Inside ESI’s parallel construction of the Arrowhead and Hopkins renewable natural gas facilities
Here’s a construction problem for you: build two industrial gas processing plants at the same time, hundreds of miles apart, with custom equipment that takes over a year to arrive and a startup phase that requires twenty vendors to show up in the right order. Oh, and don’t be late.
ESI [full company name], a turnkey design-build contractor for renewable natural gas facilities, just did exactly that. Our Arrowhead and Hopkins landfill gas-to-RNG plants were designed, built, and commissioned in parallel and delivered on schedule, Hopkins within a single day of its contractual completion date. On a two-year project, that’s not luck. Here’s how it’s done, and what every landfill owner should know before starting an RNG project.
What Is a Renewable Natural Gas (RNG) Plant?
A renewable natural gas plant converts raw landfill gas into pipeline-quality natural gas. And raw landfill gas needs the help: it’s only about 50% methane. The other half is what our veteran field construction lead David Curington affectionately calls “garbage gas”: carbon dioxide, nitrogen, oxygen, moisture, and sulfur, none of which a pipeline wants.
So what does the plant actually do? David, who has built 35 landfill energy plants over 21 years, has the best answer in the industry:
"Simple, complex - but not complicated. It's a filter, an enormous filter."
Inside that filter, the gas runs through as many as nine separate treatment processes, each with its own specialized equipment, until what comes out the other side meets utility specifications and flows straight into the grid. Yesterday’s garbage, tomorrow’s fuel. That’s the whole business, and it’s a beautiful one.
About two years from contract award to first gas, and here’s the surprise: construction is the short part.
The real schedule driver isn’t any of these phases, it’s the equipment. Custom-built gas processing machinery can take up to 65 weeks to arrive. Translation: the procurement decisions made in month one decide whether you celebrate in month twenty-four. Choose your contractor accordingly.
What Makes an RNG Contractor "Turnkey"?
A turnkey RNG contractor takes a project from blank site to operating facility under one contract: design it, buy it, build it, start it, prove it, hand over the keys. Simple to say. Rare to find.
Roughly 30 companies build landfill RNG plants in the United States, and most of them sub out big chunks of the engineering. ESI doesn’t. Process engineering, mechanical engineering, controls and programming, piping design, all of it lives under our roof. The only thing we hand off is civil sitework, and we deliberately partner with an engineer local to the project, often the same firm the landfill already trusts.
Turnkey also means thinking past the contract. Arrowhead runs at roughly 3,500 CFM of inlet gas today, but we engineered it for 7,000 SCFM. The building is oversized on purpose. The extra equipment pads are already poured. The underground conduit is already in the ground. When the landfill grows, the plant’s capacity can double without a second construction project. The owner won’t need us back for years, and that’s exactly the point.
What Challenges Come Up During RNG Plant Construction?
Want a number that surprises people? In our experience, roughly 50% of landfill construction sites can’t be built on as-is. Landfills move earth constantly for daily cover, and the ground where your plant is supposed to stand may be loose, uncompacted fill full of rock and debris.
Arrowhead was one of the 50%. The fix: excavate 10 to 12 feet of unsuitable soil, bring in engineered fill, compact it with vibratory proof-rolling, and have every lift verified by the geotechnical engineer. Some teams lose months to a surprise like that. We’ve solved it 35 times in 21 years, the project didn’t lose a day it couldn’t recover.
The other challenge on this one was self-inflicted, in the best way: two builds at once. We ran it the way ESI runs everything, as one team, a well-oiled machine. Seasoned field leadership anchored each site, backed by decades of combined construction experience and in constant contact, five or six calls a day, every day, so both projects moved in lockstep. Behind them, dedicated project managers kept procurement, scheduling, and owner communication humming for each site. Two plants, hundreds of miles apart, advancing on the same drumbeat. Nobody dropped the baton.
"It's not like they're over me i'm over them, We're a team." - David Curington
Why Is Startup the Hardest Phase of an RNG Project?
Here’s the industry secret nobody puts in the brochure: building the plant is the easy part. Commissioning is where RNG projects live or die.
Picture it: startup crews from 15 to 20 different equipment vendors, each required on site to commission their own machinery, choreographed over roughly 90 days while gas quality is analyzed continuously on both sides of the utility interconnect. Custom equipment doesn’t always perform perfectly out of the crate, and when it doesn’t, the difference between an on-time handover and months of delay is a team that’s seen it before and knows exactly who to call, and how hard to push.
We also do something after every single project that keeps us sharp: formal lessons-learned reviews, internally and with every vendor. Plant number ten will start up smarter than plant number nine. Plant number nine started up smarter than plant number eight. That’s the system.
Handing over the keys doesn’t mean disappearing. The owner of Arrowhead and Hopkins chose to operate both facilities with its own personnel — and contracted ESI to get those teams ready. Under six-month support agreements at each site, our operations specialists are on the ground right now, training the owner’s people to run their plants safely, efficiently, and confidently.
Prefer not to self-operate at all? Contract operations is part of the same turnkey offering. Either way, the goal was never a finished building. It’s a facility that runs well for decades.
How much of landfill gas is methane?
About half. Raw landfill gas is roughly 50% methane; the rest, carbon dioxide, nitrogen, oxygen, moisture, and sulfur compounds — must be filtered out to reach pipeline quality.
How long does it take to build an RNG plant?
About two years from contract award to first gas: 6–8 months of engineering, 7–8 months of construction, and roughly 90 days of commissioning. Long-lead equipment, up to 65 weeks, typically drives the schedule.
Can an RNG plant be expanded after it’s built?
Yes — if it was designed for it. Arrowhead runs at about 3,500 CFM today but was engineered for 7,000 SCFM, with an oversized building, spare equipment pads, and pre-run conduit ready for future capacity.
Do RNG plant owners have to operate their own facilities?
No. Owners can self-operate, with contractor-led training, as at Arrowhead and Hopkins, or contract the builder to operate the plant long term.
How many companies build landfill RNG plants in the U.S.?
Roughly 30 companies nationwide build landfill gas-to-RNG facilities. Very few offer fully in-house process, mechanical, controls, and piping engineering.
ESI designs, builds, commissions, and operates renewable natural gas facilities nationwide, and we’ve got the on-schedule track record to prove it. If you’re evaluating an RNG project at a landfill, talk to the team that’s built 35 of them.