Valuable Railbelt asset
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Bradley Lake hydro has the cheapest power but also transmission constraints
Alan Bailey for Petroleum News
During an Oct. 23 presentation to the Regulatory Commission of Alaska Curtis Thayer, executive director of the Alaska Energy Authority, talked about the importance of the Bradley Lake hydroelectric project to power supplies in the Alaska Railbelt, and the steps that AEA is taking to improve access to power from the facility through the transmission system.
Thayer characterized Bradley Lake, situated in the southern Kenai Peninsula, as the "crown jewel" of the Railbelt power generation arrangements.
"It provides 10% of the energy on the Railbelt and it provides it at 4-cent power, which is one of the cheapest on the Railbelt," Thayer told the commission. And 17% of the Bradley Lake power goes all of the way to Fairbanks, he commented.
The Dixon Diversion AEA is currently assessing the Dixon Diversion Project, a project that would divert water from the nearby Dixon Glacier to increase the annual electricity production from Bradley Lake by around 50%. The project would involve directionally drilling a tunnel from the glacier to Bradley Lake and, thus, raising the water level in the lake by somewhere around 14 to 28 feet. And the Bradley Lake powerhouse has the space to install an additional generator, in support of the project, Thayer said.
Thayer said that it is possible that the project could be completed and put into operation by 2030, at which point it could account for 7.5% of the unmet needs for natural gas in the region by that time.
Transmission upgrades However, use of the power from Bradley Lake is constrained by limitations in the power transmission system on the Kenai Peninsula and in the transmission line that connects north to other sectors of the Railbelt electrical system. As previously reported by Petroleum News, AEA and Anchorage-based Chugach Electric Association are in the process of upgrading the transmission line from the northern Kenai Peninsula to Anchorage, increasing the voltage of the line from 115 kilovolts to 230 kilovolts.
AEA has also started work on planning a subsea high voltage direct current transmission line between Nikiski on the Kenai Peninsula and Beluga on the northwest side of the Cook Inlet. In addition to greatly increasing the transmission capacity from the Kenai Peninsula, having a second line connecting to the Anchorage region would improve the resilience and reliability of the transmission system -- the current single transmission line constitutes a single point of failure in the system, thus constraining the ability to reliably share the output from power generation assets, including renewable energy systems, across the Railbelt.
In October 2023 the U.S. Department of Energy awarded a $206.5 million grant to AEA under the federal Grid Resilience and Innovation Partnership, or GRIP, program, for the construction of the HVDC line and the installation of battery energy storage systems in the central and northern sectors of the Alaska Railbelt electrical grid. The grant is contingent on support from matching funds and has to be completed within eight years.
GRIP grant accepted In September AEA signed an agreement to accept the grant, thus setting the eight-year time limit. The agency has an initial tranche of matching funds that can enable work on the project to begin -- the state has allocated an initial $12.7 million towards the matching funds, while the Railbelt electric utilities had $20 million in bond funding available. Petroleum News understands that the grant award was announced too late in the year for more substantial funding to be included in this year's state budget.
At this point AEA is conducting some engineering analysis for the project, Thayer said. The agency anticipates completing preliminary design by the end of this year. The biggest challenges are the availability of the necessary HVDC cabling and the availability of a ship to lay the cabling, Thayer commented. It will also be necessary to conduct the process for environmental permitting, do contractor selection and acquire long lead time items, he said.
A second transmission line is also needed between Southcentral Alaska and Healy, to the north of the Alaska Range. That would significantly increase the transmission capacity between the Anchorage region and Fairbanks while also eliminating the single point of failure represented by the current line. There are already two transmission lines between Healy and Fairbanks.
However, AEA did not succeed in obtaining a federal grant for the northern transmission line in the second round of the GRIP awards program, Thayer said, commenting that no entities that received grants in the first round had received grants in the second round. However, there is a need for that northern intertie. The five military bases on the Railbelt do not feel secure with their electricity supplies, given the single transmission lines, Thayer added.
The need for batteries Another issue relating to the use of Bradley Lake power results from the tendency for the power across the Railbelt system to oscillate when a large electrical load is lost or if there is a trip in the power generation. The Bradley Lake system, at one end of the transmission network, can have a large impact on these oscillations. Battery energy storage systems operated by the Railbelt utilities are used to counterbalance the oscillations. AEA is planning to pay the utilities for the use of the batteries for this purpose, using available bond funding associated with Bradley Lake. However, the agency needs to figure out terms for the funding agreement that do not jeopardize federal tax credits associated with the battery purchases, Thayer said.
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