Microalgae to Hydrogen


Picture: eng.unimelb.edu.au

We are delighted to share that, Dr. Pratik Gholkar (our alumnus) along with his supervisors, Prof. Yogendra Shastri (IITB) and Prof. Akshat Tanksale (Monash) has has devised a new way to produce hydrogen and methane with significantly reduced carbon footprint using microalgae.  The study titled: ‘Renewable hydrogen and methane production from microalgae: A techno-economic and life cycle assessment study’ can be read here- https://linkinghub.elsevier.com/retrieve/pii/S0959652620337719

The research group has used reactive flash volatilisation (RFV) gasification technology to produce hydrogen using microalgae, giving rise to newer and cleaner forms of energy. Findings show the greenhouse gas emissions of hydrogen production using RFV on microalgae is 36% less compared to the steam reforming of methane gas – the current best practice for hydrogen production. With additional renewable energy processes, such as hydro-electricity, integrated with the researchers’ hydrogen production process, carbon emissions could drop by as much as 87%.

Currently, the production of microalgae does not meet commercial demand. However, microalgae cultivation for energy applications could also provide additional revenue streams for rural communities, potentially making them self-sufficient, researchers say.

Dr Pratik Gholkar, said “Assuming a market price of $10/kg for hydrogen compressed to 700 bar pressure, the payback period for hydrogen production was 3.78 years with nearly 25% investment return. Moreover, the life cycle climate change impact was 7.56 kg of carbon dioxide for every kilogram of hydrogen produced,”

“This is an exciting look into the resources and technology available to the world in our quest to reduce the use of fossil fuels and drastically cut the amount of carbon emissions.”

Using India-based JSW Steel (the funding agency for this research) as a case study for their source of CO2 for microalgae cultivation, the research team estimated just under 12,800 kg an hour of microalgae would be available for hydrogen production at a rate of 1240 kg/h.

While the costs to develop infrastructure to cultivate microalgae and then refine it into hydrogen and methane are expensive, the overall return on investment in the long-term could make hydrogen and methane cost-effective and environmentally friendly fuel sources.

Dr Yogendra Shastri from the Department of Chemical Engineering at IIT Bombay said climate change concerns have led to an increasing push for cleaner energy options, and microalgae could be a potential candidate to produce renewable fuel. He said “Hydrogen is acknowledged as clean fuel since it doesn’t lead to the emission of greenhouse gases when used. However, the production of hydrogen also needs to be sustainable. Biodiesel production from microalgae is limited due to low lipid extraction efficiency, less than 20%, and the high cost of microalgae harvesting and drying. Furthermore, microalgae-based hydrogen and methane production haven’t yet been commercialised due to expensive pre-treatment, such as harvesting, drying and lipid extraction; low carbon conversion efficiency; and tar accumulation.”

Prof. Akshat Tanksale from Monash University said “Hydrogen and methane are clean sources of fuel and green chemical synthesis only if they are produced from renewable resources. At present, 96% of hydrogen and all methane is produced using non-renewable resources. Microalgae as a feedstock is attractive due to its high carbon dioxide fixation efficiency, growth rate, photosynthetic efficiency, ability to grow in brackish water – like rivers and lakes – and the ability to cultivate it on land not suitable for agriculture. Water and renewable electricity integration with microalgae harvesting can bring down the costs and increase the sustainability of hydrogen production from this process.”