BioCycle Magazine

Fuel alternatives for heavy equipment

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High fuel prices are leading composters and wood grinders to reevaluate diesel-guzzling heavy equipment, looking to alternatives that are both more cost-efficient and environmentally friendly. This could be as “simple” as filling up existing machines with biodiesel blends, could involve swapping out a diesel model for an electric one, or even go as far as generating electricity on site to power electric equipment.

New specifications for biodiesel blends recently approved by ASTM (American Society for Testing and Materials) were an anticipated development that may expand availability of the fuel. The new specifications include use of up to 5 percent (B5) biodiesel in conventional petrodiesel, new standards for blends ranging from 6 percent (B6) to 20 percent (B20) biodiesel for on- and off-road diesel, as well as changes to existing blend stock specifications for 100 percent (B100) biodiesel. ASTM blend specifications for B20 biodiesel are specifically important for automakers and engine manufacturers, seen as a final hurdle preventing full-scale acceptance of B20.

Biodiesel can be produced domestically from renewable sources, has improved lubricity and lower emissions, and may be less expensive than conventional petrodiesel (depending on the region, market price of oil, etc.). Also, no engine modifications are needed to use blends up to B20. Still, several factors need to be considered before switching to biodiesel. For instance, can large enough volumes be sourced consistently in your area? What blends are approved within the equipment's warranty? What are the costs of switching to biodiesel, and will a greener image attract more business?

Royal Oak Farm, a 500 tons/day SSO (source separated organics) composter in Evington, Virginia, has been using off-road B20 biodiesel for all of its off-road equipment (windrow turner, screen, shredder, loaders, etc.), as well as on-road B20 for its truck fleet. However, Royal Oak's switch to biodiesel was an environmental decision, not economic. “When we started using off-road B20 about six months ago, it was 10 cents less than conventional diesel, but now it's as much if not more,” says Ken Newman, Vice President of Royal Oak Farm. “We are an organics recycling company, and therefore want to be environmentally responsible. Although there is some discussion about using food crops for fuel, we think it's the right move at this point.”

Most of the biodiesel Royal Oak Farm buys is from Foster Fuels, a company based in Virginia that sources virgin soy oil. While demand continues to grow for biodiesel manufactured from recycled oil, Newman notes that it is more difficult to get that oil certified by ASTM, and to source it in large enough quantities. When running biodiesel in expensive equipment, ASTM certification is necessary to maintain warranties. “We receive paper work from the biodiesel blenders saying it's B20 and ASTM certified,” says Newman. “Most of our equipment is new, and if something goes wrong, they can test to see what fuels were used and determine whether it was in violation of the warranty.”

Higher blends of biodiesel could be used in older equipment no longer under warranty, but Newman points out that biodiesel has a cleaning effect - it can purge the system and clog fuel filters, which if not monitored could lead to serious problems. Because of these solvent qualities, it's important to be consistent with a fuel choice, instead of switching between biodiesel and petrodiesel. Royal Oak Farms is in the final stages of constructing a 16,000-gallon fuel tank on site, which will allow it to maintain a steady supply of biodiesel, as well as save money by purchasing fuel in bulk. The tank has three compartments: off-road biodiesel storage, on-road biodiesel storage and one for fueling. Newman anticipates a three-year payback on the investment for both the tank and fueling station, which cost approximately $100,000 to install.
Santa Cruz (CA) Resource Recovery Facility (SCRRF) also uses B20 biodiesel for all of its equipment, including excavators, skid steers, quarry trucks and collection vehicles. B20 is more expensive than petrodiesel in California as well, but Craig Pearson, Superintendent of Waste Disposal at SCRRF, decided to use it anyway. “We use B20 because it benefits the environment, and promotes a good public image that shows we're trying to do something to get off of the oil addiction,” says Pearson, who took his position as Superintendent a little over a year ago.

Pearson's predecessor had used B80 biodiesel in the landfill's equipment, but that led to some mechanical issues. “Our equipment wasn't designed to handle that percentage of biodiesel,” he explains. “We went back to B20, and everything is working well again.” He notes that some of SCRRF's equipment recommends a maximum of B5, or even no biodiesel, but that there seems to be an industry-wide consensus that there aren't any problems with blends up to B20. “Because we have on-site mechanics, we are less worried about violating manufacturers' warranties,” he adds. “Our mechanics say that B20 is okay to use, and that's what matters since they're the ones working on the equipment.”

Although biodiesel cuts down on some emissions, stringent air quality control in California requires more than switching from petrodiesel. “We're working towards new emissions, but it's not necessarily the fuel that's a concern, it's the engines,” explains Pearson. “The California Air Resources Board stipulates that as fleets get older, you have to replace Tier One motors with newer Tier Three motors that are more efficient and reburn fuel.”

Air quality control regulations, particularly in California, have led some operators to move away from diesel engines and towards electric models, which eliminate on-site emissions. Electric models cost more to set up, however they alleviate air quality permitting issues, are cheaper to run and open up different possibilities for alternative fuels from renewable sources. For instance, the Peterson 6700, a 1200 HP diesel grinder, costs approximately $118/hour more to run than its electric counterpart, the Peterson 6750. “This estimate is based on our machines working at 70 percent capacity, with diesel averaging $4/gallon, and electric averaging 10 cents/kW/hr,” says Cody Peterson of Peterson Pacific Corp. “It also takes into consideration the added maintenance fees for diesel equipment, including oil filters, air filters and scheduled maintenance. CAT recommends an overhaul of its engines at 150,000 gallons, or 6,000 operating hours. Electric models have less moving parts, and if set up correctly, wouldn't need that type of work until 50,000 hours, which is significant.”
Johannes Pohl, CEO of Komptech USA, notes that they also have seen more interest in electric models. He points out that although elevated fuel prices are relatively new in the U.S., they have been a reality for years in Europe, where Komptech is based. “Fuel costs suddenly became a big issue for customers here, with more demand for our slow-speed, high-torque grinders,” says Pohl. “High fuel prices are nothing new for us, because we learned to deal with them in Europe a while ago. Our diesel models are extremely efficient, only consuming 12 to 15 gallons/hour, instead of 40 to 50 gallons/hour, and our electric shredders operate hydraulically, allowing for smaller, more efficient motors. It is more cost-effective to use electric grinders and screens, if an operation can be stationary.”

The set up for electric equipment is more complicated than for diesel models, which can be dropped off anywhere, filled with diesel fuel and turned on. Because they are stationary, choosing an electric grinder takes forethought as to the layout of the facility. And, they require 3-phase power, which can be expensive to install and has varying rates. Commercial electricity prices are based in part on the maximum load, which occurs during start-up and can be considerable with large grinders. “To minimize the peaks in energy draw, electric grinders can utilize Variable Frequency Drives (VFD), which control the amount of energy supplied to the motor,” says Cody Peterson. “Without VFD, if you overload the engine, it pulls everything from the line possible, which would drain power from everyone around you.”

Despite these improvements, 3-phase electricity is still needed, and can be cost-prohibitive to install. “One facility I worked with was quoted $250,000 to extend 3-phase power for two miles,” says Craig Coker, Principal of Coker Composting & Consulting in Virginia. “If 3-phase is already available, then running an electric motor is much more efficient.”

Besides the expense of installing 3-phase electricity, it can also take awhile for the utility to install. This is a problem Paul Elias, Central Western Sales Representative for Peterson, has seen in California. “Many operators in California want to go electric, to meet air quality regulations and to save money in the long run, but they can't get 3-phase power,” says Elias. “I have four or five companies right now waiting to swap over to electric, but the utility, Pacific Gas and Electric (PG&E), is saying it'll be a year or longer to install 3-phase electricity. This means that they're continuing to run inefficient, often Tier One diesel grinders, which pollute a lot.”

One solution Elias advocates is using a medium-sized gasifier to run a generator set. “Because they're 500 kW or less, the emissions are low enough to not be tagged by the strict air quality regulations,” he says. “An electric grinder can essentially process its own fuel, material that could be gasified and used to make electricity for the grinder, with excess power sold back to the grid.” Because PG&E needs to meet a renewable portfolio requirement, with 20 percent of its electricity from renewable sources, they are eager to sign Power Purchase Agreements with this type of operation.

Phoenix Energy, for instance, sells and installs gasification systems and generators. Its units are in power increments of 250 kW, and can be constructed in a modular fashion to accommodate different types of biomass fuels. “Our systems are one more way to keep materials on site,” says Greg Stangl of Phoenix Energy. “Less material needs to be transported out, and no fuel needs to be transported in.” It takes approximately 2,600 tons of wood per year to run the 250 kW engine - a fraction of the throughput of a large facility. “At 8,000 operating hours in a year, that's 2,000 MW of electricity, which starts to add up quickly, especially if prices for electricity continue to climb,” adds Stangl.

The process of gasification is not new - when used with wood, it is similar to making charcoal. “Essentially, the wood is cooked without oxygen, making a low-octane natural gas,” says Stangl. “The gas is then cleaned, cooled and burned in a modified generator set.” The electricity is sent to a parallel switch gear that sends power to the facility, and puts excess electricity into the grid. It can be configured to output 3-phase power.

Two Phoenix Energy systems have been sold in the U.S., and are in various stages of production. One application is at an almond processor, gasifying almond shells. Another, in the San Joaquin Valley of California, processes wood waste and plans on using heat from the generator to dry fines from the grinder. “It's about a three to five year turnaround on investment, depending on the operator's energy needs, what local electricity costs are, etc.,” notes Stangl. “We actually recommend that our customers don't sign into Power Purchase Agreements (PPA), because power companies are federally required to purchase electricity you produce, and the price is running up fast. With a PPA, you might lose out by locking in on a lower price.”

It takes approximately four months to install a Phoenix Energy system, and costs around $1 million. “Financing can be tricky, but banks are getting interested in renewable energy projects,” he adds. “The projects are a net environmental gain, and banks are realizing that the return on investment is much shorter than a lot of other renewable energy projects, like solar panels, which can be 10 to 12 years.”

With skyrocketing fuel prices and increasing awareness of the environment, alternative fuels and equipment efficiency will continue to be a hot topic. “It's exciting, because high fuel costs are driving innovation,” says Elias at Peterson. “Things may seem to be moving slowly now, but we're going to see more changes, more innovation.”

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