WRI's 24/7 Carbon-Free Energy team has compiled a list of reports, case studies and other resources to help market participants advance and implement 24/7 carbon-free energy (CFE). The resources below are organized topically under the categories of Overview Resources, Impacts and Benefits, Case Studies, Methodologies, Time-Based Certificates, and Policy. You can also find WRI-hosted webinars on various topics related to 24/7 CFE on the Events page.

Disclaimer: The following documents are provided as supplemental material and have not been reviewed for quality by World Resources Institute.

Overview Resources

The following resources provide a general overview of 24/7 CFE: what it is, why it is important and how energy buyers can get started on 24/7 CFE.

An Introduction to Energy's Hottest New Trend: 24/7 Carbon-Free Electricity (Roberts, 2021) (Volts podcast and newsletter)

David Roberts of Volts provides a short introduction to 24/7 CFE, including the evolution of renewable energy tracking, the fundamentals of matching hourly load with renewable energy production, and how demand-side management, energy storage and clean-firm generation can help electricity grids reach 100% 24/7 CFE. This is the first of three articles on 24/7 CFE by Roberts: the other two are on alternatives to 24/7 CFE and the longer-term impacts of 24/7 CFE on carbon emissions and renewables.

Actions Large Energy Buyers Can Take to Transform and Decarbonize the Grid: Procurement Practices for Achieving 100% Carbon Free Electricity (Bird et al, August 2021) (WRI Peer-reviewed Issue Brief)

Large energy buyers play an important role in the clean energy transition, but they will need to take additional actions in the coming decades to help create a zero-carbon electric grid by 2050. This WRI report describes how transformative procurement practices, including 24/7 CFE procurement, can optimize how, when and where clean energy is deployed to help reduce long-term emissions.

24/7 Carbon-free energy for cities: Opportunities, challenges and pathways for urban energy systems (C40 Cities, May 2022)

In this report by C40 Cities — a network of nearly 100 mayors around the world focused on the climate crisis — cities are categorized into six typologies based on three levers of 24/7 CFE readiness: energy resource and technology; regulation and policy; and finance. The report provides an array of recommendations for cities in each category on how they can move towards electricity system decarbonization.


Impacts and Benefits

While 24/7 CFE is still relatively new, researchers have begun to explore the emissions and grid impacts of matching electricity consumption with CFE sources on an hourly basis.

System-level Impacts of 24/7 Carbon-Free Electricity Procurement (Xu et al, 2021) (Princeton University ZERO Lab)

The Princeton ZERO Lab conducted the first detailed analysis of the electricity system-level impacts of 24/7 CFE procurement. This study models the economic and emissions impacts of voluntary 24/7 CRE procurement by commercial and industrial consumers.

Clean Power by the Hour: Assessing the Costs and Emissions Impacts of Hourly Carbon-Free Energy Procurement Strategies (Dyson et al, 2021) (RMI)

In this RMI study, the authors use a model to analyze the costs, short-term emissions impacts, and long-term implications of 24/7 CFE strategies in several U.S. and European electricity markets.


Case Studies

Some large energy buyers have established 24/7 CFE goals and have begun to document their progress. Below are case studies from organizations that have developed 24/7 CFE plans.

24/7 by 2030: Realizing a Carbon-Free Future (Google, 2020)

Google has set a 100% 24/7 CFE goal by 2030. In this paper, Google provides an assessment of its current 24/7 CFE performance across all of its data center sites, describes the rationale for the 2030 24/7 CFE target and lays out a roadmap for how it will use technology, transactions and policy to meet its goal.

Our Path to 24/7 Renewable Energy by 2025 (Pepper et al., 2021) (Peninsula Clean Energy)

Peninsula Clean Energy, a Community Choice Aggregator (CCA) that provides electricity to about 765,000 people in California, set a goal to deliver 100% 24/7 renewable energy by 2025. This white paper introduces Peninsula Clean Energy’s vision for 24/7 renewable energy, details its progress to date and describes its plan to achieve its goal.



Below are resources from Google and others about how they are approaching and measuring 24/7 CFE.

24/7 Carbon-Free Energy: Methodologies and Metrics (Google, 2021)

In this paper, Google provides a detailed overview of their current 24/7 CFE framework and methodology, including the two key metrics they use to track their progress: a CFE Score and Avoided Emissions (tCO2e).

A Path Towards Full Grid Decarbonization with 24/7 Clean Power Purchase Agreements and an Analysis of 24/7 PPAs (Long Duration Energy Storage Council, 2022)

Written by the Long Duration Energy Storage (LDES) Council with support from McKinsey & Company, this paper describes how Power Purchase Agreements (PPAs) can be structured to achieve 24/7 CFE goals. It includes a proposed standardized methodology to assess these agreements for quality and ambition.

The CFE Manager: A New Model for Driving Decarbonization Impact (Google, 2022)

This Google paper describes a new 24/7 CFE procurement method, which they call the CFE Manager model. In this model, which Google argues can help energy buyers match hourly electricity demand with CFE and simplify the procurement process, a third-party firm identifies and procures a portfolio of CFE resources for an energy buyer.


Time-Based Certificates

A commonly accepted standard for tracking and trading time-based clean energy attributes will make 24/7 CFE a realistic goal for more energy buyers. The standards and platforms associated with hourly energy attribution certificates, which are often referred to as Time-based Energy Attribute Certificates (T-EACs) or Granular Certificates (GCs), are in active development.

Timely Progress Towards around-the-Clock Carbon-Free Energy (Texier, 2022) (Google)

This Google blog post describes how the company uses hourly certificates and how it has accelerated development of systems and standards to track hourly energy data and trade time-based energy attribute certificates.

A Path to Supporting Data-Driven Renewable Energy Markets (Gerber, 2021) (Midwest Renewable Energy Tracking System)

The Midwest Renewable Energy Tracking System (M-RETS) facilitated the first-ever time-based energy attribute certificate retirement in 2021. This report describes how M-RETS is involved in time-based energy attribute tracking and how it envisions the operation of a full-scale, time-based energy attribute marketplace.

Granular Certificate Scheme Standard (EnergyTag, 2022)

EnergyTag is an independent, non-profit organization that is defining and building a market for Granular Certificates (GCs) with support from key organizations in the energy certificates market. This document outlines the first version of an EnergyTag standard.



Large energy buyers can contribute to decarbonization by making and meeting 24/7 CFE goals, but broader policy changes can help scale these 24/7 CFE efforts.

Beyond 100% Renewable: Policy & Practical Pathways to 24/7 Renewable Energy Procurement (Miller, 2020) (University of California, Davis in The Electricity Journal)

This academic paper summarizes the evolution of voluntary renewables procurement, outlines the role of policy and market design in renewable energy goals, and provides a broad framework for 24/7 renewable energy procurement.

A Policy Roadmap for 24/7 Carbon-Free Energy (Google, 2022)

This report by Google identifies the policies that they believe are most critical to accelerating electricity grid decarbonization and achieving 24/7 CFE.

A Timely Match (Douglas and Hunt, 2021)

In this whitepaper, Eurelectric and RE-Source (in collaboration with members of the 24/7 RES-E Task Force) identify and describe three “building blocks” for 24/7 hourly matching in Europe and beyond: flexibility; data for 24/7 matching; and measurement, metrics and certificates. The whitepaper also includes several case studies about large energy buyers with 24/7 CFE ambitions. 


Collaborations and Working Groups

Do you want to get involved in the movement toward 24/7 CFE? Here are a few ways that organizations can join efforts to accelerate 24/7 CFE.

United Nations 24/7 Carbon-free Energy Compact

This compact is a set of principles and actions about 24/7 CFE that organizations around the world have signed to hasten the establishment of a decarbonized electricity system. For the latest information, including an updated list of signatories, visit the United Nations and Sustainable Energy for All’s (SE4All) 24/7 Carbon-free Energy Compact website.

Clean Energy Buyers Institute (CEBI) Next Generation Carbon-Free Electricity Procurement Initiative (NextGen Initiative) (CEBI)

CEBI (formerly the Clean Energy Buyer’s Alliance) created the NextGen Initiative to enable energy buyers to maximize the decarbonization impact of their procurement decisions. The Initiative advocates for the standardization and accessibility of granular energy data, as well as the development of platforms, processes and standards related to 24/7 CFE and other innovative procurement practices.

EnergyTag Working Groups (EnergyTag)

EnergyTag convenes three working groups—for Standard and Guidelines, Market Development, and Policy and Awareness—that inform the organization’s strategy around implementing Granular Certificates.