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Renewable Natural Gas Project - Conclusions & Recommendations

General - RNG

  1. Create a renewable natural gas procurement program for California’s natural gas corporations

    To ensure that California achieves its fugitive methane reductions and renewable energy and climate change objectives it is of some urgency that a viable market alternative to the federal RFS is created that will attract the investment capital necessary to develop RNG production facilities in-State. To this end long-term procurement requirements should be set for certain gas corporations to create RNG market certainty and bolster investor confidence. This would be analogous to the long-term Power Purchase Agreements that catalyzed large scale solar deployments and would include, for example, contract terms of at least ten totwenty years and a price schedule that supports project development and ensures adequate cost containment and ratepayer protections.

  2. Ensure cooperation between different government entities for the adoption of unified standards to meet the goals of SB 1383

    It is crucial to establish that all relevant agencies are closely aligned and on the same timetable with regards to meeting the goals of SB 1383. Often, RNG production facilities face obstacles because of the considerable differences between the permitting processes in different parts of the state. We recommend the creation of statewide standardized permitting templates for RNG production facilities with the potential for automatic approvals for technologies that have been approved as best available technology (BAT) in one region to be approved in other regions. A task force could be created to identify and resolve conflicting regulations, eliminate or modify outdated specifications or requirements, and form a database for approved equipment, designs, processes, and procedures. These measures would lead to an expedited permitting process for RNG projects.

  3. Revisit regulations for RNG pipeline injection standards

    Research has found that the siloxane and minimum heat standards for RNG pipeline injection in California are so stringent that they often become unattainable. Furthermore, the existing fossil gas in California’s pipelines can often fail to meet the specifications set for RNG. Consequently, RNG that has been conditioned and could improve the quality of and decarbonize the gas in the pipeline - is being rejected. While additional research is still needed to identify what the standard limits should be, overly stringent standards, effectively prohibit the injection of RNG into California’s common carrier pipelines.

  4. Increase capacity for RNG by incentivizing the conversion of diesel fleets and increased deployment of medium- and heavy-duty natural gas vehicles to be fueled by RNG

    It would be very useful to involve all stakeholders (engine & truck manufacturers, truckers/haulers, regulators, CNG/RCNG providers, etc.) in a detailed review of the advantages and the disadvantages of converting diesel trucks and fleets to Low-N0x natural gas engines fueled by RNG. Once this report has been created, strategies to overcome barriers of diesel conversion to natural gas engines can be developed. Furthermore, initiatives and incentives to upgrade state, county, city, and municipal fleets can be created. Finally, in order to allow the conversion of diesel fleets to CNG vehicles fueled by RNG, it is necessary to resolve issues surrounding the expansion of on-site, private and public CNG fueling stations.

  5. Guarantee the value of RINs and other financial incentives

    One of the largest obstacles impeding RNG adoption is the financial precarity of the RIN market, which is susceptible to non-negligible price fluctuations. Stability in RNG values would encourage investment in RNG. Guaranteeing a RIN price would require changing the underlying legislation, which is unlikely. Other efforts could be made to advocate pathways that would accomplish the same thing. The LCFS has been helpful in providing a “fallback” price and a feed-in-tariff or partial or full loan guarantees on project investments made (relying on the RIN value) may be able to reduce the risk to financial investments.

  6. Encourage co-digestion

    Co-digestion of different types of feedstock has proven to significantly improve the efficiency of anaerobic digesters and increase the production of biogas as a feedstock for RNG. However codigestion is a complex process that would benefit from further research, especially given the fact that when done incorrectly, co-digestion can worsen the performance of anaerobic digesters. For it to be successful, it’s important that the feedstock composition remains consistent. Aside from further research to perfect co-digestion strategies, it is also crucial to financially incentivize codigestion. An important obstacle to wider use of co-digestion is that it alters the RIN (credit) category and market value of the RNG it produces. Allowing RNG created from co-digestion to qualify for the RIN category (D3, D5, etc) given the proportion of each category of feedstock within the digester would solve this problem and encourage co-digestion. Such a measure would be crucial to encourage wastewater treatment plants to accept food waste, and therefore an important step in diverting organics from landfills.

  7. Establish a viable “eRIN” pathway in the RFS

    The RFS allows for the possibility of creating RINs through the combustion of biogas that generates electricity for charging EVs. However, all applications for pathways of this nature have been unsuccessful. Since electricity generation is one of the most common uses for biogas and there is a rapidly growing number of EV fleets, the EPA should collaborate with industry players to resolve the issues with the “eRIN” pathway. This would help the RFS spur even more investment in biogas energy projects.

  8. Provide grants and subsidies for emissions cleaning to prevent flaring

    Flaring biogas is a common practice because it is a relatively cheap and easy way to clean up biogas and curb harmful atmospheric emissions. However, it is a waste of a biofuel that could be used in place of fuels like diesel and coal that have much worse environmental impacts. Introducing grants or subsidies for technologies that would allow biogas-producing facilities currently flaring to instead harness the biogas energy and still pass local air quality standards could prove helpful in this effort.

  9. Support the development of advanced technologies to increase methane capture, and increase biogas-derived RNG production from existing facilities

    Many existing facilities have the capacity to substantially improve their methane capture methods and increase their RNG production. Financial and technical support should be provided by federal, state, and local agencies to upgrade already existing RNG production facilities such as landfills, waste water treatment plants, dairy farms and other livestock operations with digesters, etc.

Organics Diversion

  1. Create a quick, streamlined permitting process for new ADs and composting facilities

    It is estimated that 100 new composting and AD facilities will need to be constructed for California to meet its goal of 75% organic waste diversion. A faster, easier permitting process is necessary for all of these new facilities to be built on SB 1383’s aggressive timeline.

  2. Optimize organic waste management based on a map of current and potential waste streams and waste treatment facilities

    It would be useful to create a statewide map identifying current and potential organic waste streams as well as current AD and composting facilities. This map could be used to optimize the process of directing organic waste streams to the appropriate AD or composting facility, while minimizing transportation and the costs associated with it. Furthermore, it could be used to identify areas which lack the necessary infrastructure and inform the placement of new facilities or identify existing facilities that could increase their capacity through retrofitting.

  3. Create a detailed timeline for retrofits, new construction and permitting

    Based on the map outlined in the point above, it would also be useful to develop a detailed timeline, bearing in mind SB 1383’s goals, to establish when and where retrofitting and new construction should occur. This timeline will provide government agencies a useful outline to establish when and where their efforts are most needed.

  4. Develop impactful programs to reduce contamination of organic waste streams

    One of the most crucial aspects of organics diversion is source separation. Facilities that receive source-separated organics with low contamination rates are able to produce more biogas and/or higher quality compost. There are many ways to incentivize effective waste separation. One idea would be to install cameras in waste collection trucks to enable rapid customer feedback and education using real-time waste analysis. Households or commercial units with contamination rates higher than a certain percentage could be sent warning emails with recommendations on how to lower their waste contamination. Fines could be issued to repeat offenders. Alternatively, waste management facilities could implement a sliding scale for tipping fees depending on contamination rates. Another very important aspect of the effort for reducing contamination fees is education outreach, particularly at a young age. This could take the form of obligatory school field trips to waste management centers. Further research should be conducted on how best to educate communities on the importance of source separation. Methods of putting the onus of these measures on haulers should be explored since they enjoy the highest profit margins in the waste management industry.

  5. Encourage and financially incentivize compostable packaging and compostable alternatives to single-use plastics

    One of the most effective ways to keep waste out of landfills is to design the products we use to be disposed of in an environmentally friendly manner. When it comes to diverting organics, one useful measure would be to financially incentivize the production and use of compostable packaging and compostable alternatives to single-use plastics, such as utensils and cups.

  6. Encourage WWTPs to accept food waste into their ADs

    As mentioned before, co-digestion presents a lot of potential for increased efficiency and RNG production. Currently, few WWTPs are accepting food waste for co-digestion because of the variability it can introduce to the process. The inconsistent food waste feedstock could have adverse effects on biogas production. Therefore, continued research on co-digestion in WWTPs is necessary to determine the methods and technologies needed to optimize this process. The results of this research would inform estimates of cost, permitting requirements, and RNG offtake options for upgraded wastewater treatment plants.

  7. Redirect green waste to compost facilities and food waste to ADs

    It is important to recognize that not all organic waste is best used in the same way. While food waste is the ideal feedstock for ADs, green waste should be directed immediately to compost facilities.


  1. Identify potential pipeline interconnection and injection sites for large dairy operations

    RNG potentials for all dairy farms need to be identified in order to determine the viability of
    either direct pipeline injection from single dairies or from dairy clusters. The clustered model
    involves dairies that are close to each other individually collecting their biogas and trucking it to a
    central location where it is processed and then injected into the pipeline. This method needs to
    be studied further in order to be optimized.

  2. Encourage the co-digestion of manure from dairy farms with organic waste

    There is a large opportunity for greater biogas production at a higher quality when food waste is
    combined with manure inside the bio-digester. Consequently, opportunities for partnerships
    between dairy farms and surrounding restaurants or other food processing operations should be
    explored. This could help improve the economics of a biogas energy project. It would also
    provide a nearby sink for organic waste streams.

  3. Create an expedited project approval and permitting process for biogas energy projects at

    The regulatory burdens that are currently placed upon dairies paired with the financial difficulties
    many of them are already facing are preventing many farms from becoming involved in the RNG
    and biogas capture industry. These regulatory burdens should be minimized to encourage the
    formation of new infrastructure and dairies’ involvement in the industry, specifically through the
    creation of an expedited project approval and permitting process.

  4. Expand the loan and grant programs available for biogas projects for agricultural and rural

    There needs to be greater financial opportunities for smaller dairies and businesses who wish to
    invest in digesters at both the state and federal level. This would allow the dairies who are
    currently unable to enter the market because they lack the necessary capital for building the
    initial infrastructure for biogas energy projects to get involved in the biomethane industry.

  5. Research methods to reduce methane emissions from cattle

    Although research is already in place to find ways to reduce the methane emitted from cattle,
    further study should be conducted. Cattle diet has already shown significant promise in
    decreasing such emissions and should be given particular attention.