A major obstacle standing in the way of full‐scale adoption of renewable energy sources is their intermittency and seasonal variability. To better understand the power generation dynamics, the effect of air density due to temperature on power and energy generation figures was modelled. The model uses historical ERA5 data and considers changes in weather patterns in a subarctic climate where seasonal changes are most pronounced. The power generation figures of using a mean and a dynamic air density value were compared and the results show that power generation estimates may be under‐ and overestimated by on average 5% up to 10% in winter and summer, respectively. This can have implications for the sizing of power transmission infrastructure and energy storage in both on‐grid and off‐grid applications as well as power availability. The topic is highly relevant in the Nordic countries where roughly 10% of new global added wind capacity is installed annually.

Hydrogen is a versatile feedstock for various chemical and industrial processes, as well as an energy carrier. Dedicated hydrogen infrastructure is envisioned to conceptualize in hydrogen valleys, which link together the suppliers and consumers of hydrogen, heat, oxygen, and electricity. One potential hydrogen valley is the Bay of Bothnia, located in the northern part of the Baltic Sea between Finland and Sweden. The region is characterized as having excellent wind power potential, a strong forest cluster with numerous pulp and paper mills, and significant iron ore and steel production. The study investigates the hydrogen-related opportunities in the region, focusing on infrastructural requirements, flexibility, and co-operation of different sectors. The study found that local wind power capacity is rapidly increasing and will eventually enable the decarbonization of the steel sector in the area, along with moderate Power-to-X implementation. In such case, the heat obtained as a by-product from the electrolysis of hydrogen would greatly exceed the combined district heat demand of the major cities in the area. To completely fulfil its district heat demand, the city of Oulu was simulated to require 0.5–1.2 GW of electrolyser capacity, supported by heat pumps and optionally with heat storages.

Hydrogen storage is a key enabler for linking stable industrial H2 demand with the variability of renewable electricity used for H2 production. This study applies particle swarm optimisation within a techno-economic framework to evaluate the role of lined rock cavern (LRC) H2 storage in a wind-dominated Nordic context. The results show that integrating large-scale H2 storage enables a fully fossil-free H2 supply across all hours of the year, with optimal storage capacity corresponding to approximately 30 days of demand. Although the inclusion of storage increases capital investment and raises the levelized cost of hydrogen (LCOH), its direct contribution to total system cost remains relatively small (approximately 5%). At the same time, storage provides operational flexibility by decoupling H2 production from real-time electricity availability, enabling greater utilisation of low-cost electricity from day-ahead markets. Controlled relaxation of the Renewable Fuels of Non-Biological Origin (RFNBO) regulation would enable even better grid integration with only a minor increase in emission footprint of the produced H2 in the studied region of Oulu, Finland.

Power-to-X (P2X) technology holds great potential for decarbonization and sees an active growth of R&D, pilot projects, and scaling initiatives. Such projects are surrounded by tremendous uncertainty due to their long lifespan, dependency on market and policy evolution, and high upfront costs. Thus, the usage of adequate analytical tools is of paramount importance to design, evaluate, and execute P2X projects. In this chapter, we took one such techno-economic report for a P2X project and replicated its one-at-a-time sensitivity analysis and scenario analysis with the more powerful SimDec approach. The breadth of the newly acquired insights inspired the authors to upgrade the analysis to reflect present-day circumstances in order to determine what findings SimDec could contribute to the evolving situation. In all analyzed cases, SimDec showed an excellent capability of combining uncertainty and sensitivity analysis for deriving comprehensive actionable insights for investment projects. <!----> <!----> <!----> <!---->