Future power

Hydrogen is not a source of energy; it does not occur naturally. It is an energy carrier similar to electricity. The only difference is that electricity cannot be stored. But hydrogen can be stored in the form of compressed gas or liquid, and used whenever required. The product of combustion of hydrogen is water; that is why it is called a clean form of energy. However, it has to be produced from fossil fuels like petroleum, natural gas and coal, or through electrolysis of water using electricity, which is very expensive.

Further, the properties of hydrogen are unique. It is a very light gas, its density is eight times less than that of natural gas and considerable energy is required in storing it in compressed gas or liquid form. Its ignition limit range of concentration within which the fuel will ignite if an ignition source is present is large. Thus safety aspects involved in its storage, transportation, dispensation, and end-use are very critical.

8226; How does it compare with natural gas and petroleum products as fuel?

First of all, natural gas is a naturally occurring fuel; whereas hydrogen is not. Hydrogen can, of course, be produced from natural gas, which is predominantly methane, through the steam-reforming process, with a conversion ratio of only 60 to 70 per cent. This means that 30 to 40 per cent of the energy of natural gas is lost in the production of hydrogen. Furthermore, energy is required for storage and transportation of hydrogen as opposed to natural gas. Also, there is no significant benefit environmentally since CO2 is emitted during its production. Thus, producing hydrogen from natural gas is neither energy efficient nor environmentally beneficial. Hence, it is better to use natural gas directly.

Similarly, petroleum, used for producing hydrogen, has to be gasified into synthesis gas and then steam-reformed to produce hydrogen. Again, the whole process consumes energy with no net benefits in energy efficiency or emissions.

8226; Can we use hydrogen in IC engines of transport vehicles?

Theoretically, yes. However, the IC engine would require design modifications. Very few automobile companies in the world are working on development of engines for this purpose. Hydrogen can be blended in small percentages with CNG and can be used in CNG fired IC engines with very minor modifications.

8226; Why are advanced countries like the US, Japan and Europe engaged in development of hydrogen-based vehicles?

Most developments in advanced countries are based on Fuel Cell technology. The overall efficiency of Fuel Cell based automobile vehicles is higher than the IC engine, even with conversion of hydrocarbon fuels to hydrogen. This gain thus leads to overall reduction in GHG emissions. The main hindrance today in the commercialisation of Fuel Cell vehicles is cost, which will have to be brought down 15 to 20 times to make these competitive.

8226; What are the new technologies being developed for production of hydrogen?

Hydrogen production technologies being researched on today are high efficiency electrolysis processes, microbial fermentation using cellulose materials, electrolysis using photovoltaic PV cells, small-scale electrolysis units for distributed production, and high temperature nuclear reactors for splitting water into hydrogen and oxygen on a large scale. Production of hydrogen from coal would be feasible for India only with economically viable large-scale coal gasification using high ash coals; one gasification project in collaboration with a foreign technology supplier is being planned in India.

8226; What are the possibilities of producing hydrogen from renewable energy sources?

Hydrogen can be produced using electricity generated from wind turbines and PV systems. However, costs are presently very high. Research is in progress for producing hydrogen from biomass through the gasification route. But major problems with respect to purification of biogas to get the synthesis gas and economic design of small size steam reformers, are yet to be resolved.

8226; What is the path that India should adopt for development and use of hydrogen energy?

The most important first step is to develop a set of scenarios of the future incorporating the role of hydrogen as part of India8217;s overall energy strategy. To look at hydrogen energy by itself would be a misplaced and misdirected approach. Secondly, major research and development should be taken in hand to make hydrogen production economically viable. For that purpose the target should include the use solely of non-fossil fuel sources of energy.

Once some clarity emerges on the most cost effective forms of production of hydrogen from renewable sources, the country has to evaluate distribution, storage and usage plans for hydrogen on a large scale. Safety would be a critical element of any such plan. It is only on the basis of detailed assessment that infrastructure and distribution facilities would need to be established. In our situation, there is a clear advantage in hydrogen being used for stationary applications, such as for fuel cells to produce electricity on a decentralised basis, rather than use for transportation only.

8226; Is there any purpose in targeting 1 million vehicles using hydrogen by 2020?

Such an approach would be totally ill-conceived and nowhere within the realm of economic viability. Nor does it seem part of an integrated energy strategy. Such a plan or strategy has all the elements of Muhammad bin Tughlak shifting his capital city.

The article is co-authored with Y.P. Abbi