Safety assessment of flow battery electrolytes - SABATLE
The problem addressed
Redox flow batteries are an emerging technology for medium and
large-scale stationary energy storage and are considered as a viable
option to buffer fluctuations in the energy grid. These fluctuations
are caused by the increasing share of renewable energy (e.g. solar
and wind energy) whose production is dependent on weather and
seasonal conditions.
The core elements of a redox flow battery (RFB) are two tanks filled
with the electrolytes. Currently used electrolytes feature several
issues such as limited regional availability, stability, volatile
price, lack of sustainability and – often neglected – significant
toxicity. In SABATLE, we aim at investigating the safety and
(nano)toxicity aspects of current and emerging electrolytes in redox
flow batteries as well as the corresponding environmental impacts by
performing a life cycle assessment of the whole life cycle from
resource extraction to the end-of-life.
Keywords:
ecotoxicity
nanotechnology
lifecycle assessment
Research questions
The project focuses on toxicity aspects of an
emerging technology, namely redox-flow batteries. This topic has not
been addressed in scientific literature so far. In particular, we
screen the toxicity and environmental impacts of currently available
redox flow battery electrolytes (e.g. vanadium) and compare them to
organic electrolytes (derived from 2-methoxyquinones) from a
renewable feedstock (lignin) currently being developed at some of the
partners. We follow a holistic approach using different tools,
databases and extensive toxicity testing (human toxicity,
ecotoxicity, nanotoxicity) which never has been applied to redox flow
battery electrolytes so far. In SABATLE, we explore the whole value
chain of the electrolytes - from raw materials to electrolyte
production to after-end-of-life and provide a detailed assessment of
the involved processes and materials. We will perform life cycle
analysis and impact assessment to reveal the environmental
performance of the lignin-based system compared to its conventional
counterparts as well as to highlight hotspots in life cycle stages
and processes. Further, the inclusion of SaSbD in
organic redox flow battery design is an innovative aspect and
unprecedented in the field of redox flow battery electrolytes. In
contrast to current redox flow battery electrolytes where
environmental and hazard assessments have not been addressed, this
project offers an opportunity to reduce potential hazards and
environmental impact of an emerging technology.
Scientific disciplines: chemistry/chemical engineering
Expected outputs
The main objective of the proposal is to assess currently used and
emerging electrolytes in redox flow batteries towards their
(nano)safety and sustainability aspects and to provide design
guidelines to make such electrolytes inherently safe throughout the
whole value chain. The specific objectives (O1-O4) are aligned with
the call objectives (safety of the energy storage system; risk
assessment of impacts on human health and the environment; safety of
the production process; SaSbD principles; public concerns,
governance, standardization)
O1: SaSbD concept development to inherently improve
both, the safety of the electrolytes and the sustainability approach
throughout the whole value chain (→WP2,
WP5).
O2: Testing of electrolyte solutions in zebrafish, algae and
daphnia to assess their human toxicity and ecotoxicity, including
consideration of accidents and after end-of-life scenarios including
nanotoxicity (→WP3).
O3: Life cycle assessment of the electrolytes from production
to after end of life including recycling issues (→WP4).
O4: Provide results for the governance of advanced
materials/nano-materials, considering and contributing to
OECD-testing guidelines and standardization (→WP5,
WP6).
The project will generate outputs of relevance to the following stakeholders:
- Regulatory bodies: Real-life relevant knowledge on the
applicability and/or identify the need for electrolyte modifications,
as well as a blueprint for applying the SaSbD-concept to nano-enabled
electrolytes will be established.
- Energy suppliers: The
development of safe, sustainable RFB electrolytes gives them an
opportunity to extend the renewable energy production towards
sustainable energy storage in the form of RFB systems.
- Public
bodies (e.g. municipalities), the results will provide the
opportunity to assure supply security for critical infrastructure
using safe and sustainable RFB technology with lowest possible
environmental impacts. This will also increase acceptance on a
socio-political and community level.
- Redox-flow battery (RFB)
manufacturers: the results provide a guideline to improve their
environmental impact of their technology in both production and
operation, thereby creating unique selling points over
non-sustainable competitors.
Workplan
The approach is divided into 6 work packages that will cover all
aspects and objectives (O1-O4) related to the safe redox flow
batteries from an electrolyte point of view. This includes a
coordination & management work package (WP1), 4 scientific work
packages (WP2-WP5) and a dissemination & communication part
(WP6). The expertise in the consortium covers the whole value chain
starting from the raw material and its production (Mondi AG), the
conversion into electrolytes including modification (TUG), toxicity
testing (Biobide), LCA (UG) and development of safe and sustainable
guidelines including interaction with regulatory bodies and
stakeholders (BNN).
Associated deliverables
Providing sustainable energy storage is a challenge that must be overcome to replace fossil-based fuels. Redox flow batteries are a promising storage option that can compensate for fluctuations in energy generation from renewable energy production, as their main asset is their design flexibility in terms of storage capacity. Current commercial options for flow batteries are mostly limited to inorganic materials such as vanadium, zinc, and bromine. As environmental aspects are one of the main drivers for developing flow batteries, assessing their environmental performance is crucial. However, this topic is still underexplored, as researchers have mostly focused on single systems with defined use cases and system boundaries, making the assessments of the overall technology inaccurate. This review was conducted to summarize the main findings of life cycle assessment studies on flow batteries with respect to environmental hotspots and their performance as compared to that of other battery systems.
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The SABATLE project was one of the first of its kind to adapt and employ the use of the Safe-and-Sustainable-by-Design approach to energy storage systems. As energy storage system we chose organic flow batteries, which aim at replacing the electrolyte, namely commercially available vanadium against biobased redox active molecules. The SSbD considerations included the value chain from cradle to grave, included social LCA impacts as well as toxicity testing of some compounds. Application of the SSbD approach showed that by analysis of all process steps, the safety of the overall process can be significantly increased. The main outcome of the project was a case study which was presented at the EuroNanoforum in Lund 2023 and submitted for publication in December 2023. It highlighted that the implementation of SSbD during technology development is capable to design better processes from both economic, ecologic and safety point of view. Another important outcome of the project was the analysis of current LCA methods to assess flow battery technoeconomic and environmental performance where we identified several methodological shortcomings which were summarized in a ChemSusChem Paper published in early 2023. In addition, the project was presented to a variety of stakeholders and was disseminated in many conferences on national and international level (e.g. American Chemical Society meeting). SABATLE also served as the seed for two more funding initiatives which both started in September 2023 (Safera SUESS, SSbD, LCA of post-lithium ion batteries and EIC VanillaFlow, toxicity of redox active molecules).
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Participating researchers
Stefan Spirk
(Institute of Bioproducts and Paper Technology, Graz University of Technology,
Austria)
— project coordinator
Werner Schlemmer
(Institute of Bioproducts and Paper Technology, Graz University of Technology,
Austria)
Johanna Scheper
(BioNanoNet Forschungsgesellschaft,
Austria)
Susanne Resch
(BioNanoNet Forschungsgesellschaft,
Austria)
Claudia Mair-Bauernfeind
(Institute of System Sciences, Innovation and Sustainability Research, University of Graz,
Austria)
Tobias Stern
(Institute of System Sciences, Innovation and Sustainability Research, University of Graz,
Austria)
Leo Arpa
(Mondi AG,
Austria)
Arantza Muriana
(Biobide,
Spain)
Iñaki Iturria
(Biobide,
Spain)
Oihane Jaka
(Biobide,
Spain)
Ana Isabel Puertas
(Biobide,
Spain)
Juan Carlos Solis
(Biobide,
Spain)
Funding organizations
OSALAN (Spain)
BMK (Austria)
Information last updated on 2021-03-22.
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