The Commander, Navy Region Northwest (CNRNW) proposes to design, install, generate and deliver electrical energy, collect operational and environmental data during a demonstration of the Verdant Power Kinetic Hydropower System (KHPS) in Puget Sound. This is a technology demonstration project involving an in-water test for up to one year followed by complete system removal.

Electricity generated during the demonstration will be routed to an isolated electrical load at a nearby naval installation, not directly connected to privately generated power systems (utility grid). The proposed action is identified as the Navy Puget Sound Kinetic Hydropower System demonstration project or NPS-KHPS. Congress directed the Navy to study the possible use of KHPS technology in Puget Sound, and appropriated funding for Phase I of the project.

This demonstration project is in keeping with the National Defense Authorization Act of 2007, which requires 25% of electrical power from renewable sources by 2025. The project is also consistent with Navy’s objectives to develop reliable power delivery to its facilities worldwide and reducing dependence on fossil fuel while supporting its mission capabilities and readiness objectives.

KHPS Technology

The proposed project includes design and installation of a small grouping of turbines on the sea floor that aligns with the direction of currents to generate electricity as tides flow in and out of Puget Sound (Image 1).

Image 1 - Verdant Turbine

Underwater cables will transmit the electricity generated by the turbines to a land-based facility, where the electricity will be used (Image 2).

Image 2 - Schematic

Project Locations

Of eight candidate areas in Puget Sound, two areas remained that are being studied further for the KHPS technology demonstration test: Marrowstone South and Marrowstone North (Image 3). The Marrowstone South location is preferred due to better tidal characteristics. These two alternative sites will be considered in the Navy Environmental Assessment.

The screening criteria for identifying suitable sites within the three areas include:

+ Sufficient tidal flow (e.g., strong tidal currents)
+ Suitable range of depth and slope for installation of the turbines
+ Proximity to Navy installation
+ Avoiding or minimizing adverse effects on sensitive environmental resources
+ Avoiding Tribal, commercial, and recreational fishing
+ Avoiding interference with commercial and Navy vessel operations

Image 3. Project Locations

Based on available resource (tidal current velocity), the proposed location for the Navy KHPS array has been narrowed down to two sites near Marrowstone Island (Image 4).

Image 4 - Marrowstone Sites