Depending on the region, most energy comes from hydro, nuclear, waste-to-energy, fossil fuels, peat or wind. From the official statistics it’s clear that fossil fuels are less used these days but they still play an important role.
In the Helsinki region, we have a couple of combined heat and power generation plants that rely on wood pellets and coal – technically speaking there are also solar power plants but they’re not very useful in wintertime. The CHP plants provide not only electricity but also the hot water used throughout the city. The surplus heat made during the low-demand hours is stored in big heat accumulators (essentially huge water tanks) and then released during peak hours.
One of my favourite parts about Helsinki is that the power plants are prominent parts of the landscape – I find it’s a great reminder than most of our lives are based on energy and heat use! I think anyone who’s ever been to Helsinki has seen the Salmisaari power plant without even realising what it is, it’s also quite neat that they show in real-time the energy/heat generation and use at the front.