Search

Today, advanced energy storage technologies, particularly electrochemical batteries, represent an increasingly economic option for supporting the integration of renewable energy resources and providing the grid with greater operational flexibility. Crucially though, the large-scale deployment of these assets, and the development of successful business models to support them is heavily reliant on policy, regulation and market design. In this paper, we present a comprehensive review of the array of federal, ISO/RTO and state-level rules and regulations shaping today's energy storage deployment across the United States. We highlight the fragmented and heterogeneous nature of existing market participation models available for advanced energy storage across restructured power markets and emphasize the need for design changes to power markets at all timescales to allow for the more efficient integration of energy storage. We also reflect on how well FERC's recent Order 841 does in terms of providing a framework for the establishment of more fit-for-purpose market participation models for storage, something that will be key for today's evolving power sector as it becomes more dependent on intermittent renewable resources.

There are a large number of accounts about rapidly declining costs of batteries with potentially transformative effects, but these accounts often are not based on detailed design and technical information. Using a method ideally suited for that purpose, we find that when experts are free to assume any battery pack design, a majority of the cost estimates are consistent with the ranges reported in the literature, although the range is notably large. However, we also find that 55% of relevant experts’ component-level cost projections are inconsistent with their total pack-level projections, and 55% of relevant experts’ elicited cost projections are inconsistent with the cost projections generated by putting their design- and process-level assumptions into our process-based cost model (PBCM). These results suggest a need for better understanding of the technical assumptions driving popular consensus regarding future costs. Approaches focusing on technological details first, followed by non-aggregated and systemic cost estimates while keeping the experts aware of any discrepancies, should they arise, may result in more accurate forecasts.

We develop three novel enhanced mixed integer-linear representations of the power limit of the battery and its efficiency as a function of the charge and discharge power and the state of charge of the battery, which can be directly implemented in large-scale power systems models and solved with commercial optimization solvers. Using these battery representations, we conduct a techno-economic analysis of the performance of a 10 MWh lithium-ion battery system testing the effect of a 5-min vs. a 60-min price signal on profits using real time prices from a selected node in the MISO electricity market. Results show that models of lithium-ion batteries where the power limits and efficiency are held constant overestimate profits by 10% compared to those obtained from an enhanced representation that more closely matches the real behavior of the battery. When the battery system is exposed to a 5-min price signal, the energy arbitrage profitability improves by 60% compared to that from hourly price exposure. These results indicate that a more accurate representation of li-ion batteries as well as the market rules that govern the frequency of electricity prices can play a major role on the estimation of the value of battery technologies for power grid applications.

We investigate six different lithium-ion battery modeling approaches to highlight the importance of accurately representing batteries in decision tools. Advanced mixed-integer-linear battery models account for efficiencies as a function of the discharge power, power-limits as a function of the state-of-charge, along with degradation, which are usually not accounted for in power systems models. The revenue potential from offshore wind paired with battery systems is then examined using the more advanced representation where degradation is the sum of the capacity fades resulting from calendar- and cycle-aging. The impacts of variability of offshore wind output along with energy- and capacity-market prices are evaluated using publicly available data from 2010 to 2013 using NYISO as a test case. For 2013, results highlight that without accurate battery representations, models can overestimate battery revenues by up to 35%, resulting primarily from degradation-tied costs. Advanced dispatch algorithms that account for calendar- and cycle-aging of the battery can help operate the battery more efficiently. Locating the battery onshore yields higher revenues and with wider useable SOC windows, it is possible to monetize higher arbitrage opportunities, which can compensate for any additional degradation-tied costs. The added value of a MWh of energy storage varies from $2 to $4.5 per MWh of wind energy, which leads to a breakeven cost range of $50–115 per kWh for the battery systems. As such, energy- and capacity-market revenues were found to be insufficient in recovering the investment costs of current battery systems for the applications considered in this analysis.

We conduct a techno-economic analysis of Li-ion NMC-G prismatic pouch battery and pack designs for electric vehicle applications. We develop models of power capability and manufacturing operations to identify the minimum cost cell and pack designs for a variety of plug-in hybrid electric vehicle (PHEV) and battery electric vehicle (BEV) requirements. We find that economies of scale in battery manufacturing are reached quickly at a production volume of ∼200–300 MWh annually. Increased volume does little to reduce unit costs, except potentially indirectly through factors such as experience, learning, and innovation. We also find that vehicle applications with larger energy requirements are able to utilize cheaper cells due in part to the use of thicker electrodes. The effect on cost can be substantial. In our base case, we estimate pack-level battery production costs of ∼$545 kWh−1 for a PHEV with a 10 mile (16 km) all-electric range (PHEV10) and ∼$230 kWh−1 for a BEV with a 200 mile (320 km) all-electric range (BEV200). This 58% reduction, from $545 kWh−1 to $230 kWh−1, is a larger effect than the uncertainty represented by our optimistic and pessimistic scenarios. Electrodes thicker than about 100 or 125 microns are not currently used in practice due to manufacturing and durability concerns, but relaxing this constraint could further lower the cost of larger capacity BEV200 packs by up to an additional 8%.

SUMMARY We compare battery performance simulations from a commercial lithium-ion battery modeling software package against manufacturer performance specifications and laboratory tests to assess model validity. A set of commercially manufactured spiral wound lithium-ion cells were electrochemically tested and then disassembled and physically characterized. The Battery Design Studio® (BDS) software was then used to create a mathematical model of each battery, and discharge simulations at constant C-rates ranging from C/5 to 2C were compared against laboratory tests and manufacturer performance specifications. Results indicate that BDS predictions of total energy delivered under our constant C-rate battery discharge tests are within 6.5% of laboratory measurements for a full discharge and within 2.8% when a 60% state of charge window is considered. Average discrepancy is substantially lower. In all cases, the discrepancy in simulated vs. manufacturer specifications or laboratory results of energy and capacity delivered was comparable to the discrepancy between manufacturer specifications and laboratory results. Results suggest that BDS can provide sufficient accuracy in discharge performance simulations for many applications. Copyright © 2012 John Wiley & Sons, Ltd.

There are a large number of accounts about rapidly declining costs of batteries with potentially transformative effects, but these accounts often are not based on detailed design and technical information. Using a method ideally suited for that purpose, we find that when experts are free to assume any battery pack design, a majority of the cost estimates are consistent with the ranges reported in the literature, although the range is notably large. However, we also find that 55% of relevant experts’ component-level cost projections are inconsistent with their total pack-level projections, and 55% of relevant experts’ elicited cost projections are inconsistent with the cost projections generated by putting their design- and process-level assumptions into our PBCM. These results suggest a need for better understanding of the technical assumptions driving popular consensus regarding future costs.

There are a large number of accounts about rapidly declining costs of batteries with potentially transformative effects, but these accounts often are not based on detailed design and technical information. Using a method ideally suited for that purpose, we find that when experts are free to assume any battery pack design, a majority of the cost estimates are consistent with the ranges reported in the literature, although the range is notably large. However, we also find that 55% of relevant experts’ component-level cost projections are inconsistent with their total pack-level projections, and 55% of relevant experts’ elicited cost projections are inconsistent with the cost projections generated by putting their design- and process-level assumptions into our process-based cost model (PBCM). These results suggest a need for better understanding of the technical assumptions driving popular consensus regarding future costs. Approaches focusing on technological details first, followed by non-aggregated and systemic cost estimates while keeping the experts aware of any discrepancies, should they arise, may result in more accurate forecasts.

The effect of a pretreatment using reactive ball milling and calcination on the graphitizability of an anthracite coal is explored. A thermal anneal of Buck Mountain anthracite at 1400 °C in argon increased the Lc crystallite dimension (from 12 to 20 A) and led to an increase in the oxidation temperature of the product. Ball milling of the coal reduced particle size with a nominal effect on carbon order and the degree of graphitization after the 1400 °C thermal anneal (Lc from 18 to 29 A). Ball milling in cyclohexene led to a substantial increase in the graphitizability at 1400 °C (Lc from 12 to 50 A). The enhanced reactivity was due to both carbon structure and introduced metal. The products of the mechano-chemical pretreatment and thermal anneal consisted of nanographene ribbons and multi-walled nanopolyhedral particles. It oxidized at moderate temperatures and had a high (74.3%) degree of graphitization based on X-ray diffraction analysis; the derived material has potential as filler for production of graphite.

Reactive ball milling in a cyclohexene solvent significantly increases the oxidative reactivity of an anthracite coal, due to the combined effects of particle size reduction, metal introduction, introduction of volatile matter, and changes in carbon structure. Metals introduced during milling can be easily removed via a subsequent demineralization process, and the increased reactivity is retained. Solvent addition alters the morphological changes that occur during pyrolysis and leads to a char with significantly increased reactivity. When the solvent is omitted, similar effects are seen for the milled product, but a significant fraction of the char is resistant to oxidation.

Demineralized Summit (DS) anthracite, DS annealed at 1673 K, and graphite are used to explore the effect of precursor order on structural transformations and H2 evolution that result during reactive ball milling. Carbon structure was assessed before and after milling with temperature-programmed oxidation, X-ray diffraction (XRD), ultraviolet Raman spectroscopy, N2 adsorption, He density, and solvent swelling. Graphite milled in cyclohexene is primarily nanocrystalline graphite, with 8 wt % amorphous content leading to low-temperature oxidation, swelling, increased surface area, and mesoporosity. Milling the disordered DS leads to signs of increased sp2 clustering, increased cross-linking, a significant ultramicroporosity with pores less than 8 A, and low-temperature H2 evolution. The carbon fraction of annealed DS behaves similarly to graphite in the mill.

Battery cost is among the largest barriers to mainstream adoption of electric vehicles. This dissertation examines near future battery technology and cost by (1) validating existing physics-based battery performance models using laboratory testing and manufacturer specifications, (2) constructing battery design optimization and production cost models to identify the least-cost design and investigating how key design-decision variables affect performance and cost for a variety of vehicle power and energy requirements, and (3) conducting expert elicitation on future battery costs and the key factors that drive cost. The validation, cost, and optimization modeling work use LiNi0.33Co0.33Mn0.33O2/LixC6 (NMC-G) as the chemistry of choice. Validation results of Battery Design Studio™ (BDS) a Li-ion battery modeling software indicated that BDS predictions of total energy delivered under our constant C-rate battery discharge tests are within 6.5% of laboratory measurements for a full discharge and within 2.8% when a 60% state of charge window is considered. Once validated, BDS is used to develop a power meta-model that predicts the 10–sec power capability of a cell design as a function of its capacity (Ah) and cathode coating thickness (microns). The production cost model is a process-based model and is constructed adopting process step information from existing literature. Subsequently, an optimization model is developed which estimates the cheapest cost battery pack design for a set of five different electrified vehicles (EVs) whereby the role of design-decision variables like cathode coating thickness is investigated among others. The energy and power requirements for the EVs, used as constraints in the optimization model, are calculated using the Powertrain Systems Analysis Toolkit (PSAT). Battery pack costs calculated are in the range of costs reported in the literature. Results indicate that higher capacity cells manufactured using higher electrode coating thicknesses can decrease manufacturing costs by 5-8%. Results suggest that economies of scale can be reached at a plant size of about 200MWh. Expert elicitation indicates that a variation of NMC-G is likely to be the cheaper cell-chemistry by 2018 with no major technological breakthroughs. Some experts also expect manufacturing improvements resulting in higher electrode coating thicknesses and cell capacities expected by 2018.

We compare battery performance simulations from a commercial lithium-ion battery modeling software package against manufacturer performance specifications and laboratory tests to assess model validity. A set of commercially manufactured spiral wound lithium-ion cells were electrochemically tested and then disassembled and physically characterized. The Battery Design Studio® (BDS) software was then used to create a mathematical model of each battery, and discharge simulations at constant C-rates ranging from C/5 to 2C were compared against laboratory tests and manufacturer performance specifications. Results indicate that BDS predictions of total energy delivered under our constant C-rate battery discharge tests are within 6.5% of laboratory measurements for a full discharge and within 2.8% when a 60% state of charge window is considered. Average discrepancy is substantially lower. In all cases, the discrepancy in simulated vs. manufacturer specifications or laboratory results of energy and capacity delivered was comparable to the discrepancy between manufacturer specifications and laboratory results. Results suggest that BDS can provide sufficient accuracy in discharge performance simulations for many applications.

Hydrogen storage materials based on the hydrogen spillover mechanism onto metal-doped nanoporous carbons are studied, in an effort to develop materials that store appreciable hydrogen at ambient temperatures and moderate pressures. We demonstrate that oxidation of the carbon surface can significantly increase the hydrogen uptake of these materials, primarily at low pressure. Trace water present in the system plays a role in the development of active sites, and may further be used as a strategy to increase uptake. Increased surface density of oxygen groups led to a significant enhancement of hydrogen spillover at pressures less than 100 milibar. At 300K, the hydrogen uptake was up to 1.1 wt. % at 100 mbar and increased to 1.4 wt. % at 20 bar. However, only 0.4 wt% of this was desorbable via a pressure reduction at room temperature, and the high lowpressure hydrogen uptake was found only when trace water was present during pretreatment. Although far from DOE hydrogen storage targets, storage at ambient temperature has significant practical advantages oner cryogenic physical adsorbents. The role of trace water in surface modification has significant implications for reproducibility in the field. High-pressure in situ characterization of ideal carbon surfaces in hydrogen suggests re-hybridization is not likely under conditions of practical interest. Advanced characterization is used to probe carbon-hydrogen-metal interactions in a number of systems and new carbon materials have been developed.