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Platform power?
Hilcorp looking at whether redundant platforms could be tidal power sites
Alan Bailey for Petroleum News
ilcorp Alaska is researching the future possibility of some of its redundant offshore oil platforms in Cook Inlet becoming sites for tidal power stations, David Duffy from the Hilcorp Land Department told the Cook Inlet Regional Citizens Advisory Council board meeting on Sept. 9. The company operates 15 offshore platforms in the inlet, four of which, the Spark, Spurr, Baker and Dillon platforms, are no longer in use and are being decommissioned. The huge tides in the Cook Inlet create strong tidal currents that could be used to drive turbines for power generation.
“As a company of entrepreneurs we’ve been evaluating what can be done on those platforms and (what) should be done,” Duffy said.
The Spark and Spurr platforms are associated with the North Trading Bay unit on the west side of the inlet, while the Baker and Dillon platforms are associated with the Middle Ground Shoal unit in the middle of the inlet.
The company is plugging and abandoning the wells associated with the platforms and removing cranes and workhouses. Duffy said that Hilcorp views the platforms as an investment in infrastructure. He commented that the company has evaluated various uses for defunct oil platforms around the world but has not identified any of these options that would be appropriate in the Cook Inlet. The development of tidal power on the Cook Inlet platforms is, however, a possibility that has been considered in the past but, thus far, has not proven economically viable, he said.
An exploration project Hilcorp is now approaching an investigation of the possibility of platform tidal power in the style of an energy exploration project: First validate the resource and then, if the resource exists, evaluate the technology for using the resource. As a next step, it is then necessary to determine whether the technology can work effectively and viably at the platform locations, Duffy said.
Given that Hilcorp does not have in-house tidal power expertise, the company opted to partner and collaborate with the National Renewable Energy Laboratory, the Pacific Northwest Natural Laboratory and the Alaska Center for Energy and Power at the University of Alaska Fairbanks. Work on the project began in March.
DOE grant It turned out that NREL had previously developed an inventory of potential tidal resources in the Cook Inlet - both the laboratories and ACEP view the Cook Inlet as having a world class tidal energy resource and as having the greatest tidal resource in the United States, Duffy said. The NREL assessment indicated a theoretical resource of about 18 gigawatts for power production for the inlet. That is equivalent in energy terms to about 1 trillion cubic feet of natural gas. However, only about half of that resource is technically recoverable. And then, taking into account the costs and logistics of tidal power development and operation, there are probably about 2 gigawatts of power available, equivalent to about 100 billion cubic feet of gas. By comparison, the average daily electricity load across the entire Alaska Railbelt is around 0.6 to 0.7 gigawatts, while Hilcorp currently produces about 50 billion cubic feet of gas annually, Duffy said.
Moreover, applying the NREL model to the locations of Hilcorp’s offshore platforms indicated great tidal resources at the platforms, Duffy said.
A need for viability Unfortunately, however, currently available tidal power technologies have relatively low power outputs, far below the outputs of existing power generation plants in the Cook Inlet region. Consequently it appears that, despite the abundant tidal energy resources, there is not yet any commercial project ready for implementation - tidal power technology is still decades behind wind and solar power in terms of development maturity, Duffy said. However, the laboratories and the university view the Cook Inlet as a key location for a demonstration project on a megawatt scale, he said.
A demonstration system Duffy said that Hilcorp applied to the Department of Energy for a grant to support the laboratories and university in a project with an objective of installing a demonstration system, probably on the Dillon platform - Dillon experiences the strongest tidal currents of the four “lighthoused” platforms and is furthest ahead in Hilcorp’s platform decommissioning program. The hope is to work with a tidal power vendor to conduct a short term demonstration project some time next year, Duffy said.
The research team anticipates conducting data collection and surveying around the platform this fall and has been talking to the Alaska Department of Natural Resources about how to make the project happen. And, given the public funding, data from the project will become publicly available.
Duffy also said that there is a need for basin-wide, community level research into the commercial feasibility of hydropower development in Cook Inlet. While Hilcorp is involved in the research and development, some other entity such as a utility or the state could end up owning a tidal energy project, he added.
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