Taste of Victory

Motivated by a zero-waste commitment, Gills Onions LLC, Oxnard, Calif., embarked on an industry-first sustainability journey that began to really take flight in 2005.

As the nation’s largest fresh-cut onion processor, the company was facing several challenges in the areas of onion waste management and energy usage.

At the time, Gills Onions was processing 0.8 million pounds of onions per day, generating 200,000 pounds of onion peel waste and 200,000 gallons of wash-down wastewater each day.

The onion peel waste was being applied to fields, incurring extensive costs for hauling and insurance, while also posing risks for soil and groundwater contamination. In addition, the electrical requirements to operate the company’s 100,000-square-foot processing and refrigerated warehouse space equated to a base load of 0.8 megawatts (MW) and an average annual spend of more than $1.4 million.

Two Problems, One Solution
Gills Onions’ desire to reduce both waste and energy usage led them to collaborate with University of California, Davis to explore new ways to repurpose the waste rather than simply disposing of it.

This exploration included testing the anaerobic digestion of onion juice. The results of those tests proved that onion juice was, in fact, easily digestible and presented an opportunity for the company to self-generate power using biogas produced through the anaerobic digestion process.

Choosing to partner next with HDR Inc., a multi-national engineering firm based in Omaha, Neb., the two companies put a team of engineers and contractors in place and moved ahead with a full-scale plan.

The process involved the evaluation of several technologies and equipment for the final system components, research and supporting documentation for permitting with the City of Oxnard and the Ventura County Air Pollution Control District (VCAPCD), and all aspects of the mechanical, civil, process and controls engineering design.

The team selected Netherlands-based Biothane to design and build an anaerobic digester custom-designed for processing the onion juice. The team also discovered an industrial fuel cell technology by FuelCell Energy of Danbury, Conn., that was selected to convert the methane into energy. The process behind the cleaning and conditioning of the resulting methane was led by the Gas Technology Institute, Des Plaines, Ill., and made possible through a grant awarded by the California Energy Commission.

Before Gills Onions could begin construction of its new waste-to-energy (WTE) system, the company faced a challenge obtaining the required equipment permits from the local air district, the VCAPCD. Because systems like Gills Onions’ are newly designed and largely unprecedented, the permitting process does not follow standard protocol. Gills Onions contacted Yorke Engineering LLC, an environmental consulting firm based in San Juan Capistrano, Calif. Yorke specializes in air quality permitting and compliance throughout California and could help Gills Onions navigate the uncharted waters of WTE permitting.

Yorke Engineering is no stranger to unusual WTE permitting situations. Founded in 1996, the consulting firm has routinely acquired permits for systems that produce power from landfill gas, sewage digester gas and wood waste, to name a few.

The Clean Air Act Amendment of 1970 established the National Ambient Air Quality Standards. If a geographical area’s emissions pollutant levels are higher than these standards, the area is designated as “non-attainment,” and if the pollutant levels are below the established thresholds, the area is designated as “attainment.” Gills Onions is situated in a non-attainment area.

Some of the important items Yorke Engineering had to consider for Gills Onions’ project were the types of air emissions the equipment would produce and methods of compliance with existing government rules and regulations.

Criteria air pollutants that were accounted for included ozone (nitrogen oxides combined with volatile organic compounds, or VOCs), nitrogen oxides, sulfur oxides, carbon monoxide and particulate matter. The specific requirements of such a unique permit depends on the pollutants and quantities emitted by the system. Part of Yorke Engineering’s job was to quantify criteria pollutant emissions, perform a health risk assessment, complete a regulatory analysis, and present them to the VCAPCD in a formal permit application.

Yorke Engineering also used its specialized knowledge of complex and constantly changing local and federal rules and regulations to demonstrate that Gills Onions would be in compliance with air quality regulations once the system was permitted. In addition to the VCAPCD’s established rules, the WTE system had to meet air toxic health risk requirements, National Emission Standards for Hazardous Air Pollutants and New Source Performance Standards.

The federal New Source Review can require emission offsets, or units of mitigation often purchased or sold by companies to compensate for produced emissions, demonstration that the air quality will not be significantly impacted by the new equipment, and a means of control for emissions, or Best Available Control Technology (BACT) and Lowest Achievable Emission Rate (LAER).

Meeting Standards
In Gills Onions’ case, to comply with BACT/LAER, different systems were installed to control the pollutant emissions and to reduce possible nuisance odors. The system used an enclosed flare, an iron sponge a bio-filter, and a carbon polishing treatment system to control hydrogen sulfide emissions as well as odors.

The company also utilized a boiler to heat the bioreactor to a specified nitrogen oxide concentration and two fuel cells to generate electrical power. To address potential odors, which can present a nuisance to nearby homes, Gills Onions used a biological scrubber and wet scrubber.

Permits usually require some form of emissions monitoring to demonstrate compliance. Types of monitoring can include recordkeeping, source testing and/or continuous emissions monitoring system. The VCAPCD required source testing of the boiler, flare and bio-filter every two years, recordkeeping to measure monthly natural gas use, and providing regular maintenance, inspection and repair records of the bio-filter and iron sponge.

Gills Onions has tried to incorporate operational flexibility into the design of its WTE system to avoid having to make any drastic agency-required changes later on. It was also important to wait for permit approval before proceeding with construction to ensure all requirements would be met.

The District was committed to understanding the processes, components, and functions of the new units. Gills Onions received their Permit to Operate¬ with operating conditions, which enabled installation of the Advanced Energy Recovery System (AERS).

Gills Onions unveiled the resulting sustainable AERS in 2009. The multi-component system is broken down into four specific functions: onion processing (including juice extraction), biogas production by anaerobic digestion, biogas conditioning and energy production by fuel cells.

This WTE process produces more than 100 cubic feet per minute (cfm) of biogas, which is conditioned and used to generate 0.6 MW of clean electricity, fulfilling up to 100 percent of the processing plant’s base load electricity requirements.

Gills Onions’ pioneering efforts in environmental sustainability has earned them numerous honors and awards, including:

• 2010, 2011 WRAP (Waste Reduction Award Program) recipient
• 2011 U.S. Innovation Award from McDonalds
• McDonald’s 2010 Best of Sustainability Supply Chain Award in the categories of Climate/Energy and Waste Management
• 2010 Food Plant of the Year from Refrigerated Frozen Food magazine
• 2010 California Green Leadership Award – Waste Management category winner in partnership with a grant from the California Energy Commission
• American Council of Engineering Companies’ (ACEC) 2010 Grand Conceptor Award for our Advanced Energy Recovery System (AERS)
• 2010 Platts Global Energy Awards Recognition Finalist – chosen from over 200 worldwide nominations
• Ventura County Resource Conservation District Recognition 2010
• 2009 Governor’s and Environmental and Economic Leadership Award (GEELA)
• Pacific Coast Business Times 2009 Business of the Year
• 2009 Energy Solutions Center Partnership Award for Innovation Energy Solutions
• Cool Plant Project Winner 2008

Above and Beyond
Gills Onions didn’t stop there. In 2012, the company added a significant new improvement to its facility’s energy efficiency during peak usage hours through the installation of the patented VRB® Energy Storage System manufactured by Prudent Energy of Bethesda, Md. Because of the VRB, Gills Onions will not only inventory onions, but electricity as well, and save hundreds of thousands of dollars on its utility bills in the process.

Like many industrial power consumers who rely on the grid for all or some of its electricity, Gills Onions’ utility costs spike during high-use periods, especially during six afternoon hours when the local utility, Southern California Edison (SCE), uses peaking generators to meet demand. This additional cost of power production is passed to the customer via time-of-use (TOU) rates.

But SCE also has a demand charge that can hit hard on customers’ power bills. Unlike the charge for the energy itself, the kilowatt (KW) demand charge is assessed for the peak use during the month, as measured in 15-minute intervals.

For example, the Gills Onions plant may have a fairly steady power usage, as would be typical for a 24-hour food processor, varying between 1,000 and 1,200 KW. However, if a number of motors or compressors started up at once, the usage during the 15-minute period could spike, and the measured demand could increase by 300 to 500 KW. This short spike in power would then set the demand charge for the entire month, which could be three times higher than off-peak. Avoid these charges, and the potential for significant savings becomes clear. That’s exactly where Prudent’s VRB® system kicks in.

Prudent Energy will typically charge its giant battery during nighttime, off-peak hours, storing electricity like a warehouse might hold any other commodity. That power from the 600-KW, six-hour battery system will then be used during peak pricing and usage hours, which is where the savings pour in. And according to Prudent, its VRB system has additional value: it is durable, produces virtually no air emissions, and requires very little maintenance or support.

With daily time-of-use rates and costly demand charges from the electric utilities, not to mention the compelling business need to show a commitment to sustainability, Prudent says California’s commercial and industrial companies can look to benefit from its advanced energy storage system as a way to manage their electricity costs.

Peak demand pricing and TOUs are not unique to California. Many utilities across the country already use them, and the trend is growing as new power generation becomes increasingly expensive and the grid becomes more strained.

The flow battery addition was unveiled at a co-hosted invitation-only ribbon cutting ceremony held on July 11, 2012.

Co-author Nikki Rodoni is director of sustainability at Gills Onions LLC and co-author Ashley Beck is technical editor at Yorke Engineering LLC.