Environmentally driven: SD 23 Central Okanagan School District utilizes CNG school buses in its fleet

SD 23 Central Okanagan School District utilizes CNG school buses in its fleet By Shayna WiWierSki Photos by harold Schock.

When the SD 23 Central Okanagan School District needed nine buses replaced in 2011 it was a great opportunity to try out something new.

The school district ended up getting nine compressed natural gas (CNG) buses, which are fueled by CNG, a fossil-fuel substitute for gasoline and diesel. Not only is the overall cost of fuel per kilometre lower, but the environmental footprint is much less and they emit way less fumes than a traditional bus.

Currently, there are 17 CNG buses in SD 23’s 72-bus fleet, which also consists of diesel and propane buses. Although the school district hopes to have them all CNG eventually, the buses are replaced based on when they are up for renewal.

“Every year we are allotted so many buses for renewal. They don’t all age at the same level, it’s either 15 years or kilometre limited, whatever comes first, then they are up for replacement,” said Harold Schock, energy and sustainability manager for SD 23. “The Ministry of Education decides that a replacement can occur, then they provide funding to replace them.”

The school district had been looking at the CNG option since it was better for the environment and would cost the district less money in the long run. Since they needed nine buses replaced at once it was economically feasible to replace the old diesel buses with CNG since they require their own filling station.

The school district has two filling stations at their home base, an overnight fueling station, where buses are plugged into any of the four station arrays at the end of the day, as well as one curbside fast fill station that takes about 20 minutes to fill up. The buses do take a little longer to fill then conventional diesel bus, but once the CNG tanks reaches 3,000 PSI, the filling station stops. The overnight station can have up to 16 buses plugged into it.

Since they rely on their own fuel station, that affects the length of distance they can travel.

“We are limited to the amount of buses that we can operate by the extra-curricular activities the buses are doing during the day. Since our neighbouring cities don’t have CNG filling stations we are limited to a 200-kilometre radius, there and back, plus a buffer of 100 kilometres so they don’t run out of CNG,” said Schock, adding that they are making the ministry more aware that they would like to see more fueling stations in the province so they can take the buses on more long-range trips.

The buses themselves are the SAF-TLiner HDX CNG school bus by Thomas Bus, based in North Carolina. They are all pusher buses, meaning the engine is in the back. They feature a seating capacity of 84 people (although one of the buses is used for special-needs children, which can handle a combination of students and three or four

wheelchairs) and the engines are 250 HP Cummins with a six-speed Allison transmission. The CNG buses go much further compared to diesel buses before they require an oil change. For example, diesel buses would require an oil change after 4,000 kilometres, and the engine oil is black from the carbon created in the combustion chamber. The CNG bus engine oil is very clear and very low in carbon at 4,000 kilometres.

“Our newer conventional buses cost about $0.15 per kilometre to service, whereas the [CNG] buses are closer to $0.20 when comparing just the consumable maintenance parts. CNG buses save us money in the long run because the cost of fuel per kilometre is cheaper in CNG,” said David Misener, transportation manager for SD 23 Central Okanagan School District. “Our district saves over $50,000 dollars a year in fuel for our 17-vehicle fleet. Since they’ve been operating since 2010, they have gone over 1.3 million kilometres.”

Not only do the buses save the school district money in fuel costs, but they also have a smaller environmental footprint, which is important because of the geographical location of the Central Okanagan School District.

“[We went with CNG] because of an environmental choice we made back in 2010 to explore alternate fuel sources. It made environmental sense since we are in a valley,” said Schock, adding that diesel at that time had a higher emission value than CNG. “Every year we have to report on our emissions on our buses and fleet vehicles. We found that CNG has a smaller environmental footprint than diesel, so it could save us 27 per cent on our greenhouse gas emissions and our carbon footprint.”

Although CNG is better for the environment than diesel, Schock mentions that the gap is getting smaller. The industry has changed now in that diesel is running a lot cleaner than engines from the past, however, there’s a lot of maintenance to make diesel engines run clean. Since the province of B.C. is so environmentally conscious, both Misener and Schock hope to see the industry evolving and seeing advancements in cleaner fuels in the future.

“B.C. is trying to lead the way with LNG and CNG. It's my hope one day that we would have an LNG bus,” said Misener. “If you look at the success of LNG transport truckThe CNG buses are better for the environment and cost less over time.

ing and LNG passenger ferries technology, transportation buses will be next area to grow with LNG. In B.C., energy conservation has advanced our economy. The province has created the framework to help with environmental concerns and we are doing our small part.” n

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