Geoenergin i samhället : En viktig del i en hållbar energiförsörjning : forskningsläget

With the fi rst oil crises in the beginning of 1970, the Swedish governmentinvested in, at that time, innovative technology using the underground asa source of energy for space heating. By developing these shallow geothermalsystems the goal was to decrease the dependence of oil.The result of these efforts is that some 25 % of the world’s total amount ofshallow geothermal systems is placed in Sweden. Today, heat and cold derivedfrom the underground is the third largest renewable energy source inSweden. It has been estimated that the shallow geothermal systems contributewith 11–12 TWh to the heat supply in Sweden.There is a lack of proper data for calculations of how much thermal energyis captured from the underground. Hence, the statistics shown in this reportare based on reasonable estimates, having the sales of heat pumps as aprime source of information.The Swedish Energy Agency chose not to report the domestic contributionfrom small-scale geothermal plants in Swedish statistics. Only the fi guresfrom the heat pumps in the district heating systems are reported. On theother hand in the statistic reports to EU, the Agency calculates with a significant amount from small-scale ground source heat pumps. This indicatesthat shallow geothermal should be more properly dealt with in the energysupply statistics.The geothermal storage systems are used for combined heating and coolingof commercial and institutional buildings, often in a large scale. Someof these systems are also applied to district heating and cooling as well asin some industries. The unique technology to store thermal energy in theunderground from one season to another makes a great positive impact tothe economy and to the climate.From an environmental perspective, shallow geothermal should be equivalentto solar energy and some other renewables. The electricity needed torun the plants should preferably be evaluated based on current directivesfor calculations of carbon dioxide emissions within each country.Shallow geothermal systems are most often reasonable profi table, lookedupon as short term repayment of the investment. In addition, the user isless sensitive for price changes on the energy market. This is due to thehigh effi ciency of such systems. Evaluated with LCC-analyzes, shallowgeothermal shows even higher profi ts. This is a result of low operatingcosts, low maintenance cost and a long life span.Godkänd; 2012; 20121109 (bon