Daniel Huertas-Hernando

Balancing Market Integration in the Northern European Continent: A 2030 Case Study

Increased production flexibility will be needed for the operation of a future power system with more uncertainty due to an increased share of uncontrollable generation from renewable sources. Wind energy is expected to cover a large portion of the future renewable generation. In this paper, a comparison is carried out between two balancing market models, simulating a non- and fully-integrated northern European market in a future 2030 scenario. Wind power is modelled based on high resolution numerical weather prediction models and wind speed measurement for actual and forecasted wind power production. The day-ahead dispatch and balancing energy markets are settled separately. First, the day-ahead market is modelled with simultaneous reserve procurement for northern continental Europe. Available transmission capacity is taken into account in the reserve procurement phase. In a second step, the balancing energy market is modelled as a real-time power dispatch on the basis of the day-ahead market clearing results. The results show the benefit of balancing market integration for the handling of variable production. Cost savings are obtained from balancing market integration due to less activation of reserves resulting from imbalance netting and increased availability of cheaper balancing resources when integrating larger geographical areas.

Analysis of grid alternatives for North Sea offshore wind farms using a flow-based market model

Offshore wind farms are gradually being planned and built farther from the shore. The increased integration of wind power, also onshore, and the demand for improved power system operation give rise to a growing need for transnational power exchanges. Grid connection is a critical factor for successful large scale integration of offshore wind power. In this paper a comparison study between two different grid building strategies for offshore wind farms in the North Sea is presented for the 2030 medium wind scenario of the TradeWind project [1] (302 GW installed wind capacity). These two strategies are: i) A strategy based on radial wind farm connections to shore and point-to-point interconnections between countries, called radial grid; ii) A strategy based on the use of offshore nodes to build an HVDC offshore grid, called offshore grid. The comparison addresses different power system aspects, such as the total socio-economic benefit associated with each strategy, power exchanges between countries, offshore wind power utilization, grid congestions and utilization of HVDC cable capacity. We find that the offshore grid gives a total benefit over the economic lifetime of the grid for the European interconnected power system of 2.6 billion Euro compared with the radial grid. Our results show that even for moderate amounts of installed wind capacity, the offshore grid strategy is better than the radial one, assuming the future European power system will have a large penetration of offshore and onshore wind power.

Impact of system power losses on the value of an offshore grid for North Sea offshore wind

Grid connection is a critical factor for the integration of large scale wind power. This factor is even more important in the framework of transnational power exchange which is a way to improve power system operation. In this paper a comparison study has been carried out between two different grid building strategies for offshore wind farms in the North Sea using the 2030 medium wind scenario from the TradeWind project [1]. These strategies are i) radial and ii) meshed grid configuration. The paper has considered active power losses for both strategies and capture the effect of losses on different power system aspects, such as the total soci-economic benefit associated with each strategy, offshore wind power utilization, power exchange between the grid points, grid bottlenecks and utilization of HVDC connections. Using a meshed grid compared to radial there will be a total benefit of 2.7 billion Euro over the economic life time of the grid. However this benefit will be increased by 0.3 billion Euro by taking into account the grid losses for both cases. The results shows the benefit of using meshed offshore grid for future European power system with a large penetration of off- and onshore wind power.

Benefits of asymmetric HVDC links for large scale offshore wind integration

The large remote offshore wind clusters that are planned in the North Sea will most likely be connected with a meshed HVDC grid. Power will mostly flow from the offshore wind clusters to shore, creating asymmetrical requirements for the HVDC links that will consist of several parallel HVDC systems. To realise an asymmetrical link, some of those systems could be designed unidirectional, resulting in possible changes and simplifications (especially to the protection system). Assessment of a future scenario has shown that 42% of the HVDC systems can only be operated unidirectional. The remaining systems could in theory be used both directions, but power flow optimisation has shown, that this will in many cases not happen. A first cost calculation has shown that almost 6% of the investment cost can be saved when asymmetric design is implemented. This indicates the need to consider asymmetric design and to develop unidirectional HVDC systems.