Investigating possibilities to integrate solar heat into district heating systems of Lithuanian towns

Lithuanian district heating sector is one having ambitious targets while implementing national energy policy goals. It is strongly orientated towards extending usage of renewables, basically biomass. Notwithstanding with this, other renewable sources can also play important role following the experience of other countries. Solar energy is one of emerging options rapidly developing in Scandinavia, Germany, Austria and Netherlands. Use of on-roof and on-ground collectors together with short term and seasonal storage facilities allows usage of solar energy from solar collectors both: for reduction of heat losses in the networks as well as for providing significant share of heat without fuel burning. Economic feasibility as well as technical behavior of different types of seasonal heat storages is still under investigation, however fast development of technologies might prove this solution as feasible opportunity in nearest future. The cost of solar heat depends mainly on capital investment to the solar collectors and storage, as fuel costs are zero and maintenance costs are insignificant. Therefore investment support is crucial for feasibility and competitiveness of such systems. From the technical point of view, temperature level is very significant factor for efficient functioning of solar heating systems. This point is worth to address in complex with building's heating system and heat supply network renovation.