Beijing Diesel Retrofit Pilot Program

In cooperation with U.S. Environmental Protection Agency and the Beijing Environmental Protection Bureau (BEPB), China’s State Environmental Protection Administration (SEPA) has conducted a diesel retrofit demonstration project in Beijing. The project entailed installation of emissions control equipment on 25 Euro I and Euro II city buses in Beijing, many of which used low-sulfur fuel in combination. The project was conducted from November 2005 to December 2007.

Three emissions reduction retrofit devices were demonstrated on the buses:

• Diesel oxidation catalyst (DOC) that can reduce particulate matter (PM) by as much as 30%;
• Catalyzed flow-through diesel particulate filters (FTDPF) that are continuously regenerated. These FTDPFs can reduce diesel PM by approximately 50%;
• Non-catalyzed wall-flow catalytic filters (WFDPF) that are electrically-regenerated. These WFDPFs can reduce particulates by more than 90% when used with low-sulfur diesel fuel.

The U.S. EPA provided technical and financial support to the diesel retrofit demonstration project. The goals of the demonstration project were to promote clean air; serve as a model for other cities; demonstrate retrofit capabilities; and to demonstrate the importance of ultra-low sulfur diesel fuel. The retrofitted buses were assigned to operate on one of two different fuels to demonstrate the importance of low-sulfur diesel fuel. The first fuel was the Beijing standard No. 2 diesel fuel having a nominal fuel sulfur content of 350 ppm, by weight, and the second fuel was also a No. 2 low-sulfur diesel fuel that is specially refined for minimum sulfur content of less than 50 ppm.

This project also demonstrated the importance of employing adequate maintenance procedures on existing buses before implementing a diesel retrofit program. Installation of retrofit technologies on buses in Beijing that had not been repaired or received regular engine maintenance resulted in poor emission performance and premature failures of the retrofit devices. Once bus engines had received maintenance and repairs, retrofit technologies delivered their expected performance levels and continued to deliver emission reductions during the remainder of the project.

The following retrofit technologies were installed on Euro I and Euro II buses:

Emissions testing using an on-board emission measurement system for DOCs on Euro I and Euro II buses showed conversion efficiency between 3.5 to 22% for PM reduction. The FTDPFs on Euro I and Euro II buses showed PM conversion efficiency ranging from 19 to 70% and the WFDPFs on Euro II buses showed PM conversion efficiency between 85 to 93%.

More information on this is available at: www.vault.swri.org/retrofit.

Mexico City Diesel Retrofit Pilot Project

The Mexico Center for Sustainable Transport (CTS-Mexico), with funding from the U.S. Environmental Protection Agency, U.S. Agency for International Development and the World Resources Institute, conducted a pilot project to reduce diesel emissions from existing buses in Mexico. The project was conducted in cooperation with the Mexican local public agencies, such as the Mexican Federal Government’s Environmental Ministry (Semarnat) and the Mexico City Secretariat of Environment (SMA). For this pilot project, twenty working buses in the Red de Transporte de Pasajeros del Distrito Federal (RTP) fleet were retrofitted with either a diesel oxidation catalyst (DOC) or a diesel particulate filter (DPF) and were fueled with ultra-low sulfur diesel fuel (ULSD, 15 ppm sulfur max.). Twelve of the buses were retrofitted with DPFs and eight with DOCs. The DPF was a passively regenerating technology that combined a DOC with an uncatalyzed wall-flow ceramic filter element. This DPF technology has been U.S. EPA verified to reduce PM by 90%; CO by 85%; and hydrocarbons by 90%. The DOC was also EPA verified to reduce PM by 20%; CO by 40%; and hydrocarbons by 50%.

Emission testing was measured using RAVEM (Ride-along Vehicle Emissions Measurement), a portable emissions measuring laboratory, to obtain second by second measurement of gaseous and PM emissions during normal Mexico City driving and operating conditions. The buses were assigned to three different routes. Due to budget restrictions, only 15 of the 20 retrofitted buses were chosen for exhaust emissions testing. The emission testing conducted at 4,000 km and 55,000 km for the three routes showed average emissions of:

This pilot project demonstrated that DPFs, when used with ultra-low sulfur diesel fuel, can reduce harmful diesel PM by up to 99%, even after a year of continuous operation.

Minibuses jockey for passengers in Mexico City.

   

Hong Kong Diesel Retrofit Project

During the 1990s, almost all commercial vehicles in Hong Kong were fueled by diesel, accounting for about two thirds of the vehicle mileage traveled within the metropolitan region. These diesel trucks and buses accounted for almost all the particulate matter and 75% of nitrogen oxide (NOx) emissions in 1997. Beginning in 2000, the Hong Kong Environmental Protection Department (Hong Kong EPD) began implementing measures to control emissions from all vehicles, targeting the reduction of PM and NOx emissions by about 80% and 30%, respectively, by 2005. The Hong Kong government set aside HK$1.4 billion for this program that included both replacement of some diesel vehicles with cleaner alternatives (e.g., LPG-fueled or electric light buses) and the retrofit of existing diesel trucks and buses.

In 2001, Hong Kong EPD completed a retrofit program that targeted pre-Euro light diesel vehicles. In this effort approximately 24,000 light diesel vehicles were retrofit with diesel oxidation catalysts (DOCs) that cut diesel PM by about 30% from these pre-Euro diesel vehicles. Since December 2003, all pre-Euro light diesel vehicles (up to 4 tons vehicle weight) have been required to be retrofit with DOCs.

In 2004, Hong Kong completed a DOC retrofit program on pre-Euro medium and heavy diesel vehicles that did not require the use of on-board equipment during idling. Approximately 34,000 trucks were retrofit with DOCs as a part of this program. In 2005, this same retrofit program was extended to "long idling" pre-Euro heavy diesel vehicles with another 2,500 trucks successfully retrofit with DOCs. On these pre-Euro heavy diesel trucks, retrofit DOCs cut particulate emissions in the range of 25 to 35%. These retrofit programs were followed by regulations that required retrofit DOCs on all pre-Euro heavy trucks (from April 2006 for most trucks, from April 2007 for "long idling" heavy trucks).

Bus companies operating in Hong Kong have retrofit about 2,000 older pre-Euro and Euro 1- compliant diesel buses with DOCs, and are now retrofitting Euro 2 and Euro 3-compliant buses with diesel particulate filters. Honk Kong has required that diesel fuel limit fuel sulfur levels to 50 ppm or less since January 2005 and since the end of 2007 has instituted policies that provide financial incentives for the sale of diesel fuel with no more than 10 ppm S.

   

South Korea Diesel Retrofit Project

In 2004, the Ministry of Environment in Seoul, South Korea launched a pilot project to reduce diesel vehicle emissions, by adopting a plan to reduce PM and NOx emissions by 50 to 70%. The plan started implementation in 2005 and is targeted to continue through 2014 with an expected budget of US$5-6 billion over 10 years, of which US$4.7 billion will be used to retrofit diesel vehicles with emission reduction devices or convert to LPG or CNG vehicles. The plan targets 1.1 million diesel vehicles in the Seoul Metropolitan Area for retrofit, conversion to LPG or CNG engines, or vehicle scrappage. The retrofit program requires that heavy-duty vehicles be equipped with a DPF system that achieves PM reductions of at least 70%. For medium-duty vehicles, the program requires that the vehicles be equipped with partial DPFs (pDPF) that achieve at least a 50% PM reduction. For light-duty applications, the program requires that the vehicles be retrofitted with a DOC and/or pDPF systems that achieve at least a 25% PM reduction. The installed DPF systems are expected to reduce PM emissions by 90-95%; the installed partial DPF systems are expected to reduce PM emissions by 30-75%; and DOCs are expected to reduce PM emission by 25%. Through April 2005, 470 DPFs and 1,064 DOCs were retrofitted on diesel vehicles. The Ministry of Environment plans to install 581,744 DPFs/partial DPFs and 235,550 DOCs by 2010.

Tokyo Diesel Retrofit Project

In December 2000, the Tokyo Metropolitan Government (TMG) adopted a new "Ordinance on Environmental Preservation", which included a variety of regulatory measures to control air, water, soil, and noise pollution. Included in these measures are "Countermeasure Against Vehicle Pollution" program, which includes diesel emission control regulation. This diesel retrofit program requires that certain categories of in-use diesel vehicles be retrofitted with emission control systems to reduce PM emissions or be banned from traveling in the TMG area. The new Ordinance took effect on April 1, 2001, with the diesel retrofit program becoming effective on October 1, 2003.

The diesel retrofit program applies to in-use diesel buses, trucks, and special category vehicles based on buses and trucks, such as campers, garbage collection trucks, and refrigerator/freezer vehicles. The program requires that the in-use diesel vehicles be retrofitted with diesel particulate filters. Passenger vehicles are not subject to this retrofit requirement. The PM emission reduction requirements depend on the vehicle emission level at the time of its manufacture. Older vehicles have more aggressive PM reduction requirements while new vehicles that meet more stringent new engine emission standards have more relaxed PM emission reduction requirements. The retrofit program has a two-tier structure: Tier 1 requirements became effective in October 2003 and the Tier 2 requirements became effective in 2005. Details of the requirements are detailed in Table 1 below.

All PM emissions reduction devices have to be approved by the "PM Reduction Device Designation Committee", established by the TMG. Once the diesel vehicle is retrofitted, vehicles are affixed with stickers with the approval number of a given PM control device. Additionally, three neighboring prefectures adopted similar measures.

After two years, the program achieved 44% reduction in PM emissions. Comparing the level of carbonaceous aerosols in Tokyo before and after this regulation, it was found that the ratio of elemental carbon/total carbon was significantly decreased from 0.567 to 0.502 after the regulation, although the absolute mass concentration of submicron particles did not decrease significantly.

Tokyo Diesel Retrofit Vehicle Sticker

Other Examples

Successful international diesel retrofit projects have also been completed on bus fleets operating in many large cities of Europe including London, Brussels, Paris, Milan, Copenhagen, Gothenburg, and Stockholm. In most cases these European buses have been retrofit with high efficiency, diesel particulate filters to maximize reductions of diesel PM in urban centers (buses are operating on diesel fuel with a maximum of 50 ppm S). An increasing number of European cities and regions have also put in place Low Emission Zones to reduce vehicular pollution. In many instances these Low Emission Zones mandate vehicles meet minimum emission performance standards that in some cases include retrofit requirements for existing buses and trucks. More detailed information on European Low Emission Zones is available at: http://www.lowemissionzones.eu/content/view/63/90/lang,en/. Diesel retrofit programs have also been successfully applied to construction equipment used in large tunnel projects through the Alps in countries including Switzerland, Germany, and Austria. In these projects construction equipment must be equipped with filters approved through the Swiss VERT approval process. More than 10,000 filters have been successfully retrofit on a large variety off-road equipment in Europe through the VERT program. An application database of retrofit filters that have received VERT approval is available at: http://www.akpf.org/db/. MECA’s European international affiliate organization, AECC, also has a website that provides information on European retrofit experience. The AECC European diesel retrofit website is available at: www.dieselretrofit.eu.

Diesel retrofit projects have also been successful in other regions of the world including urban buses operating with retrofit filters and low sulfur diesel fuel in Santiago, Chile. A bus retrofit demonstration project is currently underway in Pune, India with the support of the U.S. EPA. This project includes installation of both passively regenerated, high efficiency diesel particulate filters and partial filters on buses fueled with low sulfur diesel fuel.