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Elin Halvorsen-Weare

Elin Halvorsen-Weare
SINTEF Ocean · Energy and Transport

Ph.D.

About

21
Publications
5,478
Reads
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532
Citations
Additional affiliations
October 2011 - December 2014
SINTEF
Position
  • Post Doctor
August 2007 - October 2011
Norwegian University of Science and Technology
Position
  • PhD Student

Publications

Publications (21)
Article
The installation process of offshore wind farms is complex and requires a high level of coordination, agile scheduling and systematic methods. High risks and costs are involved and especially weather conditions have an impact on the marine operations. A computer tool for optimisation and simulation of marine operations has been developed in close c...
Article
This paper considers the problem of determining the optimal vessel fleet to support maintenance operations at an offshore wind farm. We propose a two-stage stochastic programming (SP) model of the problem where the first stage decisions are what vessels to charter. The second stage decisions are how to support maintenance tasks using the chartered...
Article
Maintenance costs account for a large part of the total cost of an offshore wind farm. Several models have been presented in the literature to optimize the fleet composition of the required vessels to support maintenance tasks. We provide a mixed integer linear programming (MILP) description of such a model, where on the higher level, the fleet com...
Article
Full-text available
The offshore wind sector has achieved significant cost reductions in recent years. However, there is still work to be done to maintain and surpass these savings across current and future farms. There is increased competition to reduce costs within the industry itself. Additional challenges are foreseen at future sites located further from shore, in...
Chapter
One of the biggest challenges in the development of offshore wind farms is the cost and limited opportunities for maintenance and access. This calls for new solutions when it comes to operation and maintenance (O&M) strategies, condition monitoring and logistics, just to mention some examples. To assess different solutions and to select the best on...
Article
Full-text available
Maintenance operations at offshore wind farms are challenging due to the offshore element; maintenance technicians and spare parts need to be transported from an onshore port or offshore station to the individual wind farm components in need of maintenance. The vessel resources needed to support these maintenance tasks constitute a major part of th...
Conference Paper
Full-text available
Maintenance provides a large part of the cost of an offshore wind farm. Several models have been presented in literature to optimize the fleet composition of the required vessels. A drawback such models is that they are based on perfect information on weather and incidences to schedule for the coming year. Our research question is what will happen...
Conference Paper
Full-text available
The offshore wind energy industry is expected to continue its growth tendency in the near future. The European Wind Energy Association expects in its Central Scenario by 2030 a total installed capacity of 66 GW of offshore wind in the UE. Offshore wind farms (OWFs) are large scale infrastructures, requiring maintenance fleets to perform operations...
Article
Full-text available
We present a discrete optimisation model that chooses an optimal fleet of vessels to support maintenance operations at Offshore Wind Farms (OFWs). The model is presented as a bi-level problem. On the first (tactical) level, decisions are made on the fleet composition for a certain time horizon. On the second (operational) level, the fleet is used t...
Article
Full-text available
This paper considers the offshore supply vessel (OSV) planning problem, which consists of determining an optimal fleet size and mix of OSVs as well as their weekly routes and schedules for servicing offshore oil and gas installations. The work originates from a project with Statoil, the leading operator on the Norwegian continental shelf. We presen...
Article
Full-text available
In this paper we consider the problem of determining the optimal fleet size and mix of vessels to support maintenance activities at offshore wind farms. A two-stage stochastic programming model is proposed where uncertainty in demand and weather conditions are taken into account. The model aims to consider the whole life span of an offshore wind fa...
Article
In the mixed capacitated general routing problem, one seeks to determine a minimum cost set of vehicle routes serving segments of a mixed network consisting of nodes, edges, and arcs. We study a bi-objective variant of the problem, in which, in addition to seeking a set of routes of low cost, one simultaneously seeks a set of routes in which the wo...
Article
A fleet of vessels and helicopters is needed to support maintenance operations at offshore wind farms. The cost of this fleet constitutes a major part of the total maintenance costs, hence keeping an optimal or near-optimal fleet is essential to reduce the cost of energy. In this paper we study the vessel fleet size and mix problem that arises for...
Article
Full-text available
Different vessel types for transferring technicians for maintenance and inspection of offshore wind farms are often evaluated and compared by their limiting significant wave height for accessing the wind turbines. The limiting significant wave height is also the parameter that is often used as the access criteria in strategic decision support tools...
Article
Full-text available
Performing maintenance operations at offshore wind farms involves one major challenge compared with the onshore counterpart: All maintenance personnel and spare parts need to be transported from an onshore port or offshore station to the individual wind turbines by vessels or helicopters. The vessels and helicopters required for these tasks will co...
Article
Liquefied natural gas (LNG) is natural gas transformed into liquid state for the purpose of transportation mainly by specially built LNG vessels. This paper considers a real-life LNG ship routing and scheduling problem where a producer is responsible for transportation from production site to customers all over the world. The aim is to create route...
Article
The supply vessel planning problem is a maritime transportation problem faced by amongst others the energy company Statoil. A set of offshore installations requires supplies from an onshore supply depot on a regular basis, a service performed by a fleet of offshore supply vessels. The problem consists of determining the optimal fleet composition of...
Chapter
In the supply vessel planning problem, a set of offshore installations receives supplies from an onshore supply depot on a regular basis. This service is performed by a fleet of offshore supply vessels. The supply vessel planning problem then consists of determining the optimal fleet size and mix of supply vessels and the corresponding weekly voyag...
Article
Full-text available
Liquefied natural gas (LNG) is natural gas that has been transformed to liquid form for the purpose of transportation, which is mainly done by specially built LNG vessels travelling from the production site to the consumers. We describe a real-life ship routing and scheduling problem from the LNG business, with both inventory and berth capacity con...

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