# Social Cost of Carbon and Social Cost of Methane

**Citation:** 4 CCR 723-4 Rule 4528  
**Type / status:** regulation / current  
**Agency:** Colorado Public Utilities Commission  
**Effective:** Not stated  
**Published:** Not stated

(a) The cost of carbon dioxide emissions shall be established by the Commission based on the most recent social cost of carbon dioxide developed by the federal government, in accordance with the following: (I) the cost of carbon dioxide emissions starting in 2020, shall not be less than the base cos

## Document text

(a) The cost of carbon dioxide emissions shall be established by the Commission
based on the most recent social cost of carbon dioxide developed by the federal
government, in accordance with the following:
(I) the cost of carbon dioxide emissions starting in 2020, shall not be less
than the base cost of $68.00 per metric ton in 2020 dollars;
(II) the Commission shall update the social cost of carbon values to the
present dollar year for each year after 2020 by applying an escalation rate
equal to or greater than the escalation rates established in the federal
technical support document.
(b) For net present value calculations of the social cost of carbon dioxide emissions,
the utility shall use a discount rate equal to the lesser of 2.5 percent or the
discount rate established by the federal technical support document.
(c) The cost of methane emissions shall be established by the Commission based
on the values set forth in the federal technical support document or on the federal
government’s most recent assessment of the global cost of methane as updated
to reflect the latest available values derived from peer-reviewed, published
studies, in accordance with the following:
(I) the social cost of methane emissions, starting in 2020, shall not be less
than the base cost of $1,756 per metric ton in 2020 dollars;
(II) the Commission shall update the annual social cost of methane emissions
values to the present dollar year for each year after 2020 by applying an
escalation rate equal to or greater than the escalation rates established in
the federal technical support document or the addendum to the 2016
federal technical support document if the social cost of methane is not
included in the federal technical support document; and

(III) the social cost of methane emissions shall use the best available leakage
rates to determine the methane emissions from fossil gas extraction and
processing, in addition to the greenhouse gas emissions identified in rule
4527, and consistent with § 40-3.2-107(2)(b), C.R.S.
(d) For net present value calculations of the social cost of methane emissions, the
utility shall use a discount rate equal to the lesser of 2.5 percent or the discount
rate established in the federal technical support document.
(e) For net present value calculations of portfolios of resources presented pursuant
to rules governing clean heat plans or any type of DSM plan, the utility shall also
present net present value calculations using the utility’s weighted average cost of
capital universally on all costs included within the relevant portfolio.

## Provenance

- Official: Yes
- Source: <https://www.sos.state.co.us/CCR/DisplayRule.do?action=ruleinfo&ruleId=2260&deptID=18&agencyID=96&deptName=Department%20of%20Regulatory%20Agencies&agencyName=Public%20Utilities%20Commission&seriesNum=4%20CCR%20723-4>
- Source ID: `co-sos-ccr`
- SHA-256: `51c29a3ebcb131e53269e24d350a961fab2fc86390f5cafb13c117e896a327c1`
- Retrieved: 2026-08-12T04:36:48.096Z
- Exported: 2026-08-23T22:10:21.197Z
- Document slug: `co-ccr-4-723-4-4528`

### Source metadata

```json
{
  "jurisdiction": "US-CO",
  "code": "4 CCR 723-4",
  "ruleKey": "4528",
  "pipelineScope": "colorado-jurisdictional-gas-utilities",
  "legalScope": "Current 4 CCR 723-4 rules regulating Colorado jurisdictional gas utilities and gas master-meter operators, including construction, operation, system safety, gas infrastructure planning, metering, service, and enforcement provisions. This is an adjacent gas-utility corpus, not a replacement for the repealed dedicated 4900-series pipeline-safety rules.",
  "applicabilityCaveat": "Part 4 applies according to Colorado Public Utilities Commission jurisdiction and each rule's scope. The former dedicated pipeline-safety rules 4900 through 4975 are reserved after repeal; this connector does not represent them as current. Part 4 does not replace federal pipeline-safety requirements, determine whether a facility is interstate or intrastate, or resolve operator-specific orders, waivers, tariffs, or later rulemaking.",
  "references": [],
  "ruleInfoUrl": "https://www.sos.state.co.us/CCR/DisplayRule.do?action=ruleinfo&ruleId=2260&deptID=18&agencyID=96&deptName=Department%20of%20Regulatory%20Agencies&agencyName=Public%20Utilities%20Commission&seriesNum=4%20CCR%20723-4",
  "pucRulesUrl": "https://puc.colorado.gov/gasrulesandregulations",
  "ruleVersionId": "12549",
  "editionEffectiveOn": "2026-06-14",
  "publicationStatus": "The Colorado Secretary of State identifies the source as the official publication of state administrative rules. The edition date applies to the compiled rule version and is not represented as the effective date of every provision.",
  "rights": "Official state rule text is preserved with attribution and source links. Public accessibility does not imply rights in agency marks, third-party material, or incorporated standards; commercial redistribution requires review.",
  "region": "CO"
}
```