The Liberal government launched a six-year, $3.9-billion design and development plan Wednesday that Prime Minister Justin Trudeau says will eventually connect Quebec City and Toronto with a high-speed rail line.

Natural gas, which emits less carbon than coal when burned, is a plentiful resource that many say is the future of fossil-fuel-generated electricity. But it's still a source of air pollution and competes with other types of clean energy.

Electricity is a major source of government revenue, but also a source of conflict. Each province manages its electrical resources in its own best interests, and this strong regional focus leads to rivalries.