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Deep Green Island Mode 2

Periodic Reporting for period 4 - DGIM2 (Deep Green Island Mode 2)

Reporting period: 2021-02-01 to 2021-07-31

Island living may call to mind a tranquil, natural and eco-friendly way of life, but life on an island comes at a high price. Island energy is expensive, polluting, inefficient and dependent on external supplies with significant negative impacts on emissions and the economy [1]. Such is the case with Europe’s 2 400 islands – home to some 15 million Europeans.

It is estimated that European islands produce 17.5 million tonnes of CO2 every year [2]. These microsystems are almost entirely reliant on diesel.

Wind and solar power are not always suitable options for these communities as the energy they generate is unpredictable and intermittent. Conventional tidal energy requires fast tidal flows (over 2.5m/s) which only occur in a few hot spots around the World.

Minesto has developed an underwater kite technology, called Deep Green (DG), to convert energy from low-speed currents and tides. The Deep Green Island Mode (DGIM) is a stand-alone tidal and ocean current energy converter for off-grid applications. The DGIM is an underwater kite, that when steered in an 8-shaped trajectory, obtains a speed of several times the speed of the actual current. This generates the following unique performance characteristics:

- Unlocks the possibility of harvesting electricity in low-speed current areas (>1.75 m/s) and depths (>60m) where other tidal devices are not cost-effective. The low-velocity sites are both significantly larger in potential energy production and in terms of geographical area, representing at least half of the tidal sites and most of the ocean current sites globally.
- Launch, recovery, and maintenance are normally carried out when the flows are low around the tidal slack periods. Working in low flow sites significantly increases the useable time in the slack period, affecting the efficiency of the operations and hench availability.

The aim of the DGIM2 project was to install the first commercially viable DGIM tidal powerplants in a production and customer environment on the Faroe Islands. The purpose was to demonstrate the capabilities of DGIM to replace diesel generators in microgrids.

[1] https://ec.europa.eu/energy/sites/ener/files/documents/170505_political_declaration_on_clean_energy_for_eu_islands-_final_version_16_05_20171.pdf
[2] www.irena.org/DocumentDownloads/Publications/IRENA_Off-grid_Renewable_Systems_WP_2015.pdf
The main result is that by the end of the period, the DGIM powerplants had delivered electricity to the Faroese grid over full tidal cycles with satisfactory performance.

The work is here summarized per work package:

WP1 Project management was headed by Patrik Pettersson from the technology development organization. This WP included managing contracts, risks, finances, and deliverables.

WP2 Site Creation and Preparation was performed by help of the Faroese utility company SEV. During fall 2019, a site location in Vestmannasund had been selected for installation of the powerplants. By summer 2020, all licenses, permits, and agreements for lease had been secured.

WP3 Power Plant design, procurement and manufacturing was organized and executed as a Power Plant delivery project. It included conceptual and detailed design phases, producing procurement specifications as well as manufacturing. Further, at Minesto’s prototype assembly facility in Gothenburg, Sweden, workshop testing was performed, including final complete system integration tests prior to shipment to the operational site.

WP4 Balance of Plant (BoP) design, procurement and manufacturing was responsible for the site infrastructure and organized in the same way as WP3. The work scope was executed by the technology development organization in Gothenburg, with key individuals participating from the operational branch of Minesto. All components, except the foundation, were part of the final complete system integration tests in Gothenburg prior to delivery.

WP5 Off- and Onshore Operations was managed and executed by the operational branch of Minesto, in close cooperation with WP3 and WP4 during the design phase of the project. WP5 provided important input to all the system assemblies that must be installed and/or recovered as a part of the operations.

WP6 Commissioning and Certification included both planning and preparation types of activities. WP6 was managed and executed by the technology development organization, with support from operations on vessel management and other marine operations.

WP7 Dissemination and Communication made the project visible through frequent updates to project stakeholders and the general public by means of press releases, presentations in conferences and events, updates to the Minesto website, YouTube videos, as well as posts on LinkedIn, Twitter, and Instagram.

WP8 Commercial Roll Out Plan was prepared by the executive team at Minesto. The WP developed an operational strategy, a marketing strategy, an investor-ready business plan and protected the intellectual property generated in the project. WP8 also further developed an analysis of the commercial viability and bankability of the Deep Green technology.
Progress beyond the state of the art

The project has successfully resulted in subsea tidal kites feeding renewable energy from low flow tidal currents to an electrical grid. This has not happened before, anywhere in the world.

The project has proven that the marine operations required for DGIM can be executed cost-efficiently using small vessels, even in the winter months, by developing a new type of anchoring system and verifying this in operation.

The project has improved and simplified the power plant, providing Minesto with a solid benchmark and base for commercial roll-out of the technology.

The project relocated sensitive equipment from the tidal kites to a shore location, which included the challenge of controlling the generator from several kilometres away. This allows for cost-effective power conversion and is an important output of the project.

Socio-economic impact and wider societal implication of the project

The project has focused on island mode systems, relatively small in size, but with potential to remove the need for running diesel generators in remote coastal communities.

The next step for this technology is to build the first commercial demonstration array of Deep Green power plants. This will create jobs locally at the operational sites, but more importantly, show the significant potential of this technology to lower greenhouse gas emissions on a global scale by becoming an integrated part of the renewable energy mix.

The project was performed in collaboration with a customer, SEV, the Faroe Islands’ utility company. SEV has extended the Power Purchase Agreement with Minesto for the tidal energy site in Vestmannasund until the year 2023. The electricity generation strategy of SEV and the electricity demand in the Faroe Islands show that a tidal energy system, such as the Deep Green Island Mode, has the potential to become a significant energy source, supporting the realisation of the Faroese target of a 100% renewable energy mix by 2030.
Powerplant towed to install location.
Map showing location of Vestmannasund, Faroe Islands
Powerplant close-up, with workers at top joint
The Deep Green technology
The two powerplants, on quay in Vestmannasund.
Powerplant showing kite, tether and bottom joint on quay.
Tidal energy by Minesto in the Faroe Islands
The Vestmannasund project setup
Minesto photo of the Vestmannasund strait, Faroe Islands