Retrofitting Construction Equipment

Construction equipment is built to be operational for many years and a large percentage of this equipment is powered by diesel engines. In fact, much of the older construction equipment still in use today may be functional for another two or three decades. The problem is the diesel engines found in older construction equipment pose huge environmental and health hazards because they emit higher levels of particulate matter and other pollutants that create smog and do not meet the current emission standards upheld by their newer diesel engine counterparts. A push by state and provincial and federal government to introduce more stringent emission standards has led to retrofitting incentives and programs designed to reduce diesel emissions in older on-road and off-road vehicles and equipment.

[edit] What is Retrofitting?

The term retrofitting has been used to broadly define many things. In reference to the reduction of diesel emissions, it simply applies to the use of various diesel emission control and reduction devices. However, it can also be used to define a wider range of options to reduce diesel emissions.

Retrofit refers to the installation of a range of exhaust emission control devices on equipment engines that usually have some operational life left.

Rebuild refers to making routine upgrades maintenance checks on engines. Diesel engines have the tendency to gradually release more diesel emissions over time due to wear and tear. Also the lifespan of an engine is typically shorter than the chassis or undercarriage of the machine. Certain components of the engine may need some rebuilding after three or four years to meet the manufacturer’s original specifications. Some manufacturers even provide options now to improve emissions beyond original performance levels. Rebuilding can also entail repairing an existing engine.

Refuel typically refers to using cleaner diesel fuels in engines such as ultra-low sulfur diesel (ULSD) and other renewable fuels, as well as fuel products like biodiesel and emulsifiers.

Replace means simply that: replacing equipment when it gets too old for a newer lower-emission model usually ahead of schedule. Replacing equipment is considered a feasible, cost-effective option especially for older, heavier, diesel machines.

Re-power refers to swapping the old engine on a piece of equipment for a newer one. This is also a cost effective way to preserve the longevity of a machine, as the engine will typically not outlast the body or chassis. Installing a new lower-emission engine in an older machine can buy a machine years more of operational time.

Reducing idling is also seen as a viable measure of reducing diesel emissions. Machines spend a lot of time idling on the job site. Limiting idling time not only saves money and fuel usage, it cuts down on the general wear and tear of an engine.

[edit] Why Retrofit?: The Danger of Diesel Engines

Construction equipment remains one of the biggest culprits in contributing to harmful diesel emissions. Diesel engines release several emissions that are toxic to the environment and to the health of people. Diesel particulate matter (DPM), also known as particulate matter (PM), is soot or a complex solid and liquid aggregate comprised of carcinogen-packed small particles. When breathed in, they penetrate deep inside the lungs and can lead to a number of respiratory and cardiovascular diseases and illnesses. Diesel emissions also contain smog-forming pollutants. In fact, a typical diesel vehicle releases about one and a half to two times as much nitrogen oxide (NO_x) compared to a standard gas vehicle.^[1] When nitrogen oxide and other organic compounds are mixed in sunlight and stagnant air, they generate smog. Other hazardous pollutants released are carbon monoxide (CO), hydrocarbons, and sulfur dioxide (SO₂). Sulfur oxides are a major cause of acid rain and hydrocarbons are a component of smog.^[2]

Many tests and trials conducted in the U.S. reveal the amount of harm caused by diesel emissions from heavy-duty off-road equipment. For example, a trial carried out in New England on equipment retrofitted with what are known as exhaust emission control or retrofitting technologies indicated that when used, they achieve a substantial reduction in emissions. Other emission tests carried out on diesel construction equipment in Houston, Texas demonstrated that when vehicles used a new diesel blend of fuel composed of diesel, purified water, and an additive package, nitrogen oxide was reduced by as much as 41 percent and particulate matter, as much as 69 percent. When exhaust emission control technologies were used, nitrogen oxide emissions were reduced by up to 81 percent, diesel particulate matter emissions up to 69 percent, and carbon monoxide emissions up to 95 percent.^[3]

[edit] Retrofit Technologies

There are three general types of emission control devices widely used, each with its own advantages and disadvantages.

A diesel oxidation catalyst (DOC) is the most common emission control device used on construction equipment today. A DOC can reduce volatile organic compounds (VOC) and CO emissions from construction equipment by as much as 20 to 75 percent.^[4] A DOC contains a flow-through core made of metal or ceramic. The flow channels are coated with a metal catalyst like platinum and packaged inside a metal container similar to an exhaust muffler. The DOC is designed to rest inside the exhaust stream of a vehicle. As the exhaust flows through it, the catalyst promotes the oxidation of VOC, CO₂, and water. DOCs are the most cost effective of all emission control devices.

Flow-through filters (FTF) can be used on a wide range of construction equipment. They also provide greater emission benefits than a DOC. FTFs reduce VOC and CO emissions between 50 to 89 percent and particulate matter by around 50 percent.^[5] The flow-through filter is very similar to a DOC but uses a different type of core material to house the catalyst such as wire mesh, wire fleece or sintered metal cores, all coated with a precious metal catalyst packaged inside a metal container. An FTF also promotes oxidation similarly to a DOC but works to eliminate more particulate matter than a DOC.

A diesel particulate filter (DPF) can be categorized as either passive or active. A passive DPF works without any additional energy input other than heat in the exhaust coming out of the engine. An active DPF includes a system that adds energy to the exhaust to increase its temperature. A passive DPF can be used on almost all construction equipment and an active DPF can be used on all diesel engines. A DPF can reduce particulate matter emissions by more than 85 percent.^[6]

[edit] The Push to Reduce Diesel Emissions

The reduction of diesel emissions is one of the primary concerns of the U.S. Environmental Protection Agency (EPA). According to the EPA, “reducing emissions from diesel engines is one of the most important air quality challenges facing the country today.”^[7] It reports that more than 11 million diesel engines in operation do not meet the EPA’s new clean diesel standards.^[8]

[edit] EPA and the Clean Air Act

In 1990 the U.S. Congress adopted what is known as the Clean Air Act Amendments (CAA).^[9] Since that time, the EPA has instituted several rules for reducing diesel emissions. The first set of emission standards addressed mostly on-road vehicles. Off-road equipment and construction equipment were exempt from meeting emission standards until 1996. Some engines were not even being regulated until 2003. By the spring of 2004, the EPA became more stringent in imposing standards for off-road machinery, demanding a 90 percent reduction in nitrogen oxide and particulate matter over a period of seven years, starting in 2008. Unfortunately one of the criticisms is that, though this new rule will result in a substantial reduction in diesel emissions from new engines, the full benefits will probably not be seen until well after 2030 when the majority of older construction equipment currently in use is retired. The EPA also does not require older equipment to be outfitted with the new retrofit technology options designed to clean up machines.^[10]

On a positive note, the EPA does administer a number of programs and even provides funding for construction projects that foster diesel emission reduction. Clean Construction USA is part of the EPA’s National Clean Diesel Campaign. The EPA realizes it make take years before existing equipment is completely phased out of use. In the interim, EPA encourages industry stakeholders to maintain their equipment, reduce idling, retrofit diesel engines, replace older equipment, commit to using cleaner fuels, and re-power equipment.^[11] National programs such as EPA’s Voluntary Diesel Retrofit Program launched in 2000 also provide educational outreach and financial incentives for diesel engine retrofits in construction equipment and heavy-duty equipment currently on the road.^[12] For example, in October of 2008, EPA partnered with the state of New Jersey to announce a retrofit of construction equipment worth US$1.5 million. The money will go towards retrofitting both publicly and privately owned construction equipment such as tractors and bulldozers.^[13]

[edit] B.C.’s Air Action Plan

A number of action initiatives announced by the British Columbia provincial government in reducing diesel emissions in older commercial and industrial vehicles was announced as part of the B.C. Air Action Plan. Two of the actions involve retrofitting heavy-duty vehicles with diesel oxidation catalysts operated by the government by 2009 and getting big diesel trucks to stop idling.^[14] B.C. set a precedent in 2007 by becoming the first province in Canada to make diesel oxidation catalysts mandatory on older diesel-powered trucks made between 1989 and 1993.^[15] The Canadian government estimates that the amount of particulate matter emitted from an older truck is equal to 60 new trucks.^[16] For now, buses and construction equipment are exempt from meeting this requirement.

[edit] A Case Study in Construction Retrofitting: Boston’s Big Dig

Boston’s Central Artery Tunnel Project – commonly known as the Big Dig – was a major highway construction project aimed at reducing traffic congestion and improving mobility in Boston’s downtown corridor. It was also the first major retrofit construction project in the U.S. to be completed over three phases. Under the Clean Air Construction Initiative Program, 200 pieces of equipment were outfitted with diesel oxidation catalysts, which led to a reduction of 36 tons of carbon monoxide and 12 tons of hydrocarbons.^[17] Some of the construction equipment outfitted with the diesel oxidation catalysts included cranes, small and large excavators and bulldozers, and lifts. The average cost to retrofit each machine fell in the range of $500 to $3,500 depending on engine size.^[18] Two other retrofitting measures were deployed as well. Equipment was banned from idling for longer than five minutes and all construction equipment was refueled with ultra-low sulfur diesel and emulsified diesel fuels.^[19]

[edit] References

1. ↑ Technologies Make Diesels Less Dirty. The Science and the Environment Bulletin. Environment Canada. 26-01-2009.
2. ↑ What Are Diesel Emissions? Nett. 26-01-2009.
3. ↑ Technologies Make Diesels Less Dirty. The Science and the Environment Bulletin. Environment Canada. 26-01-2009.
4. ↑ Diesel Engine Retrofits in the Construction Industry: A How to Guide. Massachusetts Department of Environmental Protection. 26-01-2009.
5. ↑ Diesel Engine Retrofits in the Construction Industry: A How to Guide. Massachusetts Department of Environmental Protection. 26-01-2009.
6. ↑ Diesel Engine Retrofits in the Construction Industry: A How to Guide. Massachusetts Department of Environmental Protection. 26-01-2009.
7. ↑ National Clean Diesel Campaign. U.S. Environmental Protection Agency. 26-01-2009.
8. ↑ National Clean Diesel Campaign. U.S. Environmental Protection Agency. 26-01-2009.
9. ↑ Why Retrofit. Meeting the Challenge. Diesel Technology Forum. 26-01-2009.
10. ↑ California Clean Construction Equipment. Clean Vehicles. Union of Concerned Scientists. 26-01-2009.
11. ↑ Clean Construction USA. U.S. Environmental Protection Agency. 26-01-2009.
12. ↑ Voluntary Diesel Retrofit Program. U.S. Environmental Protection Agency. 26-01-2009.
13. ↑ Construction equipment retrofit gives environment a new look. 26-01-2009.
14. ↑ Making Heavy-Duty Vehicles Cleaner. B.C. Air Action Plan. BC Government. 26-01-2009.
15. ↑ B.C. to require filter refitting on largest polluting trucks. Today's Trucking. 26-01-2009.
16. ↑ Dirty Trucks Must Clean Up Their Act in B.C. The Airzone Blog. 26-01-2009.
17. ↑ Clean Diesel Construction Requirements. Illinois Campaign to Clean Up Diesel Pollution. 26-01-2009.
18. ↑ Diesel Engine Retrofits in the Construction Industry: A How to Guide. Massachusetts Department of Environmental Protection. 26-01-2009.
19. ↑ Case Studies of Construction Equipment Diesel Retrofit Projects. Manufacturers of Emission Controls Association. 26-01-2009.