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Orbital Marine Power

Orbital Marine Power Ltd (formerly Scotrenewables) is an innovative Scottish engineering company focused on the development of tidal energy turbine technology with the potential to produce a step-change reduction in the cost of energy from tidal stream. The company is based in Orkney and Edinburgh.

Orbital’s technology is a unique floating tidal turbine designed to provide a low cost solution for simplified and safe manufacture, installation, access and maintenance along with the ability to use low cost, small workboats for all offshore operations. The technology has been under continuous engineering development, including rigorous testing of scaled systems in both tank conditions and open ocean environments since the company was founded in Orkney in 2002.


Technology demonstrations

Three iterations of Orbital’s technology have been tested at EMEC so far: the SR250; the SR2000; and the O2. Further details on each can be found in the dropdown below.



The SR250, a scale floating tidal turbine, was tested at EMEC’s grid-connected tidal test site at the Fall of Warness from 2011 to 2013. The 250 kW device, measuring 33 m long, was constructed at Harland & Wolff in Belfast in 2010 and weighed 100 tonnes.

Initial tests involved short-term deployments of the device on its moorings followed by disconnection and towing back to harbour for inspection. The testing programme was undertaken in incremental stages, culminating in a three-month period of continuous grid-connected operation at the end of 2012. In exporting power to the UK grid, the SR250 became the world’s first floating tidal energy device to generate power into a grid.



Building on the success of SR250, Orbital developed the SR2000, a larger 63 m, 500 tonne, 2 MW ‘commercial scale’ turbine more suited for tidal array deployment.

The SR2000 arrived in Orkney in June 2016 and was first deployed at EMEC’s tidal test site in October 2016. The SR2000 project was supported by Scottish Enterprise’s WATERS II scheme along with investments from Scotrenewables’ shareholders which include ABB, DP Energy, Fred Olsen, Total and Scottish Government via the Renewable Energy Investment Fund (REIF).  The testing programme at EMEC was also supported via the FORESEA Interreg-NWE funded project.

At a rated capacity of 2 MW the SR2000 was the world’s most powerful tidal turbine. In early commissioning it reached a peak of 2.24 MW export power at the EMEC substation.

During its test programme the SR2000 achieved the following milestones:

  • In 12 months of continuous generation into the Orkney grid the prototype turbine exported over 3 GWh of renewable electricity.
  • The entire project lifecycle of the SR2000 through construction, installation, operation and decommissioning was completed with small workboats or lighter. No heavy lift or large anchor handling vessels were used.
  • At times SR2000 was measured to have been meeting around 25% of total electricity demand of the Orkney Islands.
  • During the period of a measured full week of generation the SR2000 provided almost 8% of total electricity demand of the Orkney Islands.
  • At times output from the turbine was being used by EMEC to generate ‘green hydrogen’; the first time hydrogen had been generated using tidal power.
  • The SR2000 maintained rated power in seas of 2 m significant wave height and maintained generation is seas of 3. 5m significant wave height. The largest wave the turbine withstood was >6 m. Interestingly, the SR2000 saw instantaneous power generations of over 100 kW from wave power alone.
  • The quickest maintenance intervention time demonstrated by the Orbital operational team was under 40 minutes from quayside to turbine.

The SR2000 was removed from site in September 2018 to make way for the build and installation of their optimised 2 MW floating tidal turbine, the Orbital O2.



The Orbital O2 2 MW turbine comprises of a 72 m long floating superstructure, supporting two 1 MW turbines on either side. 18 m long legs hold 100 tonne nacelle assemblies at a 14 m depth. The 20 m diameter rotors span 600 sqm, the longest blades ever seen on a tidal generator (and a 50% increase on the SR2000). A key innovation building on the SR2000 technology was the introduction of full wing leg configuration, enabling the rotors to be brought up above the water line for onsite access and maintenance. A modular gravity-based anchoring system recycled ballast from the SR2000. Each of the mooring lines used to anchor the O2 is strong enough to pick up 50 double decker buses.

The O2 was built at Texo in Dundee and 75% of the supply chain for the O2 device is based in the UK.

The device was towed to Orkney in April 2021, and has been operating at EMEC’s Fall of Warness test site since July 2021.

The development of the O2 has been supported through funding from the European Union’s Horizon 2020 research and innovation programme under the FloTEC project and the European Regional Development Fund through the Interreg North West Europe Programme under the ITEG (Integrating Tidal Energy into the European Grid) project. Watch the video below for lessons learnt in developing the world’s most powerful tidal stream turbine.

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