The territory's environmental watchdog says it's powerless right now to direct Yukon Energy's management of diesel generation and its impact on air quality over Riverdale.

Riverdale residents had asked the Yukon Environmental and Socio-economic Assessment Board to recommend changes in the management of diesel generation during its review of the Carmacks-Pelly Crossing transmission line project.

Residents of Riverdale pointed out to the board that they are the most impacted by a reduction of air quality when additional diesel generation is needed to handle peak demand on the Whitehorse-Aishihik-Faro (WAF) grid.

It is accepted and numbers in the board's final screening report released earlier this month show additional diesel generation will jump with the addition of the Minto mine and Pelly Crossing on the WAF grid coupled with a general growth in demand.

The closest Riverdale residence, it was pointed out, is within 300 metres of the generators situated at the Whitehorse dam, and all five schools in the subdivision are within 1.5 kilometres.

With the need to supplement hydro-generation with diesel as the new mine comes onto the grid with other large industrial customers expected to follow the publicly-owned Yukon Energy should change its ways, the residents suggested.

The suggestion was also echoed by the Yukon Department of Health and Social Services.

Instead of turning to the Whitehorse generators to meet additional demand, Yukon Energy should first of all fire up the Faro generator and the Minto mine generators that will become idle once the mine hooks into the grid next year.

Turning to the remote generators first will significantly reduce the impact on air quality in Riverdale, particularly during periods of wintertime inversions. That's when diesel emissions and woodsmoke are trapped over Riverdale, the residents submitted to the board.

The Yukon's Department of Health and Social Services also noted the impact of air quality and the potential harm for school children with additional diesel generation at the Whitehorse dam.

In its submission to YESAB, Health and Social Services pointed out additional diesel generation will require 222,800 litres of fuel in 2009 with the grid extension, compared to 52,600 litres without the extension.

The number of litres with the extended grid will hit 506,000 litres in 2012, compared to 162,000 without, and by 2016 1,839,400 litres, compared to 536,700 without the grid extension.

Additional generation, the health department submitted, will reduce air quality and impact on human health, particularly with additional diesel generation at the Whitehorse plant next to the 5,000 Riverdale residents.

But the department indicated Yukon Energy has said it will turn first to the newer and more efficient Whitehorse diesels when additional generation is needed.

'Place the diesels at the Minto mine and Faro first on the stacking order, then little or no diesel may be burned at the Whitehorse plant,' reads the recommendation from the health department. 'This removes the generation of potential pollutants from population centres, eliminating the human health risk.'

'Avoid operating the Whitehorse diesel plant during problematic atmospheric conditions that accumulate contaminants in a populated area.'

The health department notes in its submissions that the Whitehorse diesels are scheduled for rebuilding in the next few years. As well, operating permits for the diesel's run out next year, providing an opportunity to ensure Yukon Energy is held to the highest quality emission standards, the department suggests.

In it conclusions, the review board notes it has no ability in this review to address the concerns raised about emissions at the Whitehorse Rapids dam.

But like the health department, the board noted the operating permits for the diesels run out at the end of next year.

'Given the exclusion from the scope of the project, direct and indirect effects associated with the operation of the diesel unit(s) are not considered in the scope of this assessment,' the board states in its final screening report.

'Upon expiry of existing permits, the operation of the Whitehorse diesel unit may be subject to a YESAA assessment. It will be at that point where the direct, indirect, and cumulative effects of the operation of the diesel unit can be more appropriately addressed.'

While additional diesel generation may be required on the system at certain times, Yukon Energy maintains that provided surplus hydroelectric power currently on the WAF system will save the millions and millions of litres required annually for diesel generation at Pelly Crossing and the Minto mine.