Full Steam Ahead

Development of large-scale biomass gasification in the U.S. is in between demonstration and commercial scale, but a few companies are overcoming the challenges to make large-scale projects happen.
By Anna Austin | June 22, 2011

When Jim Taylor Jr. founded Taylor Tree in 1953, he had no idea that it would pave the way to development of the first large-scale biomass gasification power facility in the U.S.

That tree recycling business, with help from his son, Jim Taylor III, was transformed into a successful construction and demolition (C&D) debris recycling company, a key component in his future biomass gasification plant model.

Construction of the 20-megawatt (MW) plant in Montgomery, N.Y., has finally begun after more than five years of planning, permitting and financing. As is often the case with a first-of-its-kind project, multiple obstacles had to be overcome throughout the process. Now, the goal of Taylor Biomass Energy is to show policymakers, project financers and the public that biomass gasification is a clean, viable way to get rid of waste while generating renewable electricity on a large scale.

Hatching an Idea

“In 1989, New York state enacted a solid waste law that declared our land-clearing debris was now a regulated waste to become known as construction and demolition debris,” Taylor explains. “There were 40-some tree service companies and no C&D processing facilities, so I decided to create the first permitted C&D facility in the state, and it also turned out to be one of the first in the U.S.”

During the next 20 years, Taylor’s company developed the core competencies of sorting and separating waste streams, and as a result was hired for the World Trade Center Disaster Recovery Project at Fresh Kills Landfill on Staten Island, according to Taylor.

By 2000, Taylor Recycling Facility had accomplished about 45 to 50 percent recovered recycled products. “At that point in time, I made the decision that we needed another technology to be able to recycle the remaining 50 to 55 percent,” Taylor says. “In New York, our solid waste policy at the time called for reducing, recycling, reusing and recovering the energy content, and landfilling or incineration as the last tool. The step we bypassed was recovering the energy content, as there was no technology of this type. Little did I know that I would eventually be the one company to bring a new, innovative alternative energy technology to the market for the first time ever, one that would recover the energy content.”

Mark Paisley, the man behind the science of Taylor’s gasification process, has been involved in gasification research for nearly 40 years, including work at Babcock & Wilcox Co. and Battelle. “I’m one of the few people who were around when the biomass field wasn’t even called that,” he chuckles.

Paisley has several patents on gasification processes, and invented what is known as Rentech Inc.’s Rentech-SilvaGas process. In 2005, he teamed up with Taylor and developed a new process, which will be deployed at the Montgomery plant.

Taylor’s process is unique because it’s an indirectly heated gasification process, Paisley says. “Air or oxygen is not used to convert the biomass, but rather hot solids circulating around the system, and it incorporates a unique gas conditioning reactor as an integral part of the gasification process,” he says.

As opposed to the conventional approach of applying various scrubbers, catalytic reactors or other purification mechanisms to adjust the composition of the gas to clean it up, the Taylor gas conditioning reactor, as an integral part of the gasification process, converts the condensable materials—or tars—in the gas into an additional synthesis gas. “At the same time, it adjusts its composition so that the gas is significantly higher in hydrogen, making it more suitable for things like synthesis operations,” Paisley says.

While the Montgomery project will utilize biomass residuals such as C&D materials and municipal solid waste, Paisley says, the process is amenable to any form of biomass. “Flexibility is an important part of the process,” he says. “That way, you can pick and choose what source makes sense for a particular project, and that gives you the ability to locate the project wherever you need to.”

Though most biomass energy projects claim they can use any feedstock, Paisley says flexibility varies by technology. “[For gasification] some fixed-bed and some fluid-bed technologies are a little less forgiving than a lot of the indirectly heated technologies,” he says. “Some technologies, based on their reactor configuration and types, require specific feedstock preparation. That can create limitations because now you have to have additional equipment up front to prepare the feedstock. Flexibility is important because one type of biomass may not always be available.”

ICM Inc., another gasification process developer, shares Paisley's perspective on feedstock flexibility.

Ready for Deployment

ICM says it has successfully processed more than 13 different feedstocks at the company’s commercial demonstration unit in Newton, Kan.

Good system controls are a central component in ICM’s gasification system and allow for its feedstock flexibility. “We can control what’s happening in the gasification unit, increasing its operability,” says Tom Ranallo, ICM’s vice president of operations.

The company has “really put the unit through the test,” amassing more than 2,220 hours of operation over the past two years, Ranallo says. It’s now ready for purchase and several power projects that will utilize the gasifier are in various stages of development.

Initial development of the system began about four years ago, as a way to potentially alleviate fuel costs at ethanol plants. “This was when natural gas prices were very high,” Ranallo says. “We started looking at different technologies on the gasification side because we thought it might be a good way to get these plants off natural gas and to generate their own power. That’s becoming more common, but the challenge now is that natural gas is cheap. As we saw prices come down, the economics around the system began to change so we began looking at other applications.”

ICM’s largest design is a 450-ton-per-day, 15-MW unit. Costs vary since each application requires a uniquely engineered solution, Ranallo says. “You have to understand the feedstock components and engineer around them,” he says. “For projects that generate power, we’ve generally seen that the cost of the thermal island, the gasifier piece with the power island—the turbine and the generator on the backside—is about $3 million to $4 million per megawatt, excluding the feed handling system. That’s a good rule of thumb.”

Development comes with two sets of challenges, some on the technology provider side and some on the project developer side, Ranallo says. For ICM, the biggest challenge has been emission controls.

Since few gasification units have been deployed for commercial applications in the U.S., ICM is dealing with first-time permitting and emissions issues, Ranallo says. In what it believes is the best available solution, ICM has partnered with emission control solution provider Eisenmann Corp. to incorporate its technology on the back end of the gasifier. “We realized upfront that it was critical,” Ranallo says. As ICM has been running multiple feedstocks through the gasifier, it has been gathering emissions and testing data to compile an emissions database to help developers with their permitting.

“Cleaning and cooling producer gas has been the Achilles heel of gasification,” Paisley says. “Biomass gasification is a very old technology, pre-1900s. The cleanup and adjustment of the composition of that gas has been something that people have been working on for a long time. There are old references, I have one dated 1923, that shows all kinds of various approaches to gas cleanup from absorbers to filters to various scrubbers.”

Today, people have zeroed in on catalytic systems in an attempt to make the gas easier to transport and use within an industrial facility, or to keep it from plugging up lines, Paisley says. “That’s one of the reasons I’ve focused on the gas conditioning reactor within the Taylor process, because it addresses those issues.”

From Paisley’s perspective, the challenges on the developer’s side relate almost exclusively to financing. “The technology is sound,” he says. “The gas turbine manufacturers are comfortable with a medium calorific value gas like we produce, and are happy to provide you with guarantees that say ‘if you give me this gas, our turbine will produce x amount of megawatts.’”

Because there is no inventory of gasification technologies out there, banks and sources of capital for these projects are reluctant to provide financing.

Ranallo agrees. “Financing is key,” he says. “We’ve had finance groups looking at our gasifier to get them comfortable with the technology and our approach to it, and that will help ease their minds so they can feel good about financing some of these waste-to-energy projects.”

Another issue surrounding large-scale commercial deployment is the price of electricity. Jim Childress, executive director of the Gasification Technologies Council, says that’s the main reason commercial-scale gasification-to-power hasn’t taken off in the U.S. “How to do [gasification] is known, it’s just a matter of competitiveness with coal combustion,” he says. “People have been burning coals for years, and it costs less to burn coal on a large scale than it does to gasify biomass.”

Also, on the developer side, locking down a steady feedstock supply and securing power purchase agreements are necessary and potentially challenging, Ranallo adds.

Progress in the U.S.

Both Taylor Biomass and ICM are also working on international projects. Childress says that while interest is growing among the GTC’s 65 domestic and international members, most of whom are involved in some aspect of large-scale fossil fuel gasification, in the U.S. biomass gasification is being done at smaller or demonstration scales.

“There have been some [large-scale] applications in Europe, but in the U.S., that’s where we are,” Paisley echoes. That has largely been driven by U.S. DOE policies over the past several years, he says. “The DOE has focused on liquid fuels—ethanol specifically—and even though they were interested in power some years ago, they sort of abandoned that for a while. There’s some renewed interest now, but we’re one of the few large-scale projects underway and probably the furthest along relative to the production of power in the U.S.”

Another hindrance is a misconception of what biomass gasification really is. “During our permitting process and public hearings, you run into people who believe that if it is high temperature by definition, it’s incineration,” Paisley says. “That’s obviously not correct from a technological standpoint, as it’s hard to operate an incinerator without air going through it. The technical community typically understands that gasification is an intermediate step. You can almost look at it as a pretreatment step where you have the ability to clean up all of the potential environmental issues so that when you do the final conversion to electricity, it’s far superior to a direct-combustion process.”

Paisley is hopeful that anti-biomass sentiment in the U.S. will soon be overcome so that biomass gasification will be more readily accepted, allowing for widespread implementation. “Not just for the Taylor process, but all [gasification] processes,” he adds. “I’m a firm believer in biomass energy and its potential because, as far as renewables go, biomass gasification gives us the ability to produce virtually any energy product that we want, from power to liquid transportation fuels to natural gas substitutes. It gives us the ability to grow our energy.”

Author: Anna Austin
Associate Editor, Biomass Power & Thermal
(701) 738-4968
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