jueves, 28 de julio de 2011

Industrial-Strength Waste to Energy

While project developers in the U.S. and Canada work diligently to get their first biogas plants financed and permitted, Spanish-owned Ros Roca Group recently commissioned the largest food waste-to-power plant in Europe.

The 5-megawatt (MW) facility is now operating and will take in about 120,000 tons of a mixture of solid and liquid commercial food waste every year from supermarkets, restaurants and food processing plants.

Over its lifetime, it will use 2 million tons of waste, according to Ian Handley, vice president of Ros Roca’s U.S. division. The plant was constructed for the largest waste management contractor in the U.K., Biffa Waste Services, which also built one of the first industrial-scale anaerobic digestion (AD) plants in the country. Ros Roca's  origins are in the manufacture of garbage trucks, which eventually led the company to enter the waste treatment market.

Because food organics are typically heavily contaminated—up to 15 percent—the plant employs a sophisticated pretreatment process ahead of the AD, which involves crushing the material and then dumping it into a mixing tank to introduce water. “It’s then put through a screening process to strip out what we call the light fractions or plastics, and then into a grit trap to take out the heavy fractions,” Handley explains. “A lot of the smart stuff is actually done on the front-end, in preparation for insertion into the digester.”

The plant is in an urban area on the site of an existing landfill, and disproves the common assumption that these types of AD facilities must be sited far away from people and other businesses. “There’s a lot of misconception in the marketplace that these plants, because of odors, need to be well-removed from residential areas,” Handley says. “That’s not true, as today’s odor controls allow them to be built quite close.”

The landfill site is within 200 meters (656 feet) of a prime retail development area, he adds. “Using this model, we’re trying to illustrate what’s possible in the U.S.; that you don’t have to have something that’s 50 or 60 miles away from a metrop
olitan area. You can build very close to the source of the feedstock.”

In the past eight years, Ros Roca has built 25 of these AD plants throughout Europe, and was recently contracted to build a 180,000-ton plant in India.

Handley says while things are beginning to move in the U.S., it’s at a much slower pace, and development is mostly in states where it is incentivized.

Project Challenges

From Handley’s perspective, a country’s energy incentives play the most significant role in successfully implementing industrial-scale AD projects. While Europe’s incentives are enticing, the U.S. in general offers little. “We actually see more scope [in the U.S.] for slightly smaller plants—about 50,000 tons—that use the biogas for gas injection into the grid or to produce biomethane to fuel vehicles. That’s because electricity here is so cheap,” Handley says.

Daniel Rickenmann, CEO of W2E Organic Power, says the biggest hurdle in developing its project in South Carolina was determining where it fit in current regulations. “Since we are really the first digester [of this kind] in the state, it’s a new concept,” he says. “We’re taking in solid waste, but also composting and recycling. Fitting under just recycling would speed up the permitting process, but when you’re bringing in food-related solid waste there are a lot more regulations.”

Anand Gangadharan, CEO of Novi Energy, which is developing a 3-MW community digester project in Fremont, Mich., says it took the company more than five years to develop the project under construction right now. “The biggest [challenge] was financing, and making sure our equity partners all understood why this technology is proven, how it works, and that just because it is not popular in the U.S. does not mean that it isn’t worth the investment,” he says.

Much like project financers, various state and local agencies have to be brought up to the learning curve as well. “It hasn’t been done before, so there was a bit of education,” Gangadharan says. He hopes that with the successful commissioning of this plant, financing and permitting will become a whole lot easier. “It’s taken us a long time to educate various financial intuitions, but we finally found one that supported this project,” he says.

So what is the actual cost to build an AD plant? For an 80,000-ton plant, the capital cost—including planning and permitting—typically approaches $30 million, according to Handley. “Once again, that depends on incentives, but that size of plant in the U.K., where incentives are very attractive, can get a seven-year payback with a 22 percent return on investment,” he says. “Over here, the American Biogas Council is trying to deliver those incentives to encourage further development of AD in the U.S. Permitting and financing are the biggest log jams, but financing often brings you back to incentives.”

Paul Sellew, CEO of Harvest Power Inc., agrees that funding and incentives go hand-in-hand. Development is difficult in states that don’t have renewable portfolio standards (RPS), he says. “You’re up against the lowest-cost fossil fuel which is often coal, and it’s difficult to compete with that.”

The good news is that more than half of U.S. states do have an RPS. While a few separate organics from waste, it is the exception to the rule, Sellew says. “More than 95 percent of society-generated food waste ends up in the landfills or incinerators, so we need to build-out the collection/separation infrastructure as we’ve done for the rest of the recycling industry. Many parts of the country already separate out cans, papers, newspapers, cardboard and yard waste, but food waste is still mixed in.”  
These two components allow the economics of AD projects to work. “When we look at other countries such as Europe that have built-out this type of an industry, we see they’ve used both of those things,” Sellew says.

U.S. Projects on the Build
Harvest Power has two compost facilities in California and Pennsylvania, and is currently developing a 2.5-MW, two-stage batch, high-solids AD facility in Richmond, British Columbia, and a 5.5-MW low-solids AD project in London, Ontario. Sellew says he matches the technology—high solids or low solids—to the feedstocks available in a region. “If you have a lot of yard waste, you have a stackable organic waste stream and you mix the food waste in,” he says. “If you don’t, it is more of a slurry and that is pumpable.”

Sellew expects the Richmond facility will be operating by the end of this year and the London facility to begin running in the first quarter of 2012.

To get feedstock suppliers on board with a project, Sellew says it should be presented as a way for them to be cost competitive. “If a company has a particular focus on corporate sustainability, then they’ll be interested in making sure their organic wastes are dealt with in the appropriate manner,” he says. “Extracting the energy value, followed by utilization of the nutrient value in pelletized organic fertilizer or compost-based soil, are the best uses.”

If a developer can’t get a handle on its feedstock source, then a project isn’t going to work, according to Handley. “Within the context of the U.S., things are really no different than anywhere in Europe,” he says. “Who has the waste is the prime focus of attention, and a lot of people are paying a gate fee to landfill it.”

Novi Energy chose Fremont, Mich., as the site for its flagship organic waste-to-power project because it is the headquarters of Gerber Baby Food, according to Gang-
adharan. “The area is also the fruit and vegetable belt of Michigan, and there are a substantial amount of food processing companies in the area,” he says.

While this project is a first for the company, Novi Energy has been in the consulting and project development business for nearly a decade. “Five or six years ago we were in Michigan talking about energy efficiency improvements with some of our industrial clients when we came upon this opportunity,” Gangadharan says. “A lot of companies were essentially at the limits of their nutrient management plans, and they were all talking about how to further improve.”

High energy costs were another major topic at the time, so Novi came up with the plan to develop a community digester power project. “We showed them that if we were to process these organic wastes into biogas and use it to produce steam or electricity, then it would kill two birds with one stone.”

The plan was based on a great deal of research, which included the evaluation of community digesters in Scandinavian countries, particularly Denmark. Novi found that they have a lot of appeal compared to single-waste digesters. “We chose a technology that allows us to process these types of sophisticated waste, including pharmaceutical alcohols, biofuel industry waste and byproducts, various food manufacturing wastes including meat, dairy and fruit and vegetable products, cheese whey, ice cream waste and sugar syrup.”

Some of the feedstock contracts, including the one with Gerber, last 20 to 30 years, according to Gangadharan.

Rather than contract waste haulers to bring feedstock to the digester, Novi has its own truck fleet and, because of the wide range of feedstocks involved, it takes biohazards management seriously. “When one of our trucks goes to a farm to pick something up, unless the truck is going right back to the same farm, it is washed so that no hazards are spread from one facility to another,” he says. “The trucks are specially ordered and made; some have a unique coating on the bottom so mud and muck doesn’t cling to it. We have a structured waste transfer in our plant so it’s all done in negative air pressure, in closed facilities.”

The digester, which will begin to take up to 100,000 tons of organic waste each year by next summer, has a PPA in place for the 3 MW of power it will produce.

In South Carolina, W2E Organics has partnered with Eisenmann Corp.’s biogas division to build an AD plant that will take in pre- and post-consumer food waste and grease trap waste. Eisenmann has been involved in more than 90 similar installations across Europe, and this will be the company’s first U.S. plant that will focus on this type of waste.

Rickenmann says W2E is permitted to use 48,000 metric tons of waste and will build the project in two phases; the second phase will double its capacity. He notes that the plant will use only 7 percent of the organic waste available within a 20-mile radius of the facility.

 The 1.5 MW of electricity generated in phase one will be sold to power utility Santee Cooper under a long-term PPA.Contracts with waste haulers and feedstock providers are in order, and the fertilizer byproduct is nearly spoken for. “We have several large farmers in South Carolina who have sent letters of intent to take our fertilizer product,” Rickenmann says. “A lot of them have been studying European farming models that use a lot of liquid organic fertilizer, these studies are showing they’re getting higher yields and cutting back on—even being close to eliminating—the use of commercialized fertilizers.”

Rickenmann says that while this waste-abundant location worked out for the project, the incentives were not the greatest from a profit standpoint, and that includes selling the power at a good rate and collecting tipping fees. He looks at that in a positive light, however. “The fact that we are going to be successful shows us that we can go pretty much anywhere else in the U.S. and make this work,” he says. “Though there are 152 digesters in the U.S., most are ag based. It’s not a new concept—it’s actually old—it’s just a matter of adapting the technology to a different waste stream that has more energy potential. It’s an exciting time, and I think we’re going to see a lot more creativity out there.”

Author: Anna Austin   July 28, 2011
Associate Editor, Biomass Power & Thermal
(701) 738-4968