How H. G. Wells Might Develop a Renewable Hydrogen Economy
- November 28, 2018
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The eminent writer and futurist, H. G. Wells, conceived the story for his popular novel, “The War of the Worlds”, after having conversations with his brother about events in Tasmania in the 19th century. In Tasmania, European settlers armed with modern weapons soon overwhelmed and subjugated the less technologically sophisticated, native populations. Wells conjectured what would happen if an advanced civilization descended from the sky and waged war against humans who are only equipped with 19th century technology. The result was his iconic science fiction novel which has been made into several feature films and television movies.
As Wells' story goes, microorganisms were the only inhabitants of Planet Earth that were able to offer resistance and to ultimately defeat the Martians which mankind otherwise could not, even with all the aid and assistance of modern science, technology, and weaponry. Ironically, what are often thought as the lowest of nature’s creatures, microorganisms, were more than up to the task to repulse and vanquish the seemingly invincible Martian armies. After the Martians were routed, the book's protagonist noted,
“And scattered about it, … were the Martians--dead!..slain, after all man's devices had failed, by the humblest things that God, in his wisdom, has put upon this earth.”
If Wells were around today, he may have thought, like some of us, that if microbes can win an interplanetary war, why can't they help us create a viable renewable hydrogen economy? Let's break it down.
Sustainability Principles and the Hydrogen Economy
Key sustainability considerations for a renewable hydrogen economy include:
- Ability to deploy hydrogen generation technology with minimal or no resource interlinkages. The economic hazards with resource linkages are detailed by McKinsey ;
- Ability to deploy hydrogen generation using a distributed resource mode as a opposed to using a scheme calling for centralized, large production installations;
- Ability to leverage existing infrastructure to conserve both capital resources and implementation time;
- Ability to generate hydrogen using a multi-tasking renewable technology platform that generates multiple renewable products with one process to buttress the value proposition by spreading revenue generation and economic risk over more than one renewable;
- Ability to employ feedstocks that are intrinsically net-resource positive so that other sustainability metrics such as EROI (Energy Return on Investment) are optimized.
The list above may seem daunting, but it is achievable with the adroit application of microbial processes.
By making microorganisms our partners, instead of adversaries as the Martians did, we get to utilize collective ecological assets bequeathed from 4 billion years of biochemical evolution.
It is notable that naturally-occurring microorganisms, not genetically-engineered ones which are difficult to cultivate, are a feasible engine to drive hydrogen generation. There are also other required components as noted by the list above that are needed to build a platform.
The Architecture for a Renewable Hydrogen Platform
First, let us consider infrastructure. There are numerous, existing installations for a process called anaerobic digestion. This process converts organic matter into renewable energy called biogas that is a mixture of methane and some hydrogen and can be optimized to produce mostly hydrogen. In the US alone, there are over 2,000 plants which have anaerobic digesters, or bio-digesters, that are capable of being modified to produce hydrogen gas. The graphic below, courtesy of the American Biogas Council shows a diverse distribution of anaerobic systems across the US. This represents a significant infrastructure that can
play a role in initiating, cultivating, and invigorating a national renewable hydrogen enterprise.
The feedstock that is usually fed to anaerobic reactors is biomass whether it is human waste, such as domestic wastewater or its derivatives, or other materials that are either plant matter or organisms that consume plant matter. Biomass not only contains carbon which can be converted to rich energy sources such as hydrogen and methane, but it also contains inorganic chemicals such as ammonia and phosphates that are key ingredients for high grade fertilizers. In order for microbial systems to convert biomass into energy, it must first "disassemble" this material so that the carbon can be converted to energy. As the biomass components are unraveled, ammonia, phosphates, organic nitrogen, and other compounds are released as free-standing components. Once these chemicals are released, they can be captured and processed to be sold as green, renewable fertilizers which have the same chemical composition as "fossil fuel" fertilizers.
By contrast, non-green ammonia is made using the Haber-Bosch Process shown below. This process is very energy intensive and requires natural gas (methane) and and catalysts to make the ammonia. The process alsouses high pressures and temperatures and is basically a synthetic and resource-inefficient means to accomplish nitrogen fixation.
By using biomass to make hydrogen, one can also make valuable renewable fertilizer products which adds to the sustainability equation and the commercial value proposition.
The use of biomass as feedstock for anaerobic digestion technology to produce hydrogen is net-energy positive because the energy content of this material is in excess of the amount needed to make the hydrogen and fertilizer products. This suggests that EROI values for making renewable hydrogen will be very favorable subject to confirmation with a thorough analyses.
Finally, the use of biological processes to generate hydrogen does not exclude or displace other approaches such as combining solar with electrolysis to ensure that the process is net carbon negative. The sustainability space is so diverse that it is almost impossible to find a "one size fits all" approach that works in every situation. However, the compelling facet of the approach described herein is the ability to generate multiple renewable products, energy as renewable hydrogen and fertilizer chemicals with one process using a multi-tasking, ubiquitous and under-utilized feedstock, biomass.