Cornwall Transit – Cornwall, Ontario - Mid-Sized Transit Service Helps Change Thinking About Natural Gas

Cornwall Transit has proven that natural gas can be a cost-effective transportation fuel for mid-sized urban bus fleets, as well as large fleets. Today, the company is operating about one third of its fleet on natural gas, with excellent driver and passenger acceptance and no significant maintenance or operational problems.

Natural gas and transit fleets
Compressed natural gas (CNG) has long been considered an ideal fuel for urban transit buses because of its low price and environmental benefits. However, the high cost of fast-fill CNG refuelling equipment has prevented many small- and mid-sized transit systems from making the move to natural gas. In the mid-1990s, Cornwall Transit decided to tackle the problem – and found an innovative solution.

Cornwall Transit serves the city of Cornwall, Ontario (population 47 500), with 35 buses that transport about 1.3 million passengers per year. The transit service's commitment to effective and efficient service, with an emphasis on energy conservation and environmental protection, was a key factor behind the decision to invest in natural gas buses.

Cornwall Transit takes the lead
As the first step in introducing natural gas to the fleet, in 1994 Sherman Goodwin, Cornwall Transit Manager, changed an order for five diesel buses to five CNG buses. The price was an additional $50,000 for each bus, but the original delivery date could still be met.

Next, a used slow-fill natural gas compressor was purchased from the local gas utility and installed outside the bus garage, with a discharge line running into the building. This eliminated the need for costly indoor storage of natural gas, which is generally required for fast-fill systems. It also reduced the cost of the compressor to about $75,000 plus $25,000 for installation.

Inside the garage, a refuelling system was installed for $35,000. The system ran along the length of one wall of the garage, where the CNG buses are parked between midnight and 6:00 a.m. for refuelling. All Cornwall Transit buses are off the road during these hours, so the refuelling does not affect the availability of the CNG buses.

The conversion program also required changes to the garage itself (this was part of the $35,000 cost noted above). This included replacing the building's original electrical heating system with 10 gas-fired radiant tube heaters and one gas-fired makeup air unit on the roof. As well, four exhaust fans were modified to draw air from both the ceiling and the floor. All electrical equipment that could produce sparks was made explosion proof.

Sensors were also installed to monitor carbon monoxide and nitrous oxide levels in the bus storage area. A signal from one sensor triggers two of the exhaust fans and the makeup air unit. Signals from two sensors, though, start all four exhaust fans and the makeup air unit. More sensors were placed above the refuelling port for each bus, to monitor natural gas levels. If any of these sensors detect gas levels at even 20 percent of the concentration needed for natural gas to explode in air, the following safety precautions automatically occur:

The natural gas compressor shuts down.

Ventilation in the garage increases.

The natural gas heaters shut off.

An audible alarm sounds to warn occupants of the situation. The alarm shuts off only when natural gas levels are below 20 percent of the explosive level. At this point, the ventilation system continues to operate, and the compressor remains shut down until the control is reset by hand.

Capital investment quickly repaid
The total capital cost of the initial CNG integration project was about $485,000 (including the $250,000 premium for the natural gas buses). In an unrelated retrofit project, Cornwall Transit had previously upgraded the ventilation system in the garage at a cost of $100,000. (Newer transit buildings with modern ventilation systems could likely be modified at a much lower cost).

The Ontario Ministry of Transportation agreed to include the additional cost of the buses, the compressor and the building upgrades in its 75 percent capital-cost grant allocation. As a result, Cornwall Transit recovered $363,000 of its investment. The remainder was repaid in about two years through fuel-cost savings. (At first, the company saved an estimated $13,000 a year in operating costs on each of the five natural gas buses).

Impressive results and positive reaction
In 1995, while the CNG buses were still under warranty, Cornwall Transit put them to a gruelling test. The buses were driven an average of 74 000 kilometres each over the 12 months, compared with an average of 22 500 kilometres for the diesel buses. The CNG buses came through with "flying colours." Despite the arduous driving schedule, the CNG buses experienced no significant maintenance problems and delivered major cost savings due to relatively low natural gas prices.

For the most part, Cornwall Transit's drivers have noticed little difference between the on-street performance of CNG and diesel buses. Although drivers have noted slower acceleration from stops with the natural gas buses, this is considered a plus for passenger comfort. Public feedback on integrating natural gas buses into the fleet has been overwhelmingly positive. Cornwall Transit's commitment to "clean natural gas" was widely praised in local media and trade magazines. And the company received inquiries from transit systems across Canada and in the United States.

Seven more CNG buses added to the fleet
Since the original purchase, Cornwall Transit has added seven natural gas buses to its fleet, bringing the total to 12. (Two of these vehicles were "handivans" converted from gasoline to natural gas.) In total, the CNG buses had logged about two million kilometres by the end of 2001, with no significant issues arising from either the vehicles or the refuelling system. While the company has experienced maintenance problems with some of the new buses, they are not related to the use of natural gas. The original compressor, which was overhauled in 2000 at a cost of $70,000, continues to work well.

Nevertheless, Cornwall Transit does not envision further expansion of its CNG fleet, for two principal reasons. First, the refuelling system cannot service more than 12 buses at a time, and installing a higher capacity system would be costly. Second, the Government of Ontario no longer shares the cost of urban transit. As a result, Cornwall Transit must spend its limited capital budget on the most affordable buses available. For example, the company recently purchased two refurbished diesel buses.

Project has changed industry thinking
Based on current market conditions, Cornwall Transit has determined that increased use of natural gas is not cost-effective at this time. Diesel buses now cost about $75,000 less than CNG buses and have lower maintenance costs. While the price of natural gas continues to be lower than diesel fuel, the overall operating costs for a natural gas bus are slightly higher than for diesel. Cleaner fuels (low-sulphur diesel) are available, which has improved the environmental performance of diesel buses.

Still, Cornwall Transit considers the CNG program a success and remains committed to using natural gas in the 12 vehicles. "Circumstances have changed somewhat since the original integration project, but our experience has also changed industry thinking on what can be accomplished by a small transit operator," says Mr. Goodwin.

Source : Office of Energy Efficiency - Natural Resources Canada

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