With waning support for marine energy in the UK, Sustainable Marine Energy decided to head East. Elaine Maslin reports.
The Plat-I design. Image from Sustainable Marine Energy.
Sustainable Marine Energy (SME) set out to be a tidal energy developer, but took a change of tack last year, both in what it was designing and for where. The move has seen the Isle of Wight and Orkney-based firm diversify into producing a new, simpler design for Southeast Asian markets and to start supplying anchoring and mooring solutions to the wider marine markets, including aquaculture.
SME’s Plato-O device is a taut-moored, submerged tidal energy unit, which sits beneath the sea surface. It comprises three connected “pontoons,” for buoyancy, hosting two SchottelHydro SIT turbines.
Last year, work on a 240kw Plat-O (O for offshore) prototype (with two, SIT 250 turbines) was halted when there was an issue with a cable connection. It was due to be reinstalled at the European Marine Energy Centre (EMEC) at Orkney, Scotland, in September 2016, but, the firm decided to re-think the project, largely due to falling support for marine energy development in the UK.
This led to the development of the Plat-I (I for inshore), a floating (on the surface), trimaran kit-orientated device, which is four-point catenary moored, via a turret, using synthetic or chain mooring lines, with fixed, removeable anchor points. It has been designed for more sheltered sites, compared to those off the likes of Scotland. This is a more conventional design, with a long hull and outriggers, off which four, SIT 250 turbines (providing 248kW) will hang (and can be lowered and raised for work), the benefit of which is accessibility in a dry environment, says Andy Hunt, SME’s engineering manager.
“It strips out a lot of the complexity and cost, not having to make components water pressure tight and access is easier.” Another possible benefit is that the hull could have available payload capacity for other uses, potentially seeing it supporting fishing or other industries, Hunt says.
“There needs to be a realization that the UK market has gone, since the budget last year, with confirmation there was no allocation,” SME’s Jason Hayman told the Scottish Reneweables’ Marine Energy conference in Inverness in September. “Plus, the EU referendum [meaning uncertainty around EU funding].” Meanwhile, areas like the Philippines have 14% predicted growth rates and a lot of “islands hungry for energy,” he says. There, wave energy could “compete and add value,” he adds.
SME is currently building a Plat-I unit in Peterhead, northeast Scotland, for this market. Once built, it’s due go through a 6-8-week sea acceptance test in Connel Sound, near Oban, Scotland. It is then due to be deployed to a demonstration site in Singapore, under a project with Schottel, and Singapore-based firms Envirotek and OceanPixel.
Meanwhile, the firm also decided it could market the anchoring and mooring technology it’s developed to hold its tidal energy devices in place, including a rock anchor. As part of its work, the firm has developed the A-ROV (anchoring ROV). It’s a seafloor drill, which can be remotely positioned then operated from a vessel, such as a multicat.
This was initially used to operate a screw anchor. SME has since developed Raptor, a rock anchor/bolt. This is a drilled rock anchor, which has an inner stem which drills into the rock, then stops and an outer stem then tappers into the rock, forcing cutting fingers over the lower cone (over the drill bit), reaming the lower taper into the rock. This is then tensioned by pulling the top and bottom tapers together.
With this solution, the firm has already been working with the aquaculture industry, but sees other opportunities. “The ocean economy is growing fast,” Hayman says. “We can tap into that.”
Last summer, four Raptors were installed at EMEC, in 35m water depth, in less than an hour. Each can take 150-tonne load, with 20cm accuracy positioning, says SME. In March this year, the firm did its first project in aquaculture for a long-line mussel farm. Some 26 screw anchors were installed over four days. The anchors could also be used for navigation buoys, fish cages, feed barges, etc., Hayman says. The firm is working on additional versions of Raptor with higher load capabilities.