Wave Energy Research at Uppsala University and The Lysekil Research Site, Sweden: A Status Update (original) (raw)
Related papers
Wave Energy from the North Sea: Experiences from the Lysekil Research Site
Surveys in Geophysics, 2008
This paper provides a status update on the development of the Swedish wave energy research area located close to Lysekil on the Swedish West coast. The Lysekil project is run by the Centre for Renewable Electric Energy Conversion at Uppsala University. The project was started in 2004 and currently has permission to run until the end of 2013. During this time period 10 grid-connected wave energy converters, 30 buoys for studies on environmental impact, and a surveillance tower for monitoring the interaction between waves and converters will be installed and studied. To date the research area holds one complete wave energy converter connected to a measuring station on shore via a sea cable, a Wave Rider TM buoy for wave measurements, 25 buoys for studies on environmental impact, and a surveillance tower. The wave energy converter is based on a linear synchronous generator which is placed on the sea bed and driven by a heaving point absorber at the ocean surface. The converter is directly driven, i.e. it has no gearbox or other mechanical or hydraulic conversion system. This results in a simple and robust mechanical system, but also in a somewhat more complicated electrical system.
An experimental wave power farm is being developed on the Swedish West coast. It will consist of one marine substation connecting up to seven wave energy converters (WECs) of the linear generator point absorber type that is researched at Uppsala University. The substation will be put on the seabed and connect the WECs to the local electric grid onshore via a common power cable. In the substation, the voltage generated by the WECs is rectified onto a controllable DC-bus. An ACvoltage is then created and synchronized with the 1kV-grid voltage. The substation is also used to electrically control the damping of different units. Various techniques and algorithms will be evaluated. In this article, the design and implementation issues of the marine substation are discussed. The on-going work with experimental result from the laboratory is presented. The contents of the article include e.g. the electrical system design, cooling, communication to shore, stand-alone operation, mechanical design of the substation hull and subsea connections. The substation is planned to be deployed in the ocean in the spring of 2013.
For testing and evaluating purposes, a pilot wave power plant is under construction at Islandsberg on the West Coast of Sweden. The concept suggested for wave energy conversion consists of a surface following buoy, a point absorber, connected to a three-phase permanent magnetised linear generator placed at the seabed. The motions of the buoy drive a piston in the generator, thereby converting the energy of the waves into electric energy. This paper describes the test site and the two measurement set- ups that are in use in order to receive information for the design and optimisation of the direct driven linear generator. A Datawell Waverider buoy provides wave data in the form of time series of wave elevation and wave variance spectra. The second set- up, built in house, measures loads on a full-scale point absorber.
JOURNAL OF APPLIED PHYSICS 106, 064512, 2009
The full-scale direct-driven wave energy converter developed at Uppsala University has been in offshore operation at the Swedish west coast since 2006. Earlier simulations have now been validated by full-scale experiment with good agreement. Based on that, a theoretical model for a passive system having optimum amplitude response at frequencies coinciding with Swedish west coast conditions has been developed. The amplitude response is increased by adding supplementary inertia by use of the additional mass from a submerged body. A sphere with neutral buoyancy is chosen as the submerged body and modeled as being below the motion of the waves. The model is based on potential linear wave theory and the power capture ratio is studied for real ocean wave data collected at the research test site. It is found that the power capture ratio for the two body system can be increased from 30% to 60% compared to a single body system. Increased velocity in the system also decreases the value for optimal load damping from the generator, opening up the possibility to design smaller units.
Ocean wave converters: State of the art and current status
2010 IEEE International Energy Conference, 2010
Solutions to today energy challenges need to be explored through alternative, renewable and clean energy sources to enable a diverse energy resource plan. An extremely abundant and promising source of energy exists in oceans. Ocean energy exists in many forms. Among these forms, significant opportunities and benefits have been identified in the area of ocean wave energy extraction, i.e., harnessing the wave motions and converting them into electrical energy.
Renewable Energy
Power generation from wave power has a large potential to contribute to our electric energy production, and today, many wave power projects are close to be commercialized. However, one key issue to solve for many projects is to decrease the cost per installed kW. One way to do this is to investigate which parameters that have a significant impact on the wave energy converters (WEC) performance. In this paper, experimental results on power absorption from a directly driven point absorbing WEC are presented. The experiments have been carried out at the Lysekil research site in Sweden. To investigate the performance of the WEC, the absorbed power and the speed of the translator are compared. The result confirms that the buoy size and the translator weight have a large impact on the power absorption from the generator. By optimizing the buoy size and translator weight, the WEC is believed to produce power more evenly over the upward and downward cycle. Moreover, to predict the maximum p...
A Nearshore Heaving-Buoy Sea Wave Energy Converter for Power Production
There exists nowadays an ever-increasing demand for clean and renewable energy, due to the high level of pollution conventional energy production plants produce. Extracting energy from sea waves in Lebanon is a technology that has not yet been developed. In this paper, the potential of harvesting wave energy to produce electrical power on the Lebanese shore is investigated. As such, a compact wave-harvesting device was built. It consists of a float-rack-pinion system that transmits the vertical heaving motion of the waves and converts it into a rotating motion. This in turn is used to produce electricity through an alternator. A prototype was built and successfully tested in shallow water near shore to light up a 3-W lamp. The mechanical design of the manufactured device along with the operation process will be presented in details. In addition, the test results will be summarized along with the potential improvements that can be applied to the system.
Wave Energy Plants for the Black Sea – Possible Energy Converter Structures
Proceedings of the International Conference on Clean Electrical Power (ICCEP '2007), Capri (Italy), 2007, pp. 306-311
It is crucial for the mankind to develop clean renewable energy sources. Ocean energy is one of the candidates being a huge, yet unexploited renewable energy source on the Earth. Preliminary surveys show that marine power has a potential to supply a significant part of the future energy needs. Hence all the researches done in the field of the wave energy conversion should be of real interest. In this paper the wave energy potential of the Black Sea near the Romanian coasts, a possible power take off system to be set up here, respectively a comparative study on two possible linear generators to be used in such wave energy power converters will be presented.
Wave energy converters and their impact on power systems
2005 International Conference on Future Power Systems, 2005
The objective of this paper is to give an introduction into ocean wave energy converters and their impact on power systems. The potential of wave energy is very large. There are a lot of different methods and systems for converting this power into electrical power, such as oscillating water columns, hinged contour devices as the Pelamis, overtopping devices as the Wave Dragon and the Archimedes Wave Swing. The main characteristics of these wave energy converters are discussed. A lot of research, development and engineering work is necessary to develop the experimental systems into reliable and cost-effective power stations. The wide variety of systems makes it difficult to say general things about power quality. However, the large variations of output power are a common problem. Whether this can be solved by using wave farms has to be investigated further.