Richard Gleeson
Northern News Services

Yellowknife (Apr 12/02) - City Hall is continuing some quiet work it has been doing toward becoming a greener organization.

Mayor Gord Van Tighem says energy efficiency is no longer seen as a strictly environmental measure. People now realize it makes good business sense.

"When you go to different meetings they no longer talk about greenhouse gas emissions, they talk about introducing municipal efficiencies."

The city's conservation initiatives are tied to an environmental goal. It has committed to reduce its greenhouse gas emissions to 20 per cent below 1990 levels by 2013.

Toward that end, the city will this year establish what greenhouse gas emissions were in 1990 and what they are this year.

Most of the energy saving measures to date have focused on one of the municipality's biggest money sinks, the cost of providing piped water service.

The city's water supply comes from the Yellowknife River through eight kilometres of pipe sitting on the bottom of Great Slave Lake. It enters the city water system at Pumphouse No. 1, just off School Draw Avenue.

Raw water coming into the pumphouse is heated by a large boiler to prevent it from freezing in water mains. On average over the last nine years, that boiler has accounted for 25 per cent of the municipalities total fuel consumption, city statistics show.

In the past, the city heated its water 24 hours a day seven days a week between the months of November and April to prevent it from freezing and damaging in the underground pipes.

For the past six years the city has been keeping increasingly close tabs on the temperature of its piped water during winter.

"What we do now is just keep it above freezing," city public works director Greg Kehoe said. "There's really no benefit if the water is 40 C."

City numbers show that cutting back the temperature of the water to four or five degrees closer to freezing, fuel consumption by the boiler has dropped from 580,00 litres in 1992 to an average of 210,000 in recent years.

Heating water less is one of a number of measures that resulted in the 64 per cent reduction.

A comprehensive renewal of the city's system of water mains, initiated during Dave Lovell's time as mayor, is probably is the most costly and beneficial change to the system.

The city's old, leaky water mains are being replaced by insulated longer-lasting pipe. During the transition a new leak detection system was introduced.

The two measures, combined with efforts by organizations such as the Arctic Energy Alliance to raise awareness of home energy use, have resulted in a 16 per cent reduction in total water use over the last decade. The reduction came during a period when the city's population grew by 15 per cent.

Last year, Pumphouse No. 1 got a little more efficient with the addition of a device that controls the output of the pumps that push the water into the city system. The variable frequency drive regulates the output of the electric pumps, and consequently the energy they consume, according to the pressure in the water mains.

"In the old way, the pump runs at zero or 100 per cent," said city works engineer Julian Huang. "With the VFD it runs according to demand."