UC San Diego Hydrogen Blending Project

This demonstration project will assess the feasibility of blending carbon-free hydrogen into the natural gas distribution system to help achieve regional and state decarbonization and climate goals.

Replacing fossil fuels with carbon-free fuels is a crucial step towards reaching the goal of carbon neutrality. UC San Diego and San Diego Gas & Electric (SDG&E) are collaborating on this project to demonstrate that hydrogen can be safely and effectively blended into the natural gas distribution system resulting in reduced consumption of fossil fuels and greenhouse gas emissions.

The project will assess the amount of hydrogen (up to a maximum of 20% by volume) that can be blended into the natural gas stream without any impact to typical equipment and materials found in California’s gas infrastructure. Detailed data will be collected by SDG&E regarding operational performance and impact on materials. The findings will be utilized to inform the California Public Utilities Commission (CPUC) and other stakeholders in the development of a systemwide hydrogen blending standard.

Hydrogen (H2) is a carbon-free, gaseous energy carrier. Through the process of electrolysis (splitting water into hydrogen and oxygen) resulting hydrogen can be injected into the existing natural gas pipeline infrastructure, and the resulting gas blend can be used to generate heat and power with lower emissions than using natural gas alone.

Pending approval by the CPUC, development and design activities are planned to start in Q2 2023, construction in Q2 2024, and hydrogen blending would occur between Q4 2024 and Q1 2026. The site would be fully restored to its original conditions by Q3 2026.

SDG&E will temporarily site hydrogen equipment on campus, including an electrolyzer to produce clean hydrogen from water, a gas blending skid, and a hydrogen storage tank.

The specifications for the planned equipment have undergone rigorous audit by SDG&E, ensuring they meet required national and international hydrogen safety and operational standards.*

Further, a safety assessment for all hydrogen equipment will be conducted by an external hydrogen safety consultant during the planning and design phase of the initiative.

After the project is completed, this equipment will be removed, and the site will be restored to its original condition.

* International standard for hydrogen generators using water electrolysis; National Fire Protection Association standard for hydrogen safeguards for the generation, installation, storage, piping, use, and handling of hydrogen in compressed gas form.

Project safety is top priority. We do not anticipate any changes to current UC San Diego safety and emergency practices. During the time of operation, SDG&E will closely monitor the distribution system feeding the common building gas appliances, which are owned by UC San Diego. Pre-, during and post-project safety protocols include:

• A hydrogen system safety assessment, as well as hydrogen safety training for SDG&E personnel, campus fire marshal, and other relevant UC San Diego campus personnel conducted by independent third parties specializing in hydrogen safety.
• Testing of existing and new leak survey equipment and recurrent leak surveys by SDG&E.
• Equipment inspections by SDG&E.
• Gas system operational and equipment tests, meter replacements, and other operational activities that SDG&E performs in a natural gas distribution system.

Any additional project-specific protocols and emergency response plans will be developed and disseminated in advance of the project.

Earthquake and wildfire hazards have been considered, and the equipment will meet appropriate standards related to these risks.*

* Seismic codes of the International Building Codes and California Building Codes; American Society of Mechanical Engineers codes and standards for hydrogen service; National Fire Protection Association standard for the storage, use, and handling of compressed gases and cryogenic fluids in portable and stationary containers.

The natural gas in the hydrogen blend used in this project contains the same odorant as traditional natural gas. We do not anticipate a change to gas odor. Following the best practices of the Plan-Do-Check-Act model, SDG&E will perform monthly odorant sampling to confirm that hydrogen does not affect the efficacy of current natural gas odorant. Additionally, leak surveys of all project equipment will be performed monthly by SDG&E, and as needed per customer requests.

There is no anticipated disruption to any gas services throughout the entire duration of the project.

SDG&E and UC San Diego have independently conducted noise evaluations for equipment operations during the project. The project will comply with code levels for areas classified as noise sensitive for nearby facilities. Furthermore, the project equipment does not operate continuously, and should any issue arise, the hours in which it operates can be set to certain periods. 

No, but it will be the first in San Diego.

Blending of up to 20% hydrogen into natural gas has been previously demonstrated by SoCalGas in end-use appliances in a laboratory and blending within a university’s gas distribution system has previously been demonstrated with great success in the UK.

This UC San Diego-SDG&E real world demonstration project has been modeled after these other successful evaluations and pilot projects. Further, the data and information gathered from the project will fill important knowledge gaps toward long-range decarbonization efforts. Hydrogen blending into California’s natural gas pipeline infrastructure can potentially help accelerate the transition toward the use of clean hydrogen as a fuel and energy storage medium, and help the state meet a number of climate and air quality goals. This project builds on the latest search: The Hydrogen Blending Impacts Study commissioned by the California Public Utilities Commission and performed by UC Riverside. The study recommends utilities conduct “real world” demonstrations utilizing the actual natural gas infrastructure with 5-20% hydrogen gas blends over extended periods to assess the effect of hydrogen on materials, components, facilities, and equipment through California’s infrastructure.

Education, outreach, and survey materials will be coordinated in conjunction with UC San Diego throughout all phases of the project to ensure communications are timely, meaningful, and address concerns.

Questions on the project can be directed to [email protected].

Hydrogen used in this study will be produced onsite via a dedicated, grid-connected electrolyzer (splitting water to produce hydrogen and oxygen).