Energy became a key election issue just weeks into the marathon campaign, with the leaders facing questions about their positions on a number proposed pipeline projects.

But some party leaders have been clearer than others on controversial projects.

The Green Party is the only one to oppose all current pipeline project proposals that plan to ship raw bitumen out of Canada. During the August leaders debate, Leader Elizabeth May attacked the Conservative and NDP’s stance on pipeline projects. In particular, she took aim at NDP Leader Tom Mulcair about whether he supported the Kinder Morgan project proposed for B.C. “It’s pretty straight forward,” she said. “They plan to put three times as many tankers moving out of Vancouver loaded with diluted bitumen, hazardous risky material.”

May has said every current pipeline proposal is about “getting raw, unprocessed bitumen to tidewater.”

Among her explanations of why the Green Party rejects all proposed pipelines is that they are based on a “risky economic strategy.” She has also expressed concern that a single accident could “cripple the entire billion dollar fisheries and tourism industry.” Instead, the Green Party has said it wants a national energy strategy with a strong climate plan.

Here’s breakdown of each of the other parties' stance on four major pipeline proposals.

KEYSTONE XL

TransCanada’s $8 billion Keystone XL project would carry crude oil and bitumen from Alberta’s oilsands through the U.S. to Nebraska, where it would connect with existing pipelines to Texas refineries.

The proposed 1,900-kilometre pipeline has become a sore spot for U.S.-Canada relations over its years-long delay. While the Conservative government has branded the pipeline as a benefit to both countries, U.S. President Barack Obama has expressed doubt about the number of permanent jobs it will create, and vetoed a Republican-backed bill to bypass a State Department review and begin construction of the project.

Last month, U.S. Republican Senator John Hoeven predicted Obama would reject the pipeline when Congress went on break in August. And TransCanadasources close to the project recently told The Canadian Pressthat they feel rejection is likely.

But with Canadian politicians on the campaign trail, it’s unclear how the Oct. 19 federal election will affect the timing of a U.S. decision on Keystone.

Conservatives - YES

Harper has made his position on the Keystone pipeline crystal clear, once calling the U.S. approval of the project is a “no brainer” and, at a later date, describing the approval as inevitable-- if not under the Obama administration, than the subsequent administration. The project’s approval has undoubtedly been one of Harper’s highest priorities as prime minister.

The Conservative government has long-touted the benefits the proposed pipeline offers, including job creation and the replacement of oil imports from insecure countries like Venezuela with a reliable supply from Canada.

The Conservatives also point to an environmental review by the U.S. State Department concluding that the pipeline would not significantly impact the environment, as some environmental groups have warned.

NDP - NO

NDP Leader Tom Mulcair opposes the pipeline, saying the project represents the export of 40,000 jobs to the U.S. Rather, Mulcair has said he would like to see the bitumen moved within Canada to keep those jobs in the country and “take care of Canada’s energy security.”

There has been some controversy around the job numbers relating to Keystone. While an analysis by the U.S. State Department found that the pipeline would support 42,100 jobs during the one- to two-year construction period, only 35 permanent and temporary jobs will remain in place once Keystone XL is complete and fully operational.

The federal New Democrats have support for their position on Keystone from Alberta NDP Premier Rachel Notley, who has said her newly elected government won’t lobby for the pipeline.

Mulcair has said he would strengthen the environmental review process for pipeline projects to ensure they meet Canada’s international obligations to reduce greenhouse gas emissions.

Liberals - YES

Liberal Leader Justin Trudeau has said he backs Keystone because it is in the public interest.

However, he has criticized Harper for letting the project come between Canada and the U.S., calling it a “diplomatic failure.” Speaking in June to Canada 2020, a progressive think tank, Trudeau accused Harper of doing nothing to address the Obama administration’s environmental concerns relating to Keystone.

The Liberals have suggested the pipeline may have had a better chance of approval if the Conservative government had done more on climate change.

ENERGY EAST

TransCanada’s Energy East pipeline would ship up to 1.1 million barrels of oilsands crude per day to refineries and export terminals in Quebec by 2017, and to New Brunswick by 2018. The company wants to convert the current natural-gas pipeline, which ends in eastern Ontario, to oil service, and add new pipe in order to deliver crude to Quebec and New Brunswick.

The 4,600-kilometre pipeline’s lengthy route through many provinces -- Alberta, Saskatchewan, Manitoba, Ontario, Quebec and New Brunswick -- also makes it a sensitive project.

In October 2014, TransCanada submitted its project application for the Energy East pipeline to the National Energy Board (NEB), which now has 15 months to review the application. That gives the NEB until early 2016 to make a recommendation to the federal cabinet on the project.

But a cloud of criticism hovers over the $12-billion proposed pipeline, with opponents of the project describing it as unsafe for the environment.

Conservatives – YES, IN PRINCIPLE

Harper has said that the Energy East pipeline is a good project in principle, as it’s important that Canada get its energy products to market. However, the Conservative government has highlighted the fact that all pipeline projects must undergo a review process.

NDP - MORE CONSULTATION NEEDED

Mulcair has faced criticism for his position on Energy East. Trudeau has accused him of double-speak on the project by sounding doubtful about it when speaking in French, and more optimistic in English. While the project is widely opposed in Quebec, it has huge support in western Canada -- both regions the NDP would like to gain more seats, forcing the party to walk a fine line on the pipeline.

If elected, the NDP has said it would introduce a new approval process for big energy projects and restart the process for Energy East. The party also says more consultation is needed on the project before making a decision.

"You can't say 'yes' to Energy East or any other project right now because the public simply can't have confidence (in the process),” said Mulcair last week. "So the first thing we'll do is put back the process, and re-start Energy East under that credible process."

Notley, however, has said she is in favour of Energy East, expressing hope that Quebec will support the project if Alberta does its part to protect the environment along the way.

Liberals – MORE CONSULTATION NEEDED

Trudeau has said he won’t fully support Energy East until more public consultations are held to address environmental concerns related to the project.

Amidst Trudeau’s hesitancy to back the pipeline, his Liberal colleague in New Brunswick, Premier Brian Gallant, has said he hopes the provinces and territories can co-operate on energy projects like Energy East. Gallant says the project would help grow the economy and create jobs -- some 2,300 in New Brunswick alone, according to TransCanada.

NORTHERN GATEWAY

Enbridge’s 1,177-kilometre Northern Gateway pipeline would carry bitumen from Alberta’s oilsands to the B.C. coast town of Kitimat, and then be shipped overseas.

The Conservative government conditionally approved the Northern Gateway project last June on the basis that it meets the 209 conditions set out by a joint federal review panel in 2013. Those conditions include consultations with affected aboriginal communities, as well as authorization from federal and provincial governments.

The B.C. government has also said that Northern Gateway still doesn’t meet the five conditions for approval set out by the province, which include a full environmental review and respect for aboriginal and treaty rights.

Environmental and aboriginal groups have expressed fierce opposition to the Northern Gateway pipeline, filing almost 20 legal challenges against the project since the feds approved it last year.

Conservatives – CONDITIONAL YES

The Harper government has long said that Northern Gateway is crucial to the development of Canada’s natural resources sector, making it a big part of its energy strategy.

However, it’s important to note how the Harper government’s approach to the pipeline has changed over the years. Harper, who once said Energy East was of “vital interest” to Canada, only issued a press release when cabinet approved the project, and didn’t put up any caucus members at the time to talk about the decision. The Harper government has since emphasized the work that the “proponent” -- or Enbridge -- has to do to fulfill the public commitment it made to engage with Aboriginal groups and local communities along the pipeline’s route.

NDP - NO

The NDP immediately denounced the government’s conditional approval of the pipeline last year, saying it is part of Harper’s “big oil agenda.”

If elected, Mulcair has said an NDP government would immediately reverse the decision to accept the NEB’s approval of the pipeline. The NDP leader also believes the pipeline will be an election issue in B.C., where many of the affected communities are located.

And, again, Mulcair finds support from Notley in Alberta, who has said her government won’t lobby for the Northern Gateway project.

Liberals – NO

Liberal Leader Justin Trudeau also opposes the Northern Gateway pipeline.

“If I win the honour of serving as prime minister, the Northern Gateway pipeline will not happen,” he said after the government approved the project last year.

“This government has been nothing but a cheerleader for this pipeline from the very beginning when Canadians needed a referee.”

TRANS MOUNTAIN

Kinder Morgan’s $7-billion twin pipeline would triple the bitumen-carrying capacity of the current Trans Mountain pipeline, by adding nearly 1,000 kilometres of new pipe between Edmonton and Vancouver. From there, it would be shipped to Asian markets. The proposal would also increase the number of tankers in Vancouver’s Burrard Inlet from five to 34.

Earlier this month, the NEB issued 145 draft conditions that the company must meet if the Trans Mountain expansion is to be approved, including improved emergency response, increased consultation with First Nations and details about plans to protect endangered species.

Kinder Morgan boasts that Northern Gateway would create 180 local jobs worth $17 million and more spinoff jobs for contractors and suppliers.

But environmental groups and several First Nations are opposed to the project, saying it threatens B.C.’s sensitive coastline and the Great Bear Rainforest. For instance, an independent review by the the Tsleil-Waututh Nation in B.C. found that a spill could kill as many as 500,000 birds and destroy up to 25 kilometres of shoreline.

Conservatives - YES

The Conservative government has pressed for the Trans Mountain pipeline as part of its push for oilsands development and pipeline growth.

NDP – MORE CONSULTATION NEEDED

In the first leaders’ debate of the federal election earlier this month, Mulcair refused to say whether he would approve or reject Energy East, despite repeated calls from Green Party Leader Elizabeth May to do so.

"Do you support Kinder Morgan?" the Green leader repeatedly asked Mulcair.

Mulcair did not directly answer May, rather saying the project needs to go through a rigorous review process first.

“Ms. May takes the position that you can say no to them, all of them, in advance. Mr. Harper is taking the position that you can say yes to all of them in advance. We want a clear, thorough, credible process that the public can have confidence in,” said Mulcair during the debate.

Liberals – OPEN TO THE PROJECT

Trudeau has indicated that he’s willing to consider the proposed the Trans Mountain project if it passes environmental review and gets support from the affected communities. He has said that Kinder Morgan can learn from Enbridge’s experience that “community buy-in is at the centre of infrastructure projects.”

With files from the Canadian Press