Studies have shown micro-hydropower (MHP) opportunities for energy recovery and CO₂ reductions in the water sector. This paper conducts a large-scale assessment of this potential using a dataset amassed across six EU countries (Ireland, Northern Ireland, Scotland, Wales, Spain, and Portugal) for the drinking water, irrigation, and wastewater sectors. Extrapolating the collected data, the total annual MHP potential was estimated between 482.3 and 821.6 GWh, depending on the assumptions, divided among Ireland (15.5–32.2 GWh), Scotland (17.8–139.7 GWh), Northern Ireland (5.9–8.2 GWh), Wales (10.2–8.1 GWh), Spain (375.3–539.9 GWh), and Portugal (57.6–93.5 GWh) and distributed across the drinking water (43–67%), irrigation (51–30%), and wastewater (6–3%) sectors. The findings demonstrated reductions in energy consumption in water networks between 1.7 and 13.0%. Forty-five percent of the energy estimated from the analysed sites was associated with just 3% of their number, having a power output capacity >15 kW. This demonstrated that a significant proportion of energy could be exploited at a small number of sites, with a valuable contribution to net energy efficiency gains and CO₂ emission reductions. This also demonstrates cost-effective, value-added, multi-country benefits to policy makers, establishing the case to incentivise MHP in water networks to help achieve the desired CO₂ emissions reductions targets.

Pressure management in water supply pipe networks using conventional pressure reducing valves (PRVs) results in the dissipated energy being lost. In pursuit of more energy efficient solutions in the sector, researchers are exploring the technological and economic feasibility of replacing PRVs with low-cost hydroelectric converters such as pump-as-turbines (PATs). The present study addresses two problems: (1) is it possible to accurately estimate the energy recovery potential of a PRV site using only the statistics of its recorded operating conditions? and (2) can we define a bound representing minimal average operating conditions at PRVs for which their upgrade to PAT is expected to be economically viable? The first problem was addressed by calculating descriptive statistics of yearly recordings of the operating conditions at 38 real-world PRVs from Ireland and Spain, and carrying out linear least-squares regression analysis in which the statistics were used as predictor variables. The results imply that global plant efficiency can deviate up to 33.33% depending on the level of variation of the operating conditions, and that a realistic value of the expected global plant efficiency is around 0.4277 rather than 0.65 that was used in some of the previous studies. To address the second problem, the study first identifies the range of variability of the operating conditions and total installation costs for 340 hypothetical PRV sites whose average operating points (OPs) were evenly distributed across the investigated domain. The optimal net present value (NPV) was assessed for all hypothetical sites and their variability scenarios. The results suggest that there is a high probability that sites with the gross hydraulic power of 12 kW or larger will be economically viable for the upgrade.

Novel anthropomorphic robotic systems increasingly employ variable impedance actuation in order to achieve robustness to uncertainty, superior agility and efficiency that are hallmarks of biological systems. Controlling and modulating impedance profiles such that it is optimally tuned to the controlled plant is crucial to realise these benefits. In this work, we propose a methodology to generate optimal control commands for variable impedance actuators under a prescribed trade-off of task accuracy and energy cost. In contrast to classical optimal control methods that typically require an accurate analytical plant dynamics model, we employ a supervised learning paradigm to acquire both the process dynamics as well as the stochastic properties. This enables us to prescribe an optimal impedance and command profile (i) tuned to the hard-to-model stochastic characteristics of a plant and (ii) adapt to the systematic changes such as a change in load.

Numerical optimization is gradually finding its way into drinking water practice. For successful introduction of optimization into the sector, it is important that researchers and utility experts work together on the problem formulation with the water utility experts. Water utilities heed the solutions provided by optimization techniques only when the underlying approach and performance criteria match their specific goals. In this contribution, we demonstrate the application of numerical optimization on a real-life problem. The Belgian utility De Watergroep is looking to not only reinforce its distribution networks but to also structurally modify the network’s topology to enhance the quality of water delivered in the future. To help the utility explore the possibilities of these far-reaching changes in the most flexible way possible, an optimization problem was formulated to optimize topology and pipe sizing simultaneously for the distribution network of a Belgian city. The objective of the problem is to minimize the volume of the looped network and thereby work towards a situation where most of the customers are fed by branched extremities of the network. This objective is constrained by pressure and fire flow requirements and thresholds on the number of customers on the branched sections. The requirements for continuity of supply under failure scenarios are guaranteed by these constraints, as verified in the final solution. The results of the optimization process show that it is possible to design a network which is 18.5% cheaper than the currently existing network. Moreover, it turns out the—previously completely meshed—topology can be restructured so that 67% of the network length is turned into branched clusters, with a meshed superstructure of 33% of the length remaining.

Purpose – Tourism is one of the fastest-growing sectors in the world, and many developing countries saw it as the chance of economic development accelerating. However, tourism potential is different among countries as well as within one country. The scope of this paper is to reveal the regional differences in business conditions considering tourism development in Serbia. Methodology – Instead of using a wide number of different individual indicators measuring regions’ tourism performances, it is more appropriate to use one composite indicator for depicting complex issues in regional tourism development - a composite index was developed using Data Envelopment Analysis. Data Envelopment Analysis is a sort of methodology that constructs an ‘efficiency frontier’ based on each region’s individual data using mathematical linear programming. It determines the best practice by measuring the relative position of each of the regions in terms of the value of the set of observed indicators. Such presentation of the existing region’s development in the tourism field and recommendations for possible improvement are clearer to the general public and non-scientific audience. The composite index is calculated as the weighted sum of the corresponding individual indicators, where the weights are endogenously determined by mathematical linear programming to obtain the maximum possible value. Findings – The results of DEA showed which parts of Serbia have the best business conditions for tourism development, considering the different factors (regional development index and subindexes). The results have been contrasted to chosen tourism statistics on the regional level, with a reference to the limitations during the research process. The proposed composite index is used to point the differences in regional business conditions which could be further influenced by government policies to tackle the specificities and needs of each separate region during tourism development. Contribution – DEA is a known methodology in regional development analysis, but it hasn’t been so much used in business conditions regional analysis before. Having different indicators which shaped business climate within one region, using DEA one tried to analyze the entrepreneurship possibilities with a spatial reference to the tourism development. This is an important contribution in the context of local economic and social development especially within poorly developed regions in Serbia