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Thought Leadership Publications

The 21st Century Power Partnership publications provide information about and analysis of market design and regulatory issues for clean energy and 21st century power systems. Published work appears in scientific journals and the National Renewable Energy Laboratory publications database.

Lessons Learned for Rapid Decarbonization of Power Sectors

September 2022
This report covers key lessons learned for the rapid decarbonization of power systems, emphasizing best practices in planning, building, and operating power systems. This report is the result of a collaborative effort among various Clean Energy Ministerial (CEM) workstreams and partner initiatives. The contents are not intended to be comprehensive of all power sector topics, and there may be overlap between content in each section due to the nature of this first-of-its-kind collaborative effort to deliver unified messaging on power sector decarbonization to energy ministers. This work is intended to complement other work at the CEM and offers options for consideration, not specific policy recommendations.

Full report

Fact Sheet

Clean Grid Vision: A U.S. Perspective

September 2021
Clean Grid Vision: A U.S. Perspective aims to present perspectives on the main issues in future grid development, covering both supply and demand. It focuses on the lessons learned through the National Renewable Energy Laboratory and the Century Power Partnership Initiative's studies of the U.S. power sector that have measured the impacts of high-penetration variable renewable energy and tested strategies for enhancing grid flexibility and reliability. As such, this report is limited in its scope and does not attempt to review or summarize all power system literature. Although it refers to relevant external literature to provide context when needed, this study is primarily a summary of the National Renewable Energy Laboratory and the Century Power Partnership Initiative's research over the past five years on five topics, which each correspond to the five chapters in the report:

Executive Summary:
This describes the report and summarizes its high-level insights.

Chapter 1: Clean Grid Scenarios:
Serves as a broad introduction to the type of future power systems envisioned in the Clean Grid Vision: one with high penetrations of variable renewable energy generation and a variety of flexible resources.

Chapter 2: Distribution Issues and Tools:
Reviews considerations for the power system relevant to the continued growth in distributed energy resources as well as the tools and best practices necessary to manage their growing role across the power grid.

Chapter 3: Transmission Grid-Supporting Technologies:
Covers the ways high renewable penetration will bring challenges to power system reliability and stability. It also summarizes how renewable generation technologies can provide a wide range of grid services that can maintain and improve grid reliability and stability.

Chapter 4: Demand-Side Development:
Focuses on developments on the demand side of the electricity system in the United States, including energy efficiency, demand-side management, and beneficial electrification.

Chapter 5: Global Power Market Trends:
Outlines the evolution of the electricity sector toward competitive modern markets against rapid changes in technologies, business models, and other market factors.

Electric Vehicle and Power System Integration: Key Insights and Policy Messages from Four CEM Workstreams

September 2020
This report summarizes how key stakeholders and policies can ease the integration of rapidly growing EVs and their interaction with the power grids upon which they depend for charging. The report is the result of a deliberate collaboration between four CEM workstreams: 21st Century Power Partnership Initiative (21CPP), Electric Vehicles Initiative (EVI), International Smart Grid Action Network initiative (ISGAN) and Power System Flexibility campaign (PSF). Included are policy messages based on current experience, with a particular focus on the role of critical stakeholders in a transformation that crosses multiple sectors. Many of these findings emerged from a highly interactive virtual workshop held on 19-20 April 2020, which engaged approximately 75 international experts from 18 countries and diverse backgrounds.

Ten Principles for Power Sector Transformation in Emerging Economies

May 2019
This document provides action-oriented principles for emerging economy decision-makers to consider while pursuing power sector transformation pathways.

Status of Power System Transformation 2019: Power System Flexibility

May 2019
As power systems around the world transform, power system flexibility has become a global priority. A range of operational, policy and investment-based interventions are available to render modern systems more flexible, thereby facilitating cleaner, and more reliable, more resilient, and more affordable energy. This report identifies challenges and opportunities to unlock system flexibility and accelerate power system transformation (PST) efforts. It provides an overview of the policy, regulatory and market instruments which can be implemented in different power sector contexts to mitigate these challenges.

Innovative Utility Offerings at the Distribution Edge: Case Studies from Around the Globe

May 2019
This report catalogues several innovative approaches utilities are taking to meet consumer preferences in a fast-changing world. It comprises a series of case studies for products and programs that enhance the consumer experience, provide greater access to distributed energy resources, and generally respond to the changing realities of the utility/customer relationship.

Status of Power System Transformation 2018: Advanced Power Plant Flexibility

May 2018
This report provides a comprehensive overview of how power plants can contribute to making power systems more flexible, as well as offering a range of guidance on strategies to promote cost-effective and system-appropriate power plant flexibility measures. Based on a wealth of real-life case studies and data, it provides a reference source for the technical capabilities of power plants in a diverse set of country contexts. In particular, it showcases a number of technical options and examples of how retrofits to existing power plants have been a cost-effective tool for enhancing system flexibility. In addition, it provides examples of policy, market and regulatory instruments available to unlock power plant flexibility and discusses how these instruments can be combined into a comprehensive roll-out strategy. The report is aimed at policy makers and regulators who are not experts in engineering, but who need to understand power plant flexibility in order to enhance system planning and upgrade policy, market and regulatory frameworks.

Executive Summary

Main Report

Summary for Policy Makers

Next-Generation Performance-Based Regulation: Emphasizing Utility Performance to Unleash Power Sector Innovation

May 2018 (Update)
We have re-organized the original report into a new 3-volume series, which you can read here:

Volume I

Volume II

Volume III

Next-Generation Performance-Based Regulation: Emphasizing Utility Performance to Unleash Power Sector Innovation

September 2017
Performance-based regulation (PBR) has established a pathway for reforming hundred-year-old regulatory structures to unleash innovations within 21st century power systems. The old regulatory paradigm, built to ensure safe and reliable electricity at reasonable prices from capital-intensive electricity monopolies, is adjusting to disruptive technological advances that are transforming the way electricity is generated, delivered, and consumed. PBR enables regulators to recognize the value electric utilities bring to customers by enabling advanced energy technologies and integrating smart solutions into the utility grid and utility operations. These changes in the electric energy system and customer capacities have catalyzed increased interest in motivating regulated entities to move beyond traditional cost-of-service performance regulation. This report addresses best practices and lessons gleaned from more than two decades of PBR in practice and analyzes how those can be applied to design innovative PBR programs.

Status of Power System Transformation 2017

June 2017
Power sectors around the world are undergoing significant change due to the rapid uptake of new supply- and demand-side technologies. Large-scale wind and solar power as well as distributed energy resources are influencing the planning, operation, and profitability of power systems. Policymakers, utilities, and other stakeholders need to apply innovative approaches to transform the power system, with the objective to achieve sustainable, affordable and reliable electricity. This report provides an overview of current trends across the globe, with a focus on the integration of renewables and local grid development. A framework for assessing the status of power system transformation is also introduced and applied to Indonesia, South Africa, Mexico, and Australia.

Policies for Enabling Corporate Sourcing of Renewable Energy Internationally

May 2017
Interest in renewable energy (RE) procurement in new markets is on the rise. Corporations are increasing their commitments to procuring RE, motivated by an interest in using clean energy sources and reducing their energy expenses. Many large companies have facilities and supply chains in multiple countries and are interested in procuring renewable energy in the grids where they use energy. The policy environment around the world plays a key role in shaping where and how corporations will invest in renewables. This report explores the policy and regulatory enabling environment for corporate sourcing of renewables.

Policies for Enabling Corporate Sourcing of Renewable Energy Internationally overview brochure

Clean Restructuring: Design Elements for Low Carbon Wholesale Markets and Beyond

May 2016
Countries around the world are in various stages of reforming and restructuring their power systems to better meet development needs. Changes in technology, business models, societal needs, and environmental goals are increasing pressure for countries to consider improvements to their power systems. This report addresses key issues associated clean restructuring—the transition from traditional, vertically integrated utilities to competitive wholesale markets that rely on variable renewable electricity sources, demand response, and other clean energy options.

Clean Restructuring: Design Elements for Low Carbon Wholesale Markets and Beyond overview brochure

Status Report on Power System Transformation

May 2015
Power system transformation is a complex, active process that is taking place at different rates and in different forms around the world. This transformation has multiple drivers, including technological advances, policy goals, and social change, and multiple enablers, especially policy, financial, and business model innovation. This report aims to bring the power system transformation picture into sharper focus, bolstering the evidence base for power system transformation by providing a collection of empirical examples of the types of innovations that are emerging around the world.

Power Systems of the Future: A 21st Century Power Partnership Thought Leadership Report

February 2015
This report summarizes key forces driving transformation in the power sector around the world, presents a framework for evaluating decisions regarding extent and pace of change, and defines pathways for transformation. Powerful trends in technology, policy environments, financing, and business models are driving change in power sectors globally. In light of these trends, the question is no longer whether power systems will be transformed, but rather how these transformations will occur. Three approaches to policy and technology decision-making can guide these transformations: adaptive, reconstructive, and evolutionary. Within these approaches, the report explores the five pathways that have emerged as viable models for power system transformation.

Two-page overview

Making Coal Flexible: Getting From Baseload to Peaking Plant

January 2015
Power systems in the 21st century—with higher penetration of low-carbon energy, smart grids, and other emerging technologies—will favor resources that have low marginal costs and provide system flexibility. Such flexibility includes the ability to cycle on and off as well as run at low minimum loads to complement variations in output from high penetration of renewable energy. Can coal-fired power plants continue to operate cost-effectively if they cycle routinely? Yes, according to experiences from an actual multi-unit North American coal generating station. This flexibility requires limited modifications to hardware, but extensive modifications to operational practice.

Also available in Mandarin

The Evolving Role of the Power Sector Regulator

April 2014
This report seeks to briefly characterize the evolving role of the power sector regulator. It describes seven existing objectives of power sector regulators and nine emerging objectives, highlighting key challenges and outlining interdependencies. As the preliminary installment in a series, it aims to lay the groundwork for subsequent reports and case studies that will explore these topics in depth.

Flexibility in 21st Century Power Systems

May 2014
Flexibility of operation—the ability of a power system to respond to change in demand and supply—is a characteristic of all power systems. Flexibility is especially prized in twenty-first century power systems, with higher levels of grid-connected variable renewable energy (primarily, wind and solar).

Research Highlights fact sheet

Flexible Coal: Evolution from Baseload to Peaking Plant

December 2013
Twenty-first century power systems, with higher penetration levels of low-carbon energy, smart grids, and other emerging technologies, will favor resources that have low marginal costs and provide system flexibility (e.g., the ability to cycle on and off to follow changes in variable renewable energy plant output). Questions remain about both the fate of coal plants in this scenario and whether they can cost-effectively continue to operate if they cycle routinely. The experience from the CGS plant demonstrates that coal plants can become flexible resources.

Market Evolution: Wholesale Electricity Market Design for 21st Century Power Systems

October 2013
This report reviews the suite of wholesale power market designs in use and under consideration to ensure adequacy, security, and flexibility in a landscape of significant variable renewable energy. It also examines considerations needed to ensure that wholesale market designs are inclusive of emerging technologies, such as demand response, distributed generation, and storage.

Integrating Variable Renewable Energy in Electric Power Markets: Best Practices from International Experience (Research Highlights)

This fact sheet highlights a 2012 report on best practices to enable variable renewable energy grid integration. The report studies cases from Australia (South Australia), Denmark, Germany, Ireland, Spain, and the United States (Colorado and Texas), which have effectively integrated variable RE utilizing diverse approaches.