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This study examines the optimal integration of high proportions of wind energy into an electricity grid which traditionally depends on hydroelectricity. Wind power in the Brazilian Northeast (NE) is expected to generate 57% of the NE’s electricity supply by 2020. As rainfall in the NE region is susceptible to climate change, it is anticipated that wind energy could substitute lost hydroelectric availability. The Weather Research and Forecasting (WRF) Model is used to simulate wind speeds for all of 2014 and calculate wind power across the entire NE region of Brazil. The NE region’s aggregate hourly wind generation and net load curve are then estimated for increasing wind penetrations using the planned rollout of wind farms in the region as a baseline. The maximum wind energy penetration in the region is estimated to be approximately 50% before significant amounts of energy would need to be curtailed or exported to other Brazilian regions. It was found that wind energy generation from coastal wind farms in the region best correlates with the hourly and monthly variations of the NE subsystem’s load curve. Conversely, inland wind farms on the NE’s elevated plateaus typically generate more power late at night, but have higher capacity factors. [ABSTRACT FROM AUTHOR]

Purpose: To explore financial alternatives to implement PV power generation projects based on the provisions of Normative Resolution n. 482/2012 of the Brazilian Electricity Regulatory Agency (Aneel). This regulation sets forth the general conditions to the access of microand minigeneration granted to the electric energy distribution systems through the energy product offset method. Originality/gap/relevance/implications: This paper discusses the need for regulatory changes, greater government participation in the granting of financial and tax incentives so that PV solar power technology in distributed generation can be financially viable for residential consumers. Key methodological aspects: Investment analysis in PV systems used the Net Present Value (NPV) valuation method. The research assessed two scenarios for Grid-Connected PV Systems (GCPVSs), with different solar power usage levels for a residential consumer. Summary of key results: The results point to a low financial viability in the implementation of distributed microgeneration projects, suggesting the need to remove the tax burden and reduce financing costs. Key considerations/conclusions: The study shows the need of flexibilization of the Brazilian regulatory model, with changes that enable the expansion of renewable energy offers, with positive economic outcomes for tariff affordability. Tariff benefits from distributed microgeneration can positively reflect on captive customers, provided that investment risks are reduced. [ABSTRACT FROM AUTHOR]

This paper forecasts the supply curve of non-conventional renewable technologies such as wind and solar generating stations in Argentina, Brazil, Chile and Mexico using technological and economic parameters. It also estimates the additional investment costs in solar and wind generation for reaching the renewable energy target in each of these countries. To assess the power supply profile from 1 axis tracking PV and horizontal axis wind turbine (three blade) stations, two different scenarios are developed for 2014 and 2025. Scenario 1 estimates the PV and wind annual electricity yield by using polycrystalline silicon (cSi poly) as semiconductor material for PV cells and a Vestas 90–3.0 MW turbine for the wind for 2014. Scenario 2 assumes a more efficient technology, such as CPV. In fact, the model employs 45% efficiency triple junction cells using ∼3500 m2 for each 1 MW installed capacity in 2025. Moreover, this scenario also assumes a more powerful type of turbine, i.e. Vestas 112–3.075 MW. The biggest potential for wind power is found to be in Argentina, followed by Brazil, Mexico and Chile. In addition, a 550 MW installed capacity CPV power station, using triple junction cells could generate up to 4 TWh in Chile in 2025. [ABSTRACT FROM AUTHOR]

Several studies have reported the adverse effects of recalcitrant compounds and emerging contaminants present in industrial effluents, which are not degradable by ordinary biological treatment. Many of these compounds are likely to accumulate in living organisms through the lipid layer. At concentrations above the limits of biological tolerance, these compounds can be harmful to the ecosystem and may even reach humans through food chain biomagnification. In this regard, advanced oxidation processes (AOPs) represent an effective alternative for the removal of the pollutants. This study focused on the AOP involving the use of ultraviolet radiation in homogeneous and heterogeneous systems. Based on the literature review, comparisons between natural and artificial light were established, approaching photoreactors constructive and operational characteristics. We concluded that the high availability of solar power in Brazil would make the implementation of the AOP using natural solar radiation for the decontamination of effluents feasible, thereby contributing to clean production and biodiversity conservation. This will serve as an important tool for the enforcement of environmental responsibility among public and private institutions. [ABSTRACT FROM AUTHOR]

Reservoirs of hydropower plants (HPP) can amend water, energy, and food security in semi-arid regions. However, during severe droughts, the priority of energy demand leads to critical conditions of water availability. To reduce water use for energy, one possible measure is the adoption of solar power, an abundant energy source in semi-arid regions. This study assessed the influence of adding floating photovoltaic power (PV) in the large-scale reservoir of Sobradinho HPP, located in the São Francisco River (SFR), in Brazil, from 2009 to 2018. The simulated scenarios varied the installed PV power capacity from 50 to 1000 MW. For each scenario, water allocation was modified based on the solar-hydro equivalence that restrained the historical outflow of Sobradinho to maintain water in the reservoir. Besides, a diverse operation rule for the reservoirs in cascade of SFR was adopted to avoid ecological impacts of low streamflow. The scenarios were assessed in water security, solar-hydro electricity output, capacity factor of the powerplant, water and energy losses by evaporation and spilled water. Results show that a PV system starting from 250 MW was necessary to improve water security during the severe drought, reserving 0.7–2.3 of the annual water demand. In addition, the capacity factor was optimized from 29% to 34–47%. However, as the HPPs installed at SFR work as one system, the constrain of the river flow reduced the hydroelectricity by 4.4% for 750 MW. We concluded that PV significantly influenced water security and ecological conditions of SFR, with benefits in the range of 250–750 MW. The research provides assessment on substituting hydro for solar power on the operation of reservoirs in cascade and identifies the correlated benefits in social and ecological aspects. This information can support decisions of water and energy supply system operators and public policies focused on integrated resources management in semi-arid regions. [Display omitted] • Large reservoirs in semi-arid regions offer opportunities for floating PV. • Assessment of water and energy securities through hydro-solar hybrid generation. • WEF Nexus approach on multi-purpose reservoirs operating in cascade. • Local benefits in water and energy may be counterbalanced by regional energy losses. • Support guidelines for governance towards sustainable pathways in semi-arid region. [ABSTRACT FROM AUTHOR]

The use of intermittent renewable energy sources (IRES) in traditional energy systems must be suitably planned, as their variability affects the reliability and costs of electricity generation. Assessing the complementarity among multiple IRES and determining their optimal mix can mitigate the impacts of variability from independent sources. Although complementarity studies have considered a single time series per source to evaluate complementarity, this approach is not suitable for large areas, because the spatial variability may be lost when multiple time series are merged. In contrast, if data are not merged, optimisation might lead to impractical results. We propose the use of factor analysis for grouping similar data and present two optimisation models that are easily reproducible and not restricted by the number of decision variables. To this end, we considered the south-eastern and central-western areas of Brazil, where the share of IRES remains small but is expected to increase, and includes global solar radiation, wind speed, and river inflow IRES. The river inflow data were clustered into 11 groups. As solar radiation is evenly distributed in the region, rendering models with two or more factors unsuitable, all measurement stations were grouped. In contrast, as wind speeds vary significantly, the corresponding data were not merged but treated separately. The complementarity between data groups was assessed using the Pearson correlation coefficient. Overall, the different IRES exhibited low correlation, suggesting their complementarity. Despite their different objectives, both optimisation models indicate that the photovoltaic generation share in the IRES mix should be around 50%. Obtaining such optimal mixes can guide the expansion of IRES adoption for electricity generation in the region. Image 1 • Complementarity of hydro, photovoltaic and wind energy is studied in SE/CW Brazil. • Factor analysis is proposed as a method for grouping energy series. • Two optimisation models unrestricted by the number of sources are presented. • Photovoltaic energy has proved to play a central role in both optimised mixes. [ABSTRACT FROM AUTHOR]

Summary: The positive impact of the complementarity between renewable generation sources has been presented in several studies, but this concept has been neglected in many studies of expansion planning. This paper presents a new approach to introduce the complementarity between renewable energy resources and regions into the expansion planning for 100% renewable energy systems. A novel objective function is proposed to optimize the electricity mix and the water flow of hydropower reservoirs, considering the daily and yearly variations. A case study is presented with the objective of assessing the optimum mix (for the complementarity perspective) between solar, wind, hydro, and biomass power to ensure the expected monthly and hourly energy demand for Brazil in 2050. In the Brazilian case, when the complementarity between regions was considered, it was possible to ensure the electricity demand increase without new large reservoirs and with a high contribution from all renewable generation sources. A mix to ensure the daily and annual demand in 2050, which promotes the best complementarity, is presented, resulting in a share of 27%, 16%, 34%, and 23% for photovoltaic, wind, hydro, and biomass power, respectively. [ABSTRACT FROM AUTHOR]