Solar Thermal Systems Vs. Photovoltaic Systems. Case Study: Single Family Building In Lithuania

Solar thermal systems have been installed in Lithuania for over 20 years, and the main trend is to use them on a small scale. Large-scale solar photovoltaic systems only blossomed in 2013 due to a very good feed-in tariff. Small-scale (up to 10 kW) solar photovoltaic systems became more attractive after the national energy distribution operator offered the possibility of electrical energy 'storage' in the grid after 2015. Only in recent years have photovoltaic system prices dropped significantly, and a subsidy system been started for renewable energy sources in single-family buildings. This has increased interest in these renewable energy sources.The popularity of renewable sources is growing because of increasing traditional energy prices and the support of government policies. In certain cases, however, the renewable energy systems are competing with each other. This is noticeable in the single-family building sector, where solar thermal systems are often in competition with photovoltaic systems. There is no unambiguous answer to which system is more profitable for the owner of the building, as this depends on many aspects, which are discussed below. Herein, also, an analysis of the annual balance of various forms of energy used in building engineering systems is presented, which allows us to make an economic comparison between the systems, and to determine the ecological effects of produced green energy.The aim of this study was to compare solar thermal and photovoltaic systems in technical, energy production, environmental and payback time aspects for the single-family building case in Lithuania.