Get answers about interconnecting biomethane to PG&E’s pipeline

What is biomethane?

Biomethane is like natural gas except it comes from renewable sources. Major sources include non-hazardous landfills, dairies and wastewater treatment plants. When organic waste from those sources decomposes without oxygen, it creates what is called "biogas." The biogas can be processed into biomethane and made safe for injection into pipeline systems or to generate electricity.

When raw methane from organic sources is emitted into the atmosphere instead of being converted to biomethane, it’s a major source of greenhouse gases. Capturing it as biomethane and injecting it into pipelines can reduce greenhouse gases and help California meet its environmental goals.

What financial incentives are available for biomethane interconnection projects?

The State of California provides financial reimbursements to offset biomethane developer pipeline interconnection costs. Under Assembly Bill 2313, these reimbursements can be up to 50% of the interconnection costs or $3 million per project, whichever is lower. If a project involves a cluster of dairy farms, the reimbursements can be up to 50% of the interconnections costs or $5 million, whichever is lower. Reimbursements for biomethane interconnection costs are implemented by the California Public Utilities Commission (CPUC) decisions and policies and carried out by regulated investor owned gas utilities like PG&E. In December 2020, the CPUC approved adding an additional $40 million of Cap-and-Trade allowance proceeds to the biomethane monetary incentive program.

What could impact my interconnection project with PG&E?

PG&E works with biomethane project developers to examine the following four factors:

Location - Long distances can increase costs and permitting requirements.

Capacity - Need sufficient room (capacity) in the pipeline to receive the biomethane.

Pressure - PG&E must ensure injecting biomethane is done safely and within acceptable pressure ranges at the point of injection.

Gas demand - Customer gas demands on the pipeline must be adequate and stable to accept the continuous supply of injected biomethane from the proposed project.

Go to interconnecting biomethane

What is the interconnection process?

Estimated costEstimated time
1. Interconnection Screening Study

No cost

Up to 15 business days

2. Preliminary Engineering Study


Up to 90 business days

3. Detailed Engineering Study and Construction


up to 180 business days

*Project costs will vary depending on project scope, the season in which construction occurs and on details associated with the project location (e.g., environmentally sensitive areas, railroad or major road or highway crossings, etc.).

For the Interconnection Screening Study, PG&E will provide:

  • Location of the nearest gas pipe system that can accommodate the supply volume without restriction
  • Maximum Allowable Operating Pressure (MAOP) and Normal Operating Pressure (NOP) of that gas pipe system
  • Estimated length of pipe needed to interconnect a producer’s biomethane supply
  • The takeaway capacity of the pipe system closest to the upgrading facilities

For the Preliminary Engineering Study, PG&E will provide:

  • Confirmation that the identified pipe can receive the proposed supply 24X7
  • An AACE Class 5 estimate for point of receipt and pipeline interconnection facilities**
  • Route, Land, Permitting Assessment including a route walk with the developer

** American Association of Cost Estimators Class 5 estimate is based on an accuracy range of +100%/-50%.

For the Detailed Engineering Study and Construction, PG&E will provide:

  • Project schedule and cost estimate updates at 30%/60%/90% design phases
  • Interconnection contract at completion of design based on final cost estimate

What is the heating value (aka BTU requirement) for PG&E to accept biomethane?

Because the heating value varies across the PG&E system, PG&E does not specify a heating value number. Per PG&E’s Gas Rule 21, “the gas shall have a heating value that is consistent with the standards established by PG&E for each Receipt Point.” For each project request, PG&E will review the provided heating value content of the new gas supply and the estimated delivery volumes in order to determine if the gas supply can be safely received into the pipeline at the project receipt point. Blending studies may be performed by request but at actual costs to the Interconnector. 

What are the biomethane gas quality requirements?

PG&E’s gas quality requirements are specified in its tariff Gas Rules 21 & 29. The California Public Utilities Commission (CPUC) approved gas quality standards for renewable natural gas (biomethane) in 2014 as recommended by the California Air Resources Board (CARB) and Office of Environmental Health Hazard Assessment (OEHHA) to protect human health and safety. These important gas quality standards were vetted in an extensive three-year long public process involving environmental, regulatory, developer and utility stakeholders.

Who can I contact at PG&E to discuss interconnecting my biomethane project? If you want to interconnect a biomethane project to our gas system, please complete the Request for Gas Supply Interconnection and send via e-mail to

Download the Interconnection Fact Sheet (PDF, 885 KB)