HOT|COOL NO. 2/2019 - "Smart Heating System Integration"


By Lars Andersen, CEO, Geotermisk Operatørselskab A/S

Throughout the world, governments and the private sector have established greenhouse gas emission targets. For example, the EU and most other European countries have set short-term targets for 2020 and 2030 for the reduction of greenhouse gas emissions, the development of renewable energy, and energy savings. These targets have been a catalyst for the development of renewable energy resource technologies and the commissioning of renewable energy projects. One example is the growing interest in geothermal energy to replace the burning of fossil fuels for providing thermal energy to district heating networks.


The EU Commission on behalf of the European Member States has agreed to the goal of reducing their greenhouse gas emissions by 100% by 2050. This means that we are rapidly approaching the last call for investments in energy projects based upon fossil fuels, which have a lifetime of more than 25 to 30 years. This is illustrated in Figure 1, which shows the invest index versus commissioning date for fossil fuel based energy projects and renewable energy projects. The investment index is defined as the investment period, which is assumed to be 30 years, divided by the number of years that plant is designed to operate. The investment index for fossil fuel based and renewable energy projects is the same for projects commissioned up until 2020, as both types of projects have a design life of 30 years. For projects commissioned after 2020, the investment index remains constant for renewable energy projects, whereas the investment index increases for the fossil fuel based energy projects. This is because after 2020, the operational life of fossil fuel based energy projects becomes progressively shorter with each passing year as time approaches 2050, resulting in a decrease in the time period to recoup capital investments and an increase in the cost of energy for the consumer. In other words, for the case of fossil fuel based energy projects for every year that we move closer to 2050 the depreciation period is shortened, resulting in heat prices which are higher than those from renewable energy projects.

Geothermal drilling, Iceland.

WHO HAS THE COURAGE TO MOVE QUICKLY TO GEOTHERMAL ENERGY? Geothermal energy is a renewable energy source that can eliminate the need to burn oil, gas, coal and/or biomass for generating thermal energy for district heating. Geothermal energy is sustainable and secures a local, stable energy supply, which is immune to volatile global fuel prices. There are over 240 geothermal district heating systems in Europe with geothermal power production capacities ranging from 1 to 50 MW. Traditionally, geothermal wells have targeted reservoirs at depths up to 3,000 meters for the production of hot water for direct use in geothermal district heating. More recently, production from geothermal reservoirs at depths of 1000-2000 meters with temperatures in the range of about 35 to 60 o C has been used in combination with heat pumps to provide hot water for district heating. Targeting these relatively shallow reservoirs for the production of geothermal energy can significantly reduce the capital expenditure for establishing a geothermal well field, as the risk and cost of drilling shallow wells are less than those of deep wells.

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