Discovering the Next-Generation Plant Protection Products: A Proof-of-Concept via the Isolation and Bioactivity Assessment of the Olive Tree Endophyte Bacillus sp. PTA13 Lipopeptides

Endophytic microorganisms (EMs) have recently attracted interest for applications in plant protection, mainly due to their bioactive compound-producing capacity. Therefore, we underwent the task of isolating olive tree EMs and investigating their bioactivity against the devastating pathogen Colletotrichum acutatum. Several EMs were isolated; however, the Bacillus sp. PTA13 isolate exhibited the highest toxicity to the phytopathogen. Bacteria of the genus Bacillus exhibit superior bioactive metabolite-producing capacity, with the lipopeptides (LPs) of surfactin, iturin, and fengycin groups being the most studied. A total LP extract and several fractions were obtained, and their bioactivity was assessed against C. acutatum strains. LPs of the major surfactin, iturin, and fengycin groups and the minor gageotetrin and bacilotetrin groups were annotated. The results confirmed the bioactivity of the major LPs, with fengycins being the most fungitoxic. Interestingly, the minor LP fraction exhibited selective toxicity to the fungicide-resistant C. acutatum isolate, an observation that highlights the significance of our approach to comprehensively mine the total LP extract. This work represents a proof of concept of the exploitation of EMs in customized olive tree plant protection and aligns well with strategies that focus on the sustainability and safety of food production via the development of next-generation plant protection products.

Design and Analysis of a Solar Energy Driven Tri-generation Plant for power, Heating and Refrigeration

A tri-generation plant producing power, heat and refrigeration has been designed and analyzed. Using solar energy as input. The power side of the plant employs supercritical carbon dioxide (sCO2) recompression cycle. The refrigeration side includes an aqueous lithium bromide absorption system. Thermal energy has been extracted from many places in the plant for heating purposes. A detailed thermodynamics model has been developed to determine performance of the plant for many different conditions. Thermal efficiency, energy effectiveness and exergetic efficiency of the system has been calculated for different operating conditions. It turns out that the pressure ratio of the recombination cycle and effectiveness of the energy exchanger for transferring energy from the power side to the refrigeration side play important roles.

Modeling, Implementing and Evaluating of an Advanced Dual Axis Heliostat Drive System

Heliostat tracking is a critical component of the solar field of concentrating solar power tower (SPT) systems and can be the source of significant losses in power and profit when it lacks the necessary accuracy. This paper presents an advanced heliostat drive system for the SPT generation plant. An integrated model for the heliostat drive system based on dual axes tracking is proposed using an inexpensive angle sensor. The mathematical model of the integrated drive system is developed, including the solar, tower, and heliostat models. The MATLAB simulation model for the proposed integrated drive system is developed and evaluated. An experimental prototype for a dual-axis heliostat is built using Class-E DC choppers and an inexpensive Gyro angle sensor. The prototype is tested and considered in the Dhahran region in Saudi Arabia under different operating conditions. A comparative study between simulation and experimental results is conducted to assess the efficacy and accuracy of the proposed controller drive system and validate the developed integrated model. Both simulation and experimental results demonstrate the effectiveness of the proposed dual-axis trackers to follow the sunbeams throughout the year.

Local Energy Communities in Spain: Economic Implications of the New Tariff and Variable Coefficients

The European Union advocates for legislative support to local energy communities. Measures include the promotion of dynamic energy allocation and discriminatory electricity tariffs such as the recent Spanish framework. However, the impact of these normative changes is not yet evaluated. This paper inquires into the impact of dynamic allocation coefficient and different electricity tariffs on the profitability of local energy communities. To do so, a linear optimisation model is developed and applied to real consumer data in Spain around a variable capacity photovoltaic generation plant. Comparing the economic performance of the static or variable power allocation under the effect of changing electricity tariffs. While both measures are beneficial, the new electricity tariffs result in larger profitability increases than the planned variable coefficients. The combination of measures allows for profitability improvements of up to 25% being complementary measures. However, installations that maximise the potential for electricity generation are still not as profitable due to the low purchase price of surplus energy. While discriminatory electricity price tariffs and variable allocation coefficients are positive measures, further measures are needed for these communities to install generation plants as large as the potential that each case allows.

Determination of the Optimal Size and Location of an Electricity Generation Plant That Uses Lignocellulosic Residues From Costa Rican Northern

The northern zone of Costa Rica has extensive forestry and agro-industrial development, which generates a large number of lignocellulosic residues that do not have an economic value but could represent a vast energy potential. Therefore, the objective of this study was to determine the optimal size and location of an electricity generation plant from the forest and agro-industrial biomass. The researchers worked with two forest species residues (Gmelina arborea and Tectona grandis) and two agro-industrial residues (Anana comosus and Saccharum officinarum), representing the most extensive cultivations in the region. The material was characterized, then GIS layers of the species cultivation areas were analyzed and related to the roads and protected areas to define the twelve potential points where the power plant should be installed. Later the optimal supply radius of the plant and the optimal site conditions were determined. The study determined that the tree species have an average caloric power of 19059.50 kJ/kg, significantly higher than the agro-industrial ones (16684.9 kJ/kg). It was determined that 1,056,527.67 tons of dry biomass are generated per year, 6.5% of the biomass is arboreal, and 79.97% comes from A. comosus. Also, it was determined that the optimal supply radius for the plant is 30 km. Longer distances make the project financially unviable. Considering this, the annual energy potential of the twelve points was evaluated, which varied from 4.06 to 101.82 MW. Point eleven was determined the best positioned by the biomass source and optimal environmental conditions for establishing the power plant.