A new project has been supported by the Technology Strategy Board to provide a lower cost, optimised installation vessel for tidal energy array installations.

Installing tidal energy devices is both costly and technically challenging, but a new Dynamic Positioning (DP) flat-top barge could be the answer that the industry has been waiting for.

Adding DP capability to a versatile flat-top barge offers a real cost effective tidal energy installation solution with multiple benefits.

Successfully installing devices in locations with the best resources poses a significant trial for the tidal energy sector. So far, single turbine installations have been carried out by offshore spec DP vessels sourced from the oil and gas sector. These vessels and their DP systems are not designed for operation in the high energy commercial sites where these devices will be deployed. They also typically have day rates in excess of £100,000, significantly increasing the financial price-tag of a tidal energy installation.

The Technology Strategy Board, the UK’s government-backed innovation agency, awarded a grant of £1.5m to the DP Barge project consortium in November 2012. The grant is for the consortium to design, develop and commission a barge with DP capabilities optimised for high energy locations providing a lower cost alternative for tidal array installations.

The Grant followed the Technology Strategy Board's invitation in March 2012 for companies to develop innovative projects to support marine energy array technologies.

According to figures published in the Accelerating Marine Energy report by the Carbon Trust in 2011, installation costs can account for a third of the levelised cost of energy [LCOE] of a tidal energy project. Often the best tidal energy resources, such as those in the Pentland Firth, are situated in remote locations with harsh maritime conditions and strong, non-linear tidal flows. Combined with deep water and a slack tide lasting less than 20 minutes, these conditions are technically challenging to operate in.

Jack-up barges and moored heavy-lift vessels have also been used to install single tidal units. However, current construction jack-up barges are not intended for use in deeper water, high velocity flows and are being operated at the limits of their capabilities; the mooring systems associated with most moored heavy-lift vessels means they are time consuming and have limited suitability for installation of large arrays.

The method being developed by the consortium, known as ‘Dynamic Positioning’, enables a vessel to autonomously maintain its position and heading by using its own thrusters. The DP Barge project will equip a flat-top barge with a dynamic positioning system designed specifically for operation in high tidal flow. .

The DP Barge project consortium is made up of 4 companies committed to innovating technical solutions for the tidal energy sector. They are IT Power (project lead), Keynvor MorLift Ltd (marine contractor and ship owner), Reygar Ltd (DP controller developer) and A&P Falmouth (shipbuilders).

The barge will have significant deck space and heavy lift capacity to enable multiple operations to be conducted from a single platform, allowing installation of a wide variety of tidal energy devices with their associated sub-systems and drilling equipment.

A key objective of the project is to maximise the operational window of the vessel in energetic tidal sites through the use of an optimised DP control strategy and propulsion system.

The vessel will be designed to be operated by a smaller crew than generally required for a large heavy-lift vessel. The vessel’s suitability for a wide variety of tidal turbines means that developers won’t need to directly invest significant sums in the construction of a bespoke vessel, whilst offering high positional accuracy.