Seattle Post-Intelligencer: If you’re watching for more energy conservation in the coming four years, you might look no farther than down your street. There’ll be a different kind of glow on the pavement. Seattle plans to spend an estimated $23 million to upgrade 40,000 of its 84,000 street lights over by replacing their high-pressure sodium lights with state-of-the-art light-emitting diodes (LEDs). It’s a big up-front investment, one that city officials say will eventually be paid back because the LEDs …