Energy security is a multidimensional and evolving concept. Moreover, it is increasingly popular as a research subject. A large body of research concentrates on defining and measuring energy security, e.g. (Ang et al., 2015) and (Månsson et al., 2014), but no academic consensus has been reached in either composing a clear definition or an indicator that would be useful for political decisionmaking. The latter is largely due to the lack of a money-metric translation between different dimensions of energy security (Bohringer and Bortolamedi, 2015 € ). Therefore, it is sensible to take into account inter alia the unique geographical, political and economic environment of a nation and analyse energy security of the system per se instead of analysing the complex issue through an indicator. In November 2016 Finland updated its National Energy and Climate Strategy (the Strategy), which includes targets on e.g. increasing the share of renewable energy sources (RES) by 2030. Concurrently, the issue of generation adequacy1 during winter demand peaks has been present in the political discourse and in media especially since the record-high demand peak in early 2016 and the cautionary adequacy forecast in 2017 by The European Network of Transmission System Operators for Electricity (ENTSOE) (ENTSO-E, 2017a). The authors have previously analysed the resilience of the Finnish power system in 2016 (Ja€askel € € ainen et al., 2017; Ja€askel € ainen and Huhta, 2017 € ) with the conclusion that the system still had enough generation capacity and measures of intervention to cope with severe unexpected faults. However, several simultaneous market trends amplify the stresses regarding security of supply, inter alia the increasing share of weather dependent power production, prolonged low level of electricity market price and decreasing installed capacity of thermal power plants. Moreover, the national strategic objectives of further increasing the share of RES and phasing out coal in energy use both amplify the phenomenon. Thus, the issue of generation adequacy in the Finnish electricity market in the coming decades remains open for debate. This paper analyses the development of generation adequacy in Finland until 2030 in the energy policy scenarios of the Strategy by modelling the implications of similar conditions as were experienced in early 2016 with the EnergyPLAN simulation tool. In addition to the scenarios in the Strategy, we analyse a third scenario with pessimistic Assumptions regarding investments in power plants and cross-border transmission lines. Moreover, as the Nordic energy system is so heavily dependent on hydropower production, we analyse the interdependence between hydrological situation in the Nordic countries and generation adequacy in Finland by applying the effects of a severe drought in the Nordic energy system in the analysed scenarios. In order to assess the implications of a severe drought on the Finnish energy system, we model the hydrology during the worst drought in the 20th century (1939e1942) with the current hydropower capacity using Finnish Environment Institute’s Watershed Simulation and Forecasting System (WSFS). Furthermore, we briefly analyse the environmental impacts of hydropower operations during drought and peak demand in Finland.