All right, you CleanTechies out there. Settle down. We know hydrogen fuel cells are not the answer for electric cars. But they could be an important part of cleaning up emissions from some of the world’s largest polluters — the heavy duty diesel engines used to power ships, long haul trucks, construction equipment, mining operations, and the like. Let’s not permit our bias in favor of battery operated vehicles to cloud our judgment.
In the US, almost all the hydrogen used for transportation is actually made from natural gas. We know natural gas burns cleaner than coal and diesel fuel, but it is derived mostly from fracking, a process that contaminates huge amounts of water and releases enormous amounts of methane into the atmosphere.
Researchers for years have been trying to create hydrogen the way nature does — through photosynthesis using energy from sunlight. There are several methods of doing this, but all of them are relatively inefficient, costly, and require the use of catalysts that are either too expensive or highly toxic — or both.
Now a team of researchers at the University of Cambridge and the Ruhr University Bochum says they have successfully created a proof of principle model that splits water into hydrogen and oxygen using only sunlight, natural enzymes, and artificial photosynthesis technology. Erwin Reisner, a professor of energy & sustainability at Cambridge tells Newsweek, the research represents a “milestone” in semi-artificial photosynthesis.
“Solar energy conversion to produce renewable fuels and chemicals — i.e., solar fuel synthesis — is an important strategy for powering our society in a post-fossil era,” says Reisner, the lead author of the study.
“Natural photosynthesis has evolved to store solar energy and to ‘fix’ the greenhouse gas carbon dioxide (CO2) into sugars, but this process is not very energy efficient.
“Artificial photosynthesis mimics natural photosynthesis and aims to produce sustainable hydrogen from water through water-splitting or carbon-based fuels from CO2 fixation, but is commonly hampered by expensive, toxic or inefficient catalysts. We try to establish a new line of research by combining the best of the natural and artificial worlds and take highly efficient and abundant biological catalysts, such as enzymes, and combine them with synthetic materials in solar devices for efficient solar fuel synthesis.”
Reisner’s team uses hydrogenase, an enzyme present in algae, together with synthetic pigments, to split water into its component parts using nothing but sunlight. The prototype system is capable of absorbing more solar light than natural photosynthesis. “Compared to the natural pathway, this new system makes wider use of the solar spectrum, delivers high conversion yields, and bypasses several competing metabolic steps, which is not achievable using synthetic biology or materials science alone,” Reisner says
The research is not yet ready for commercial applications, but Reisner says the process created by his team “widens the toolbox for developing future semi-artificial systems for energy conversion.” The world should welcome any discoveries that promise to reduce greenhouse gas emissions. Hydrogen may not power our cars — despite the best efforts of Toyota, Honda, and Hyundai — but it could help reduce or eliminate the massive emissions from cargo ships.
According to The Economist, just 15 cargo ships operating on heavy bunker oil emit more sulfur dioxide pollution than all the cars in the world combined. Batteries alone won’t get all those containers from one side of the ocean to the other but hydrogen from semi-artificial photosynthesis just might.
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