Microalgal biofuels – what is the environmental cost?


Maxence Plouviez.


Frenchman Maxence Plouviez has always been interested in the environment and humanity’s impact upon it—an interest he has taken through to a PhD on the other side of the planet.

“Climate change has always been an area of interest to me, whether it be trying to understand it, stop it, mitigate it or even inform people about it,” Mr Plouviez says

“When biofuels came along, everyone was going crazy with the idea that it could be the solution to all our problems with a low carbon footprint. They had the idea that in five to ten years we would all make the switch to this green solution that would benefit the climate. As it always happens, great ideas brought great amounts of money to invest, but we failed to look deeper to determine whether it was the solution we all thought it was.”

Mr Plouviez, of the School of Engineering and Advanced Technology, focused on whether significant amounts of nitrous oxide (N2O) is produced during microalgae cultivation, a process used in the manufacturing of products like biofuels.

“Nitrous oxide is a potent greenhouse gas and ozone depleting pollutant; if sufficient amounts of this gas is produced in the process, then the environmental footprint would be much larger than first expected. While the ability of microalgae to synthesise nitrous oxide has been suspected for decades, the potential environmental implications of this synthesis have only been recently acknowledged.”

Mr Plouviez looked at the emissions by monitoring microalgal cultivation in an outdoor pilot study.

“Based on the data, if we start producing globally meaningful amounts of algal biodiesel, then we will be generating potentially massive nitrous oxide emissions, which could have a significant environmental impact.”

“However, it must be noted that microalgae biotechnology is still at its infancy so there is an opportunity to understand and anticipate the N2O emissions issue before it becomes globally significant.”

The research determined the first microalgal N2O pathway and calculated preliminary emission factors to predict N2O emissions during microalgal cultivation. It also proposed mitigations strategies and suggested that nitrous oxide emissions should be carefully monitored during microalgal production, and accounted for in relevant impact assessments.

Easy road?

Finishing his research within three years, Mr Plouviez says it wasn’t all smooth sailing, “I had my daughter one and half years into it, so that made it a little more challenging. I say to any young student now thinking about doing it – it’s hard work, but stay humble, work hard and you’ll be okay." 

When Mr Plouviez walks on stage to receive his PhD, it will be the first graduation he has ever been able to attend, missing his masters’ graduation in France to start his study in New Zealand. Mr Plouviez’s parents will be attending all the way from France to share the moment with his Swedish wife and young daughter.

After graduation, Mr Plouviez will continue working at Massey as a post-doctoral fellow. His focus will be on a project which has just received $920,000 from the Royal Society of New Zealand's annual Marsden Fund. The study, The greedy algae that are great for our environment: why do they pay an energy penalty to gorge phosphate? led by Professor Benoit Guieysse, willlook at the mysteries surrounding polyphosphate. Polyphosphate is found in all organisms and is involved in functions such as energy, phosphorus storage and stress response.

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