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Fall 2020

Sustainability of Renewable Energy Technology

Renewable energy sources are presented a solution to a green future but do they fill that goal?

Malgorzata (Gosia) Chwatko

Everyone daydreams about the future, about their career, family, or life goals. While dreaming, many of us picture electric cars or reduced reliance on fossil fuels. In some countries, such as France, these goals are already being realized. The entire country is already transitioning to selling only electric vehicles. This green transition is part of a goal for a sustainable world, which begs the question: are solar and wind power technologies sustainable? Switching to renewable energy production should decrease the total amount of greenhouse gas emissions, but the manufacturing processes or breakdown of these products can still have negative environmental consequences. These effects often do not receive much attention but have important societal ramifications. Only a comprehensive examination of the synthesis, use, and breakdown of products, from cradle to grave, can tell us how sustainable these technologies are relative to saving the world from greenhouse gases or pollution. 

Cradle

Figure 1: Energy technologies are created from many compounds such as metals, plastics and complex composites

To manufacture a functional solar panel or a wind turbine system, various materials must be combined. In addition to the energy generating component, such as the solar panel or wind turbine, an energy storage component is necessary to better match the human energy consumption. Typically, a combination of metals and plastics is necessary to yield different properties to produce the housing and battery electrodes for the energy storage component(s). Their production can generate a lot of hazardous waste, which then requires proper disposal pathways. In many circumstances, these materials come from nonrenewable sources such as fossil fuels or metals mined from the Earth’s crust. For example, the housing and glues within renewable energy systems are composed of polymers, many of which are made from nonrenewable sources such as fossil fuels. Similarly, metals such as cobalt are mined from the Earth, which can lead to environmental damage. Considering these impacts, it would be easy to pinpoint the “cradle” as being non-sustainable. However, significant progress is being made by three Energy Frontier Research Centers to look into sustainable sources. The Center for Lignocellulose Structure and Formation (CLSF) is studying cellulose, which is an important component of plant cells. Cellulose has already inspired commercial materials  such as rayon and cellophane. (Rayon is commonly used in clothing, while cellophane makes up the packaging used for enclosing different foods.) CLSF is learning more about cellulose structure and developing new syntheses to obtain the material more easily. The Nanostructures for Electrical Energy Storage Center has even successfully applied cellulose-based materials as paper electrodes in a lithium-ion battery. Beyond the battery-based efforts, the Catalysis Center for Energy Innovation is developing pressure-sensitive adhesives from lignin, which can be used in other aspects of the design. Lignin is commonly discarded during wood processing in the paper industry. These efforts and more, demonstrate that research focus on device production can provide sustainable alternatives by finding renewable feedstocks and production routes.

Use

Figure 2: Visual description of the energy use which spans all hours, in comparison to solar energy production. Reprinted from sitn.hms.harvard.edu.

The current design of both wind turbines and solar panels has been carefully engineered for longevity and power. Current designs anticipate the lifetimes of both technologies to be approximately 25 years. Progress in terms of achieving longevity and power make the most of current technology to achieve sustainability. To push the technology further, especially on the energy storage front, multiple EFRCs are investigating the mechanisms involved in lithium battery use. The battery use in their applications is necessary to better match energy output from the sun or wind to general energy use all around the clock, day and night.

The NorthEast Center for Chemical Energy Storage looks at lithium transport and the formation of dendrites in batteries, which is one of the primary and most drastic modes of failure in battery technology. If we can decrease the occurrence of these failure events we can increase the lifespan of the technology. As one of their goals, the Breakthrough Electrolytes for Energy Storage Center aims to design new electrolytes that can achieve a higher concentration of active species to boost energy density. With these efforts, we can keep pushing technology forward and increase the time from creation to disposal for materials used in energy storage.

Lastly, various researchers are looking for alternative chemistries relative to what is used in traditional Li-ion batteries. As mentioned previously, lithium and other metals exist in small quantities on Earth and their extraction can negatively affect the region from which they are extracted. One proposed solution is to use sodium batteries, which rely on a more commonly found element. Sodium is extremely common, and as humans we even eat its ionic form as a complex with chloride, sodium chloride (better known as salt).

Grave

Figure 3. Energy technologies heading to landfills

While the ultimate lifetime of solar and wind power technologies is currently 25 years, some of the components may fail earlier. It is also projected that by 2050, the world will produce up to 78 million tons of photovoltaic waste. Because most, if not all components, are not easily degradable, this may quickly overwhelm our ability to recycle and/or dispose of these materials. Blades from wind turbines are already problematic because of the inability to recycle them and their large size which many landfills cannot accommodate.

Recycling has been proposed as a solution for a lot of single-component materials, but complex mixtures are hard to separate. Components of both wind and solar technologies fall into this category based on their construction. As such, the difficulty in recycling poses a threat to the sustainability status of these technologies. Fortunately, the Basic Energy Sciences program of the US Department of Energy has identified these needs, including energy storage and plastics upcycling. Hence, it is possible that one of the proposed efforts will look into challenging materials such as composite materials.

Combining all these factors from cradle to grave, wind and solar power technology can be a truly sustainable option in the future, thanks to all the related research being conducted in this area.

More Information

EFRC Publications

Wang S, Shuai L, Saha B, Vlachos DG, Epps TH. 2018. “From Tree to Tape: Direct Synthesis of Pressure Sensitive Adhesives from Depolymerized Raw Lignocellulosic Biomass”  ACS Central Science, 4(6): 701-708. DOI: 10.1021/acscentsci.8b00140

Chen X, Zhu H, Liu C, Chen YC, Weadock N, Rubloff G, Hu L. 2013. “Role of mesoporosity in cellulose fibers for paper-based fast electrochemical energy storage” Journal of materials chemistry A, 1: 8201–8208. DOI: 10.1039/C3TA10972K

Center for Lignocellulose Structure and Formation Website. https://www.lignocellulose.org/

Other Publications

Chowdhury MS,   Rahman KS, Chowdhury T, Nuthammachot N, Techatoa K, Akhtaruzzaman M, Tiong SK, Sopian K, Amin N. 2020. “An overview of solar photovoltaic panels’ end-of-life material recycling”Energy Strategy Reviews 27: 100431.  DOI: 10.1016/j.esr.2019.100431

Acknowledgments

Wang S, et al. The polymer synthesis and characterization work was performed by S.W. and T.H.E. and was supported financially by NSF Grant CHE-1507010 to T.H.E. The biomass deconstruction and monomer production work was conducted by L.S., B.S., and D.G.V. and was supported financially by the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001004. The University of Delaware (UD) NMR facility and RSA-G2 instrument were supported by the Delaware COBRE program with a grant from NIH NIGMS (1 P30 GM110758-01). The authors thank the UD Advanced Materials Characterization Laboratory for the use of DSC and TGA instruments. The authors are grateful for the generous donation of Kurarity LA2140e polymer from Kuraray Co. Ltd. The authors thank Kevin Liedel from UD Delaware Energy Institute for help with generating figures. The authors also acknowledge Dr. Shuang Liu for assistance with the adhesion and tensile testing experiments.

Chen X, et al. X. Chen, C. Liu and G. Rubloff are supported by Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DESC0001160. L. Hu, a NEES affiliate, and his team H. Zhu and Y. Chen, and N. Weadock are supported by startup funds from the University of Maryland. We also acknowledge the support of the Maryland NanoCenter and its FabLab and NispLab, and Professor Peter Kofinas from Fischell Department of Bioengineering for providing access to a high precision microbalance.

Chowdhury MS. The authors would like to acknowledge the contribution of Thailand’s Education Hub for Southern Region of ASEAN Countries Project (THE-AC) with code number THE-AC 062/2017. The authors admit and appreciate the contribution of The Solar Energy Research Institute of The National University of Malaysia (UKM) through the research grant number GUP-2017-031. Due appreciation is also credited to the Institute of Sustainable Energy (ISE) of the Universiti Tenaga Nasional (@The National Energy University) of Malaysia for their valuable support through the BOLD2025 Programme.

About the author(s):

  • Malgorzata (Gosia) Chwatko is a postdoctoral fellow at the University of Texas at Austin. She is a member of the Center for Materials for Water and Energy Systems (M-WET) Energy Frontier Research Center. Her research focuses on the development of new polymeric materials for applications such as water purification and energy storage. 

More Information

EFRC Publications

Wang S, Shuai L, Saha B, Vlachos DG, Epps TH. 2018. “From Tree to Tape: Direct Synthesis of Pressure Sensitive Adhesives from Depolymerized Raw Lignocellulosic Biomass”  ACS Central Science, 4(6): 701-708. DOI: 10.1021/acscentsci.8b00140

Chen X, Zhu H, Liu C, Chen YC, Weadock N, Rubloff G, Hu L. 2013. “Role of mesoporosity in cellulose fibers for paper-based fast electrochemical energy storage” Journal of materials chemistry A, 1: 8201–8208. DOI: 10.1039/C3TA10972K

Center for Lignocellulose Structure and Formation Website. https://www.lignocellulose.org/

Other Publications

Chowdhury MS,   Rahman KS, Chowdhury T, Nuthammachot N, Techatoa K, Akhtaruzzaman M, Tiong SK, Sopian K, Amin N. 2020. “An overview of solar photovoltaic panels’ end-of-life material recycling”Energy Strategy Reviews 27: 100431.  DOI: 10.1016/j.esr.2019.100431

Disclaimer: The opinions in this newsletter are those of the individual authors and do not represent the views or position of the Department of Energy.