Our methodology for comprehensive tracking of public and private investments in the manufacture and deployment of clean technologies is detailed below. 

The Clean Investment Monitor seeks to catalog, in a methodologically consistent manner, investment in the manufacture and deployment of GHG emission-reducing technologies across the U.S. There are a wide range of technologies that have the potential to reduce GHG emissions, and each of those technologies has a wide range of input components. For analytical tractability and comparability of investment data over time, the CIM includes those technologies that are eligible for tax incentives under the Inflation Reduction Act (IRA). The table below includes a detailed list of the technologies currently included in the CIM with the corresponding provision of the U.S. tax code under which they receive incentives.

To create a historical baseline against which to assess recent clean investment developments in the U.S., the CIM includes all investments in our covered technologies since 2018. This results in a database with roughly 20,000 individual facilities, 3 million zero-emission vehicle (ZEV) registrations, 20 million heat pump sales, and 4.5 million distributed electricity generation or storage installations as of Q2 2023. All investment figures are in 2022 U.S. dollars.

How we categorize investment

When the Bureau of Economic Analysis (BEA) reports overall investment trends for the U.S. economy, they capture both investment in structures and equipment (like factories), as well as the purchase of durable consumer goods (like automobiles). We have taken a similar approach with the CIM, for comparability to BEA aggregate investment data. We break out clean investment into three “segments”: investment in the manufacture of GHG-reducing technology (“Manufacturing”), and investment in the deployment of that technology, both to produce clean energy or decarbonize industrial production (“Energy and Industry”), and through the purchase and installation of that technology by individual households and businesses (“Retail”).

For the Manufacturing and Energy and Industry segments, we track investment at the individual project level through a combination of third-party data sources, company announcements and financial filings and news reports. Projects are monitored from initial announcement through construction to operation. We only include projects as “announced” in our database when a specific location and timeline for the project has been specified, and, in the case of larger projects, Front-end Engineering Design (FEED) work has begun. When project investment amounts are reported by the company, we use those in the CIM; otherwise, we estimate investment amounts using reported project-specific technology and capacity/production information and an investment cost model calibrated with recent data from comparable projects. Total investment costs are spread over the life of the reported construction period. When construction timelines are not available, they are estimated based on average construction times for similar projects.  To see how announced investment amounts are distributed over time, see figures 2 and 4 in our inaugural report.

For the Retail segment, we rely on third-party state-level data. For ZEVs, we combine state-level vehicle registration data by make and model from S&P Global with MSRP data from, and other sources. For heat pumps, we downscale national sales data from the Air-Conditioning, Heating and Refrigeration Institute (AHRI) and the federal Energy Star program to the state level using the Energy Information Administration’s (EIA) Residential Energy Consumption Survey. We estimate investment cost using data from the EIA. In the case of distributed renewable electricity generation and storage, we use state-level installation data from the EIA and installation cost data from the National Renewable Energy Laboratory (NREL). For Retail, we treat all investment as occurring in the quarter in which the registration, sale or installation is reported.

Technologies included in the Clean Investment Monitor

The table below provides a detailed breakdown of the technologies currently included in the CIM database, along with the corresponding section of the tax code under which they receive incentives.

Our methodology in depth

More information about our methodology in depth is available at the link below.