A genuinely green car is, of course, impossible. Moving a tonne of steel and plastic around could never use no energy at all and even the zero emissions hydrogen fuel cell cars will require prodigious amounts of energy to produce the hydrogen in the first place.
Buying Green – The “No-Compromise” Options
PZEVs & Hybrids
PZEVs, or partial zero-emission vehicles, include the now familiar Toyota Prius and more than a dozen other vehicles.
Car companies are promoting these cars as having better performance—and sales prove that as performance has soared so has popularity.
The Honda Civic Hybrid, for example, out-accelerates its petrol-only version and it also requires fewer stops at the service station. Public demand for the new Toyota Prius, which gets over 21. 25km per liter, has outpaced production since it was introduced in 2001.
Hybrids and PZEVs look like regular cars, but under the hood they have sophisticated technology that reduces health-threatening tailpipe emissions by 90%, and evaporative emissions (the gas vapors that escape from the fuel tank) to near zero. PZEVs typically cost significantly more than their conventional counterparts.
PZEVs burn petrol so efficiently that their exhaust is cleaner than the air in some smoggy areas. PZEVs can help reduce urban smog which so badly affects the health of city dwellers, especially children and the elderly.
Cars for People Who Want to Get off Oil or Reduce Climate Change Even More
Climate change is no longer a theory, it is a scientifically proven fact. Thirty percent of the carbon dioxide (CO2) emissions, the major source of global climate change, are from transportation. Fortunately, there are several ways of reducing CO2 emissions from your car.
The easiest option is to look for the most fuel efficient hybrid or PZEV vehicle. CO2 emissions are directly proportional to the amount of petrol you use, so a 20km per liter car emits just half of the CO2 of a 10km per liter car.
You could reduce your CO2emissions even more if you powered your vehicle with an ‘alternative fuel’ such as compressed natural gas (CNG), liquid propane (LPG), biodiesel, or ethanol. These fuels have the added advantage of reducing, often to almost zero, the use of oil, over 50% of which is imported. Let’s look at each alternative fuel option.
Biodiesel, a favorite fuel in the US bus and trucking industry, is beginning to make inroads in our local bus industry. Biodiesel is made from an oil-rich plant, such as soybeans, and can be run in a conventional diesel engine. Because it gets thick when cold, and ignites at a lower temperature than diesel, it is normally blended with diesel in cold climates. B20, the usual mix, is 20% biodiesel and 80% diesel, though 100% biodiesel (B100) can be purchased. Additionally, waste cooking oil can be run in a diesel vehicle if you have an additional tank and other simple modifications.
There are several conversion kits on the market. (See www. greasecar. co. za, for example). B100 will reduce greenhouse gas emissions by 77% (because the plants, when growing take CO2 out of the atmosphere) and reduce dependence on foreign oil by 68% (unless the plants are grown with no chemical fertilizers, and tractors run on biodiesel, in which case 100% reductions could theoretically be achieved. )
B20 reduces CO2 by 28% and fossil fuel use by 13%. While biodiesel offers a great opportunity to use waste cooking oil and surplus soybeans, many are concerned that if crops were grown specifically for fuel production that food producing land would be displaced and degraded.
Compressed natural gas
Compressed natural gas vehicles have been used extensively in Canada and Australia. In the US they have been used most extensively by companies that have a fleet of ten or more vehicles. These companies usually install a CNG fueling station at their facility so they can refuel easily.
CNG is a naturally occurring, clean-burning fossil fuel. It emits 13% less CO2 than a similarly fuel-efficient vehicle.
Ethanol has been extensively used in Brazil for decades. Ethanol is an alcohol made from plant material that has a high sugar content. In Brazil, the waste from making sugar is the main feedstock. Research is being done on the potential of other waste plant materials to produce ethanol less expensively. A favorite of US Midwest farmers, ethanol is usually blended with petrol. E85 is 85% ethanol and 15% petrol.
Ethanol is usually used in “flex-fuel” vehicles—vehicles that can be run on either petrol or ethanol. An estimated 2. 5 million ethanol flex-fuel vehicles are in use in the US today, but only a small percentage actually are using ethanol. E85 reduces CO2 emissions by 22%, and reduces fossil fuel use by 34%.
Propane, a by-product of natural gas production and oil refining, is used by fleet vehicles. It is estimated that there are approximately 275,000 propane-powered vehicles in the US today. Propane reduces CO2 emissions by 15%, but does not reduce fossil fuel use.
Hydrogen-powered vehicles have been much in the news, and have many attractive characteristics. They have the potential of making fuel choice a non-issue, since hydrogen can be produced from just about any fuel.
All car companies have hydrogen-powered prototype vehicles—but don’t expect them in the showroom anytime soon, because there are still many technical challenges in making, storing, and transporting hydrogen, as well as using it in conventional internal combustion engines or in fuel cell vehicles.
Hydrogen’s environmental advantages and its ability to compete in the market place will be determined by how it is made. Hydrogen can be made by electrolysis, using electricity to split water into hydrogen and oxygen. If the electricity to make the hydrogen were produced by wind, solar, or other zero emitting fuels, we could produce environmentally friendly zero emission hydrogen-but many feel this is not economically feasible. .
If, however, it were made using electricity from today’s power plants, CO2 costly emissions would increase–and we would need to build new power plants to produce enough electricity to meet the demand for hydrogen.
Hydrogen can also be extracted from other materials that have a high hydrogen content, such as natural gas—many people feel this would be the best approach—but it does not get us away from using nonrenewable fossil fuels, or take CO2 emissions to zero.
Like hydrogen, electricity can be produced from any fuel, and like hydrogen, electricity is only as clean as the fuels used to create it. For example, if a car ran on electricity produced from today’s coal-fired plants, CO2 emissions would be greater than those from petrol car. But if the electricity were produced from wind and solar, CO2 emissions would approach zero.
Most car companies have tried to produce full-size electric vehicles that meet consumer demands for a car that can be refueled quickly and have at least a 160 kilometer driving range. Nevertheless, electric vehicles are becoming popular in niche markets such as airports, mines, and warehouses, and smaller electric vehicles are entering the consumer market.
Some people believe that battery technology will advance soon to a point where full-size electric vehicles could play an important role in the consumer market and deliver better value than hydrogen vehicles. Only time will tell.