The potential energy of compressed air represents a multi-application source of power. Historically employed to drive certain manufacturing or transportation systems, it became a source of vehicle propulsion in the late 19th century. During the second half of the 20th century, significant efforts were directed towards harnessing pressurized air for the storage of electrical energy. Today’s systems, which are based on storing the air at a high pressure, are usually recognized as compressed air energy storage (CAES) installations. This paper aims to provide an overview of different technologies that take advantage of the energy accumulated in the compressed air. Particular attention is paid to the CAES installations that are working as electrical energy storage systems (EESs). These systems, developed originally as large capacity (>100 MW_e) and fuel-based installations, may soon become fully scalable, highly efficient, and fuel-free electrical energy storage systems. To present this opportunity, a thorough review encompassing previous and up-to-date advancements in their development was carried out. In particular, CAES concepts, such as diabatic (D-CAES), adiabatic (A-CAES), and isothermal (I-CAES), are described in detail. This review also provides the detailed characteristics of the crucial elements of these configurations, including compressors, expanders, air storage chambers, and thermal storage tanks. Knowledge of these components and their role allows us to understand the main challenges behind the further development of the mentioned CAES setups. Apart from the CAES systems that are designed as EES systems, this paper describes other prospective technologies that utilize the energy of pressurized air. Accordingly, compressed air cars and their key elements are explained in detail. Moreover, the technology renowned as wave-driven compressed air energy storage (W-CAES) is described as well, indicating that the utilization of pressurized air represents a viable option for converting ocean energy into electrical power.

The worldwide growing demand for energy from renewable sources is observed. This fact is related to a number of factors, especially environmental ones. The renewable energy sector, which can be seen in the most dynamic development is wind energy. This is due to the construction of huge wind turbines, whose power exceeds one megawatts. The main problem that should be solved is to find a proper location for such turbines. Generally, wind turbines are located offshore and onshore. The most favourable are offshore because of better wind condition what relates to power generation. Notwithstanding, it is possible to install smaller turbines in urban areas: so-called wind turbines in built-up areas or integrate wind turbines with buildings (BIWT). However, it is needed to be aware of many problems of above mentioned installations. The article presents an overview and data related to operation of wind turbines integrated with the Center of Energy AGH building.

According to the United Nations, one of the sustainable development goals is to ensure access to affordable, reliable, sustainable, and modern energy for all. Among other options, these goals can be achieved by developing and introducing micro-scale combined heat and power systems powered by renewable energy sources, including solar and biomass energy. Considering renewable energy-powered cogeneration technologies, the most promising are steam/vapor turbines, Stirling engines, and thermoelectric generators. This paper focuses on the selected operational aspects and retrofitting optimization of the prototypical micro-cogeneration system powered by a biomass-fired batch boiler and operating according to the modified Rankine cycle. The existing installation was tested, and the amount of energy transferred from the oil to the condensate and steam and the efficiency of the evaporator and the superheater were determined. A retrofitting optimization aimed at maximizing the piston engine’s power output was conducted based on the results. In particular, it was shown that the system’s power output might be as high as 9 kW_e. Moreover, the analyzed system featured a high energy utilization factor of 97.9% at optimal operating conditions. In general, it was shown that the micro-scale steam Rankine system may successfully serve as an alternative technology for micro- and distributed cogeneration systems. As a technology supplied with renewable biomass energy and operating on a cheap and environmentally friendly working medium (water), it fits very well into the idea of sustainable energy system development.

The deployment of numerous small wind turbines in densely populated urban areas offers significant potential for augmenting wind energy capture and advancing distributed generation architectures. Integrating compact wind units alongside building-integrated photovoltaics, waste-heat recovery systems, and energy storage creates resilient, complementary energy solutions—where nocturnal wind generation can offset the intermittency of solar power. In this context, building-integrated wind energy generators (BIWTs) merit careful evaluation. This paper presents a case study of a 1 kW BIWT mounted on the Center of Energy at AGH University of Science and Technology. A dedicated monitoring system recorded continuous data on wind velocity, wind direction, power spectra, electrical output, acoustic emissions, and structural vibrations. Owing to complex interactions between airflow and the building envelope, BIWT behaviour diverges substantially from that of turbines in open terrain: flow distortions induced by façades and roof geometry create novel harvesting conditions that must be quantified. Our analysis characterizes these urban wind patterns, assesses power production under varying conditions, and evaluates environmental impacts, thereby informing optimized design and integration strategies for small-scale urban wind energy systems.