NTPC’s vision is to supply reliable and cost-effective green hydrogen to become an integrated energy major in the green hydrogen value chain across the transport, industry and power sectors. The company’s focus is on hydrogen fuel cell buses in the transportation space; production of green methanol and green ammonia in the industrial space; and green hydrogen microgrids in the power sector space. The future plan also revolves around hydrogen blending in natural gas and hydrogen storage solutions to provide power to the grid.
Green hydrogen mobility
In this space, the broad value chain involves generating hydrogen with renewable energy, storing it and sending it to hydrogen dispensing points to charge the fleets. In the intra-city route of Leh and Ladakh, NTPC plans to run five buses. In the intercity routes of Delhi-Jaipur and Delhi-Agra, NTPC plans another five hydrogen buses.
NTPC is planning a green hydrogen microgrid in a village in Ladakh, which has around 500 households. Hydrogen will be produced using solar power and will then be stored. It will be converted back to power using fuel cells to be utilised at night by the households. Most of these households have limited access to electricity (around five to six hours and that too limited to 1 kW). The cost of electricity from this microgrid is expected to be five to six times the cost of electricity generated from diesel generators. Still, the hydrogen microgrid project seems to be a viable solution, as setting up the national grid in the hilly region seems to be financially unfeasible. This is a large-scale project, therefore, small-scale (1 kW-2 kW) microgrid projects will be first demonstrated across the country.
Hydrogen blending in natural gas
NTPC also plans to blend around 5 per cent of the hydrogen in the city gas terminal at Dadri. The city gas terminal is a better option for hydrogen blending in natural gas, as mostly it will be used for cooking purposes. With the blending, less natural gas will be burned, resulting in less carbon dioxide emissions for the same heat input.
Green methanol pilot
NTPC is planning two green methanol pilots, one each in Madhya Pradesh and Telangana. The company plans to capture carbon dioxide from the flue gas generated from the existing coal plants. This carbon dioxide will be stored and green hydrogen will be mixed with it to produce green methanol, which can be blended with petrol and in LPG cylinders. Moreover, green methanol can be broken down into hydrogen, which can be used in fuel cells as well.
Green ammonia pilot
The green ammonia that NTPC plans to produce at its pilot (site finalisation is in progress) will not be used for producing urea as it leads to high carbon dioxide emissions. In this pilot, air will be collected in an air separation plant to make nitrogen. The nitrogen will be mixed with green hydrogen in a reactor to produce ammonia. In fact, using solid oxide-based electrolysers, air, water and electricity can directly produce ammonia, using the Haber-Bosch synthesis. This technology is around 15 per cent cheaper than the usual process of making green ammonia and it is also more compact.
Now, it has been found that ammonia can be utilised as an energy carrier by converting it into liquid at a moderate pressure of 10-15 bar at a temperature of minus 33 degrees centigrade. To make liquid hydrogen, temperature of minus 250 degrees centigrade is needed besides a tremendous amount of pressure. The ammonia produced can be fired in boilers to save coal usage or used in fuel cells.
Key challenges and the way forward
NTPC is using electrolysers to produce hydrogen across its coal power plants. However, the capacity of these electrolysers is small. To produce green methanol, green ammonia, green hydrogen for transportation purposes and hydrogen blending in natural gas, large electroysers are needed. Such electrolysers are not available in India, and globally the suppliers are limited. Overall, these parameters lead to the use of costly solutions.
Going forward, aggressive targets are needed in this space. Many countries have already set such targets but India has been slow and conservative. Moreover, large investments are needed in hydrogen technologies to promote domestic manufacturing of electrolysers. Both suggestions will ensure that India is able to take the lead in the global hydrogen landscape by banking on its large renewable energy potential.
Based on a presentation by D.M.R. Panda, General Manager (Hydrogen), NTPC Limited