• Mandy Green

Baking Up New Ideas

Can cookies change the world? Most likely not. But the vanilla flavoring we use in cookies possibly could. Surprisingly, this yummy compound is challenging how we approach material sourcing for electrical components in power systems.


Science

Researchers at the Graz University of Technology in Austria have found a way to convert vanillin, often used in vanilla flavoring for food products, into an electrolyte core for redox flow batteries. Redox flow batteries often use vanadium or other hard metals as their core, which can have a large environmental impact during mining or disposal at the end of the battery’s life. However, vanillin is a widely available, cheap, and naturally derived alternative. It can be refined from lignin, a byproduct of the paper and pulp industry.


Every year, the paper and pulp industry produces 50 to 100 megatons of lignin and 98% of it is burned to provide steam power for their machinery. What if we take it a couple steps further? Lignin can be refined into vanillin and used as vanilla flavoring or refined again into a redox-active quinone known as MHQ. MHQ is able to be used in redox chemical reactions and when combined with phosphoric acid, it is stable enough to act as the electrolyte core in redox flow batteries. (Read how it works here.)


Sourcing

The recyclability of lignin and its derivatives has the potential to dramatically change how we build sustainable systems. It's easy to obtain, low cost, and versatile; the refining processes are relatively simple as well. It can move from one function to the next in a smooth motion and offer a natural and sustainable resource to multiple industries.


Most of the lignin byproduct of the paper industry is used internally as fuel for machinery, but a portion of it can be refined into vanillin. With a direct hookup to a paper mill, lignin could be directly sourced into the refining process and any excess would be recirculated back to the mill. The vanillin can then be used as vanilla flavoring in the food and beverage industry or refined again into MHQ. MHQ is stabilized by phosphoric acid and finally used as the electrolyte core in redox flow batteries.


Potential Lignin Sourcing Process
Potential Lignin Sourcing Process

Batteries

Batteries operate because of electron transfer in an oxidation-reduction (redox) chemical reaction. Very simply, the oxidation reaction generates electrons at the anode, which is positive, and the reduction reaction uses those electrons at the cathode, which is negative. This transfer of electrons between the positive and negative generates electricity. The reactions will vary depending on the configurations and materials used – leading to different types of batteries.


Lithium-ion batteries are currently a very popular choice and can be found in vehicles, laptops, cell phones, and other consumer electronics. They have high energy densities, making them smaller and lighter than other types of rechargeable batteries, and are beneficial for portable applications. However, they have a high tendency to overheat and get damaged at high voltages. This can pose a significant fire risk and compromise the safety of people and buildings.


Flow batteries are more beneficial in settings where the batteries are needed in a long-term and stationary situation. An average flow battery has a life span of about 20 to 30 years; their long life cycles with little degradation, ability to quickly charge/discharge multiple times a day, and decreased fire risk compared to lithium-ion batteries make them an attractive option for large-scale utility renewable energy projects.


Because of the intermittent nature of renewables, battery energy storage is often paired with renewable energy projects. The batteries store excess energy generated during peak production times and that energy can be used later when electric demand is high. Incorporating flow batteries in these projects ensures uninterrupted power for the user and less stress on the electric grid, resulting in a win-win situation. Additionally, they can be scaled to meet the power needs of each project and allow for flexibility in renewable energy application.


Impact

While the redox flow battery made by the Graz researchers still has a long way to go before commercial applicability, it shows promise in scalability and manufacturing. It has 97 to 99% efficiency over 250 cycles – more than 8 months of continuous battery operation in stationary storage with about one charge/discharge per day. With further research, these batteries can become competitive with others on the market and offer a green choice for energy storage.


Eliminating the need for heavy metals that require resource-intensive mining processes and special disposal methods make it easier to create a product that can be fully recycled at the end of its life. Combined with other eco-friendly components, it is possible to build a completely sustainable energy generation system that is both efficient and functional. Eventually, this will become an expected standard and contribute to a cleaner, more resilient network of power.


Just in the United States, average renewable capacity at proposed facilities will more than double from 34 MW to 75 MW, and average battery capacity will grow from 5 MW to 36 MW by the end of 2023. Furthermore, the projects themselves are becoming larger in scale and we can reasonably expect these numbers to climb in the future. Renewable energy is on track to become a more prevalent feature of energy grids and replace aging infrastructure as inefficient technologies are phased out.


Every year, research into sustainable technology reveals the endless possibilities of a more innovative energy environment. Diversifying the energy mix helps increase the resiliency of our systems by decentralizing production and encouraging smaller microgrids that generate power near the end user -

leading to better efficiencies and synergies for the entire industry. It will be interesting to follow future research as new discoveries are made in this sector and observe the development of a sustainable grid.


Resources

Clean Energy Institute. (2020, September 26). Lithium-Ion Battery. Clean Energy Institute University of Washington. https://www.cei.washington.edu/education/science-of-solar/battery-technology/


Hayes, M., & Hoff, S. (2020, May 18). Large battery systems are often paired with renewable energy power plants - Today in Energy - U.S. Energy Information Administration (EIA). US Energy Information Administration. https://www.eia.gov/todayinenergy/detail.php?id=43775


Honsberg, C. B., & Bowden, S. G. (2019). Basic Battery Operation | PVEducation. PV Education. https://www.pveducation.org/pvcdrom/battery-basics/basic-battery-operation


Pelzl, C. (2020, October 1). Ecological power storage battery made of vanillin. TU Graz. https://www.tugraz.at/en/tu-graz/services/news-stories/media-service/singleview/article/oekologischer-stromspeicher-aus-vanillin0/


POWER. (2020, March 2). Flow Batteries: Energy Storage Option for a Variety of Uses. POWER Magazine. https://www.powermag.com/flow-batteries-energy-storage-option-for-a-variety-of-uses/


Schlemmer, W., Nothdurft, P., Petzold, A., Riess, G., Frühwirt, P., Schmallegger, M., Gescheidt‐Demner, G., Fischer, R., Freunberger, S. A., Kern, W., & Spirk, S. (2020). 2‐Methoxyhydroquinone from Vanillin for Aqueous Redox‐Flow Batteries. Angewandte Chemie International Edition, 59(51), 22943–22946. https://doi.org/10.1002/anie.202008253