Reliable, low-carbon energy supply in Nordic climates requires coordinated use of multi-carrier energy systems (MESs) and advanced storage technologies. In the Finnish context, seasonal hydrogen storage (HSS) and sand battery–based high temperature thermal storage (SBS) are particularly important, as they enable shifting surplus renewable generation from windy and sunny periods to long, cold winters while reducing dependence on fossil heating fuels. This paper presents an energy hub (EH) optimization framework for such MESs with high renewable penetrations. The two-level model co-optimizes long-term planning and short-term operation of generation, hybrid daily/seasonal storage, energy conversion units, demand response, and vehicle-to-grid–enabled plug-in electric vehicles. Additionally, it explicitly includes battery degradation costs and assesses the coordinated use of seasonal HSS and SBS under uncertainty in renewable generations, demand, and prices. The case studies demonstrate operating cost and emission reductions of 4.8% and 6.3%, respectively, while achieving a renewable energy penetration of 91%.