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This paper presents results from case studies of the future power systems in Morocco and Egypt, with a high increase in renewable generation capacity. Datasets representing 2030 scenarios have been generated and studied with a simplified grid-market model that takes into account variable renewable generation, energy storage and electricity grid constraints. Simulation results for Morocco and Egypt are studied and compared, with emphasis on the benefit of energy storage.

Purpose: This study aims to contribute to an improved understanding of the environmental implications of offshore power grid and wind power development pathways. To achieve this aim, we present two assessments. First, we investigate the impacts of a North Sea power grid enabling enhanced trade and integration of offshore wind power. Second, we assess the benefit of the North Sea grid and wind power through a comparison of scenarios for power generation in affected countries. Methods: The grid scenario explored in the first assessment is the most ambitious scenario of the Windspeed project, and is the result of cost minimization analysis using a transmission expansion planning model. We develop a hybrid life cycle inventory for array cables, HVDC links and substations. The functional unit is 1 kWh of electricity transmitted. The second assessment compares two different energy scenarios of Windspeed for the North Sea and surrounding countries. Here we utilize life cycle inventory for offshore grid components together with inventory for a catalog of power generation technologies from Ecoinvent, and couple these inventories with grid configurations and electricity mixes determined by the optimization procedure in Windspeed. Results and discussion: Developing, operating and dismantling the grid cause emissions of 2.5 g CO2-Eq per kWh electricity transmission, or 36 Mt CO2-Eq in total. HVDC cables are the major cause of environmental damage, causing for example half of total climate change effects. The next most important contributors are substations and array cabling used in offshore wind parks. Toxicity and eutrophication effects stem largely from leakages from disposed copper and iron mine tailings and overburden. Results from the comparison of two scenarios demonstrate a substantial environmental benefit from North Sea grid extension and the associated wind power development compared to an alternative generation of electricity from fossil fuels. Offshore grid and wind power, however, entail an increased use of metals and hence a higher metal depletion indicator. Conclusions: We present the first life cycle assessment of a large offshore power grid, using results of an energy planning model as input. HVDC links are the major cause of environmental damage. There are differences across impact categories with respect to which components or types of activities that are responsible for damage. North Sea grid and wind power are environmentally beneficial by an array of criteria if displacing fossil fuels, but cause substantial metal use.

This paper describes a modelling approach suitable for assessments of future scenarios for renewable energy integration in large and interconnected power systems, based on sequential optimal power flow computations that take into account variability in power consumption, in renewable power production, energy storage, and flexible demand. The approach and the implementation as an open source Python package called Power Grid And Market Analysis is described in some detail. Particular emphasis is put on the modelling of energy storage systems, and the use of storage values as a means to define storage utilisation strategies. A case study representing a 2030 scenario for the Western Mediterranean region is then analysed using this approach. The main aim of this study is to assess the benefit for the system of adding flexibility in terms of storage associated with concentrated solar power or flexible demand. But other results are also presented, such as the resulting energy mix, generation costs, price variations, and grid congestion.

Zero Energy Buildings (ZEBs) are considered as one of the key elements to meet the Energy Strategy of the European Union. This paper investigates cost-optimal solutions for the energy system design in a ZEB and the subsequent grid impact. We use a Mixed Integer Linear (MILP) optimisation model that simultaneously optimises the building’s energy system design and the hourly operation. As a ZEB have onsite energy generation to compensate for the energy consumption, it is both importing and exporting electricity. The hourly time resolution identifies the factors that influence this import/export situation, also known as the building’s grid impact. An extensive case study of a multi-family house in Germany is performed. The findings show that the energy system design and the grid impact greatly depend on the ZEB definition, the existing policy instruments and on the current energy market conditions. The results indicate that due to the feed-in-tariff for PV, the cost-optimal energy design is fossil fuelled CHP combined with a large PV capacity, which causes large grid impacts. Further, we find that heat pumps are not a cost-optimal choice, even with lower electricity prices or with increased renewables in the electric power system. Acknowledgements. This work has been supported by the Research Council of Norway and several partners through the Research Centre on Zero Emission Buildings (ZEB) and the Research Centre for Sustainable Energy Studies (CenSES). The authors acknowledge the support from the Norwegian Water Resources and Energy Directorate (NVE) in Oslo, Norway, and Fraunhofer Institute for Solar Energy System (ISE) in Freiburg, Germany. The first and second authors would like to thank Viessmann for providing technology cost data for current market conditions in Germany. The first author would also like to thank Dr. Thomas Erge with the Fraunhofer ISE for valuable input on the current energy market conditions in Germany, and Dr. Torgeir Ericson with the NVE for constructive comments on the structure of the paper.

The future success of wave energy in the renewable energy mix depends on the technical advancements of the specific components and systems, on the grid access availability and, ultimately, on the economical profitability of the investment. Small and remote islands represent an ideal framework for wave energy exploitation, due both to resource availability and to the current high cost of electricity that mostly relies on diesel generation. Energy storage can be the enabling technology to match the intermittent power generation from waves to the energy needs of the local community. In this paper real data from La Palma, in the Canary Islands, are used as a basis for the considered test case. As a first step the study quantifies the expected power production from Wave Energy Converter (WEC) arrays, based on data from the Lifesaver point absorber developed by Fred. Olsen. Then, a stochastic optimization approach is applied to evaluate the convenience of energy storage introduction for reducing the final cost of energy and to define the corresponding optimal rating of the storage devices.