Hilcorp is investigating whether redundant rigs could be tidal power sites

Alan Bailey

for oil news

ilcorp Alaska is exploring the future possibility of some of its redundant offshore oil rigs in Cook Inlet becoming sites for tidal power stations, David Duffy of the Hilcorp Land Department said at the Cook Inlet Regional Citizens Advisory Council meeting on 9 september. 15 offshore platforms in the inlet, four of which, the Spark, Spurr, Baker and Dillon platforms, are no longer in use and are being dismantled. Cook Inlet’s huge tides create strong tidal currents that could be used to drive turbines for power generation.

“As a company of entrepreneurs, we’ve assessed what can be done on these 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 entrance, while the Baker and Dillon platforms are associated with the Middle Ground Shoal unit in the middle of the entrance.

The company plugs and abandons the shafts associated with the platforms and removes the cranes and workshops. Duffy said Hilcorp views rigs as an investment in infrastructure. He said the company had evaluated various uses for old oil rigs around the world, but had not identified any such options that would be appropriate in the Cook Inlet. The development of tidal power on the platforms in Cook Inlet is, however, a possibility that has been considered in the past but so far has not proven to be economically viable, he said.

A prospecting project

Hilcorp is currently approaching an investigation of the possibility of a tidal platform in the style of an energy exploration project: first validate the resource, 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 on the platform’s sites, Duffy said.

Since Hilcorp does not have in-house tidal energy expertise, the company chose to partner and collaborate with the National Renewable Energy Laboratory, Pacific Northwest Natural Laboratory and Alaska Center for Energy and Power in 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 Cook Inlet – the labs and CAPE consider Cook Inlet to have a world-class tidal energy resource and to have the largest tidal resource in the United States, Duffy said. . The NREL assessment indicated a theoretical resource of approximately 18 gigawatts for power generation for entry. This is equivalent in energy terms to approximately 1 trillion cubic feet of natural gas. However, only about half of this resource is technically recoverable. And then, considering the costs and logistics of developing and operating tidal power, there’s probably about 2 gigawatts of energy available, which equates to about 100 billion cubic feet of gas. By comparison, the average daily electrical load across the entire Alaska Railroad Belt is about 0.6 to 0.7 gigawatts, while Hilcorp currently produces about 50 billion cubic feet of gas per year, a said Duffy.

Additionally, applying the NREL model to Hilcorp’s offshore platform locations indicated large tidal resources at the platforms, Duffy said.

A need for viability

Unfortunately, however, currently available tidal power technologies have relatively low power outputs, well below the outputs of existing power generation plants in the Cook Inlet area. Therefore, it seems that, despite the abundant tidal energy resources, there is not yet a commercial project ready to be implemented – the tidal energy technology is still decades behind the energy wind and solar in terms of development maturity, Duffy said. However, the labs and the university see Cook Inlet as a key location for a megawatt-scale demonstration project, he said.

A demonstration system

Duffy said Hilcorp had applied to the Department of Energy for a grant to support the laboratories and the university in a project to install a demonstration system, likely on the Dillon platform – Dillon knows the most tidal currents strengths of the four “flagship” platforms and is the most advanced in Hilcorp’s platform decommissioning programme. The hope is to work with a tidal power provider to run a short-term demonstration project sometime next year, Duffy said.

The research team plans to conduct data collection and surveys around the platform this fall and has been discussing with the Alaska Department of Natural Resources how to bring the project to fruition. And, given public funding, project data will be made public.

Duffy also said there is a need for basin-wide and community-level research on the commercial feasibility of hydroelectric development in Cook Inlet. While Hilcorp is involved in research and development, another entity such as a utility or the state could end up owning a tidal power project, he added.

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