By the editors of E - The Environmental Magazine
Dear EarthTalk Which are the most fuel-efficient hybrid and/or all-electric cars available to consumers today - just the affordable ones, please?
- Jack Madison, Chicago, Ill.
Given increased environmental awareness, high gas prices and a continually slumping economy, it's no wonder that more fuel-efficient cars are all the rage these days.
The best deal going may be Honda's hybrid, the 42 miles-per-gallon Insight at $18,350. Meanwhile, the newest version of Toyota's flagship hybrid, the Prius at $23,015 garners an impressive 50 mpg. Other solid choices include Toyota's 41-mpg Camry hybrid at $25,900, Ford's 39-mpg Fusion hybrid at $28,700, Lexus' 42-mpg CT 200h at $29,120, and Lincoln's 39-mpg MKZ Hybrid at $34,755.
For even greater efficiency and lower sticker prices, consider going electric, whereby you can charge your vehicle at ordinary electric outlets at home or work. Mitsubishi's new MiEV electric at $29,125 is the most fuel-efficient car available to U.S. consumers in the 2012 model year, achieving 112 "mpg-equivalent" (the U.S. Environment Protection Agency's rating for electric vehicles that swaps in electricity for gas in its calculations) and a 62-mile range per full charge - not bad considering four adults can fit fairly comfortably inside. Another option is Smart's FourTwo Electric at $28,752, a two-seater with an 87-mpg-equivalent. And Nissan's all-electric Leaf at $35,200, which achieves 99-mpg efficiency for a range up to 100 miles.
So-called "plug-in" hybrids also allow drivers to charge their vehicles' electric batteries via common power outlets, but also can use gasoline as needed for a longer range. Though pricey at $39,145, the Chevy Volt may save you money in the long run because it gets a whopping 94 mpg-equivalent in its preferred all-electric mode. An onboard gas generator produces more electricity as the vehicle is driven, extending the car's range with a full tank of gas to some 375 miles.
Toyota released a plug-in version of its Prius selling at $32,760 this year, as well. It gets 87 mpg in electric mode - but this will only get you 15 miles without gas assistance - and a respectable 49 mpg in regular hybrid mode.
Another factor to consider when deciding which of these new uber-efficient vehicles may be right for you is the availability of additional incentives. Buyers of a new Volt, MiEV, FourTwo Electric or Leaf, for example, can cash in on a federal tax credit of $7,500 - and some states may offer additional incentives - bringing the overall cost of these cars down to within the range of similarly sized traditional car models.
The U.S. Department of Energy posts all of the relevant federal tax incentives online at its Fuel Efficient Vehicle Tax Information Center website. For state-by-state incentives, check out the Database of State Incentives for Renewable Energy, a free online resource maintained by the North Carolina Solar Center and the Interstate Renewable Energy Council.
Of course, consumers don't have to go hybrid or electric to enjoy improved fuel efficiency these days. Scion's iQ, priced at $15,265, and Honda's CR-Z at $19,545 each get 37 mpg out of sporty little gas-powered internal combustion engines.
Kia, Toyota, Chevrolet, Hyundai and Nissan also make smaller traditional cars that get a respectable 33-34 mpg for sticker prices under $15,000.
CONTACTS DOE's Fuel Efficient Vehicle Tax Information Center, www.fueleconomy.gov/feg/taxcenter.shtml; DSIRE, www.dsireusa.org; Edmunds' "Decoding Electric Car MPG," www.edmunds.com/fuel-economy/decoding-electric-car-mpg.html.
Dear EarthTalk How is it that dams actually hurt rivers?
- Missy Davenport, Boulder, Colo.
Dams are a symbol of human ingenuity and engineering prowess - controlling the flow of a wild rushing river is no small feat. But in this day and age of environmental awareness, more and more people are questioning whether generating a little hydroelectric power is worth destroying riparian ecosystems from their headwaters in the mountains to their mouths at the ocean and beyond.
According to the nonprofit American Rivers, more than 1,000 dams across the U.S. have been removed to date. And the biggest dam removal project in history is now well under way in Olympic National Park in Washington state where two century-old dams along the Elwha River are coming out.
But why go to all the trouble and expense of removing dams, especially if they contribute much-needed renewable, pollution-free electricity to our power grids?
The decision usually comes down to a cost/benefit analysis taking into account how much power a given dam generates and how much harm its existence is doing to its host river's environment. Removing the dams on the Elwha River was a no-brainer, given that they produced very little usable electricity and blocked fish passage on one of the region's premier salmon rivers. Other cases aren't so clear-cut.
According to the Hydropower Reform Coalition, a consortium of 150 groups concerned about the impact of dams, degraded water quality is one of the chief concerns. Organic materials from within and outside the river that would normally wash downstream get built up behind dams and start to consume a large amount of oxygen as they decompose.
In some cases this triggers algae blooms which, in turn, create oxygen-starved "dead zones" incapable of supporting river life of any kind.
Also, water temperatures in dam reservoirs can differ greatly between the surface and depths, further complicating survival for marine life evolved to handle natural temperature cycling.
And when dam operators release oxygen-deprived water with unnatural temperatures into the river below, they harm downstream environments as well.
Dammed rivers also lack the natural transport of sediment crucial to maintaining healthy organic riparian channels. Rocks, wood, sand and other natural materials build up at the mouth of the reservoir instead of dispersing through the river's meandering channel.
"Downstream of a dam, the river is starved of its structural materials and cannot provide habitat," reports HRC.
Fish passage is also a concern.
"Most dams don't simply draw a line in the water; they eliminate habitat in their reservoirs and in the river below," HRC said.
Migratory fish like salmon, which are born upstream and may or may not survive their downstream trip around, over or through a dam, stand an even poorer chance of completing the round trip to spawn. Indeed, wild salmon numbers in the Pacific Northwest's Columbia River basin are down some 85 percent since the big dams went in there a half century ago.
While the U.S. government has resisted taking down any major hydroelectric dam along the Columbia system, political pressure is mounting.
No doubt all concerned parties will be paying close attention to the ecosystem and salmon recovery on the Elwha as it unfolds over the next few decades.