Can we recycle captured carbon to produce green hydrogen and biomass?

The best part? The process seeks to sequester carbon biologically and without the need for thermal or mechanical energy. It aims to be an industrialised-scale, nature-based solution to decarbonisation that can capture carbon right at the source and process it using very little energy. Even better, the Hydrobe bioreactors are modular. This would allow users to stack them on site to meet the needs of carbon producers big and small.

Below, we’ll take a deeper dive into this innovative process and how it can potentially help us manage our carbon emissions in a more sustainable way.

A journey to reduce carbon emissions

Let’s start from the beginning. Imagine you operate a mine site, a powerplant, or a steel factory—any carbon-intensive industry for that matter. You know you need to reduce your carbon footprint, but your operations require a huge amount of energy. You make efforts to electrify and move toward renewable sources of energy like wind, solar, or hydropower. But at the end of the day, you still need carbon combustibles to operate efficiently.

So, you turn toward carbon capture technologies to help reduce emissions at your site. Carbon can be captured right at the source, either pre- or -post-combustion. But once you capture that carbon, what do you do with it? Traditionally, there have been two main options. The first is sequestering the carbon deep underground where it is safely and permanently stored. The second is transporting it—via truck, rail, or pipeline—to industry for use. For example, carbon is an asset to agriculture and food processing. We can use carbon to make fertilisers for crop production, and it can also help keep produce fresh during long shipments. This is carbon recycling and it allows us to get more value out of our resources. 

But what if we could get even more value out of our captured carbon? This is what Hydrobe believes is possible and drives what they are trying to develop. So, let’s consider a third option for how we manage our captured carbon: biological sequestration. Rather than storing or transporting carbon, what if we recycled it in a way that provides us with valuable products? Hear us out.

Imagine taking the carbon you’ve captured and inputting it into a chamber the size of a shipping container. The chamber includes microbial algae, water, and light. The microorganisms convert the captured carbon dioxide into hydrocarbons. Those are further broken down through additional similar-sized chambers into hydrogen gas and a liquid containing solid biomass, sugars, lipids, and proteins. The hydrogen gas is then piped out of the bioreactor. It can be used on site or sold, while the biomass and other compounds are collected or further processed into products like fertiliser, oils, bioplastics, and nutraceuticals. And the process repeats.

Interesting, right? It is a new and innovative process that fascinated us. If scalable, it would be an invaluable tool to help many industries—namely the hard-to-electrify industries—to decarbonise and reap the benefits of doing so. So, let’s dig deeper into this process of biological sequestration and what we need to drive it.  

How does the Hydrobe process work?

Like we said earlier, the Hydrobe technology is still in development. But for the sake of argument, let’s imagine it works and is widely available.

Consider you are a carbon producer that has just decided to go with Hydrobe. Your site is responsible for a significant amount of carbon emissions, so you order a series of Hydrobe bioreactors to help offset them. Remember, these bioreactors are modular, and we can stack them on site as needed. The bioreactors are delivered to your site and installed in either a row or tower configuration. Arranging them in rows means a larger footprint but stacking them on top of each other requires more energy.

Now that the bioreactors are installed, you can begin feeding carbon into the chambers. The carbon is emulsified with the liquid consisting of water and microbial algae. With the help of light, the algae converts the carbon dioxide into oxygen and energy. The energy comes in the form of biomass consisting of sugars. The biomass then passes through a sequence of bioreactors that use a unique combination of bacteria, which efficiently release those sugars into a liquid phase before fermentation. This naturally unlocks energy without the need for additional energy. Thermodynamic constraints still apply—the difference with the Hydrobe process is that thermal, chemical, or mechanical energy alternatives are replaced by biological energy. The carbon contained in your emissions activates the biological energy.

Through this process, more carbon is fixed into solid form than is generated by the energy consumption required for lighting, liquid movement, or gas flow. Therefore, end products such as hydrogen gas are carbon free. The hydrogen can serve as an energy source on site or sold as green hydrogen to those who need it. Any carbon dioxide not fixed can be recycled back through the process or be used to create methanol or synthetic gas, while the rich organic matter from the reactors can be used as high-quality biomass.

As you can see, there are multiple potential benefits to this approach, from sequestering carbon using little energy to hydrogen and biomass production. So, when will this technology be widely available for carbon producers to access?

The experts at Hydrobe started looking into this back in 2017 when they were looking for more efficient ways of generating hydrogen. This led them down the pathway of considering agricultural science and biological solutions. In 2022, Hydrobe brought on our team to provide a combination of technical and economic advisory services related to technology development and scalability of the production process. Fast forward to today, and Hydrobe has proven that the science works in a lab setting, and they are currently building a demonstration plant in Melbourne, Australia, to prove they can execute the process at scale. The demonstration plant should be ready in 2024 and, once complete, will show prospective clients how they can decarbonise in a smarter, less energy-intensive way.

Innovation is critical to combating the climate crisis

The energy transition demands that experts from all industries come together to reduce global GHG emissions. We have seen strides forward in renewable energy production like solar, wind, and hydropower. But we still need to find solutions for managing the carbon captured from fossil fuel-based power generation. We have traditional methods of doing so, but innovation is helping us to evolve. That’s why we’re both proud and excited to be working with companies like Hydrobe who are pushing the envelope of creativity and driving the conversation around decarbonisation into parts unknown.

We consider carbon capture to be a critical part of the energy transition. But we’re also excited about the hydrogen component of this new process. Capturing carbon is great. But converting that carbon into green hydrogen and biomass? That’s a win-win-win scenario. We’re really interested to see where this technology goes in the future, and we’re happy to be working closely with Hydrobe on this innovative approach.