Problems accessing GHG source data (e.g., utility or vehicle miles traveled (VMT) data) cause long delays in preparing and updating GHG inventories.
How this barrier is experienced across the state
Developing greenhouse gas (GHG) inventories present significant administrative, financial, and technical burdens for many jurisdictions. There are typically roughly 23 data sources that go into a greenhouse gas inventory. The number crunching required is extremely time consuming, especially on a one-off basis. Any GHG emissions inventory developed for CEQA purposes needs to be legally-defensible.
Participants note burdensome procedures for accessing the data as a major issue, as well as data cleaning. Of the needed data sources (see Figure 1), participants indicate that the most challenging data sets are utility data and VMT data.
According to the ICLEI US Community Protocol & the Global Protocol for Community-Scale Greenhouse Gas Emission Inventories, GHG sources and methods should be: 1) relevant, 2) accurate, 3) complete, 4) transparent, 5) consistent (over time), and also 6) accessible (this has implications for cost and availability). However, participants relayed that the sources and methodologies change all the time and are difficult to reconcile and keep up to date with; also, the wide range of methods in use means one cannot compare across neighboring regional jurisdictions
Local governments have called for transparent, consistent, and affordable data. Various tools exist but there are challenges. None share a consistent methodology that ensures inventories are comparable across jurisdictions and across communities. Some of the tools are not freely accessible. Some rely on data sets that are not relevant to local jurisdictions and are thus not useful in the CAP development process. Private tool providers may want to keep some data private and proprietary, which limits transparency and utility. Attendees suggest preferred tool providers should offer up-to-date and regular maintenance; follow accepted protocols; no black-box calculations; use local datasets and emission factors; demonstrate subject matter expertise, and be consistent across methodologies and jurisdictional boundaries.
View the details on what communities have shared with SLECC from across the state.
Key challenge discussed in - San Francisco Bay Area, Statewide
Utilities, state agencies, and regional entities hold the energy-use data needed for GHG inventories, but CPUC privacy rules, inconsistent release practices, lack of standardization, and poor interagency coordination make it extremely difficult for cities to obtain complete datasets. As a result, each local government must navigate a lengthy, months-long utility data request process and often pay consultants to recreate data that already exists, all without a centralized portal or clear access point.
Key challenge discussed in - Statewide
For vehicle miles traveled there are concerns with state-provided data; that it may not fit locally preferred protocols, that it may still require local verification in order to be incorporated into plans, and that it may not provide the wanted granularity.
Key challenge discussed in - Statewide
Mistakes are made within the utility data that have major consequences on the planning process
Key challenge discussed in - Statewide
Data must be aggregated/scrubbed to preserve privacy per 15/15 rule, a risk/liability to local governments, which also masks subsector information sometimes needed at a small-scale local level.
UCLA paper describes problems with 15/15 rule and data masking
The associated barriers with being in compliance with the 15/15 rule was flagged throughout the listening sessions as a key commonly encountered barrier standing in the way of moving forward necessary planning efforts.
Key challenge discussed in - Statewide
Increase in Community Choice Aggregation (CCAs) creates potential for additional fracturing of the data – type of plan, and transition date information required in addition to IOU data
Local Solution Opportunities
SLECC stakeholders have brainstormed the following solution opportunities that can be taken by local leaders. Existing examples of progress or pathways to make further progress are highlighted if known.
Local Solution
A shared, centralized approach to GHG inventory production and data access should be established so that cities no longer need to recreate their own inventories. Inventory datasets should be compiled and transparently shared—whether by the state, counties, regional agencies, academic institutions, nonprofits, or consultants—using standardized methods and timelines to ensure consistency and reduce duplication.
Existing Examples of Progress:
1. A partnership between UC Berkeley (led by Chris Jones) and StopWaste is developing a simplified tool to prepare inventories to local jurisdictions at little to no cost. It includes equity indicators and will soon feature policy recommendation tools. Beta testing begins in February 2025, with walkthroughs and focus groups in March. 2. County-produced inventories are happening informally in some places, demonstrating a model to scale statewide. 3. UC Irvine is funded to inventory climate action plans and GHG inventories.
Further Progress Pathways
Region(s): San Francisco Bay Area, Statewide
Local Solution
Develop a consistent, scalable approach for local transportation emissions accounting by leveraging existing regional and state data sources.
Existing Examples of Progress:
"Metropolitan Planning Organization regional travel demand models" (gold standard, origin/destination, but not always available), other proxies: EMFAC in regions, use population to parse down to cities. Chris Jones at UC Berkeley uses fleet data allocated to tract level, rolled up to cities, can be done consistently Statewide. Highway Performance Monitoring System data through Caltrans, a consistently provided measurements in a systemic way each year, but it's a small snippet of what’s available in the VMT models
Further Progress Pathways
Region(s): Statewide
Local Solution
Strengthen regional data partnerships. Collaboration with universities (e.g., UC Riverside) and COGs participating in the Fifth Assessment can help translate complex datasets for practical local application, ensuring smaller cities aren’t left behind.
Existing Examples of Progress:
Further Progress Pathways
Region(s): Inland Deserts
State Solution Opportunities
SLECC stakeholders have brainstormed the following solution opportunities that can be taken by state leaders. Existing examples of progress or pathways to make further progress are highlighted if known.
State Solution
The state should build a unified, easy-to-navigate system for producing, standardizing, and sharing local GHG and energy data. This would include: A centralized statewide energy and GHG data portal—potentially by expanding existing platforms like the UCLA Energy Atlas to serve all regions and remain up to date, and by restoring free access to key tools such as ICLEI ClearPath for local jurisdictions. Standardized GHG inventory methods, timelines, and indicators statewide, ensuring that all jurisdictions work from consistent, comparable (“apples-to-apples”) data. Regularly produced and published local GHG inventories for every city and county, updated on a predictable statewide cycle to reduce duplication, support regional planning, and inform state policy.
Existing Examples of Progress:
1. Given the very high interest in a state-led process to conduct local GHG inventories , an effort was made in 2023 to propose State legislation that would allocate budget to CARB to produce local GHG inventories for local governments (SB-511), which was suspended after receiving an estimated total cost of $18 million from the Department of Finance. 2. Local government participants expressed that they are aware of many other data portals led by the State designed to provide data to local governments
Further Progress Pathways
Region(s): San Francisco Bay Area, Statewide
State Solution
Enhance public access and coordination of climate data resources. Integrate and streamline climate data tools across universities and agencies, ensuring key datasets are updated frequently and made easily accessible to support local planning and decision-making.
Existing Examples of Progress:
Cal-Adapt follows the global climate data cycle—updated roughly every 5–6 years—and that the state is developing evolving tools like the Vulnerable Communities Platform to “add new information as it’s available” and help planners align to the latest assessment data
Further Progress Pathways
Region(s): Inland Deserts, Statewide
State Solution
Conduct Analysis on Available Tools and Resources: A comparative analysis on existing GHG inventories, as proposed by CARB, could be valuable. It should assess all available and pending tools and evaluate factors that will make a tool valuable to local governments such as: transparency, consistency across jurisdictions and with leading GHG protocols, defensibility, and likelihood that a government entity will consider the tool provider and its data as credible and unbiased.
Existing Examples of Progress:
Further Progress Pathways
Region(s): Statewide
Solution Spotlight
UCLA’s Energy Atlas partners with Regional Energy Networks to Provide Access to Energy Data
The Bay Area Energy Atlas—one of the nation’s most comprehensive energy tools—has been revamped with new features, expanded data, and a more user-friendly interface. Developed by UCLA in partnership with BayREN, the Atlas helps users explore regional energy use through interactive maps and detailed building data. From policymakers to curious residents, anyone can now dive deeper into energy trends by city, building type, or time period. New tools make it easier to compare communities and visualize consumption with monthly data through 2021.
State support for UC Berkeley’s GHG Inventory Tool
The CoolClimate Network at UC Berkeley is developing a data platform for GHG inventories and climate action metrics for local governments across California. The project was presented at CCEC 2024 and 2025 to gather input from participants. The outputs available to cities and counties (unincorporated counties are in the works) include traditional and consumption based inventories from 2010-2022. They also feature tangible metrics such as EV registrations with the DMV and heat pumps installed through TECH incentives. These detailed metrics are more informative and actionable for implementation than overall GHG emissions. They enable local governments to set concrete targets and tell compelling stories about climate action, benefits, and potential impacts in their communities. The emphasis on these metrics reflects the emerging trends of climate action practice, which seeks to be more relatable to people and integrated with equitable community benefits.
The climate action data tool allows local governments to more efficiently conduct GHG inventories and evolve their climate action efforts and communications to focus on community benefits. The practice of local government climate action was originally established in the mid 2000’s in response to a lack of federal leadership. The current context calls us not only to continue but become more effective while delivering quantifiable social benefits and having the metrics to tell compelling stories.
CARB staff and contractors participate in the project’s advisory group and are evaluating whether this tool will meet the needs of local governments.
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