2010. Pricing on the vehicles, which get 65 miles per gallon or more in combined gas/electric mode and can run on electricity alone, is as yet undecided. But chances are the car will command a premium of several thousand dollars over the cost of a regular hybrid Prius. The fact that such a feature might obviate the need for gasoline entirely-save for long trips away from charging facilities-may well make it worth the extra up-front cost for some buyers.

Those unwilling to wait for a mass-market plug-in can have their existing Prius or Ford Escape hybrid converted accordingly by any of several “aftermarket” companies at a cost of $6,000 and up. CalCars provides a comprehensive listing of vendors across the U.S. and elsewhere that can do the conversions, and also offers its own instructions for those engineering-savvy hybrid owners who can do it themselves.

CONTACTS: Tesla Motors, www.teslamotors.com; Environmental Defense, www.edf.org; California Cars Initiative, www.calcars.org; Toyota, www.toyota.com.

Dear EarthTalk: Are plans to mine uranium near the Grand Canyon, as proposed by the Bush administration in 2008, still underway? -- Denton Chase, Half Moon Bay, CA

The Obama administration has been quick to overturn several anti-environmental moves ushered in during the 11th hour of George W. Bush’s presidency, but halting uranium exploration and mining near the Grand Canyon has not been one of them.

Last fall, Bush’s Secretary of the Interior, Dirk Kempthorne, circumvented a prohibition on mining activities by authorizing uranium exploration within a million acre buffer zone around Grand Canyon National Park. Recent spikes in the price of uranium-perhaps due to renewed interest in nuclear power as an alternative to fossil fuels as global warming makes its presence felt-have led to a surge in applications for new uranium mining permits on otherwise protected federal lands.

Green groups fear that once mining starts near the Grand Canyon, similar destructive plans will also get the green light in and around other protected areas, including Arches National Park, Capitol Reef National Park, Canyonlands National Park and the proposed Dolores River Canyon wilderness area.

When Kempthorne first proposed opening up the land to uranium mining, several concerned parties-including dozens of elected officials, public utilities and Native American tribes-complained about potential threats to surface and ground water from such activities. They fear that uranium mining in the area could lead to the release of radioactivity and heavy metals like selenium into the Colorado River and its watershed, including within Grand Canyon National Park.

In lieu of federal action on the issue, green groups have taken up the cause. Some, like the Pew Environment Group, are lobbying President Obama to overturn the mining allowances; others are working the judicial angle. Three organizations-the Center for Biological Diversity, Grand Canyon Trust and Sierra Club-filed suit in federal court in October 2008 to block the Bureau of Land Management, which manages the area, from allowing uranium mining in what they consider risky and nationally significant areas. “This is an agency in dire need of leadership from the new administration,” says Taylor McKinnon, public lands program director at the Center for Biological Diversity. “The Grand Canyon deserves it.”

The battle over uranium mining near the Grand Canyon sheds light on an even larger issue: the 1872 Mining Law, enacted under President Ulysses S. Grant and still in effect today. Long a bone of contention along partisan lines, the law has so far opened up of some 350 million acres of public land across the western U.S. to virtually unchecked mining. Green groups maintain that the law, put in place to encourage westward expansion, no longer makes sense in the modern era of dwindling natural resources.

“Current federal policy that allows the mining industry to operate next to America’s national icons and against the will of local communities must be changed,” said Jane Danowitz, Pew’s U.S. public lands program director. “It’s time to modernize the nation’s 1872 mining law.”

CONTACTS: Center for Biological Diversity, www.biologicaldiversity.org; Sierra Club, www.sierraclub.org; Pew Environment Group, www.pewtrusts.org.

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Dear EarthTalk: Should we expect to see “plug-in” hybrid cars anytime soon? I’ve been hearing they are on the horizon but I wonder if that means in one year or 10. – Bill A., Stratford, CT

Gasoline-electric hybrids now, like Toyota’s popular Prius, don’t need to plug in-you just fill their tanks with gasoline and the battery keeps charged by the internal combustion engine and by energy generated from the wheels when braking (a feature known as “regenerative braking”). The battery then powers the electric motor when it is called into service during idling, backing-up, crawling in gridlock, maintaining speed while cruising, and for extra uphill power when needed. As such, the electric motor is essentially a back-up engine while the hybrid relies mainly on the gasoline engine.

Plug-in hybrids take the concept further by plugging into a regular electric outlet to enable the vehicle to operate solely on its electric motor for ranges of 40-50 miles or more on a single charge. This has profound implications for commuters who need only drive short distances to and from work every day and who may be able to do so solely on electric power. The gasoline engine then becomes the supplemental one for when the car needs to travel farther than the electric engine can take it.

According to researchers at the University of California Davis, the electricity cost for powering a plug-in hybrid is only about one-quarter of the cost of powering a like-sized gasoline vehicle. Other benefits include far fewer fill-ups at gas stations and the convenience of recharging at home.

Toyota, currently the world’s largest producer of hybrid vehicles by far thanks to the success of its Prius, announced that it expects to have a commercially viable plug-in hybrid available to consumers as early as 2010 and is now testing prototype versions of plug-in hybrids at two California universities.

Felix Kramer of the California Cars Initiative (CCI), a non-profit dedicated to promoting plug-ins, called Toyota’s announcement “stunning and very welcome,” and says that these vehicles will be the cleanest practical cars on the road in a world where gas stations dot just about every intersection. The promise of such cars, says CCI on its website, is that drivers will have a “cleaner, cheaper, quieter car for local travel, and the gas tank is always there should you need to drive longer distances.”

U.S. automakers are also jumping onto the plug-in bandwagon. General Motors says that it will have mass-market plug-in hybrids-modifications of its Saturn Vue and Chevrolet Volt-on the road by 2010. Ford has also developed a small fleet of plug-ins, but is not yet ready to offer them to the public. Fisker, a U.S. start-up focusing on the creation of high performance, energy efficient vehicles, plans to sell an $80,000 plug-in hybrid sports car by late 2009. Chrysler’s Sprinter van was the first plug-in from a major U.S. manufacturer, but it is only presently available to a limited number of institutions as a fleet vehicle.

Plug-ins have also caught on elsewhere. Chinese carmaker BYD plans to sell a plug-in hybrid sedan in the U.S. within five years. And Volkswagen hopes to have a plug-in hybrid Golf ready to roll by 2010.

CONTACTS: California Cars Initiative, www.calcars.org; BYD, www.byd.com; General Motors, http://www.gm.com/experience/fuel_economy/news/2008/hybrids/plug_in_vue_011008.jsp; Fisker, http://jalopnik.com/344419/detroit-auto-show-fisker-karma-luxury-hybrid-only-80000.

Dear EarthTalk: I was intrigued to hear that there were a number of ways one could modify or construct a roof on a house or office facility that would provide great environmental benefit. Can you enlighten? – Bill Teague, Menlo Park, CA

Most buildings are designed to shed rain, and as such are built with hard, impenetrable roofing surfaces. As a result, rainwater bounces off and collects as runoff, picking up impurities-including infectious bacteria from animal waste as well as harmful pesticides and fertilizers-on the way to municipal storm sewers, which in turn eventually empty out into local bodies of water.

Minimizing this run-off means that more impurities will remain in local soils where they can be broken down more easily into their constituent elements than if they are concentrated downstream. In order to achieve this goal, landscape architects have developed so-called “green roofs,” which utilize living plant matter and soil on top of a building in order to absorb, collect and reuse rainwater while preventing run-off. Many buildings employing green roofs are able to find abundant uses for the water they collect, from watering exterior plantings at ground level to flushing toilets inside.

According to Steven Peck of the Toronto-based non-profit Green Roofs for Healthy Cities, green roofs can play an important role in maintaining ecological integrity within otherwise paved over areas. “The roofscapes of our cities are the last urban frontier-from 15 percent to 35 percent of the total land area-and the green roof industry can turn these wasted spaces into a force for cleaner air, cleaner water, energy savings, cooling, beauty and recreation,” he says.

The U.S. Environmental Protection Agency (EPA) encourages the creation of green roofs for mitigating the urban “heat island effect,” whereby temperatures in crowded cities can soar some 10 degrees Fahrenheit higher than in less developed areas nearby. Other benefits, says the EPA, include: providing amenity space for tenants (in effect replacing a yard or patio); reducing building heating and cooling costs due to the buffering effect of the plant matter and soil; filtering pollutants like carbon dioxide out of the air and heavy metals out of rainwater; and increasing bird habitat in otherwise built-up areas.

Beyond going all out to build a “living” green roof, certain inorganic materials can also make an existing roof greener. The non-profit Cool Roof Rating Council (CRRC), for instance, suggests roofing surfaces that reflect the sun’s heat so as to reduce the urban heat island effect while improving residential energy efficiency. According to the group, “a cool roof reflects and emits the sun’s heat back to the sky.” Builders can check out CRRC’s website for a database of information on the radiative properties of various roofing surfaces so as to make the smartest choice for clients and the environment.

Another quality that makes certain roofs greener than others is how long they last. Metal roofs are known to be relatively maintenance free and last longer than shingles in most situations. Slate roofs also have an excellent reputation for lasting long, although getting work done on them can be expensive when they do need repairs. The Slate Roofing Contractors Association reports that sea green slates can last anywhere from one to two centuries, depending on where the slate is quarried and how well it’s eventually installed.

CONTACTS: Green Roofs for Healthy Cities, www.greenroofs.org; CRRC, www.coolroofs.org.

GOT AN ENVIRONMENTAL QUESTION? Send it to: EarthTalk, c/o E/The Environmental Magazine, P.O. Box 5098, Westport, CT 06881; submit it at: www.emagazine.com/earthtalk/thisweek/, or e-mail: earthtalk@emagazine.com. Read past columns at: www.emagazine.com/earthtalk/archives.php.