Technical and Economic Analysis of Modernization of Solar Power Plant: A Case Study from the Republic of Cuba

The problem of increasing the efficiency of existing power plants is relevant for many countries. Solar power plants built at the end of the 20th century require, as their shelf lives have now expired, not only the replacement of the solar modules, but also the modernization of their component composition. This is due to the requirements to improve the efficiency of power plants to ensure the expansion of renewable energy technologies. This article presents a technical and economic analysis of the choice of solar power plant modernization method, which consists of (1) a method for calculating the amount of power generation; (2) the modeling of solar power plants under specific climatic conditions; (3) the analysis of electricity generation using different types of PV modules and solar radiation trapping technologies in Matlab/Simulink; and (4) the technical and economic analysis of a 2.5 MW solar power plant in the Republic of Cuba (in operation since 2015), for which four different modernization options were considered. All the scenarios differ in the depth of modernization; the results of the analysis were compared with the existing plant. The results of the study showed that the different modernization scenarios respond differently to changes in the inputted technical and economic parameters (cost per kWh, inflation rate, losses, and power plant efficiency). The maximum NPV deviations among the considered scenarios are: a 1% increase in inflation reduces NPV by 2%; a decrease in losses from 20% to 10% increases the NPV by 2.5%; a change in cost from EUR 0.05 to EUR 0.1 increases the NPV by more than 3.5 times. The dependence of the economic results was also tested as a function of three factors: solar module efficiency, inflation, and the price per 1 kWh. It was found that the greatest influence on the NPV of the proposed model is the price per 1 kWh. Based on this analysis, an algorithm was developed to choose the most effective scenario for the conditions of the Republic of Cuba for the modernization of the existing power plants.

Techno-economic aspects and problems of the rotary rowing units introduction in the modernization and construction of ships (on the example of projects 1809 and CNF11CPD)

The article contains a detailed analysis of studies related to the use of existing and new principles of fuel economy, and reducing the cost of re-equipment and operation of vessels of the above projects. The authors of the article did not set out to analyze the technical features of these projects. Only by linking to these projects, the analysis was done for the entire fleet of this type as a whole. A technical and economic analysis of the characteristics, modeling of the main and auxiliary installations in the Matlab package, providing fuel economy on the example of ships of projects 1809 and CNF11CPD, is carried out. Then a physical simulation was carried out. As a result of testing a vessel with a rotary rowing electric installation (RSEU), a qualitative analysis of the data obtained was carried out, conclusions were drawn that allow us to judge the possibility of large-scale use of such installations in maritime transport.

Aspects Regarding the Optimal Insulation Thickness, the Cost and Energy Savings for Cold Storage in Romania

The paper presents a technical and economic analysis regarding the sandwich panels with polyurethane insulation layer (PUR) used in cold stores’ construction. The authors determine the optimal thickness of the insulating layer (OIT) corresponding to the 5 climatic zones in Romania. The operating and investment costs for cold and frozen storage in these 5 climatic zones have been assessed. The results obtained from the analysis show that regardless of the climatic zone, the OIT for cold storage is 150 mm and for frozen storage is 180 mm. The investment cost increases by 41% and the expenditure on operating energy decreases by 8.3% for 180 mm for cold storage in comparison to OIT. Moreover, this tendency is maintained as well in the other case of frozen storage, where, by increasing the thickness above OIT at 200 mm the investment cost is increased by 20% and the expenditure in operating energy is decreased by 6.7%. The SEC has an average value of 54.83 kWh·m3/yr for cold storage and 74.55 kWh·m3/yr for frozen storage respectively. The average values obtained in the paper were compared with those presented in the literature and resulted in deviations of about 1.58% for refrigeration, and hence 4.1% for freezing.

Alkali-Active Sand Slate Powder for Use as Mineral Admixture in Mass Hydraulic Concrete: Technical and Economic Analysis

This work has launched a comprehensive investigation on the macro performance and micro structure of mass concrete produced with alkali-active sand slate powder (ASSP) for use as the mineral admixture and a thorough analysis on its technical and economic effects is also conducted. Results indicated ternary blend with hybrid of 5–8 wt.% silica fume (SF) and 15–20 wt.% ASSP has the optimal compressive and flexural strength. ASSP particle participates in hydration, accelerates hydration of cement clinker within 8.5 hours, and reduces the autogenous strain of pastes by 164 × 10−6 in case of dosage less than 25% by mass. Improvement in the mechanical and deformation properties of concrete produced with the hybrid of SF and ASSP is attributed to better particles gradation, compactness enhancement, and transformation in products of hydration. On the whole, it provides another new approach for use of alkali-active rock after second processing as mineral admixture in hydraulic concrete in terms of good performance and economic effects.

Uncertanties and Risk Analysis on Ports Construction Projects Considering Technological and Market Strategic Factors

This article appropriates a new methodology for evaluating port projects involving not only economic analysis, but also strategic factors, technological and market, wich provide greater security and assertiveness on the search for the development of a Hub Port model as an option to optimize the logistics of port operations. To achieve the objectives of the proposal, a technical and economic analysis model was developed to demonstrate the feasibility of the project with the inclusion of technological features (deep of ships, modes of transport linking the port to its region of land influence, expansion area) and market components (cargo demands, free trade zone, distance from the main centers of world trade) that decisively interfere in the attractiveness of the project. Linked to this proposal, a risk analysis was carried out, including uncertainties involving economic and strategic aspects, with market and technological variables. To achieve the objectives of the study, the Monte Carlo method operated by the software “@RiskTM” was used, where the analyzes of positive and negative interferences in the project were carried out. To evaluate the proposed methodology, it was applied in two cases studies of the feasibility of a new logistics platform in Brazil and Africa, with the implementation of an offshore cargo concentrator port. One was in the State of Pará, in northern Brazil, and the other in Dakar, Senegal, which can integrate the entire South America and Africa, respectivaly. The results of those analysis show very favorable indicators for the implementation of the proposed projects. Considering that, strategic factors introduced in the study, the greatest influences were: transport modes that link the port to the land influence zone and the draft of the ships. For the offshore port of Pará, strategic factors boosted the viability result by approximately 55% for a 95% probability of success and for Dakar, in Africa, the results were 100%, both for a 14% rate and a life span of 30 years showing that strategic factors are elements very importatants, as they produced almost 100% and 70% elasticity in the results, respectivaly, so they should be considered in feasibility studies of hub ports in addition to tradicioanl economic analysis.

Evaluating the impact of excavator bucket capacity on the output of a haul truck in different variants of their positioning

When studying the influence of excavator bucket capacity on haul truck loading time, it is necessary to assess the technical and economic performance of the complex. If the cost of the machine shift of the complex will not cover the increase in productivity, then it is inexpedient to use this complex. This issue requires further, more detailed study and performance of detailed technical and economic analysis. Also, it is necessary to consider classical recommendations about ratio of excavator bucket capacity and haul truck body. It should be noted that at present, there is a significant divergence in the size range of excavators: powerful, with a large capacity bucket, rope shovels are used for mining the coalless zone; small maneuverable hydraulic shovels – for mining the coal-bearing zone. In this paper, we will try to combine the first and the second: consider hydraulic excavators with maximum bucket capacity, which is reasonable to use when mining overburden. In addition, a detailed study of the options of mutual arrangement of excavator and haul truck has not been performed until recently, this work is intended to fill this gap.

SEARCH FOR RATIONAL EBGINEERING SOLUTIONS OF DIESEL LOCOMOTIVES FOR THE EASTERN RANGE

The purpose of the study is to search for rational engineering solutions for the main autonomous locomotive for the Eastern range of OAO Russian Railways. Research methods: methods of physical and field experiments, analytical methods for calculating the dynamics of the rolling stock. Research results and novelty: it is established that the use of a four-axle truck of a diesel locomotive TEM7 does not allow to create a locomotive that meets all the requirements of OAO Russian Railways, and the design of truck TEM7 is irrational for mainline locomotives; it is proved that the one-sided arrangement of brake blocks leads to deterioration in the locomotive braking properties. The bearing and axial towline, despite the use of an asynchronous engine, has an unsprung mass 1.5 times greater than that of the previously produced domestic analogue with a collector engine and almost the same mass of the wheel-motor unit; dynamic moments in the drive due to the lack of elastic elements during prolonged operation can reach 56% of the traction torque, which worsens the traction properties of the locomotive. Conclusion: it is advisable to carry out a design study of the drive variant with a support-frame asynchronous traction engine and an axial gearbox, as well as to conduct a technical and economic analysis and design study of a cheaper version of a diesel locomotive with sections on three two-axle bogies, maximally unified with electric locomotives, with a booster tanker module and AC-DC transmission with axial regulation of eight-pole collector motors with support-frame suspension.