Decarbonising India: Carbon Emissions and Green Hydrogen Storage in the Southeastern Coast

Greenhouse gases, such as carbon dioxide (CO₂), are the most significant contributors to global warming and climate change. Therefore, the reduction in carbon emissions is one of the primary focuses of mitigating global temperature increase. Presently, India is one of the top emitters of CO₂ worldwide due to its large population and rapidly developing economy. However, the country has already taken several steps towards reducing its carbon emissions and is committed to becoming carbon neutral by 2070. A major part of meeting this goal is shifting the country’s energy production away from fossil fuels and towards clean energy sources, such as green hydrogen.

The southeastern coast of India is home to many fossil fuel-based power plants and CO₂-emitting industries, making it an ideal starting point for studies on how to decarbonise India and transition towards green hydrogen. Keeping this in mind, a team from the Indian Institute of Petroleum and Energy (IIPE) has analysed the CO₂ emissions, green hydrogen requirements, and storage potential for hydrogen in the four Indian states that constitute the southeastern coast—Tamil Nadu, Telangana, Andhra Pradesh, and Odisha. This research was published last year in the International Journal of Hydrogen Energy. “Currently, there is a lack of clarity on how much CO₂ is emitted by these four states, as well as how much energy is required to operate the power and industrial sectors in this region. There is also an absence of information on prospects of green hydrogen production in the area and what it requires in terms of resources. Our research addresses this gap,” says Dr. P. Sivasankar, corresponding author of the article.

For their research, the team first collected data from thermal power plants, cement industries, iron and steel industries, and oil refineries across the four states. They then calculated the CO₂ emissions and operational energy demand for these sectors. They found that among the four states, Andhra Pradesh was the leading emitter of CO₂, contributing around 38% of all CO₂ emissions in the region. They also found that coal-based power plants contributed around 64% of the CO₂ emissions in the region—these results indicate a substantial demand for power in the area. “These results suggest that shifting from coal to cleaner energy alternatives like solar, wind, nuclear, hydel, or geothermal energy could lead to a drop in CO₂ emissions by up to 50%,” explains Dr. Sivasankar. “We further found that cement and iron and steel industries contribute another 32.8% of CO₂ emissions in this region. By developing targeted strategies and providing suitable incentives to these industries, we can achieve even higher reductions in carbon emissions.”

The research team also projected the energy demand for the four southeastern states until 2050, considering four different GDP growth rates. They found that power demands in these states are likely to increase by 4–19 times by 2050, underscoring the need to develop energy efficiency measures and establish green hydrogen infrastructure. Next, the research team calculated how much green hydrogen would be required to meet this energy demand. “This calculation can essentially be split into two parts: first, how much electricity and water do you need to produce green hydrogen through electrolysis (the splitting of water into constituent hydrogen and oxygen)? Second, how much solar energy would be required to provide the electricity for electrolysis?” says Dr. Sivasankar. The solar energy requirement can further be reduced into a calculation of the number of solar energy panels—and their corresponding installation area—that can fulfil the energy demand.

The research team found that approximately 3–14.32 million solar panels, or an installation of 54–306.5 million sq. ft., would be required to meet the projected hydrogen demand for these four states by 2050, assuming a GDP growth between 7–11%. “A key aspect of transitioning to green hydrogen is providing large-scale storage for the gas,” explains Dr. Sivasankar. “Subsurface geological structures, such as the saline aquifers and oil and gas reservoirs of the Cauvery and Krishna–Godavari (KG) river basins in southeast India, are ideal for this purpose.” The research team investigated the hydrogen storage capacity of the saline aquifers and oil and gas reservoirs in the Cauvery and KG basins and found that they have the potential to continuously deliver stored hydrogen for seven years without refilling—thereby ensuring energy supply.

“It is worthwhile to note, however, that our calculations showed that the production of green hydrogen using renewable energy requires 1.86 times more energy than the direct use of renewable energy. Diversifying alternative energy sources beyond solar energy, such as through offshore wind farms, can be a potential solution. Improving green hydrogen technology to overcome this gap is also an important research direction,” continues Dr. Sivasankar. Another finding by the research team related to CO₂ emissions by oil refineries during water flooding and enhanced oil recovery (EOR) processes, such as CO₂ foam flooding and alkali surfactant polymer (ASP) processes. These processes are used to increase the amount of oil obtained from a petroleum field. The researchers found that although these processes enhance petroleum recovery, which can help meet increased energy demands, the CO₂ emitted during these processes is significant.

“We further suggested measures to decarbonise such upstream oil and gas operations with hydrogen under uncertainty,” adds Dr. Sivasankar. The study suggested that developing environmentally and economically sustainable technologies for different industrial operations and EOR techniques can help bring affordable energy to our population, as well as improve air quality and mitigate climate change for a better living environment. “Overall, our comprehensive analysis highlights the need for a well-balanced, mixed use of renewable energy, efficient energy storage, and green hydrogen use for India to meet its decarbonisation and energy transition goals,” concludes Dr. Sivasankar. These findings are sure to inform and improve energy policy and strategy in the southeastern region of India. Congratulations to the researchers from the Indian Institute of Petroleum and Energy for their outstanding research!