Engineering topics

Twitchell, Jeremy B.

Publications and source records attributed to Twitchell, Jeremy B..

At least 19 records

DOE OSTI2025

Do Mandates Deliver Cost Reductions for Energy Storage?

In 2013, California implemented a mandate directing the state’s investor-owned utilities to procure 1325 MW of energy storage, to help integrate nondispatchable renewable sources of energy and assist the state in meeting its environmental goals. This paper evaluates this policy’s impact of both battery deployment, and cost, finding that as of 2019, the state was effective in spurring nearly 500 MWh of battery storage deployment over what would have been installed in absence of the policy. This additive deployment would have the effect of reducing global battery cell costs by roughly $1.00/ kWh, based on learning by doing. To support these findings, we utilize both a difference in differences estimation, and a synthetic control analysis, both of which allow us to compare battery deployment in California, to deployment in other states. To pair deployment to cost reduction, we use a learning curve analysis, which links battery shipments to cell and storage block costs. For policymakers, these results provide evidence to the effectiveness of mandates in promoting storage deployment and help explain how these policies can induce downstream effects.

Boff, Daniel S.↗

DOE OSTI2024

Distributed Energy Resource Interconnection Roadmap

Adopting strategic reforms to DER interconnection can help reduce interconnection delays, fairly allocate costs, improve transparency and equity, and support efficient and strategic investment in distribution and sub-transmission grids that can accommodate a rapidly evolving energy landscape. The Interconnection Innovation e-Xchange envisions this roadmap and its transmission system companion volume as collaborative resources to facilitate continued stakeholder discussions, problem-solving, and innovation as the U.S. works together to enable simpler, faster, and fairer interconnection of clean energy resources all while enhancing the reliability, resiliency, and security of our electric grid.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2024

Energy Storage Market Transformation Through Stored Energy Targets

Aggressive energy decarbonization targets will require the rapid deployment of renewable energy in the U.S. in coming years. As the amount of variable generation on the grid grows, there will be an increasing need for long-duration energy storage (LDES) technologies to maintain grid reliability. Meeting that need will require a suite of technology alternatives with different capabilities. Many of these alternatives, however, are in a nascent state and face significant commercialization challenges. In the last decade, 10 U.S. states have enacted energy storage mandates as a vehicle for market transformation to accommodate energy storage. Those mandates, however, fail to send appropriate investment signals for LDES technologies because they are based on energy storage capacity and treat all technologies the same, regardless of duration. This paper explores the idea of replacing capacity-based storage procurement targets with stored energy targets, which would be technology-neutral policies designed to enable the market transformation necessary to support a competitive LDES industry.

Twitchell, Jeremy B.↗

DOE OSTI2024

Energy Storage to Enable Electricity as a Commodity

A lack of large-scale economical storage, demand-side flexibility, and the need to instantaneously balance supply and demand cause challenges for electricity as a commodity. With typical commodities, stock from periods of high production can be stored and sold during low production, smoothing demand and supply shocks. In electricity markets, high storage costs have long outweighed benefits, negating convenience yield; no-arbitrage models do not apply, and typical hedging strategies cannot be performed due to infinite carry costs. However, the mechanics of energy trading are changing due to advancing storage technologies, more price-responsive demands, and virtual bidding in electricity markets, shaping a system where electricity storage can be valued on factors other than diurnal arbitrage. We examine the valuation of electricity storage through the lens of commodity markets to assess the impacts of large-scale storage deployment.

energy storage↗

DOE OSTI2024

Calculating Behind-the-Meter Energy Storage Incentives on an Avoided Cost Basis

Behind-the-meter (BTM) energy storage offers the potential for shared investment by utilities and their customers, in which both parties share in the costs and benefits of battery investment. Several utilities and a handful of states have begun providing incentives to help customers purchase BTM energy storage, and in exchange, operate that battery on behalf of the customer to realize grid benefits such as meeting peak capacity needs. But there is wide variation in the value and structure of these incentives, suggesting a lack of clarity on the value of BTM storage to the grid and to non-participating customers who fund the incentives for participating customers. This paper provides an objective framework for establishing BTM energy storage incentives based on the avoided cost of generation from a marginal, gas-fired peaking plant. It also conducts several sensitivity analyses to see how those avoided costs vary with emissions pricing, gas prices, plant heat rates, and utility capital structures. This work may be of use to utilities, regulators, and energy system stakeholders in providing a value-based framework for BTM incentive programs that can be used in the absence of policy guidance.

Twitchell, Jeremy B.↗

DOE OSTI2023

Principles for Equitable Transmission Planning

Energy justice is gaining traction in the planning processes that govern the generation and supply of electric power in the U.S., with a growing number of federal and state authorities applying it as a framework to ensure that the benefits of a clean energy future extend to all levels of society. However, the principles of energy justice have not yet been integrated into electric transmission planning processes, which are designed to meet established reliability criteria and have not historically considered externalities like social inequities. This paper presents a review of transmission planning requirements in the U.S. and existing literature on energy justice, then synthesizes them to propose a framework for incorporating energy justice principles into transmission planning processes to yield more equitable outcomes. By applying procedural and recognition justice principles to create more extensive, inclusive, and diverse public participation in the planning process, planners can gain insight into—and begin to correct—the inequities created by previous planning decisions. Equipped with this understanding and informed by affected communities, planners can improve the distributional outcomes of the planning process and identify opportunities for energy system investments that will restore communities and place them on more equitable footing.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2023

Energy Storage in Local Zoning Ordinances

Increasing policy support and declining prices for battery energy storage systems (BESS) are driving rapid growth in the installation of these systems in the United States and around the world. Because a BESS is modular in nature and has limited infrastructure requirements, it can be built in close proximity to existing uses, which creates the potential for conflict. As the use of BESS grows, local planning and zoning staff are increasingly being asked to determine where the systems can be built and how their impacts on surrounding uses can be mitigated. While a large-scale BESS offers significant electric grid and societal benefits, it can also pose safety, visual, auditory, and environmental impacts on the community in which it is located. While these are material impacts, current safety codes for energy storage systems and land use frameworks provide planners with the necessary tools and processes to mitigate those impacts and ensure that their communities safely receive the benefits of energy storage systems. This report provides an overview of BESS from a land use perspective and describes their implications for zoning and project permitting. It concludes with an analysis of current energy storage zoning standards adopted by local jurisdictions in the U.S. Its intent is to objectively inform land use decisions for energy storage projects by equipping planning officials with relevant information about these technologies and knowledge of what questions to ask during review processes, so that energy storage projects can move forward in ways that will benefit electric systems while not unduly affecting host communities.

25 ENERGY STORAGE↗

DOE OSTI2023

Emerging Technologies Review: Pumped Storage Hydropower

The Air Force Civil Engineer Center (AFCEC) has tasked Pacific Northwest National Laboratory with investigating emerging technologies to inform the Air Force’s understanding of the technology and to guide key considerations for implementing technologies that are resilient and alternative sources to the traditional methods used in the Air Force today. This report explores pumped storage hydropower. Pumped storage hydropower (PSH) currently provides 93% of grid-scale storage capacity (MW) and 99% of electrical energy storage (MWh) in the United States. PSH exploits the potential energy that can be stored by pumping water to higher elevations or pressures to be dispatched when needed. In its simplest form, PSH uses energy to pump water to an upper reservoir for storage, then releases this water through a turbine and generator into a lower reservoir when needed for energy generation. This report provides a thorough technology description, technical considerations, siting considerations, economic/funding considerations associated with the technology. A Regulatory overview and risks associated with the technology are also included in the report.

13 HYDRO ENERGY↗

DOE OSTI2022

Optimal Sizing and Operation of a Hybrid Clean Energy Center

In this paper, we consider the deployment of battery energy storage systems (BESSs) paired with photovoltaics (PV) to form a hybrid clean energy center (HCEC), where the BESS is equipped for two main purposes: i) reducing the volatility of PV output and ii) shifting energy to meet an export limit. We develop a linear dynamical model to characterize the output of an HCEC and express the volatility and export power as functions of the battery's dispatch operations. We also propose an optimal sizing method via second-order cone programming (SOCP) to maximize the net benefits of the HCEC. Numerical studies are performed to illustrate and validate the proposed method.

Battery energy storage systems, photovoltaics, sec↗

DOE OSTI2022

Equitable Design of Behind-the-Meter Energy Storage Programs: A Customer Perspective

Utility deployment of energy storage is done as a utility-scale asset connected directly to the grid (front of meter) or in partnership with a customer on the customer’s premises (behind the meter). By offering incentives for customers to install behind-the-meter storage, utilities can gain operational control of the assets and operate them in a manner that benefits all customers. Some states have also begun providing increased incentive levels to low-income customers to ensure that they can equitably share in the benefits of behind-the-meter energy storage programs. This paper evaluates different approaches to energy storage procurement from the customer’s perspective and evaluates how behind-the-meter programs can be equitably structured while keeping customers financially indifferent between front-of-meter and behind-the-meter energy storage procurements.

Twitchell, Jeremy B.↗

DOE OSTI2022

Analysis of Distributed Energy Storage as a Core Grid Infrastructure via Production Cost Modeling

Energy storage plays a pivotal role in enabling power system operation with more flexibility and resilience. Unlike current practice that considers energy storages as attached ancillary devices, this paper focuses on storages as a core infrastructure by looking at their spatial distribution in the system. A sensitivity analysis based on production cost modeling is conducted to demonstrate the benefits of distributed energy storages. First, the modeling of energy storages in production cost modeling is presented. Second, potential optimal locations of distributed energy storages in a power system are discussed. Finally, multiple scenarios with various numbers and locations of additional distributed energy storages in the WECC 2030 model are created. The production cost modeling results of these scenarios show that distributed energy storages have higher utilization compared to the centralized ES units and therefore provide significantly more benefits in terms of reduction in generation cost, emission cost, and volatility of location marginal prices. A saturation effect is observed suggesting the selection of optimal locations will further improve the benefits.

Nguyen, Quan H.↗

DOE OSTI2022

Compensation for Long-Duration Energy Storage

Rapidly changing power system conditions, driven by decarbonization goals, are leading to significant growth in renewable energy sources, which can be both variable and uncertain. This has been accompanied with increased reliance on and rapid growth in deployment of energy storage technologies. Currently, approximately 90% of installed, utility-scale energy storage capacity in the United States comes from pumped storage hydropower (PSH). However, development of new PSH has been limited and all recent growth in energy storage has come from batteries, , especially as technology costs have decreased over the years. Most of the current deployment still remains in the form of short-duration (<6 hours) energy storage technologies; the average duration of new storage was 3.7 hours for projects deployed in the first half of 2021 (Wood Mackenzie and Energy Storage Association 2021).

25 ENERGY STORAGE↗

DOE OSTI2022

Study of Codes & Standards for Energy Storage Systems: A Report to Congress

The Infrastructure Investment and Jobs Act (H.R. 3684, 2021) directed the Secretary of Energy to prepare a report identifying the existing codes and standards for energy storage technologies. The stated goals for the report are to enhance the safe development of energy storage systems by identifying codes that require updating and facilitation of greater conformity in codes across different types and usages of energy storage technologies. This paper will focus on the specific codes and standards for stationary energy storage systems (ESS).

25 ENERGY STORAGE↗

DOE OSTI2022

Enabling Principles for Dual Participation by Energy Storage as a Transmission and Market Asset

Because the electric transmission system is sized to meet the highest levels of customer demand, much of its designed capacity goes unused during average operating conditions. As a uniquely flexible and scalable asset capable of providing multiple grid services, energy storage can be deployed to support the transmission system and then also provide services to energy markets when not needed for transmission. This paper reviews the technical barriers in transmission planning practices and energy market design that prevent the realization of dual-use energy storage projects that provide both regulated transmission and competitive market services. Current practices create barriers against the identification of energy storage in the transmission planning process and against the participation of a regulated transmission asset in competitive energy markets. A review of regional transmission plans identifies best practices for including energy storage in the planning process by directing planners to proactively identify such projects or by providing clear mechanisms for stakeholders to propose them. Creating a market participation model for dual-use energy storage assets requires establishing when an asset will be allowed to participate in the market, how it will participate in the market, and where it will recover its costs. In answering these questions, key principles must be satisfied, such as prioritizing reliability, incrementally building on existing market design, and balancing competing objectives. Several policy options exist for satisfying those principles, giving grid operators and stakeholders significant flexibility in developing a dual-use participation model in accordance with regional policies and conditions. By objectively framing the issue and identifying policy options, this paper may inform subsequent proceedings on dual-use energy storage and be a resource to regional market operators, utilities, developers, regulators, policymakers, and other stakeholders as they collectively work on this complex issue.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2021

Regulatory Implications of Embedded Grid Energy Storage

Electricity is unique among commodities in that its supply chain was developed without a storage component. Every other resource commodity has the ability to store excess quantities built into its supply chain – in the form of granaries, warehouses, reservoirs, etc. This embedded storage creates a buffer for mismatches between supply and demand, stabilizing prices and protecting customers. Recent technological advances in cost-competitive energy storage technologies that are scalable and flexible have made the concept of embedded electrical storage feasible, but several regulatory questions remain. This paper summarizes energy regulatory structures in the U.S. and the implications that they would have for embedded storage on the electric grid. Regulatory challenges for embedded storage include the lack of underlying standards, inclusion in planning processes, ownership models, compensation, and metrics. Two possible pathways forward are explored: an incremental one including regulatory guidance regarding the evaluation of embedded storage in existing planning processes, and a complex one involving the revision of existing reliability standards or the development of a new standard specific to embedded storage.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2021

Energy Equity and Environmental Justice (Workshop Report)

On December 11, 2020, 28 PNNL staff members discussed research to advance energy equity and environmental justice at a two-hour internal workshop. The primary purposes of the workshop were to baseline existing efforts at the laboratory and brainstorm future research activities. The workshop report documents the conversation, outcomes, and next steps.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

DOE OSTI2020

Planning Considerations for Energy Storage in Resilience Applications. Outcomes from the NELHA Energy Storage Conference's Policy and Regulatory Workshop

This report presents the proceedings and lessons learned at a conference workshop that discussed the role of energy storage in supporting electric system resilience, which took place at the Natural Energy Laboratory of Hawaii Authority’s (NELHA) Conference on Energy Storage Trends and Opportunities in December 2018. Staff from the Pacific Northwest National Laboratory (PNNL) made two presentations on the topic of resilience: the first covering a conceptual framework for incorporating resilience into resource planning processes, and the second covering a tool developed for microgrid planning that can assist in identifying resource mixes that will meet site-specific resilience needs. Throughout the presentations, presenters and workshop participants discussed the obstacles to improving electric system resilience and potential solutions for overcoming them. Following the workshop, the authors conducted additional research to further contextualize the topics discussed at the workshop and to frame the resulting recommendations for future engagement on this subject by the Department of Energy and the national laboratories.

25 ENERGY STORAGE↗

DOE OSTI2019

Southeastern Energy Storage Symposium and Workshop: Report on Proceedings and Lessons Learned

On July 17-18, 2019, the U.S. Department of Energy (DOE), Sandia National Laboratories (SNL), Pacific Northwest National Laboratory (PNNL), and Southern Research (SR) conducted the Southeastern Energy Storage Symposium and Workshop, a two-day event on energy storage technologies in Birmingham, AL. The first day of the event (Symposium) was open to all interested parties; the second day (Workshop) was open only to employees of state energy regulatory agencies. The event was conducted as part of the Energy Storage Program within the DOE's Office of Electricity.

25 ENERGY STORAGE↗