The article presents the results of research on the efficiency of photovoltaic (PV) modules cooled with water. The aim of the experiment was to improve the working conditions of solar modules. A temperature decrease was obtained for the PV module by pouring cool tap water onto the upper surface of the modules, either in imitation of rain or as a water film. The power of the cooled and non-cooled devices were then compared. The temperature of the cooled modules dropped to almost 25 °C, whilst the temperature of the non-cooled module was 45 °C. The best results were achieved by cooling modules with a water film, since there were no water splashes, and the continuous cooling of the surface leads to a 20% increase in power. During the test, the non-cooled module attained a maximum power of 105.3 W/m², compared to 125.5 W/m² for its cooled counterpart. Cooling the module, therefore, resulted in a power increase of 20.2 W/m². The results of the work may be of particular interest for small installations, especially because it cleans the modules while providing an increase in power.

The objective of this study is to assess the techno-economic potential of the proposed novel energy system, which allows for negative emissions of carbon dioxide (CO₂). The analyzed system comprises four main subsystems: a biomass-fired combined heat and power plant integrated with a CO₂ capture and compression unit, a CO₂ transport pipeline, a CO₂-enhanced geothermal system, and a supercritical CO₂ Brayton power cycle. For the purpose of the comprehensive techno-economic assessment, the results for the reference biomass-fired combined heat and power plant without CO₂ capture are also presented. Based on the proposed framework for energy and economic assessment, the energy efficiencies, the specific primary energy consumption of CO₂ avoidance, the cost of CO₂ avoidance, and negative CO₂ emissions are evaluated based on the results of process simulations. In addition, an overview of the relevant elements of the whole system is provided, taking into account technological progress and technology readiness levels. The specific primary energy consumption per unit of CO₂ avoided in the analyzed system is equal to 2.17 MJ_LHV/kg CO₂ for biomass only (and 6.22 MJ_LHV/kg CO₂ when geothermal energy is included) and 3.41 MJ_LHV/kg CO₂ excluding the CO₂ utilization in the enhanced geothermal system. Regarding the economic performance of the analyzed system, the levelized cost of electricity and heat are almost two times higher than those of the reference system (239.0 to 127.5 EUR/MWh and 9.4 to 5.0 EUR/GJ), which leads to negative values of the Net Present Value in all analyzed scenarios. The CO₂ avoided cost and CO₂ negative cost in the business as usual economic scenario are equal to 63.0 and 48.2 EUR/t CO₂, respectively, and drop to 27.3 and 20 EUR/t CO₂ in the technological development scenario. The analysis proves the economic feasibility of the proposed CO₂ utilization and storage option in the enhanced geothermal system integrated with the sCO₂ cycle when the cost of CO₂ transport and storage is above 10 EUR/t CO₂ (at a transport distance of 50 km). The technology readiness level of the proposed technology was assessed as TRL4 (technological development), mainly due to the early stage of the CO₂-enhanced geothermal systems development.