PORTLAND — A panel that sets policy for the Bonneville Power Administration says the Pacific Northwest can rely on conservation to meet most of the new demand for electricity over the next two decades. The Northwest Power and Conservation Council released its plan Thursday in Portland for public comment. The panel has representatives from Washington, Idaho, Montana and Oregon. Every five years it produces a long-term energy plan to guide the BPA, the largest electricity supplier in the region. The plan envisions that adopting more energy-efficient technology and practices could offset 85 percent of the demand for new electrical generation in the Northwest in the two decades ending in 2030.