Energy of Hydrogen

Fossil fuels are finite and increase in cost as supply dwindles. So the huge interest to the development of alternative energy souces occurs throughout the world. Consequently, battery-electric and fuel cells vehicles are on the road today. In 2007, there were 1.8 million alternative fuel vehicles sold in the United States, indicating an increasing popularity of alternative fuels. There is growing perceived economic and political need for the development of alternative fuel sources.

I think it’s appropriate to compare Battery-electric and fuel cells vehicles in this conversation. Firstly, let’s consider advantages of alternative fuel vehicles over vehicles with internal combustion engines.

· It is obvious that Battery-electric and fuel cells vehicles emit no pollutants. Battery-electric cars and fuel cell equivalents are each propelled by electric motors; however fuel cell vehicles create their own electricity.

· All internal combustion engines have efficiencies limited by the Carnot Cycle. Batteries and Fuel cell vehicles, not limited by the Carnot Cycle so it is very possible to achieve high energy efficiencies.

· Also they operate with electric motors which have very few moving parts, vehicle vibrations and noise are vastly reduced and routine maintenance (oil changes, spark plug replacement) are eliminated.

Above-listed advantages are typical for both classes of alternative fuel vehicles. In order to feel the difference let’s consider existing cars. Tesla Roadster will represent Battery-electric cars and Suzuki SX4 FCV will represent fuel cell cars.

Tesla Roadster is a lightweight (~1140 kg) two-seat sports car with 300-hp, 280 lb-ft of torque, a 244-mile range on a single 3.5-hour charge and 3.9-sec 0 to 60  mph time. Tesla’s cars run on a huge lithium-ion battery pack that can be recharged by plugging an adapter cord into a wall socket. Storage battery located behind seats is quite unusual: It’s a block consisting of 6831 lithium batteries which are identical with batteries used in cell phones and laptops. Weight of this block is 454 kg. There is a three-phased electric motor between rear wheels. Its size is impressive — diameter is 25 centimeters and length is 35 centimeters. Its efficiency is about 80-95 % depending on loading.

During braking kinetic energy isn’t spent in vain but recaptured by regenerative braking system to recharge the batteries.

The company estimates costs for trip approximately in one cent per mile. However, the company has calculated that the owner of a battery-electric car will have to replace (alas, for considerable money) the lithium-ionic accumulator, served its time, through 160-200 thousand kilometres. Nowadays the only problem of the high cost of such effective and high-capacious lithium-ion accumulators should be solved.

Overview of Tesla Roadster

*100% electrical
* 3.9-sec 0 to 60 mph, and single-speed gearbox couples the low drag and fuel efficiency of a manual transmission with the driving ease of an automatic.
* 300+ hp
* 244 mile driving range
* cost of journey is cent per mile.
*coefficient of efficiency is about 90%.

The SX4-FCV five-door hatchback uses a GM-made high performance fuel cell, a Suzuki-developed 70 MPa (10,000 psi) compressed hydrogen tank and a light, compact capacitor. This recovers energy during braking application and uses it to reduce load consumption during acceleration.

For the Suzuki SX4 FCV, General Motors is supplying the 80kw fuel cell. The Suzuki SX4 FCV also comes with a 68 kw/91 hp electric motor, a 10,000 psi compressed hydrogen tank that will help the vehicle achieve a range of 150 miles and a top speed of around 95 mph.

It should be noted that automotive fuel cells require a 5,000 hour lifespan (the equivalent of 150,000 miles)

Overview of SX4-FCV
Fuel-cell output: 80kW
Motor output: 68kW
Fuel: High-pressure hydrogen (stored in 70MPa tank)
High-voltage battery: Capacitor
Maximum speed: 95 mph
Driving range: 150 miles

So, Tesla Roadster and Suzuki SX4 FCV are excellent state-of-the-art vehicles. I hope some day we can see these cars everywhere. It’s up to you which type of alternative fuel vehicles to use. I take notice of the benefits of fuel cell vehicles are not in it’s efficiency (NiCad has a 70-90% charge/discharge efficiency) but in it’s lighter weight than batteries and the users ability to fill a tank rather than waiting to charge.

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