As India gets ready to fuel its vehicles with hydrogen — starting with Delhi — expectations are running high on decreasing pollution levels. But the changes will not come overnight.
The process of converting a diesel or petrol-run car into a hydrogen-run vehicle is similar to the process of converting it into a CNG-run car. It requires installing a conversion kit, gas cylinder and adjustments in vehicle timing. But hydrogen kits and cylinders are totally different from CNG ones due to the varying characteristics of the two fuels.
Hydrogen will be available in two forms —blended with CNG up to 30 per cent or as neat hydrogen. When blended with CNG, some modifications in the existing CNG kit will be enough to run the vehicle. “It is because hydrogen and CNG have similar ignition limit,” an official said. But this will not work for neat hydrogen.
As hydrogen has three times more energy than any other hydrocarbon, vehicle performance vis-à-vis power will improve. But the cost of production of hydrogen is four times that of CNG, making it an expensive fuel. Also, hydrogen is stored in a cylinder at a higher pressure than CNG. The much lighter gas reaches the kit, which improves its density. “Improving density and keeping the cost of the kit reasonable is the technological challenge,” said an official of the Ministry of New and Renewable Sources.
Like CNG, hydrogen produces a lot of heat and requires a special supply of coolant to keep the temperature under control. Unlike other hydrocarbons that produce carbon dioxide, a hydrogen engine produces water vapour, which can be used for cooling the engine.
Hydrogen is also more efficient when used as fuel cells for running vehicles. It reacts with the oxygen inside the cells, which produces electricity to power the motor.
Hydrogen kits are manufactured in Ireland and some other countries. Only about 500 cars in the world run on neat hydrogen. Conversion costs range between $5,000 and $7,000 per car.