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QED Naval is inviting tenders to an exciting opportunity to be a strategic partner in the high value supply chain to design, manufacture and deploy QED’s next generation tidal technology at Industrial scale as a penultimate step to demonstrate the cost reduction potential and performance of their ‘Subhub’ tidal platform and Tocardo turbines. This partnership is key to unlocking the potential of a rapidly growing global $76Bn market and making a significant contribution to net zero carbon targets.

QED is issuing as stage 1 this initial ITP with an outline scope of works in order to identify a selected list of prospective tenderers that will then go forwards to stage 2.

Each of the three elements described within this Invitation to Participate document is a separate Lot / option, each being considered initially as an individual contract and shall be awarded to either a single supplier or in Lots as deemed appropriate. Submissions will be accepted for any combination of Lots, all of which are subject to QED’s overall approval.


Following an enquiry regarding an extension to the deadline, QED Naval has decided to extend the submission deadline for Stage 1 by 3 weeks. Therefore, the indicative timetable will be extended accordingly.

Submission no later than: 12:00:00 on Friday 17th December 2021.

This timetable is indicative only.  QED Naval reserves the right to change it at its discretion.

Procurement Stage Target Date/Time
Issue ITP document 29th October 2021 17:00 BST
Deadline for tenderers to provide questions 2 weeks after the ITP has been issued
Initial ITP response / Preliminary Design & deadline 26th November 2021 12:00 BST
QED Evaluate initial ITP / Preliminary design and tender response and give notice to de-selected tenderers. Monday 20th December 2021


Select and appoint Final tenders and issue further tender information and detail Monday 27th December 2021
Deadline for submission of Final Tender documentation Wednesday 26th January 2022 17:00 BST

Negotiations (in successive stages) in order to reduce the number of tenders to be negotiated

·         Possible Visits and meetings with tenderers

Friday 18th February 2022
Issue of decline letters and letter of intent Friday 25th February 2022
Mandatory Standstill period Friday 11th March 2022
Issue formal letter of award Friday 25th March 2022
Publish contract award notice on OJEU website within 30 days of issuing formal letter of award Monday 25th April 2022 17:00 BST
Contract commencement TBC


[1] For the avoidance of doubt, if the submission deadline is different than the date published via the company website, the date on the company website shall apply.

If you wish to apply or have any questions please email us at and use the tender title above as the subject line. 


Q1 – Would you consider bids from a consortium who would focus on the design, which could then be tendered for by manufacturers?

A1 – QED, in this tender, is looking for a potential supplier who can deliver the full package of work as described under each lot.


Q2 – Can you please clarify what is meant by the term “deliver”? Is this delivery of the Subhub ex-works, to the quayside near deployment site or is this delivery to the seabed (i.e. with elements of installation)?

A2 – Delivery can refer to either of the options 1) Subhub ex-works to the quayside near deployment site or 2) delivery to the seabed (i.e. with elements of installation) if your company can provide that element of service.


Q3 – The ballast is noted as anywhere between 400-1,000 Te., what is the material proposed for this ballast?

The modularity is a very important consideration when design the ballast weight and the compartments in the bottom of the central compartment of the main hull girder. Thought of size and shape and weight of each ballast module needs to be considered when mobilising the whole platform to the quayside, slip or dock since this drives the size of crane to be used which is a highly non-linear cost function.

We would suggest that a dual 350t or 500t cranes are assumed for the launch of the Subhub which would be used to then load up the modular ballast. This would mean 50t to 75t modular ballast blocks would be feasible but this would need specialist transport to get them there. Therefore it may be better to stick to 20t blocks that slot together.

Steel ballast is preferred. Concrete takes up too much volume and is not as effective as steel/iron. A key point to make here is, it is on-bottom weight that we are quoting i.e. weight in water requirement so concrete is much less effective in this regard.

Wave loading is the major driver for the ballast so less exposed sites have much less ballast weight. We are currently looking at 400t in water ballast weight for each Subhub.


Q4 – Currently, do we need to consider any costings for external/third party approvals or review?

When considering future deployments for projects then sure there is a requirement to achieve quality standards and class approvals.


Q5 – We note that the submittal date is the 21st JAN, this does not provide very long in order to compile and price such a large scale detailed product.

A5 – This has been extended to 26th Jan.


Q6 – Would it be possible to arrange a meeting, as we have a number of questions regarding the different components of the structure?

A6 – An invitation has been issued to arrange meetings this week.


Q7 – Is a full pressure map required or just the peak pressure observed?

A7 – Nominal and peak pressure

Q8 -Also I am not too sure of the affect of deflection on parts of panels.

A8 – No need


Q9 – The larger effects are shown in the 2D shape study though that was at larger intervals than you have described in the deflections below. I think in the grand scheme of things it shouldn’t cause much issues.  Also is this full scale or tank model size?

Onshore substation

Q10 We assume there’ll be a need to supply power to offshore equipment

A10 In general yes, a backup power supply in order to operate the power electronics and SCADA systems is required. However, when the turbines are in operation, since they are PMGs, they don’t need power to start up. Because Subhub-ID has a huge payload capability of around 600t to 800t, we are thinking of using batteries instead or as well as having the option to supply power through a cable. Clearly the advantage of this are many but primarily to improve capacity factors. We believe it could also offer significant improvements in transmission efficiency and reducing costs of cabling down by going down the route of HVDC rectifying the current onshore before connecting it into the grid. However, currently this is not the current setup of the power electronics which assumes direct connection into the grid.

Q11 If so, we’d like to understand the requirements associated to the Electrical Power Unit (EPU) – are there any spatial requirement (cabinet footprint), weight requirements, door opening needs (e.g. front or back access) or specific standards to adhere to?

A11 The SPCU’s do have a spatial requirement since they are cylindrical pressure hulls with toroid-spherical dome end bulkheads, which hark back to my submarine structures days. Currently, they are similar to the ballast tanks and are approximately 3m in diameter, hence the space constraints but we are open to designing around the cabinet using racks to slide them in. It is envisaged that for the Subhub-ID we have 3 pressure hulls, one for each of the turbines, and then the final one is for the Subhub’s Platform Management Systems (SPMS), batteries and transformer for export.

It is worth noting that Subhub-ID’s design is flexible and in an array of units, one unit can act as the head node to act as a subsea hub to plug in other renewable energy supplies (wave or wind or floating solar) before transmitting it ashore. What is a submarine other than a 20MW subsea power plant.

Q12 Is the power delivery stated as 400V, with the potential to be 600V?

A12 Power delivery is currently based on 400V but we have been looking at the greater yield potential from the turbines to ramp this up to 600V. As in every electrical generating system, managing the heat is the key to generating power efficiently and especially so the PMGs. Fortunately, since we are operating subsea the seawater heat exchangers and liquid cooled circuits enable to power electronics to operate very efficiently.

Q13 Is the system supply Alternating Current (AC) or Direct Current (DC)

A13 The generator side is AC which is managed by the generator side drive units which then converts it to DC. The grid side drive unit then converts it back to AC to match the grid frequency.

Q14 Is there an estimate for supply current requirements or KVA delivery needs?

A14 There is a requirement to supply approximately 350KVA from each turbine so the platform can generate just over 1MW.

Q15 Are there any wild heat requirements?

A15 Not that I know of.

Subsea Cabling & Connectors

Q16 Is there an estimated offset (cable distance), or a range of considered offsets?

A16 The early stage arrays and demonstration zone being considered at the moment PTEC (Isle of Wight) and MORLAIS have pretty significant cable lengths up to 8km to the shore landing and substation.

Q17 How many fibre optic cores are required in the cabling?

A17 We haven’t deployed using fibre optic cores yet but over these offshore site we will obviously need to move to this technology. Our currently data requirements are low although a big part of our business model, in my mind, is the monitoring of the tidal farm. This includes platform, turbine, and environmental monitoring in real time. The environmental monitoring will include significant data loads including complex acoustic and video link signals. We would like to create a digital twin of the whole field to ensure we maximise the yield and reliability / availability of the offshore power plant. Clearly, all this data will need the proper fibre channels to transit it. To start I think a single fibre channel will suffice with another one for redundancy so 2 in total.

Q18 Do we have an indicative Cross Sectional Area (CSA) of the electrical cabling?

A18 Considering our deployments in early stage arrays of <10MW so a cable suitable this capacity.

Q19 Are there any special requirement relating to fault scenarios that the cables/connectors need to comply with?

A19 Learning from offshore wind, nearly all the early stage array failures were associated with faulty cables and poorly installed cables. Given that installing cables in tidal streams is still in its infancy and it has very different loading on the cables so has different requirements and methods to install them. Installation contractors and cable routing and design engineers, have to take this into appreciation. The design needs to be very robust and fault tolerant.

Q20 There are several references to dry mate connectors in the presentation, but no reference to wet mate connectors?

A20 Yes, always an interesting debate this but I am very much a dry mate man since all our operations assume dry mate and good deck access to connectors. This is because of the availability, voltage rating, long term reliability and lower cost of dry mates.

At some point in the future we may look at using wet mates more for utility scale deployments when equipment becomes less man-handleable and the availability and costs of wet mates comes down. However, at Industrial scale the value and performance of the dry mates satisfies our requirements at a much lower cost. Basically our Subhub installation methods overcome the need for wet mate connectors saving a significant amount of money for each turbine.

Q21 Are the connector requirements to be ROV or diver mateable?

A21 Not really, as explained above our Subhub installation method is quite unique since it has been designed to be conducted from the deck of the installation or support vessel. The Subsea Manifold, which is directly connected to the Subhub using dynamic umbilicals, can be easily brought onto the deck (2t dry weight). From there we can easily and quickly access the dry mate data and export connectors as well as all the other critical services to operate the Subhub. See below the Subsea Manifold, which has been recently upgraded to include the power and data export cables for our 3 Tocardo T1 turbines. As you can probably tell the SM spends the majority of its time on the seabed hidden from view.


Subsea Structures/Barge mounted equipment

Q22 Is there any requirement for subsea mounted equipment, or is the equipment to be mounted on the sinkable tidal barge?

A22 As above.

Q23 Are there any installation constraints, weight requirements, interface considerations etc..?

A23 The SM is designed to be easily manageable by small multi-cats at low day rates typical of those used to install moorings. I don’t really see that the SM needs to be any different to the one demonstrated above at industrial or utility scales but I think in the interest of keeping operating costs down that the weight should be <5t.

Q24 What are the water depth requirements for the equipment?

A24 The sites under consideration at the moment PTEC, 60m deep, and MORLAIS, 35m deep.

Q25 What are the hardware and software interfaces requirements for the turbine, SPCU and any other interfacing equipment? What types are these interfaces and what are the characteristics?

A25 The Subhub-CD currently uses a SCADA systems based on RS485. It comes to a control box where we interface with it using an ethernet TCP/IP software so our laptop / workstation becomes the data logger called ED Logger. I have been very impressed by this system and coms cabling which has been really put through its paces with 2 and ½ years at sea and then chucked around in the boatyard.

We have recently had an interface built for the Subhub Platform Management System (SPMS) using Labview which uses a UDP link cast from the ED Logger software (built in Visual Basic). The SPMS is designed as a supervisory controller which sits on top of all the other interfaces specifically to the turbines SCADA system called the Tocardo Turbine Array Controller (T-TAC). T-TAC is an ethernet based interface to PLCs in the control cabinets and E-boxes onboard the turbines. T-TAC control each individual turbine, the array and the whole farm of multiple Subhub units.

As well as the above, SPMS is designed to control the environmental data such as flow speed and wave height but also acoustic listening devices and even underwater video for environmental monitoring. This will enable us to detect what species of marine fauna are operating around the site and take appropriate control actions. For example, if seal or large marine mammals are detected it will switch on the camera and lights and potentially slow down or even stop the turbines.

Q26 Are any specific instrumentation required as part of the scope of supply?

A26 Our current suite of instrumentation includes pressure gauges for tank levels and tank pressure, strain gauges/load cells for leg loading, strain gauges load cells for Crossbeam and turbine loading, motion sensors and accelerometers/digital inclinometer.

We would like to add underwater cameras, omni and directional hydrophones, ADCP and ADV flow measurements, temperature and salinity.

Q27 Are there any requirements for system hydraulics? (e.g. do the turbines require any control fluid)

A27 Yes, the Subhub’s seawater inlet and vent valves are operated by hydraulics. Also, the turbines each have a HPU in the H-box to operate the brakes. However, we are looking at ways in which we can remove the brakes since there will always through up reliability and maintenance issues.

Q28 Are there any retrievability & protection requirements? (e.g. dropped object, trawler requirements etc..)

A28 Only the retrievability of the SM as discussed earlier. I recognise this is a source of frustration for the offshore/subsea operators given that these are designated no-trawler zones but they always attract trawlers or rather attract fish which use the structures as shelter. There is also an attraction of getting new nets from EU grants. However, good luck to them to them trying to shift 500t off the seabed. The Subhub is pretty damage tolerant. I would me most concerned about the umbilicals and turbine blades

Q29 Are there any redundancy requirements?

A29 Not really, we originally thought of having 2 SMs, one upstream and one downstream but the systems have proved themselves to be pretty robust and reliable with just one.

Q30 What are the fire & protection systems within the system?

A30 Currently, and shamefully, none that I know of, but I would of thought there should be since each phase of the cables is over 1,000A. In enclosed environment, non human occupied compartments, I would’ve thought we would have CO2. The thermal loading and fuses/switches must be part of this protection systems though.

Q31 What are the governing design standards that will be applicable to the system?

A31 Uncertain.

Q32 Are there any specific materials requirements?

A32 Not that I can think of but cost and environmentally friendly materials are important drivers.


Do we need a structure ?

Do we need 6ft diameter formed pipes ?

Can we clamp standard available pipes.


We have been doing all sorts of parametric modelling so we understand the impacts of changes to geometry and structure quite well. The driving fundamental principle is buoyancy and stability when submerged and on the seabed.

We need more buoyancy at the moment so increase the size of the pipes is beneficial. Standising pipe sizes would be beneficial and clamping them to the main spaceframe. I like to think of the main hull girder as a jacket on its side to minimise structure.

Beam of the structure is typically restricted by quayside, slip or docks that the platform is assembled in or by.

Ballast weight is restricted by the logistics of moving large bits of kits about.

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