The Bonneville Power Administration (BPA) last week proposed a $428 million upgrade to the Pacific Direct Current Intertie, an 846-mile overhead transmission line that delivers hydropower and wind power between the Northwest and California. The line is one of the world’s longest and highest capacity transmission links.

The BPA said the upgrades would modernize equipment that was “cutting edge when installed more than 40 years ago,” but which has since become so outdated that the public service organization had to source parts to repair the line from online auction website Ebay.

The upgrades would also increase the line’s capacity from 3,100 MW to 3,220 MW and help it avoid outages and “strengthen it against weather and other threats,” the BPA said. Over the past several years, it said, older equipment at Celilo Substation, the northern terminus of the DC Intertie in The Dalles, Ore., has failed with increasing frequency.

"Some of the equipment at our Celilo Substation is so old, finding replacement parts has become a challenge. Some of this equipment should be in the Smithsonian," Brian Silverstein, senior vice president of BPA Transmission Services said in a statement on Thursday.

The upgrades are expected to begin in 2015 in the Columbia River Gorge and will at first entail replacing aging equipment with a simplified, modern converter terminal. Crews are also expected to work to upgrade and reinforce BPA’s portion of the DC transmission line.

The project’s approval will depend on a positive environmental review that would be consistent with the National Environmental Policy Act. If a decision is made to go forward, BPA said it would identify a contractor for the project by the end of 2012. “The contractor would develop a detailed project schedule that allows time for BPA to acquire the specialized equipment for the upgrades. Production lead times can be as long as two years, so timing the orders and product deliveries accurately would be critical to the project’s success,” it said.

Construction would be scheduled to start in early 2015 and would be expected to be finished in early 2016. For one year during construction, BPA would take some equipment at Celilo off-line, reducing the DC Intertie capacity from 3,100 MW to 2,000 MW. Increased costs for the upgrade will only be charged to users of the California Intertie.

In related news, the BPA on Friday completed a new 79-mile-long transmission line that runs along the Columbia River from McNary Dam to John Day Dam. The line is one of several planned in Washington and Oregon that are expected to transmit power from wind turbines east of the Cascades to cities closer to the Pacific.

That project was reportedly completed 10 months ahead of schedule and $140 million below its original $340 million budget.

"There’s an assumption that the public sector can’t do things well, and this is an example that it can," BPA administrator Steve Wright told the Seattle Times. "It will be a significant benefit for ratepayers."

Source: POWERnews, BPA, the Seattle Times