Luna, Becky

Becky Luna is a Senior Vice President and Project Manager with Carollo Engineers and also serves as the Client Servies Director for the Midwest...

Joined:

About Luna, Becky

Becky Luna is a Senior Vice President and Project Manager with Carollo Engineers and also serves as the Client Servies Director for the Midwest Region. She obtained a B.S. in Civil Engineering and an M.S. in Civil and Environmental Engineering from the University of Illinois at Urbana-Champaign. Becky has 19 years of experience in the evaluation, design, and construction of municipal wastewater treatment facilities. Her primary areas of focus have been in solids handling and biogas facilities. She has worked with multiple municipalities to evaluate options for beneficial use of digester gas, including the analysis of procurement and construction delivery methods. She has implemented biogas upgrading facilities at several utilities to convert digester gas to renewable natural gas for pipeline injection and for use as vehicle fuel.

Luna, Becky

Titles from this speaker

Comparison of Life Cycle Costs at Operating Cogeneration and RNG Facilities

Abstract

An increasing number of water resource recovery facilities (WRRFs) are considering options for beneficial use of biogas due to an increasing focus, both internally and externally, on resource recovery and sustainability. Conversion of biogas to electricity (through cogeneration) and to renewable natural gas (RNG) (for pipeline injection or vehicle fueling) are often considered side by side as alternatives that can produce revenue and reduce the greenhouse gas footprint of WRRFs. While there are a large number of WRRFs across the country that have operated cogeneration systems over the last decades, operating costs can vary significantly depending upon the technology selected, condition of the raw biogas, and age of the system. In addition, while the technology used to convert biogas to RNG is established, pipeline injection and vehicle fueling projects remain relatively few and far between in the U.S. These unknowns make it difficult to quantify O&M costs for utilities considering a biogas utilization project. This complicates the evaluations of these systems, since long-term operating and maintenance (O&M) costs are a significant factor in selection of a recommended alternative.

The conversion of biogas to electricity through cogeneration or to renewable natural gas (RNG) for pipeline injection or vehicle fueling has received increasing interest at water resource recovery facilities (WRRFs). For both uses, operation and maintenance (O&M) data from facilities is limited, making it difficult for WRRFs to accurately assess life cycle costs. WRRFs often rely on O&M costs provided by manufacturers. This paper compares manufacturer O&M cost estimates to operational data at ten facilities that run either cogeneration or RNG upgrading facilities and finds that actual O&M costs are higher than manufacturer O&M estimates, despite conservative assumptions.

SpeakerLuna, Becky

Presentation time

13:45:00

14:00:00

Session time

13:30:00

14:30:00

SessionBiogas: Market-based Decisions for Resource Recovery

Session number507

TopicBiosolids and Residuals, Energy Production, Conservation, and Management, Policy and Regulation

Author(s)

Becky Luna

Author(s)B.J. Luna2; T.G. Mossinger3; T. Dougherty4;E. Charbonnet1;

Author affiliation(s)Carollo Engineers, Broomfield, CO 1,2,4Carollo Engineers, Portland OR3

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2021

DOI10.2175/193864718825158136

Volume / Issue

Content sourceWEFTEC

Word count12

Description: Maximizing Operator Involvement Through CMAR: Keeping Avon WWTF Running Through 3...

Maximizing Operator Involvement Through CMAR: Keeping Avon WWTF Running Through 3 Years of Construction

Abstract

Eagle River Water and Sanitation District’s (ERWSD) $49.6M Nutrient Upgrades Project at the 4.3 million gallon per day (mgd) Avon Wastewater Treatment Facility (WWTF) implemented a plan for sequencing nutrient removal improvements at the three interconnected WWTFs. Key challenges for this project included: 1) maintaining effluent permit compliance with units out of service while handling seasonal loading peaks, 2) improving access to underground and inaccessible aeration basins while maintaining structural integrity, and 3) sequencing work while mitigating impacts to neighbors. The project was delivered using the Construction Manager at Risk (CMAR) model, with collaboration from key team members at Moltz Construction, ERWSD, and Carollo. The Avon project, which achieved substantial completion in May 2023 after five years of planning, design, and construction, serves as a strong example of the value of operator involvement and CMAR delivery in maintaining operations during construction.

The Nutrient Upgrades Project at Avon WWTF (near Vail, Colorado) faced key challenges: 1) maintaining compliance with units out of service while handling seasonal loading, 2) improving access to underground basins while maintaining structural integrity, and 3) sequencing work while mitigating impacts to neighbors. The project achieved substantial completion in May 2023, serving as a strong example of the value of operator involvement and CMAR delivery in operations during construction.

SpeakerBerlin, Jeffrey

Presentation time

10:30:00

11:00:00

Session time

10:30:00

11:30:00

SessionProject Delivery Challenges: Continued Operations and Commissioning

Session locationRoom S404c - Level 4

TopicFacility Operations and Maintenance, Intermediate Level, Municipal Wastewater Treatment Design, Utility Management and Leadership

Author(s)

Berlin, Jeffrey

Author(s)J. Berlin 1; T. Drescher 2 ; B. Luna 1; J. Berlin 1;

Author affiliation(s)Carollo Engineers, Inc. 1; Eagle River Water and Sanitation District 2 ; Carollo Engineers, Inc. 1; Carollo Engineers, Inc. 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159185

Volume / Issue

Content sourceWEFTEC

Word count15

Policy Outlook Informs Sensitivity Analyses of Biogas Alternatives

Abstract

Introduction After four decades of operating a cogeneration facility to produce electricity and heat, Metro Water Recovery (Metro) commissioned a Biogas Utilization Study in 2021 to consider historical and new beneficial uses of biogas at their Robert W. Hite Treatment Facility (RHWTF) that serves Colorado's Denver metropolitan area. While cogeneration has been the industry standard for biogas utilization at water resource recovery facilities (WRRFs) for decades, biogas upgrading to renewable natural gas (RNG) has become more prevalent due to federal incentives available under the Renewable Fuel Standard (RFS) program created under the Energy Policy Act of 2005. And while the RFS program has been the historic driving force behind the shift to RNG, a drive by major companies to reduce the carbon footprint of their operations are leading to further incentives for biogas, potentially mitigating the risk of relying on a single revenue stream. This study investigated two alternatives for beneficial reuse of the biogas resource at Metro's RWHTF: - Upgrade and continue to operate the Cogeneration Facility to generate electricity and heat using biogas. - Construct a new facility that converts biogas into RNG for direct injection into a natural gas pipeline owned by Xcel Energy (Xcel) and monetize the RNG. While WRRFs across the country have embarked on similar evaluations; this project was unique in that it included an in-depth evaluation of the long-term viability of financial incentive markets, sustainability impacts, future natural gas demand, and the potential impact from current and future state policies. This evaluation was then used to inform sensitivity evaluations of the two alternatives to facilitate decision making. Monetizing RNG The study evaluated four pathways for Metro to generate a revenue source from their RNG. These revenue sources included: 1. Sale of brown gas, 2. Participation in the Renewable Fuel Standard (RFS) program, 3. Participation in state-specific Low Carbon Fuel Standard (LCFS) programs, and 4. Participation in the voluntary market. The sale of brown gas is typically tied to regional natural gas indices, with revenue calculated based on the amount of gas injected into the natural gas utilities' pipeline. The sale of brown gas can be paired with renewable credits as shown in Figure 1. The study evaluated the long-term viability of the RFS program, considered the potential for an LCFS program in the State of Colorado, state legislature geared towards the reduction of the carbon footprint of building heat, and reviewed the strength of voluntary markets. The renewable volume obligations (RVO) under the RFS are set to expire at the end of 2022, and members of Congress have voiced support for the replacement of the RFS with a national LCFS program (similar to California) that provides incentives for a wider range of low carbon fuels. To date, there remains a significant gap in RNG supply to meet the originally planned renewable volume obligations. Whether the RFS program is continued or replaced by an LCFS program, it is anticipated that a system of federal renewable credits will remain in place for the foreseeable future for RNG. The viability of an electric renewable identification number (e-RIN) pathway was also considered; however, the EPA has not approved any such project, despite receiving approval requests. The Colorado Energy Office recently evaluated the viability of an LCFS program for the State of Colorado. This report (Low Carbon Fuel Standard Feasibility Study, September 2020, ICF Resources, L.L.C.) stated that, 'Experience in California, Oregon and British Columbia has shown that LCFS programs can deliver on the above policy objectives, and that LCFS programs are a cost-effective mechanism to reduce GHG emissions and increase the share of lower carbon fuels in the transportation sector, while having a smaller cost impact on retail fuel prices relative to other decarbonization policies.' No movement has been made to date by the State legislature to introduce such a program. Many corporations and utilities have established 'carbon-free' energy goals, which has created a voluntary market for RNG. Due to the higher RIN pricing, increasing RNG demands in the voluntary markets have resulted in increasing value and revenue potential. Table 1 shows the pricing variability for the voluntary markets and illustrates the increases in the market based on current conditions and drivers towards RNG sustainability goals. Long-term Natural Gas Demand As the energy sector transitions to meet renewable energy goals, there is increasing demand for natural gas that is anticipated to continue through 2050. The U.S. Energy Information Administration (EIA) projects increasing demand for compressed natural gas (CNG) over the next 30 years at 1 percent compounded annually. CNG demand is also expected to remain strong in the transportation sector, despite the focus on electrification of light-duty vehicles. CNG continues to be the major fuel source for heavy-duty vehicles. Figure 2 expands on the uses of CNG in the transportation sector and demonstrates there is a steady increase in CNG consumption through 2050. As Xcel, the local electric and natural gas utility, further develops their renewable energy portfolio to meet their 2050 carbon-free electricity goals, natural gas is anticipated to remain the backbone of reliable energy sources and backup emergency power for the next 20 years. State of Colorado Policy Impacts The State of Colorado is targeting a reduction of greenhouse gas emissions by 90 percent of the 2005 values by the year 2050. Legislation approved in 2021 requires natural gas and electric utilities (i.e. Xcel) to reduce the use of natural gas by consumers. Xcel could purchase RNG from Metro to decrease the reliance on natural gas. While a cap-and-trade program introduced this year was vetoed by the Governor, the Public Utility Council is currently reviewing a means of implementation for the legislation which could include an avenue for RNG. Alternatively, Metro could decide to pursue this type of program on a voluntary basis with other states or utilities that have existing programs. While the State has evaluated different types of RNG legislation and potentially creating their own LCFS program, nothing has materialized that would influence Metro's decision on which biogas alternative to move forward with. Variability of Utility Costs Electricity and natural gas costs are large operating expenses for Metro's annual budget. Pricing volatility for electricity and natural gas could impact either of the biogas alternatives. The EIA forecasts that increasing renewable energy capacity will result in a slight decrease of electrical rates through 2050. However, regional differences will occur based on the level of renewable energy in the regional electric utility's portfolio. According to the EIA, natural gas pricing fluctuates based on weather, economic growth, market competition, gasoline prices, and availability. Figure 3 illustrates the yearly average Henry Hub natural gas spot pricing. Sensitivity Evaluations Sensitivity analyses were developed to capture the financial viability of both alternatives based on the changing future conditions described above. Figure 4 presents the range of life cycle costs for the cogeneration alternative, with consideration of changing electricity prices and renewable electricity credit value. Figure 5 presents the range of life cycle costs for the pipeline injection alternative, with consideration of RIN pricing, voluntary market, and natural gas market volatility. Based on the sensitivity evaluations, the pipeline injection alternative in almost all cases provides a positive financial return to Metro when compared to the cogeneration alternative. The pipeline injection alternative has a simple payback of 3 to 10 years depending on the revenue model. When comparing the base case alternatives, pipeline injection has a 20-year net present value that is $205 million higher than the cogeneration alternative. Based on the recommendations of this study, Metro is planning to proceed with preliminary design and development of a biogas upgrading and pipeline injection system.

This paper was presented at the WEF Residuals and Biosolids Conference in Columbus, Ohio, May 24-27, 2022.

SpeakerLuna, Becky

Presentation time

8:30:00

9:00:00

Session time

8:30:00

11:45:00

Session number08

Session locationGreater Columbus Convention Center, Columbus, Ohio

TopicBiosolids, Finance, Renewable Natural Gas

Author(s)

B. Luna

Author(s)B. Luna1; B. Wisdom2; D. Pier3; A. Norford4

Author affiliation(s)Carollo Engineers; 1Metro Wastewater Reclamation District; 2Carollo Engineers; 3Metro Water Recovery; 4

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May, 2022

DOI10.2175/193864718825158381

Volume / Issue

Content sourceResiduals and Biosolids

Word count9

Base text size -

Luna, Becky

About Luna, Becky

My Recent Activity