Project

The aim is to obtain knowledge of nonlinear loads which could cause unwanted dynamics or stability issues for the DC-microgrid. This leads to the investigation of the nonlinear loads: Constant Power Loads and Reversible Solid Oxide Cells.
The design of a suitable DC-DC converters and control systems are investigated to fulfill performance requirements and mitigate stability issues.

The ocean covers over 70% surface of the earth, however, we have to say that so far human being knows still very little under these waters, although we believe there should be plenty of resources we could adopt if we could find out some safe and cost-effective technology to do so. Subsea robotics has been helping human beings to extend their capabilities in recent decades, thanks to the rapid technology development. Subsea robots can commit difficult and/or dangerous tasks beyond human's natural capability, such as deepwater sea floor scanning, oil & gas exploitation and exploration, subsea pipeline installation and inspection, as well as handling some catastrophic disasters.

The proposed equipment can certainly provide us with a solid and professional subsea robotic platform, not only to verify our so-far obtained results, but also to inspire new thinking and ideas, as well as to provide relevant industries a lab-sized testing robot protocol.

The pitch system of a wind turbine is one of the systems used for regulating the power production of the wind turbine. The Pitch system may turn the blades of the turbine from approximately 0 to 90 degrees around its own axis and thus regulate the energy input from the wind to the turbine. If the blades are turned into a 90 degree position the turbine will stop rotating and the energy production is stopped. If an error occurs in the turbine and it is necessary to shut the turbine down before extensive damage occurs, an emergency stop is performed by turning the blades to their 90 degree position. The pitch system is the primary safety system of the turbine.

As the pitch system has an essential function of the wind turbine it is extremely important that the system is reliable and available. Especially for offshore wind turbines it is extremely important that no other maintenance than the scheduled has to be performed. Research shows that pitch systems are currently responsible for 22% of wind turbines' total downtime.
A combination of lower cost and increased reliability and availability on the hydraulic pitch system will reduce both the total cost of ownership (TCO) and Total Cost of Energy (TCE).

This project aims to significantly increase the reliability and availability of the pitch systems compared to current hydraulic and electric pitch systems. This is done through a modular way of thinking in which the entire system is brought out in the rotating hub and distributed in three individual systems - one for each wing. Through this transformation it is the goal to reduce the price by 20% while the number of components is lowered by 10%.

To increase uptime for a hydraulic pitch system, external leakage from the hydraulic components must be eliminated. This will be achieved through reductions in external leakage paths to both the environment in the hub of the turbine and nature where the turbine is erected. In 2012, 74% of the offshore wind turbines were installed with hydraulic pitch systems. Of the total offshore capacity, 86% of the turbines are controlled by hydraulic pitch systems (2012). It is the goal for the new hydraulic pitch system that it must be in new offshore wind turbines already being installed with hydraulic pitch, but by the modular thinking and plug and play setup it is possible to access turbine manufacturers who use electric pitch and thus take greater market share.

Mussels and other marine fouling settle on the part of offshore wind turbines and production platforms that is underwater.
The fouling worsens the load from the waves and reduces the load-bearing capacity of the structure by 25-65 percent. Today, the fouling is removed manually – typically using manually controlled underwater robots – which is a time-consuming and financially burdensome process.

The idea for the solution consists of three elements. 1. cleaning rings around the supporting structures that remove fouling when the water moves. 2. a robot that can move on the supporting structures and send a message about the size of the fouling. 3. A robot that can remove fouling by high-pressure washing underwater. The effect of the solution will be an extension of the service life of the structure, and an expected reduction in costs by 30-40 percent. In the North Sea alone, the industry currently spends a three-digit million amount annually on removing marine fouling.

A common challenge for structures submerged in water, such as offshore oil and gas platforms and wind turbine foundations, is marine fouling. The fouling consists of, for example, mussels and sea grass, which settle permanently on the structure and thereby increase both the volume and roughness of the material. This causes increased stress and fatigue of the structure, primarily due to increased wave loads and the weight of the fouling. Furthermore, the fouling complicates inspections of the structure, which are important for documenting the durability of the material. These disadvantages are reduced by cleaning the fouling off at regular intervals. Alternatively, the structure is oversized in the design phase to overcome the loads from marine fouling. Both methods are expensive for the production and/or operation of the structures and thus for energy production. In this project, two major players within Denmark's strengths, oil and gas (Total E&P) and wind (Siemens Gamesa), have joined forces to support the development of an improved concept for inspecting and combating marine fouling. The concept is based on improved robotic technology, which will raise the level of automation, as well as a compact setup that makes the operation independent of large environmentally polluting vessels, which the clean-up campaigns today depend on. The solution will finally be tested in the North Sea and will raise the technology from TRL 4 to TRL 7.

The purpose of the project is to mature the idea of ​​a novel approach for establishing reliable digital twins of offshore wind turbines, which can be employed for improved operation and maintenance of these systems. Upon successful completion of this, the intention is to apply for an Innovation Fund project or EUDP project. The aim is to develop digital twins based on closed-loop model updating and incorporate them in a systematic procedure for structural health monitoring of wind turbines, and (2) aim To develop data-driven control strategies for vibration damping.

The project follows the ACOMAR project, where the main focus for AAU is to make the control and algorithm part of ACOMAR ready for TRL8. Based on offshore tests in ACOMAR, it is expected that several algorithms and their implementation will need to be adjusted to achieve TRL8. It is expected that more tests of the navigation, control and error handling algorithms will need to be carried out at local onshore test facilities, with the aim of adapting and maturing the final product.
In conjunction with these tests, it is expected that documentation of the algorithms will be made for possible transfer. The documentation is intended to promote user-friendliness, so that the algorithms can be operated by the operators.

The purpose of the project is to develop a gyroelectric energy conversion unit for wave energy. In order to demonstrate the technology under realistic conditions, a series of experimental tests will be carried out at the Nissum Bredning Test Station on a 5 kW unit.
The following main activities will be held:
Continuation of wave basin tests on an existing prototype at AAU. Including determination of the absorbed power at different standard sea conditions. Tests with irregular waves to optimize energy absorption under realistic conditions.
Design and manufacture of a 5 kW PTO unit. In the design and in the choice of manufacturing methods, emphasis will be placed on using standard components and manufacturing methods that can also be used in a possible production of a full-scale PTO unit (15, 30 and 50 kW).
Testing and demonstration of a 5 kW PTO unit at the Nissum Bredning Test Station. Over a period of approx. 10 months from August 2015 to June 2016, a series of tests will be carried out with the PTO unit mounted to the test station platform approx. 140 m from shore.
Preparation of a measurement program data processing for the tests at AAU, as well as the testing at Nissum Bredning.
Contact with wave power developers. In the final part of the project, a number of Danish and foreign wave power developers will be contacted with a view to starting an end-user dialogue with 2-3 wave power developers.

The Danish wave energy sector consists of several large floating and loosely anchored wave power plants. These plants require specially designed anchoring systems, as “standard” solutions (largely coming from the offshore oil and gas industry) are not designed for the conditions and specifications applicable to wave power plants. For these wave power plants, it is necessary to reduce the resulting anchoring and structural loads, which can be done by making the anchoring solutions more compliant. This will reduce the costs of the anchoring solution and the structure of the plant and thereby the overall costs of the plant and its produced energy, while making the systems more reliable.

The four plants selected to be part of this project are all at a stage of development where they have either completed, or are about to complete, testing of the plants at sea. The four plants are Floating Power Plant, Wave Dragon, Weptos and Leancon. They all require comparable anchoring solutions, as the plants are large, floating, loosely anchored structures operating in water depths of around 30 – 100 m at full commercial scale. This project investigates and compares different anchoring solutions that are useful for these wave power plants. The anchoring solutions are assessed step by step, in order to carry out a systematic and thorough evaluation. The project is organised in the following work packages:

- WP 1: Design practices and tools.
- WP 2: Anchoring solutions.
- WP 3: Preliminary design.
- WP 4: Full analysis.
- WP 5: Cost evaluation.
- WP 6: Selection and results.
- WP 7: Dissemination and project management.

Throughout the project, reports will be produced presenting the results of the selected studies and milestones according to the project Gantt chart. Each of them is crucial for the next step of the analysis and will thus be of great importance. The final results of this project are numerous. It will provide experience and insight into the development of anchoring solutions for all project partners. Furthermore, it will provide the developers with detailed analyses of the various anchoring solutions, and evaluate their prices and practical applicability. Aalborg University will build up experience and know-how in the field, which will enable them, and/or a possible spin-off company, to offer design services in the field to companies in the future. It is also expected to be significant cost and reliability benefits, in addition to having an effective anchoring solution, for the partner plants.

The purpose of this proof of concept project is to further investigate the WaveSpring technology and how it can benefit wave energy plants. The results from the project will increase the efficiency of wave energy plants and reduce the price of the energy produced from the plants.