Written on: December 2, 2024
When it comes to research into renewable propane, zero carbon is nowhere near the end of this fuel’s potential.
One stunning example is the work being done by the Illinois Institute of Technology (IIT) to produce propane from carbon dioxide (CO2) and electricity generated from solar or wind. Using a system of several carbon dioxide electrolyzer stacks, they can turn captured CO2 into propane at a rate of up to 4 kilograms of fuel per day. The process has been demonstrated to achieve 97% propane selectivity, a level of efficiency in creating molecular bonds that is effectively unheard of.
If the goal of developing and producing rPG is to reduce the carbon intensity of our energy sources (i.e., the amount of CO2 produced to generate a certain amount of energy), then this research is a breakthrough in plunging the CI score well below zero. It repurposes existing carbon that would otherwise go directly into the atmosphere and turns it into a low-carbon fuel.
Lead researcher Dr. Mohammad Asadi told the Propane Education and Research Council (PERC), “This is a negative-carbon process, using only captured CO2, water, and renewable electricity as inputs. We believe that when this technology is scaled up, it will produce renewable propane at a lower carbon intensity than any other current pathway while remaining cost-competitive with conventional propane.”
In recent years, we have seen a groundswell of research into turning carbon-emitting waste into usable bio-energy, and renewable propane has been at the forefront of this work.
Researchers are finding ways to convert polymers from plastic into propane gas. The biogas dimethyl ether (DME) can be added to renewable and conventional propane and lower its overall carbon intensity into net-negative territory. We’ve seen promising results from feedstocks like camelina or pongamia pinnata, oilseed crops that can grow on dry, otherwise fallow land.
Not all this research will result in a product that can go into the production pipeline. Still, the leaps forward will result in some amazing opportunities to lower the carbon impact of our homes, businesses and vehicles. Just look at the CI score decrease potential as a result of this research:
| Energy Source | Carbon Intensity Score |
|---|---|
| The average U.S. grid electricity | 130 |
| Conventional propane | 79 |
| rPG from domestic, unrendered used cooking oil | 20.5 |
| rPG from camelina sativa | 7 |
| rPG from CO2 and electricity | Below 0 |
[Source: PERC, score is in grams CO2 equivalent per megajoule or gCO2eq/MJ]
Renewable propane continues to be a green energy solution that governments and public institutions want to invest in.
The IIT work on converting CO2 to rPG — which has partners in GTI Energy and SHV Energy (in the Netherlands) — has received nearly $4 million in funding from the U.S. Department of Energy through the Grid-free Renewable Energy Enabling New Ways to Economical Liquids and Long-term Storage (GREENWELLS) initiative.
Similarly, the State of Vermont has included rPG as a clean heat measure that reduces greenhouse gas emissions. This is an important distinction. It illustrates how a Northeast state that has been debating how to lower its greenhouse gas emissions sees rPG as a decarbonization pathway worth exploring.
Want to stay up to date on new developments in renewable propane and other low-carbon liquid gases? Please consider joining the Renewable Propane Alliance.