Alternative Fuels Comparison

Alternative Fuel Vehicles comparison

Electric

Early automobiles were electric, having electric motors powered by batteries. But their range was limited, and internal combustion engines were more powerful, at a time when there were not concerns about the supply of fuel, or the emissions. But, the recent focus on air quality and the advances in the battery technology have made the electric vehicle a viable alternative.

Electric drive systems are virtually pollution free, (in fact, they are the only vehicles to meet California's Zero Emission Vehicle requirement), and extremely energy efficient. Only 20% of the energy in an internal combustion engine gets converted into useful work at the wheels, while 75% + of the energy from a battery reaches the wheels. They are also able to provide power at almost any engine speed, unlike internal combustion engines that have to be revved to a higher RPM to achieve maximum power. Electric engines provide near peak power even at low speeds, giving them strong acceleration from a stop.

But, there are some downsides. Public recharging sites are still not widely available, and the home recharging stations, while available, can be prohibitively expensive. Also, while the vehicles themselves are emission free, the production of electricity in general does produce emissions, causing electric vehicles to have an indirect impact on the environment.

Natural Gas

Natural gas as a vehicle fuel is already a time tested success. There are over 130,000 natural gas vehicles on the road in the US, and over 2 million worldwide. Existing vehicles can be converted to natural gas, or there are some models that were designed to use natural gas. In some cases, the vehicle can be converted to a bi-fuel system. A bi-fuel vehicle has two separate fuel systems, one for gas or diesel, and the other for compressed natural gas. Natural gas is a domestic resource that will help the US reduce its dependence on foreign oil. And while it does emit more total hydrocarbons, it has lower emissions of carbon monoxide, non-methane hydrocarbon and NO x. In addition, natural gas vehicles do not emit the particulate matter that creates the smog like haze and that causes harm to respiratory and cardio vascular systems. But, natural gas vehicles cannot be refueled by pumping fuel into the fuel tank. The fuel is compressed into tanks, taking up more space, and increasing the cost of the vehicle.

Hydrogen

Hydrogen is one of the simplest fuels, used to power combustion engines and fuel cells (see Fuel Cell, below). Designing the hydrogen powered vehicles and building the necessary fueling infrastructure is in the early demonstration phases. But, the US government recognized the potential upside of the technology, as evidenced by the President's $1.2 billion Hydrogen Initiative, that calls for a decision on the commercial viability of hydrogen powered vehicles by 2017. Hydrogen can be produced by simply splitting water into oxygen and hydrogen using electricity. However, most of today's hydrogen is produced from natural gas. Hydrogen burns almost pollution free, producing only water and heat. There are minimal amounts of nitrogen oxides produced when hydrogen is burnt in an internal combustion engine due the fact that hydrogen is being burnt with air, which is 2/3 nitrogen. Unfortunately, cost and storage / transportation issues are still causing delays in this technology.

Fuel Cell

Fuel Cell is an emerging technology, and isn't expected to be readily available until 2010. Even so, the technology is generating a tremendous amount of buzz. Essentially fuel cell vehicles are electric. The difference is that instead of relying on an external source to charge batteries, fuel cell vehicles will use a chemical process utilizing hydrogen fuel and oxygen from the air to create their own electricity. Typically the hydrogen fuel is stored onboard in high pressure tanks, but the use of a reformer, (a device that will convert hydrogen rich fuels into hydrogen gas), will let you use methanol, natural gas, or gasoline in place of pure hydrogen. A pure hydrogen vehicle will emit no pollution, while a vehicle equipped with a reformer will introduce small amounts of pollutants.

Some of the benefits of fuel cell technology are:

No greenhouse gases - fuel cell vehicles that use a reformer will release small amounts of greenhouse gases, but a pure hydrogen version will only emit heat and water as byproducts of the process.

No air pollutants - fuel cell vehicles that use a reformer will release small amounts of pollutants, but a pure hydrogen version will only emit heat and water as byproducts of the process.

Helps strengthen National Energy security - fuel cell vehicles will help the Unites States break it's dependence