Distributed Renewable Electrochemical Energy and Mobility (DREEM) - submitted to NSF ERC program in collaboration with University of Delaware (lead), Penn State University and MIT

Vision overview: The vision of the ERC for Distributed Renewable Electrochemical Energy and Mobility (DREEM) is a sustainable and resilient electricity and mobility system anchored by a new generation of affordable electrochemical devices at the home and community scale. In this vision the residential and building energy users control their energy needs by installing distributed renewable energy resources (e.g., solar panels), energy storage devices (e.g., flow batteries, FBs), and mobility systems (e.g., plug-in fuel cell vehicles, PFCVs). Electrolyzers (ELs) are used to convert renewable electricity to hydrogen to power PFCVs, which provide clean mobility and electricity storage via a vehicle to grid (V2G). The DREEM system will be integrated with the distribution grid so that customers can provide valuable grid services (e.g., load following, frequency regulation, increased uptake of wind power). The DREEM system will enhance energy diversity, reliability, and 0security for both the distributed generation owners and existing large-scale electrical grid infrastructure.

world sunThe DREEM ERC's vision is transformative in nature, and its scope is broad and deep. Fulfilling this ambitious vision requires a diverse team that encompasses a wide range of talented investigators in the fields of science, technology, policy, and economics. Successful execution can result only from a well-orchestrated team effort across multiple disciplines and institutions organized and guided by a centralized leadership structure. While individual projects may be able to deliver desired outcomes on certain specific proposed sub-tasks, DREEM's overarching vision can be realized only by a cohesive, well-managed team under an ERC structure. A diverse multidisciplinary team has been assembled that is composed of leading researchers with complementary expertise from four partner institutions (UD, UNM, PSU, and MIT) and a number of affiliated universities and national laboratories. International partners have also been secured.

Intellectual Merit: The DREEM ERC's vision will be a paradigm shift from today's centralized power generation for the future renewable energy economy. This shift resembles the revolution in the computer industry when computing moved from centralized mainframes to a client-based distributed infrastructure networked to a worldwide internet, spurring massive innovation, cost reduction, and productivity increase across industries and the globe. The foundation of the DREEM system is a new generation of affordable electrochemical devices (e.g., FBs, ELs and FCs) that leverage the transformative alkaline electrolyte membrane and related catalyst technology required to overcome their chief commercialization barriers: affordability and durability. The DREEM ERC fills a current void in the sustainable and resilient infrastructure suite a distribution-scale energy and mobility system based on electrochemical devices and ideally complements current ERCs(FREEDM for power electronics, communications, and controls; CURENT for transmission; and QESST for solar devices), the DOE Hub/Joint Center for Energy Storage Research, and university-based centers focusing on fuel cells for transportation.

Broader Impacts: The DREEM ERC has the potential to revolutionize global power generation, utilization, and management and address concerns about air quality and climate change associated with fossil fuel combustion. Its success could help initiate a whole new green industry based on the transformation from centralized to distributed power generation. The Center's diverse, multidisciplinary, field-leading researchers will provide quality research, education, and training to infuse the electrochemical energy sector with the knowledge and workforce vital to the discovery of new materials and energy conversion concepts and to achieve a sustainable energy economy. The Center will also make significant efforts in technology transfer and in research and education integration involving underrepresented minority groups at all levels: K-12, undergraduate, graduate, postdoc, and continuing education. Through all of these efforts, DREEM will become a regional center for comprehensive education in the importance of clean energy to achieve a sustainable society and serve as a global leader in the development of new renewable and electrochemical energy systems.

Ten-year vision. The vision of the ERC for Distributed Renewable Electrochemical Energy and Mobility (DREEM) is a sustainable and resilient electricity and mobility system anchored by a new generation of affordable Alkaline electrolyte membrane-based electrochemical devices at the home and community scale. In this vision the residential and building energy users control their energy needs by installing distributed renewable energy resources (e.g., solar panels), energy storage devices (e.g., FBs), and mobility systems (e.g., PFCVs). ELs are used to convert renewable electricity to hydrogen to power PFCVs, which provide clean mobility and electricity storage via V2G.

The DREEM system will be integrated with the distribution grid so customers can provide valuable grid services (e.g., load following, frequency regulation, increased uptake of wind power), individually or via aggregation services. This distributed electricity and mobility system enhances energy diversity, reliability, and security for both distributed generation owners and existing large-scale electrical grid infrastructure. The DREEM ERC fills a current void in the sustainable and resilient infrastructure suite - a distribution-scale energy and mobility system based on electrochemical devices - and ideally complements current ERCs (FREEDM for power electronics, communications, and controls, CURENT for transmission, and QESST for solar devices), DOE's Hub: Joint Center for Energy Storage Research, and a number of university based fuel cell centers for transportation applications. The vision for an extensive distributed electricity generation and storage system is a paradigm shift from today's centralized power generation with little storage. This shift resembles the revolution in computing that occurred some 30 years ago, when the industry moved from centralized mainframe computing to a client-based distributed computing infrastructure networked to a worldwide internet, spurring massive innovation, cost reduction, and productivity increases. Moreover, distributed local-scale energy systems are inherently mobile and reconfigurable, similar to the current mobile computing revolution. To achieve a sustainable and resilient electricity and mobility system, a similar revolution in electricity generation and storage is needed. As the cost of solar and wind electricity generation reaches parity with conventional resources, the bottlenecks hindering progress toward a low-carbon energy economy are intermittency and insufficient electrification of the transportation sector. We propose to develop a new generation of electrochemical devices including FBs, ELs, and FCs that are affordable, durable, and reliable and to integrate these highly scalable devices into distribution grid and home/community infrastructure for electricity generation and storage and for mobility. These devices are an engineering revolution because they leverage exclusively the transformative recent advances in alkaline membrane and related catalyst research that surmounts the chief barriers to their commercialization: affordability and durability. For energy storage, we propose a combination of community-scale storage with FBs and ELs and consumer-scale storage with FBs and PFCVs. At the community scale, FBs and ELs will be located at or near power distribution substations offering a unique combination of features that are ideal for this application. For example, the power of a FB (a function of the size of the cell stack) can be decoupled completely from its energy storage capacity (a function of the size of the electrolyte storage tanks), enabling a FB to be independently engineered for power (e.g., frequency regulation) and energy (e.g., load following) applications. FBs also have instantaneous response. ELs store electricity in the form of hydrogen for use by PFCVs, which in turn can be used for energy storage via V2G. Since most vehicles spend the majority of their time parked, the size of the storage provided by grid-tied vehicles can be substantial (e.g., 50 MWh energy storage can be provided in a future power distribution feeder with 1,000 connected vehicles assuming a total 50 kWh energy availability per vehicle; the 50 MWh is more than the total electric energy currently required by a residential feeder for an entire day!) The DREEM ERC plans to deliver systems-integrated FB, EL and FC devices at the 1 kW level by the end of year 5 and 5 kW by the end of year 10. The storage function of the DREEM system will be demonstrated in the Distributions Systems Dynamics Testbed at UNM. We will combine a strong theoretical framework with large-scale simulation and finally deployment of the technology in a real-life testbed, consisting of a full-scale power distribution feeder with hardware-in-loop simulation capacity. The systems-level theoretical framework involves a Hamiltonian mechanics based control approach that provides the basis for optimization of the system topology and storage system specification. For the Mobility Testbed, we will leverage our decade-long experience at UD with the modeling, design, integration, operation, maintenance, and innovation of FC hybrid transit buses and hydrogen refueling operations, as well as extensive development of V2G hardware and software protocols and their implementation across a fleet of electric vehicles. The goal for mobility will be to translate novel technologies developed in the laboratory to practical applications in collaboration with 54 Future directions industry.

bus routeThe vision of our ERC is transformative in nature and its scope is broad and deep. Fulfilling this ambitious vision requires a diverse team of talented investigators in fields including science, technology, policy, and economics. Successful execution can result only from a wellorchestrated team effort across multiple disciplines and institutions organized and guided by a centralized leadership structure. A vital component of the team's success will be an innovation ecosystem comprising an industrial advisory board, entrepreneurship facilitators, and technology transfer partners. While individual projects can deliver desired outcomes on certain specific proposed sub-tasks, DREEM's overarching vision can be realized only by a cohesive, wellmanaged team under an ERC structure. To achieve this vision, we have assembled a diverse multidisciplinary team composed of leading researchers with complementary expertise from four partner institutions (UD, UNM, PSU, and MIT) and a number of affiliated universities and national labs. We have also secured the participation of foreign institutions in China, Germany, and the UK. Most importantly, as a team we will create a unique network of supporting companies from power production and distribution, to automakers and other OEMs, to high-tech materials and device startups.

Strategic Research Plan The vision of DREEM is a sustainable and resilient energy infrastructure enabled by a new generation of affordable electrochemical devices (FBs, ELs, and FCs) based on AEMs. Central to the vision is a paradigm shift from acidic to alkaline polymer electrolytes, enabling the use of the inexpensive catalysts and membranes necessary to make intrinsically efficient and clean electrochemical technologies economically viable. In general, all membrane-based electrochemical devices share the same three-layer structure (electrode//membrane//electrode), also referred to a membrane-electrode assembly (MEA). At each membrane-electrode interface, a designated redox reaction occurs in a thin porous catalyst layer. Consisting of an appropriate electrocatalyst and an ionomer, this catalytic layer allows for simultaneous electron conduction, ion conduction, and reactant transport. A key function of the membrane is selective transport of an ion involved in both electrode reactions to complete the electrochemical circuit. The acid/base nature of the membrane and ionomer fundamentally controls the electrochemical reactions at the electrodes.

State-of-the-art aqueous electrochemical devices (i.e., FBs, ELs, and FCs) employ PEMs primarily due to the commercial availability of Nafion, the prototypical PEM, which demonstrates excellent proton conductivity as well as outstanding chemical, mechanical, and thermal stability. Despite significant progress over the past 20 years, PEM-based devices are fundamentally limited by the acidic polymer electrolyte. For both FCs and ELs, platinum (Pt)-based catalysts are essential for meeting performance and durability benchmarks, as other catalysts are unstable in the low pH operating environment. A key barrier to commercialization is the high Pt cost ($1100/tr. oz) which accounts for 34% of stack costs at high volume production. Moreover, Pt has low natural abundance and is mass-produced in only two world regions (South Africa and Russia) suggesting that, with future high-volume production, Pt price volatility may significantly impact the market (much like oil today). In addition, Nafion, which is critical for FBs, ELs, and FCs, remains expensive (ca. $250/m2s), although economies-of-scale may lower manufacturing costs at high production rates. Thus, all of the aforementioned PEM-based electrochemical devices remain too costly for widespread adoption. DREEM aims to develop high-performance affordable electrochemical devices through alkaline membrane technology. Operating under alkaline conditions enables the use of non-precious metal catalysts (e.g., $0.44/oz for Ni, $19.46/oz for Ag, 7/2013) and other cheaper component materials, which should lead to 75% cost reductions. Of central importance has been the development of new polymer AEM and AEIs with high hydroxide conductivity, controllable solubility, and high chemical, mechanical, and thermal stability. Moreover, these hydrocarbon polymer membranes are relatively inexpensive (e.g., $2.30/m2). This breakthrough work has accelerated the pace of development for new types of electrochemical devices and has opened up a new paradigm at the forefront of electrochemical engineering. Leveraging these successes, the DREEM ERC aims to advance AEM-based electrochemical systems through the innovation pipeline from fundamental materials science to device engineering to at- scale integration and demonstration. Our approach is depicted in the three-plane strategic planning chart which shows the interconnected research activities as three thrust areas: System Demonstration, Devices, and Materials Interfaces.

stakeholders

System Demonstration (T1) will leverage existing testbed infrastructure for Distributions Systems Dynamics (T1.1) and Mobility (T1.2) at UNM and UD, respectively. Access to these established platforms will facilitate the on-ramping and real-world testing of novel AEM-based electrochemical technologies. Critical system-level data will be used to establish device-level performance requirements (e.g., power, response time, energy density) which, in turn, will help to establish the necessary criteria to down-select fundamental materials. In addition, the wealth of historical data available, in combination with established testing protocols, will inform the design of experimental procedures that best mimic real- world operating conditions. These efforts will be complemented by policy, techno-economic and lifecycle analyses (T1.3) of AEM-based electrochemical technologies to highlight potential bottlenecks and identify deployment-limiting materials. Finally, interactions with stakeholders will help to educate the public, engage both the automotive industry and grid utilities, and disseminate information to government and non-profit advocacy agencies.

Understanding of the requirements and current limitations of electrochemical systems for envisioned distributed storage and mobility applications will inform device design and characterization (T2). Indeed, system-level performance is highly dependent not only on the internal components but also on overall cell architecture and operating conditions. The performance of novel membranes (T3.1), catalysts (T3.2), and interfaces (T3.3) can be properly evaluated only via assembly into fully functioning devices, as these studies may highlight synergies and incompatibilities in material sets. Engineering research will focus on design, simulation, manufacturing, and device-level testing and characterization (T2.4) of FBs (T2.1), ELs (T2.2), and FCs (T2.3). While similar in configuration, these systems have different figures of merit, benchmarks, and barriers based on their intended applications. For FCs and ELs, a common challenge is that, despite the benefits of non-precious metal catalysts and hydrocarbon membranes, AEM-based devices must enhance power density and demonstrate durability to displace acidic devices. Likewise, AEM-based electrolyzers must enhance hydrogen production rates without sacrificing energy efficiency or durability. FBs generally employ soluble transition metal cations, as electroactive species do not require electrocatalysts to drive redox reactions but do require AEMs to prevent undesirable crossover, enable high coulombic efficiencies, and eliminate a key cost-driver in the Nafion membrane. All device- level results will feed back into the materials interfaces efforts (T3) to inform fundamental research directions, and promising devices will be prototyped for system demonstration. Moreover, the characterization effort (T2.4) with neutron (NIST) and X-ray beamline techniques (BNL) will probe the detailed structure and composition of the materials at the molecular, component, and device scale with a focus on changes over time using accelerated degradation assessments26. A clear emphasis on long- lifetime materials and devices will mitigate scale-up and commercialization risk.

Realizing enhanced system- and device-level performance requires new fundamental knowledge and materials engineering knowhow through advances in membranes (T3.1), catalysts (T3.2), and interfaces (T3.3). While improvements can be made to each component, efficient device operation requires synergistic interactions between individual components. Consequently, significant coordination and collaboration between tasks will ensure that the new materials developed will have an impact on the target devices, and rapid assessment of successes and failures will establish a dialog between science and engineering of these devices. At the heart of all three devices are AEMs which set the pH, control the redox reactions, and, in many cases, determine operating life. Enhancing AEM conductivity and stability are widely recognized goals which require advances in understanding of the fundamental limits of anion conduction and of the in-situ membrane degradation mechanisms. In particular, the degradation task ties to the catalyst and interface tasks below and provides important linkages with the devices thrust (T2).