[en] With increasing amounts of power generation from intermittent sources like wind, transmission planning has not only to account for the expected load curve but also for the stochasticity of volatile power infeeds. Moreover investments in power generation are no longer centrally planned in deregulated power markets but rather decided on competitive grounds by individual power companies. This poses particular challenges when it comes to evaluating the benefits of increased interconnection capacities in large-scale systems like the European transmission system. Within this article an approach is presented which allows assessing the benefits of interconnector investments in the presence of stochastic power infeed and endogenous power plant investments. This model uses typical days and hours as well as recombining trees to represent both load and infeed fluctuations. An application is presented covering 30 European countries and simultaneously optimizing generation investments and dispatch as well as utilization of transmission lines. The model is used to evaluate the benefits of further line extensions between the European mainland and northern European countries. We compute welfare gains and the distribution of these gains within a business as usual scenario up to 2030. - Highlights: ► Method for evaluating grid extensions in the context of competitive markets and increasing infeeds from intermittent RES. ► We investigate welfare effects of additional transmission capacities. ► Stochasticity of infeeds affects necessary generation capacities and the utilization of transmission capacities. ► Investments in interconnectors help to increase system flexibility for wind integration. ► Besides an overall benefit of grid extension some regions and stakeholders are inferior

[en] Distributed generation units are desirable from an environmental point of view but also have an impact on the costs of electricity grids at the distribution and transmission level. Therefore, investment planning has to consider all benefits and costs of DG to build DG sources at sites where they are economically efficient. Unfortunately, this is not an easy task in an unbundled industry where distribution and generation of electricity are not planned by one single institution. For this reason, this article analyses possible policy options for giving incentives to distributed generation and focuses on the long-term investment signals related to DG.