There was a time when a economy car meant a flimsy import owned by someone obsessed with saving a few cents on fuel.

These days "economy" is practiced when observing the broader conservation issues, including economizing on the use of the planet's resources and conserving life by reducing political adventures involved in the maintaining the flow of oil that "fuels" the economy. These factors are considered by some when selecting their transportation.

Those in other parts of the world who have to walk for miles for their days drinking water, or who cook with collected cow dung would find driving a two ton SUV to Starbucks to pick up a Latte beyond ridiculous.

The U.S. Department of Energy provides a comprehensive Fuel Economy Website with guides for getting better mileage, selecting cars, finding the best fuel prices, tax tips for low pollution cars and tutorials on alternate fuels and car designs.  Look up your cars to learn the number of tons of co2 you are emitting each year.

Consumer reports crunched the numbers on 260 cars tested (up to July 2008) to arrive at a list of the most economical to drive cars. Purchase price, gas mileage, as well as overall quality were taken into account.

Hybrid and all electric cars may become the standard in the not too distant future, particularly of battery performance improvements developed in the laboratory translate to 2 - 10 times the travel range currently available.

Currently one must make some careful calculations to determine if there will be a financial return on the higher cost of a hybrid. The main calculation made before signing the bottom line at the dealer is to determine the break even point for the higher investment. Say you drive 15,000 miles a year and the current cost of gas is $3 a gallon. The fuel cost for a 30 mpg conventional car would be $1500 a year, a 35 mpg "mild" hybrid getting 35 mpg would cost $1285 a year, a 40 mpg hybrid would cost $1125 a year. ( Edmunds.com analysts determined that gas prices would to be at least $5.60 a gallon for hybrid drivers to break even at 15,000 miles per year for five years.)

Here are some 5 year ROI figures for this imaginary test case.

Mpg -- anual$ -- 5 Year $ Savings

30 -- $1500 -- 0 baseline conventional milege

35 -- $1285 -- $1024

40 -- $1125 -- $1875

45 -- $1000 -- $2500

Even a top end performing Prius only saves $2500 in gas over 5 years, probably less than the premium paid for the hybrid.O f course the cost of gas is the big variable factor that no one can project accurately. If gas prices returned to $4 a gallon, the 45 mpg hybrid would save $3333 in 5 years.

Other factors not as often considered include registration, insurance, maintenance and resale value.

The big surprise a hybrid owner can be hit with is the cost of battery replacement. Though they are designed to last 150,000 and 200,000 miles with a warranty of between eight and ten years, in fact Toyota claims to not having to replace any batteries due to normal wear and tear since the Prias introduction in 2000. The manufacturers non the less appear to not be anxious to discuss the battery replacement cost, depending on the specific car model and expert quoted, costs seem to range between $3000 and $8000 it may be a common occurrence to junk a car at the end of it's battery pack life. One up side, it's likely the battery technology will improve by the time the batteries fail, replacements may be lighter than the originals, adding to improved milage.

Another factor is the cost of auto insurance for hybrids. It turns out they are higher than their conventional car counterparts. Data published by the Wall Street Journal indicate that a 2010 Toyota Camry Hybrid actually costs $650 more to insure than the conventional Camry even accounting for the10% discount for alternative fuel cars. Factors causing the higher cost include the higher cost specialist technician skills needed to repair hybrids and the greater likelihood of a hybrid being stolen. There's a higher risk factor assigned the relatively young hybrid technology due to a lack of accumulated crash damage statistics. Source: Rate Car Insurance Guide.

This unlikely meeting made even more unlike, having taken place in Denmark. The Prius driver didn't notice the traffic stopped at a red light, hit a motorcycle, then the 14 day old Tesla, pushing it under the VW Touareg. Thanks to the Lotus chassis engineering and carbon fiber body, the Tesla seems to make an able Touareg pedestal. Six people were sent to the hospital, all were released within few hours later.

How does an exotic Tesla end up in Denmark? Promoting one of the most aggressive CO2 reduction programs in the world, Denmark adds a 180% gas burner tax on top of the 25% sales tax on a car sale, bringing the price of a $20,000 car to $60,000 out the door. Electric cars are exempt from the 180% co2 tariff making them an attractive deal.

The Danish electric car infrastructure includes charging stations and battery exchange depots, provided to facilitate longer drives, which do double duty storing electric grid power, helping to even out power fluctuation caused by 20% of Denmark's electric power coming from wind farms who's output varies day to day.

Those who believe in car manufacturer - oil company conspiracies may be the best customers for the so called gas saving, power increasing miracle devices, that need some explanation for the auto makes not including the simple devices in their cars.

Popular Mechanics Magazine tested 5 such devices in 2005, dynamometer tests showed at best no change in power or mileage, while more than one of the units caused a 10% loss.

The EPA has tried out nearly 100 gadgets in their Gas Saving and Emission Reduction Devices Evaluation most of the tests date back 16 years or more (dating back to prior gas shortages) Out of all these devices, only six "indicated a very small improvement in fuel economy without an increase in exhaust emissions."

Consumer Reports gives the lowdown on 3 heavily promoted gas mileage improvement devices: Fuel Genie, TornadoFuelSaver and Platinum Gas Saver. Thanks again Consumer Reports for saving us the time and money.

One way to reduce your tailpipe carbon emissions without buying a new car, is to convert your existing vehicle to all electric operation. A number of vehicle models have been successfully converted. Yanking out your engine and fitting an electric motor and support circuits can be a machining and electric engineering challenge.

Many trial and error hours can be saved by using a kit. One conversion kit company recommends converting a roomy pickup truck rather than a sub compact economy car. The kit they offer costs $9500 but does not include the 24, old fashioned 6 volt lead-acid golf kart batteries required to power the 144 volt system. The maker specifies a top speed of 75 mph with a 40 to 60 mile range. There's a detailed step-by-step writeup on a pickup conversion. and other alternate energy info at homepower magazine, or click here for a technically detailed video tour by an S-10 conversion owner. A wiki overview of the conversion process is available, there is also vast amount of information on EVs, including a list of a dozen conversion suppliers can be found at the non-profit Electric Auto Association site.

Want more? see my Electric Conversion Survey for cost & performance stats for 50 conversions

GM produced electric S-10 pickups in the late 90s using EV-1 technology, some 60 of them were sold for fleet use and were spared the crushing fate of the leased EV-1 cars. More recently a GM collaboration with a motor manufacturer created a prototype 4 in wheel motor truck with close to 640 HP and 2000 ft lbs of torque.

Just for kicks have a look at this street legal electric S-10 drag racer. Running 400 volt batteries it ran the quarter mile in 11.083 seconds, at 119.91 mph, it can do 0 to 60 mph in less than 3 seconds. It's quite capable of burn outs too.

Some small companies are providing conversions kits to convert conventional hybrid cars, like the Prius into Plug-in Hybrid that can run for a certain range completely on batteries charged from the owners household power. These systems may prove to be more effective as persuasive demonstrations of the greater ecological benefits of pure electric power, then as money saving investments providing effectively $1 a gallon mileage during battery operation. Those committed to leading the way to a greener lifestyle can take a step forward with a plug-in conversion.

Colorado House Bill 1331, “Incentives for Efficient Motor Vehicles,” will provide tax credits of up to $6,000 for the "purchase of, or conversion to, a plug-in hybrid electric vehicle" on top of the 10% federal text credit provided by the American Recovery and Reinvestment Act. 

The California Air Resources Board may apply the same new smog test and 150,000 mile/ten year warranty manufacturer requirements to these small shop operations, this may put a damper on these grass roots efforts to expand the number of green options.

Conversion suppliers include Hypermotion and 3Prong Power. Additional information can be found at the non-profit CalCars site (apparently stuck in 2007)

Toyota will be testing 500 of their new Plug-in Hybrid Prius provided to fleet customers world wide in 2010. Delivery to individual customers is expected in 2012, The PHEV Prius Goes 12.5 Miles on a Charge and can run at speeds up to 62 mph in all-electric mode. The lithium-ion batteries charge in 1.5 hours from a 230 V power supply.

3Prong Power offers 3 different packages that work with Prius generations 1, 2 or 3 or the Ford Escape.

Another approach to becoming more green is to operate a Biodiesel vehicle, reducing offensive emissions while using domestically produced fuel. I recall seeing a young ecologically devoted celebrity talking about filling the tank of her converted Mercedes that's older than her, in the parking lot of a warehouse discount store with cooking oil. Unfortunately only the early Biodiesel adapters got to make french fry scented exhaust from used restaurant cooking oil, since at best there's only enough used oil to power a very small percentage of vehicles.

Existing diesel vehicles can be converted to also run on Biodiesel/Vegetable oil fairly easily, conversion kits costing roughly $1500 include added filters, heaters and separate fuel tanks and selector valves allowing the vehicle to continue to use petrol diesel as well. Vegetable oil in particular doesn't have the viscosity stability of petroleum oil and must be warmed up to get it to flow in the winter. Here's a lengthy piece on the technicalities of Biodiesel conversions. A big concern regarding alternate fuels is their availability, the official retail station directory will give you an idea of the number of stations in your proximity

Mike Turner drives a long commute in his 1992 Honda Civic CX, He managed to improved the EPA estimated 47 mpg/hwy. to the high 50s by driving economically using hypermiling techniques.

Seeking to further his gas mileage, He copied streamlining techniques going back to the 30s. Adding a streamlined nose, a "boat tail" and other streamlining improved his gas mileage to 95 mpg while traveling 65 mph. This beats expensive engine modifications, add-on devices or special fuels by a mile. Check out his web site, which includes images and links for other streamline cars, this might be the easiest way to super economy, providing you can handle the attention this kind of vehicle attracts.