Owners of off-road diesels in California should already be calculating fleet-average emissions of nitrogen oxide (NOx) and particulate matter (PM), comparing their numbers to CARB's targets for a matching variety of equipment, and taking action to hit those targets. Today, the only way to reduce fleet-average emissions enough is to replace Tier 0 and Tier 1 machines — anything built before 1997 — up to a maximum of 8 percent of the fleet per year with brand-new equipment. A few larger pieces can be repowered cost effectively with Tier 3 engines. Existing Tier 2 and Tier 3 machines can be retrofit, up to a maximum of 20 percent of the fleet per year, with emissions-control devices from CARB's Verified Technologies List.
But there are combinations of fuel modifications and exhaust aftertreatment waiting to be verified that could bring Tier 0 and Tier 1 machines into compliance so they can be retained rather than replaced.
Emissions Technology markets a platinum-based diesel-fuel catalyst and a system for introducing it into the engine's air intake that promises more complete combustion of the fuel charge in the cylinder and a 50 percent or greater reduction in soot produced by older diesels. The company is working to get the CARB to verify its catalyst in combination with an exhaust aftertreatment filter.
"Our field data show that combining the Combustion Catalyst System with a Level 2 diesel oxidation catalyst (a lower-cost exhaust aftertreatment device) gives Level 3 performance on a Tier 0 or Tier 1 engine — an 85-percent reduction in PM emissions. Plus, we see 8 to 10 percent fuel savings on a typical diesel engine," says George Malouf, vice president of technology at Emissions Technology.
Biodiesel delivers similar reductions in combustion soot, and it is also in the process of being adding to CARB's verified list in combination with appropriate aftertreatment. As these fuel/exhaust treatment pairings verify for use with pre-1997 diesels, they could slash the cost of fleets' compliance with California's emissions limits for in-use diesels.
This good news won't be confined to California for long.
"I think there's an outstanding possibility we'll see this (California rulemaking adopted) in 15 or 20 states after the EPA grants California its waiver," says Mike Buckantz, president of Justice & Associates, a Long Beach, Calif., environmental consulting firm. Buckantz believes the Environmental Protection Agency will grant the California ARB the waiver necessary for the state to fully implement its in-use, off-road diesel rule by the first or second quarter of 2009. "You can just look at a map of areas in PM 2.5-hour nonattainment (to identify states where the California rulemaking will be adopted next).
"All these other states have to do is go through the steps required by state law to adopt a new regulation," says Buckantz. He suggests they could begin enforcing off-road diesel rules in mid-2010. Deadlines are likely to be pushed back to reflect the later start date, but the working provisions of the rulings will, by law, be identical to the California regs.
It's prudent to wait until some alternate fuels are CARB verified to buy them, but now's the time to get educated on the technology and politics of biofuels. At this stage in their development, your economic and political actions may influence local availability of certain fuel types.
Biodiesel is made by processing vegetable oils or animal fats. The most common feed stocks in the United States are soybeans or corn. Biodiesel mixes readily with conventional diesel, and today is available mostly as B5 (5 percent biodiesel) and B20 (20 percent biodiesel). Virtually all engine manufacturers approve the use of B5, and most support engines run on B20.
Biodiesel is said to have slightly less energy than fossil diesel, but an aggregates producer with operations using B99 for three years reports no significant reduction in material moved per gallon of fuel burned in 150 pieces of its equipment that have been running in Iowa, Nebraska, Illinois and Indiana.
Biodiesel acts as a solvent, which cleaned out the quarry equipment's fuel systems and required fuel-filter changes as often as every other day for the first 500 or 600 hours of use, but caused no long-term problems. The 15,000-hour teardown of a Cat C18 engine powering an underground mining truck showed a hint of sludging in the head, but at acceptable levels. Main bearings looked good, and there were no fuel-system problems.
Biodiesel helps the quarry meet the Mine Safety and Health Administration's (MSHA) more stringent air-quality standards for underground mines without having to invest in additional ventilation shafts. The company is also buying B99 at lower cost than fossil diesel.
Biodiesel is an ester, and esters tend to attract water, so biodiesel tank farms and dispensing systems require careful attention to housekeeping practices. Well-maintained fuel-water separators on machines are also critical.