ABSTRACT
Solar energy has a unique advantage as the flow of energy is free. For other heating alternatives there is always uncertainty in the development of energy prices. The profitability of a solar heating plant is determined mainly by capital costs, together with changes in the cost of energy. Therefore interest and depreciation costs are decisive in the profitability analysis; solar heating has negligible running and maintenance costs. Solar heating investments also give a number of synergy effects and coordination gains, for example the use of a common storage tank, and these should be taken into account in the overall evaluation. When making economical comparisons it is also essential to be consistent in reasoning between the different alternatives, for example by comparing capital costs and fuel costs in the same way.
