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Energy-system scenarios are widely used to relate the developments of the energy supply and the resulting carbon-emission pathways to political measures. To enable scenario analyses that adequately capture the variability of renewable-energy resources, a specialised type of power-sector model (PSM) has been developed since the beginning of this century, which uses input data with hourly resolution at the national or subnational levels. These models focus on techno-economic-system optimisation, which needs to be complemented with expert socioeconomic knowledge in order to prevent solutions that may be socially inacceptable or that oppose political goals. A way to integrate such knowledge into energy-system analysis is to use information from framework scenarios with a suitable geographical and technological focus. We propose a novel methodology to link framework scenarios to a PSM by applying complexity-management methods that enable a flexible choice of base scenarios that are tailored to suit different research questions. We explain the methodology, and we illustrate it in a case study that analyses the influence of the socioeconomic development on the European power-system transition until 2050 by linking the power-sector model, REMix (renewable-energy mix), to regional framework scenarios. The suggested approach proves suitable for this purpose, and it enables a clearer link between the impact of political measures and the power-system development., Helmholtz Association

Wave Energy Converter (WEC) structures have been widely studied in the past decade, due to their high potential for device cost reduction. In this context, various hull geometry optimisation studies have been performed to maximise power and reduce costs, where costs were mostly represented through the device size in terms of mass, volume or surface area. In the present study, the suitability of the different objective functions is analysed, with the goal of finding an optimal hull shape with relevant cost considerations when using a flexible geometry definition. The results are given for a particular location off the West Shetland shelf to the north of Scotland. Impedance matching control at the energy period is assumed, and this means that mass distribution has no effect on the device oscillation. The differences in shape and annual energy production are presented for optimal devices oscillating in surge, and in surge, heave and pitch. Devices are optimised for maximal annual energy production, and its ratio to various size characteristics based on volume and surface area.

In this study, we seek to understand the relationship between wave energy converter (WEC) hull geometries and power take-off (PTO) reliability. To do this, we calculate the damage equivalent loads (DELs) for a PTO given three hull shapes (a cylinder, a sphere, and a barge), two sets of metocean conditions (from the center of the North Sea and off the west coast of Norway), and two float motions (heave and surge). Results indicate that hull geometry has a primary influence on DELs experienced by the PTO, and also that certain geometries result in larger variations in DELs based on whether the device is moving in heave or surge motion. These findings underline the importance of considering WEC hull geometry in early design processes to optimize cost, power production, and reliability. More importantly, this research emphasizes the need to consider the relationship between the WEC geometry and the PTO reliability early in the design process. By considering this relationship, more optimal WECs can be designed for power production and system reliability. The methods tested in this study will enable the future reliability-based geometry optimization of WEC hulls to maximize reliability and power production.

Accepted manuscript - with corrected Figure 7. Different technologies for Floating Offshore Wind (FOW) systems have been developed and multiple studies exist that aim at comparing the techno-economic advantages and disadvantages of each technology. However, the assumptions and calculations used in these different studies vary largely resulting in high variation of the final cost estimates. This points to the need of developing a consistent method that allows for technology comparison at whole system but also subsystem level. In this paper, the sensitivity of the final results to the different assumptions and calculation setups is investigated. This study provides a discussion of the suitability of the applied methods, and as a result suggests the standardisation of the procedure, while defining a set of recommendations for good practices in techno-economic assessment of FOW technologies. The suggested common framework will facilitate the comparison of different FOW technologies based on costs and increase investor confidence.

Accepted manuscript - with corrected Figure 7. Different technologies for Floating Offshore Wind (FOW) systems have been developed and multiple studies exist that aim at comparing the techno-economic advantages and disadvantages of each technology. However, the assumptions and calculations used in these different studies vary largely resulting in high variation of the final cost estimates. This points to the need of developing a consistent method that allows for technology comparison at whole system but also subsystem level. In this paper, the sensitivity of the final results to the different assumptions and calculation setups is investigated. This study provides a discussion of the suitability of the applied methods, and as a result suggests the standardisation of the procedure, while defining a set of recommendations for good practices in techno-economic assessment of FOW technologies. The suggested common framework will facilitate the comparison of different FOW technologies based on costs and increase investor confidence., For citation, please, refer to: Garcia-Teruel, A., & Jeffrey, H. (2020). The economics of floating offshore wind – A comparison of different methods. In Guedes Soares (Ed.), Proc. of the 4th International Conference on Renewable Energies Offshore (RENEW 2020) - Developments in Renewable Energies Offshore. Taylor & Francis Group, London.