Ongoing master theses

Ongoing theses

Optimal turbine placement in an offshore wind farm


In 2013, about 19% of the global energy consumption came from renewable energy sources. Wind power only provided for 0.39% of the total consumption, with an even smaller contribution if only considering offshore wind. The low contribution originates from the fact that offshore wind is a relatively new energy source where the potential in development still is high. However, offshore wind is highly relevant for future energy generation and has become an increasingly attractive investment area.

The main focus areas for offshore wind lies in Europe, USA, Japan and China, where the energy potential for offshore wind farms are great. As the leader in offshore wind, Europe already has several operational wind farms. In addition future installations are planned in all of the mentioned focus areas. One of the large future offshore projects is the 7 GW wind farm Dogger bank located outside the UK. Projects of this dimension involves large investments, where minimization of costs becomes very important.

The offshore environment is demanding in terms of installation, operation and maintenance which leads to large costs. In addition cabling, grid connection and foundation are very expensive. Further development of offshore wind as an energy source is therefore dependent on good models and methods for minimizing turbine and cable-costs.

Advisor: Dag Haugland.

Student: Eirin Mæland Fjellanger

Enrolled semester: Fall 2014


Models for a pickup and delivery problem with time windows and a single vehicle

In this thesis, computational approaches to the following problem are addressed: A transportation vehicle is given a list of transportation requests which it must service as fast as possible. Each transportation request describes a pickup location, where the vehicle must load a certain amount of goods, a delivery location, where the vehicle must unload the goods, and a strict time window in which the vehicle must have completed its pickup or delivery order. The vehicles route must be a simple path that starts and ends at the start location.

Advisor: Dag Haugland.

Student: Yacine Lakel

Enrolled semester: Fall 2014


Cable Layout in Offshore Windfarms

In an ongoing master project in optimization, the following problem is studied: For offshore wind farms given by

  • GPS coordinates of the wind turbines,
  • GPS coordinates of the target point(s) of the supply cable(s),
  • GPS coordinates of areas prohibited for cables,
  • number of substations and/or GPS coordinates of the substations,
  • maximum number of wind turbines per cable string or loop,
  • whether the cables should loop to provide redundancy,
  • whether substations should be connected by export cable to provide redundancy,
  • whether the wind turbines can have more than two neighbours and if so, the cost induced by additional neighbours,

we look for the cable layout minimizing the total cable length. In the suggested thesis, we shall study extensions of this problem. In the first extension, we assume that a cable route can be split at specific turbine locations (network nodes). The split comes with a cost, depending on the number of splits that are made (the node degree). Further, we will take into account the trenching costs. Cable links will be laid in trenches in the sea bed, and two or more links can share the same trench. Subsea trenching is extremely expensive, and substantial saving can be achieved by restricting the total length of the trenches. Thus, the second extension is to find one trench route and one cable route as well as an assignment of cables to trenches. The objective is to minimize total costs.

Possible thesis work activities include mathematical modelling, theoretical analysis, design of smart (exact or inexact) solution methods, and efficient implementation.

Advisor: Dag Haugland.

Student: Valery Tchouatchoua

Enrolled semester: Fall 2013


Optimization of the installation of offshore wind farms

Renewable energy is a growing industry within the energy sector. Harvesting energy from the wind is already a developed technology, but operating offshore involves new challenges. Constructing an offshore wind park requires a lot of planning. The challenges include demanding weather conditions, costly operations and high wear. There are two main advantages of utilizing offshore wind over its onshore counterpart. First of all, the wind resources are greater at sea than on land. This makes the offshore locations offer more potential energy, as well as more steady production and higher capacity factors. The other argument is that there is less competition for offshore areas, so that potential land use conflicts are avoided [Breton and Moe, 2009]. With offshore wind still being a young technology, today’s many challenges are expected to be reduced in the near future. Some propose a reduction of costs by up to 30 % by 2030 [IRENA, 2012]. This coming thesis work seeks to participate in exactly that.

Advisor: Dag Haugland.

Student: Stian Backe

Enrolled semester: Fall 2015


Solution Methods in Continuous Optimization for solving Energy Problems


Advisor: Jan-Joachim Rückmann.

Student: Stanley Owulabi Babatunde

Enrolled semester: Fall 2015