Offshore deployments of wave energy converters by Uppsala University, Sweden

Chatzigiannakou, Maria Angeliki; Ulvgård, Liselotte; Temiz, Irina; Leijon, Mats

doi:10.1007/s40868-019-00055-2

Cited by 8 publications

(4 citation statements)

References 25 publications

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“…The seasonal ice-cover of the Baltic Sea [39,40] is, however, known to influence the wave climate, and Tuomi et al [41] suggested ways to calculate different types of statistics taking the ice-time into account. In practice, experience from both the WESA (Wave Energy for a Sustainable Archipelago) project [42][43][44] and several field tested deployment strategies [45,46] of wave energy equipment have increased the awareness of wave energy as an available potential renewable energy source in the region. Wave energy converters are, however, not very likely to be deployed if the presence of sea-ice is consistent for long periods of time every year.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Extreme and Metocean Conditions in the Swedish Exclusive Economic Zone for Wave Energy

et al. 2020

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Here, accessibility to near-shore and offshore marine sites is evaluated based on wave and ice conditions. High-resolution third-generation wave model results are used to examine the operation and maintenance conditions for renewable energy sources with a focus on wave energy. Special focus is given to the wave field and ice characteristics for areas within the Swedish Exclusive Economic Zone including analysis of return levels for extreme values for significant wave height, which provides guidance for dimensioning wave energy converters. It is shown that the number of weather windows and accessibility are influenced by distance from the coast and sea-ice conditions. The longest waiting periods for the closest weather window that is available for Operation and Maintenance (O&M) is in ice-free conditions shown to be strongly correlated with the fetch conditions. The sheltered Baltic Sea is shown to have very high accessibility if marine infrastructure and vessels are designed for access limits of significant wave height up to 3 m. In the northern basins, the waiting periods increase significantly, if and when the ice-conditions are found to be critical for the O&M activity considered. The ice-conditions are examined based on compiled operational sea-ice data over a climatic time period of 34 years. The results are location specific for the Swedish Exclusive Economic Zone, but the analysis methods are transferable and applicable to many other parts of the world, to facilitate assessment of the most promising areas in different regions.

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Section: Introductionmentioning

confidence: 99%

Assessment of Extreme and Metocean Conditions in the Swedish Exclusive Economic Zone for Wave Energy

et al. 2020

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“…In the first method ( Figure 5a) the buoy is deployed subsequently from its generator. The generator is first lowered to the seabed with a crane while being pressurized [40]. A diver removes the lifting slings and shackles, closes the pressurization valve, and pulls off the pressurization hose.…”

Section: Methods 1-wave Energy Convertors (Wec) and Buoy Deployment Sementioning

confidence: 99%

Deployment and Maintenance of Wave Energy Converters at the Lysekil Research Site: A Comparative Study on the Use of Divers and Remotely-Operated Vehicles

Remouit

Chatzigiannakou

Bender

et al. 2018

JMSE

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Ocean renewable technologies have been rapidly developing over the past years. However, current high installation, operation, maintenance, and decommissioning costs are hindering these offshore technologies to reach a commercialization stage. In this paper we focus on the use of divers and remotely-operated vehicles during the installation and monitoring phase of wave energy converters. Methods and results are based on the wave energy converter system developed by Uppsala University, and our experience in offshore deployments obtained during the past eleven years. The complexity of underwater operations, carried out by either divers or remotely-operated vehicles, is emphasized. Three methods for the deployment of wave energy converters are economically and technically analyzed and compared: one using divers alone, a fully-automated approach using remotely-operated vehicles, and an intermediate approach, involving both divers and underwater vehicles. The monitoring of wave energy converters by robots is also studied, both in terms of costs and technical challenges. The results show that choosing an autonomous deployment method is more advantageous than a diver-assisted method in terms of operational time, but that numerous factors prevent the wide application of robotized operations. Technical solutions are presented to enable the use of remotely-operated vehicles instead of divers in ocean renewable technology operations. Economically, it is more efficient to use divers than autonomous vehicles for the deployment of six or fewer wave energy converters. From seven devices, remotely-operated vehicles become advantageous.

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“…The test sites are located in an area about 10 km off the Swedish west coast, as shown in Figure 2a [34], where the UU Project deploys and tests the WECs. The research site fulfills three important geographical requirements and economic consideration: (a) the seabed is flat enough to accommodate over 10 prototypes of WEC; (b) the nearby harbor offers good accessibility and transmission conditions; and (c) biological and environmental studies are available as the test site is close to biological stations.…”

Section: Wave Energy Project At Uppsala Universitymentioning

confidence: 99%

Damping Studies on PMLG-Based Wave Energy Converter under Oceanic Wave Climates

et al. 2021

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Wave energy converters (WECs), which are designed to harvest ocean wave energy, have recently been improved by the installation of numerous conversion mechanisms; however, it is still difficult to find an appropriate method that can compromise between strong environmental impact and robust performance by transforming irregular wave energy into stable electrical power. To solve this problem, an investigation into the impact of varied wave conditions on the dynamics of WECs and to determine an optimal factor for WECs to comply with long-term impacts was performed. In this work, we researched the performance of WECs influenced by wave climates. We used a permanent magnet linear generator (PMLG)-based WEC that was invented at Uppsala University. The damping effect was first studied with a PMLG-type WEC. Then, a group of sea states was selected to investigate their impact on the power production of the WEC. Two research sites were chosen to investigate the WEC’s annual energy production as well as a study on the optimal damping coefficient impact. In addition, we compared the WEC’s energy production between optimal damping and constant damping under a full range of sea states at both sites. Our results show that there is an optimal damping coefficient that can achieve the WEC’s maximum power output. For the chosen research sites, only a few optimal damping coefficients were able to contribute over 90% of the WEC’s annual energy production. In light of the comparison between optimal and constant damping, we conclude that, for specific regions, constant damping might be a better choice for WECs to optimize long-term energy production.

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Offshore deployments of wave energy converters by Uppsala University, Sweden

Cited by 8 publications

References 25 publications

Assessment of Extreme and Metocean Conditions in the Swedish Exclusive Economic Zone for Wave Energy

Assessment of Extreme and Metocean Conditions in the Swedish Exclusive Economic Zone for Wave Energy

Deployment and Maintenance of Wave Energy Converters at the Lysekil Research Site: A Comparative Study on the Use of Divers and Remotely-Operated Vehicles

Damping Studies on PMLG-Based Wave Energy Converter under Oceanic Wave Climates

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