Standard technical solutions are not cost-effective for many small hydropower sites. This study aims to demonstrate the workflow for the tailor-made variable-speed axial propeller turbine and provide proof of this concept. The turbine is designed to meet the site’s specific space limitations and operating range needs. The runner shape is adjusted to the variable-speed operation and defined hydraulic profile using a parametric geometry model and CFD-based optimization. The variable-speed propeller turbine shows excellent flow control while keeping the mechanical design simple. The tailor-made approach minimizes construction costs using existing structures and is highly suitable for mini-hydropower applications. The prototype—an atypical turbine designed for highly restricted space and installed on-site—serves as proof of the concept. The findings on the design of axial variable-speed turbines are presented.

Despite significant achievements in energy development in Georgia, the issue of energy independence is still relevant. The electricity produced in the country cannot meet the growing demands. In addition, Georgia has energy potential, which is not yet fully harnessed, in particular, in terms of hydropower resources. Based on existing studies, only 20–22 % of the hydropower potential is currently harnessed in the country. For a country like Georgia, it is promising to develop hydro resources of small river to generate electricity and partially meet local needs.

Discharge measurement is the base of proper water management. The effective design and operation of hydraulic structures under both normal and extreme flow conditions depend on the quality of hydrological data. Understanding the water system requires consistent and long-term measurement. Despite that, the gauging station network is sparse, and its numbers are declining worldwide. This article aims to draw attention to the possibility of accurate flow measurement using existing hydraulic structures. Flow over a hydraulic structure profile is a physically well-defined phenomenon as the construction shape is fixed and simple compared to river profiles. The discharge can be derived from rating curves, turbine characteristics, and several easily measured variables. That allows continuous discharge measurement. The accuracy is compared with the gauging station on the river. Suitable technical solutions for ensuring and monitoring ecological flow are discussed.

Every country takes care of energy independence and security by using different energy sources and remarkably increasing electricity production by renewable energy sources. Ukraine is not an exception, especially when the energy infrastructure is significantly damaged during the war and there is a lack of capacities in the energy system. Because of this, the Government of Ukraine is planning a number of measures to launch systems of domestic mini-power plants.Ukraine has favourable conditions for developing the network of small-scale hydropower plants. While the hydropower potential of the largest Ukrainian rivers is used, the potential of small rivers is used only partially. The small-scale hydropower plants were built during the last century very actively. In 1912 the first small-scale hydropower plant was built. From 1923 to 1960, there were 956 hydropower plants with different capacities from a few kW to a few MW. However, at the end of the 1980s, the interest in small hydro decreased because of the construction of the large hydropower plants in the river Dniester and Dnipro, heat and nuclear power plants. Only 49 plants were in operation. Since 1995 the interest in small hydro has increased again. Nowadays, there are about 150 hydropower plants in operation.The paper examines the past and present state of small hydropower plants and perspectives on their development in the future, both by building new or reconstructing existing power plants. The list of hydropower plants with a short description of possible reconstruction is given. Moreover, the way of reducing the negative influence of hydropower plants on the environment is studied. Taking into account the energy issues in Ukraine, the possibilities of off-grid operation of hydropower plants are considered.The importance of energy security was evident from the issues that Ukraine is recently facing. Building new and reconstructing old small-scale hydropower plants will help to ensure the energy security of other types of electricity generation.