As the P.E.I. government looks to convert more public buildings to biomass heat, the Official Opposition is questioning the net environmental impact, and government says it too is looking for answers.

The capital budget tabled by the King government last week commits $6.6 million to add 13 more public buildings to the list of 33 schools, hospitals and other buildings converted from heating oil to biomass heat.

But as the Opposition pointed out in question period Friday, the environmental benefits of switching to wood heat depend on how the wood is harvested, whether plantings keep up with harvested trees, and how long trees are allowed to grow before they're cut.

"When we burn biomass for energy, we initially and immediately emit greenhouse gases, more than burning coal per unit of energy," Green Party energy critic Stephen Howard told the House.

"We then draw the carbon back out of the atmosphere as trees or other crops grow back, but the time to get those greenhouse gases back can be decades."

Island-wide survey next year

The province's Energy Minister Steven Myers said he has some of the same questions and concerns as the Opposition, some of which have been answered, "and some of them are still outstanding."

"I think we've done a lot as far as reducing how much fossil fuel we burn, particularly in our bigger buildings, and that's something that we should continue to work towards," Myers said.

"I agree we want to do it in a sustainable manner. We're just working through those efforts right now."

Energy Minister Steven Myers said he has some of the same questions as the Opposition when it comes to the environmental impact of biomass heating. (Rick Gibbs/CBC)

The province has committed to planting one million trees per year, up from the current 900,000.

But there's no clear indicator of how many trees are harvested each year. For that figure, the province relies on an Island-wide survey using Lidar technology, which is similar to radar, but uses light from a laser.

The survey is done once per decade, with the next survey taking place in 2020.

"So it's a matter of figuring out if we're planting a million trees a year, how does that compare to the number of trees we're harvesting?" Environment Minister Brad Trivers said in an interview.

"And of course making sure that when we harvest trees for biomass or other reasons we're making sure we plant back what we harvested so that we get a net benefit."

'Data should come first'

Government said contractors who provide biomass are required to follow sustainable harvesting standards. The province has voluntary guidelines for other woodlot owners.

Trivers said the province has created a new position for a forest auditor to "make sure that we're harvesting the right wood" for biomass heating "and we're harvesting in the right methods."

Opposition energy critic Stephen Howard questioned the net environmental impact of biomass heating. (Rick Gibbs/CBC)

"Part of our plan here seems to be to plant a bunch of trees to capture some carbon, which is a good idea of course, but part of the plan is also taking those trees and burning them," said Howard.

"If we don't strike the right balance there then we can throw everything off."

Howard said the province is moving forward with more investments in bioheat before it has the data to show whether the move is sustainable given current forestry practices.

"We shouldn't move forward with a plan to burn more trees if we don't have the proper sustainable management plan in place," he said. "The data should come first."

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