HOT|COOL NO. 4/2020 - "Large and Growing Markets"

District heating is the power grid's best friend

The market share of renewable energy in the Norwegian heating market is almost 100 % and at the beginning of 2020 a national ban on the use of fossil oil for heating entered into force.

By: Trygve Mellvang Tomren-Berg Norsk Fjernvarme (Norwegian DH association)

Waste heat is key In the 1980s, modern large scale district heating started to emerge in the Norwegian heatingmarket, driven bymunicipal- owned waste incineration plants in cities like Trondheim, Oslo, and Ålesund. The purpose of waste incineration was, and still is, to get rid of unsustainable landfills. But in addition, the excess heat from the plants is a valuable local energy resource to free up capacity in the cities' power grids during the cold winter months. Our power system's bottleneck has always been the peak hour demand of electricity during winter. District heating provided a solution framed as " the Norwegian district heating model:" to utilize excess heat and local renewable energy sources to reduce peak hour demand in the power grid. The concept of district heating using energy resources, otherwise wasted, continued through the next decades in several parts of Norway. In 2009, a national ban on landfills was introduced, leading to the building of more waste incineration plants. However, the urban district heating developement was not solely excess heat from waste incineration based, but also waste heat from other industries and local bioenergy sources.

How can district heating compete in a heating market dominated by electrical heating based on renewable energy? For most European countries, this question may seem irrelevant since we all know fossil fuels dominate the European heating sector. In Norway, the situation is different. Norway is blessed with unique possibilities for hydropower through nature, and hydropower has been the backbone of our power system for decades. Today, almost 100 % of electricity production comes from renewable hydropower. Usually, domestic production is more extensive than domestic consumption, and electricity prices have been low. Because of this hydropower dominated system, large scale combined heat and power plants (CHP) have never really been necessary for Norway. The concept of using excess heat from power production has likewise never been an alternative in the heating market. Consequently, when the oil crisis hit in the 1970s, heating solutions based on fossil oil were replaced or supplemented with much cheaper direct electrical heating, not other heating solutions. Very different from our neighbours in Sweden, where CHP was the go-to solution in urban areas and a driving force for the district heating revolution in the Swedish heating market in the 1970s.

At the same´time, the use of power to heat in district heating systems was starting to grow.

Flexible use of electricity It may seem like a paradox, but Norway's history of using electricity for heating, and a tariff system designed for it, has been paving the way for power to heat-solutions for district heating as well.

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