Every so often industry throws out something strikingly innovative, something that merges function with a radical form that seems intuitively logical at the same time, something that disrupts entrenched perceptions – perhaps something that has the ability change the vision of that sector. Arguably this is what was delivered when Orbital Marine Power launched its new O2 floating tidal turbine in Dundee, Scotland, a few weeks ago.
To judge by the nameplate rating, 2MW, there might seem little innovation from Orbital since their full-scale prototype the SR2000, which delivered a record-breaking test programme at the European Marine Energy Centre (Emec) in 2016-2018, was also rated at 2MW – but things get a bit different beyond that.
Most notably the structural configuration of the system is eye-catchingly different: twin legs attached at the waterline of the circular main tube hull, which, under the operation of a neat hydraulic-actuated linkage system, move perpendicular to the hull in a gull-wing motion. With the legs retracted to the up position this now gives low-cost service access to the 1MW drive trains at either leg end as the nacelles breach the water surface and at the same time ensures a low two-metre towing draft.
The twin-rotor drive-trains themselves are conventional configurations of inline main shaft unit and generator and Orbital has teamed up with rotational equipment specialist SKF for the delivery of a full transmission system that also feature pitch control units. The departure from a stall regulated system used on the SR2000, coupled with the new structural configuration has meant Orbital have been able to significantly improve the economics of the 2MW system by increasing rotor diameters from 16m to 20m resulting in a 50% increase in swept area and lowering the rated speed to 2.5 metres a second.
In the context of a new British industrial opportunity and a contribution the UK’s steeply ambitious carbon reduction targets it would appear the right drivers are present
Beyond that a more subtle change is the removal of the single turret mooring point of the SR2000 for simpler, lower cost forward and aft mooring connectors that hold the platform in line for flood and ebb tides whilst the pitch system rotates the blades to deal with extracting energy from both directions.
All these characteristics are rolled into the world’s most powerful and most advanced tidal turbine and produce something that looks rather of another world, perhaps a different galaxy, but are a product of experience driven innovation from the team at Orbital that have been pioneering floating tidal stream technology for well over 15 years. A programme that has recently generated a suite of new patent filings around the radical revised technology and enabling solutions the company is developing.
One philosophy that has held constant is avoiding large construction and heavy lift vessels from the entire programme. While maintaining low risk, simple gravity anchors, all elements of site construction and turbine installation has been completed using modest small multi-cat vessels with low day rates – an approach which de-risks construction programmes from major cost volatility and overruns.
And the operational phase follows suit: thanks to the fully accessible design, servicing can be executed with small, coded vessels, typically no larger than a Rib. As tidal stream projects tend to be located no more than a few kilometres from the shoreline, service teams can operate out of local harbours and respond to unplanned interventions in minutes and schedule planned maintenance for totally forecastable slack water and neap tides.
So, with the O2 entering operational service at Emec by the middle of the year, is the tide turning more favourably for the tidal sector? Set in the context of stimulating a new British industrial opportunity while contributing towards the UK’s steeply ambitious carbon reduction and renewable energy targets it would appear the right drivers are present.
Industry players and associations are calling on the UK government to set a target of 1GW for marine renewables to deliver in the 2030s. And as evidence of the growing momentum: the outcome of a recent Environmental Audit Committee review firmly concluded that Westminster should move to create a target and a specific market support mechanism within the CfD [Contract for Difference] to cater for this emerging, promising sector – as early as an inclusion in this year’s planned round 4.
Should market policy stars align in the UK for tidal energy, and one could expect international markets to follow, the spacecraft-like O2 might benefit from good timing and positioning itself for scalable project opportunities within UK waters whilst gathering early commercial exposure with this first part debt funded O2. In parallel the business is running a sophisticated and targeted R&D programme, under EU funding, to pull in existing supply chain expertise to turbo-charge a cost reduction programme in an understanding of market requirements to see rapid cost reductions going forwards.
It is a bold and innovative vision Orbital are delivering – perhaps strong enough to finally get an industry off the launch pad.
· Andrew Scott is CEO of tidal energy technology developer Orbital Marine Power