07121-DW1902

Goal
The goal of this project is to evaluate options and develop a conceptual design for a seafloor power system to be used in offshore oil and gas operations. The system will be a hybrid system, in the sense that it will combine energy conversion and energy storage capabilities. The project will result in a comprehensive analysis of the options available for developing such a system, culminating in a conceptual design for the best option, based on its technical merits and economic feasibility.

Performers
Houston Advanced Research Center, The Woodlands, TX 77381
Lawrence Livermore National Laboratory, Livermore, CA 94550
Naval Facilities Engineering Service Center, Port Hueneme, CA 93042
Yardney Technical Products, Pawcatuck, CT 06379
Shell Oil Company, Houston, TX 77252
Chevron Oil Corporation, San Ramon, CA 94583 GE, Houston, TX 77027

Background
As oil and gas development moves into deeper and deeper water depths, engineers begin to push the limits of current capabilities for delivering the power necessary to drill for and produce hydrocarbons. At increasing depths, the technically and economically viable options for developing resources from surface locations become fewer. Subsea options are already being applied in many areas, but the need to deliver power to operate subsea equipment in ultra-deepwater locations can be a limiting factor. Development of subsea (deep-ocean) hybrid power systems will enable wider access to ultra-deepwater offshore oil and gas resources. Subsea generation of electrical power also has the potential to reduce carbon output, improving the environmental operating performance of offshore platforms through reduced emissions. However, a comprehensive analysis of the options available for developing such a system has yet to be carried out.

Deliverables for this project will include a series of reports on project tasks as they are completed and a final report integrating the results of the project. The report topics will include:

1. Functional requirements and basis of design for deep sea hybrid power systems.
2. Conceptual designs of alternative deep-ocean hybrid power systems, with generation and storage capability, with sufficient capacity to power drills, pumps, and other sub-surface equipment, with hypothetical requirements of 20,000-100,000 hp (14 to 70 megawatt)
3. Technical evaluation and ranking of conceptual designs, with selection of the best combination of conversion and storage technologies for further development.
4. Conceptual design of an energy conversion module prototype capable of long-term reliable operations at pressures up to 5,000 pounds per square inch, and temperatures approaching the freezing point of water; including a budgetary estimate for the cost of such a system.
5. Conceptual design of an energy storage module prototype capable of operating under the same conditions and including a similar cost estimate.
6. Preliminary Risk Assessment of the selected conceptual hybrid power system.
7. Comparison of the carbon emissions that each alternative power system would provide if deployed.
8. Plan for further development, qualification and commercialization of the hybrid power system.
9. Final report documenting results and findings of this work.

Potential Impacts
The product of this project will be knowledge that can be used to accelerate the development of a hybrid power system that will in turn accelerate development of ultra-deepwater fields that cannot be developed using currently employed combinations of surface and subsea architectures. The resulting benefit will be accelerated production of oil and gas from these ultra-deepwater fields, and the concurrent acceleration of royalties and tax revenues.

Accomplishments
The team has completed preliminary conceptual designs of alternatives. Conceptual designs have been sized, with estimates of volume, weight and cost, spanning about 1 megawatt to 260 megawatts. The COE accounting for power generation equipment, energy storage equipment, pressure vessels for non pressure-compensated systems, and tanks for submergence and surfacing are thus far accounted for for all designs, and for all sites, thereby enabling a site-by-site ranking.

The team has held several workshops to screen the various conceptual designs that were developed. These designs have been evaluated and will be discussed in the final report. In addition, an environmental evaluation of the designs has been performed. A draft of the final report has been developed and is currently being reviewed within the project team.

Current Status
The Project Management Plan and the Functional Requirements/Basis of Design document have been completed. The project team has screened various energy conversion and storage systems. Based on this screening, the most promising generation-storage combinations, based on performance data were selected to prepare detailed sub-scale conceptual prototype designs. A Risk Assessment of the conceptual prototype systems has been performed and their respective Technology Readiness Levels (TRLs) will be documented in the final report. The environmental report estimates the environmental impact (carbon footprint) of these systems when deployed, as compared to conventional gas turbine power generation.

Potential systems to be screened included: Ocean-current driven systems; radioisotope thermoelectric generators; thermionic generators; small pressurized-water reactors with low-enrichment fuel, similar to those used on commercial ships; proton-exchange membrane fuel cells powered with hydrogen and oxygen, similar to that used on submarines; and fuel-cells, internal combustion engines or turbines capable of using natural gas from deep-ocean wells.

Battery technologies screened included: compressed-gas storage; liquid redox batteries; secondary batteries in sealed pressure vessels; pressure-tolerant secondary batteries; and other non-conventional battery systems, (for example, oil-compensated polymer-gel lithium-ion batteries; polyurethane potted polymer-gel lithium-ion batteries; lithium-ion batteries; and lead acid batteries.

A forward plan is being developed to be included in the final report. This plan may be followed to transition this project (Phase I) into Phase II: the design and fabrication of prototypes, with both surface and sub-sea testing. A successful technology could then be commercialized through appropriate industrial partnerships. This project scope encompasses Phase I only. Phase II costs are estimated to be between $16 MM and $18 MM depending on the type of system chosen for sub-scale prototype construction and testing. Due to issues with subcontractors (Lawrence Livermore) the project end date has been extended.

Project Start: October 31, 2008 (Phase I only)
Project End: May 31, 2010 (Phase I only)

DOE Contribution: Phase IA - $480,000.00
Performer Contribution: Phase IA - $120,000.00

Contact Information:
RPSEA – James Pappas (jpappas@rpsea.org or (281) 313-9555)
NETL – Jay Jikich (Sinisha.Jikich@netl.doe.gov or 304-285-4320589)
Performer Company – Richard Haut (rhaut@harc.edu or 281-364-6093)

Additional Information

Final Project Report [PDF-3.36MB]

E&P Focus Article [PDF] Spring 2009