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In the evaluation of scenarios for a sustainable and resilient energy transition in isolated systems in the Amazon, a part of the photovoltaic generators should be installed centrally to guarantee a central system of high performance, availability and reliability without cutting down more forest areas, while another significant part of the generators should be installed distributed on rooftops and in agrovoltaic projects.
In the Amazon, more than 3 million people are served by isolated mini-grids. The hundreds of mini-grids powered by diesel gensets operated by independent power producers (IPPs) and public electricity companies in the Amazon region use government subsidies that cover 100% of fuel costs. Often, to transport a liter of diesel to these remote and difficult-to-reach areas, more than a liter of diesel is consumed. In 2023 alone, the burning of subsidized diesel in the Amazon mini-grids will emit 1.6 MtCO2eq, with a fuel cost of 2.5 billion dollars, which is distributed among all Brazilians through the Fuel Consumption Account.
The supply of electricity depends on the logistics of supplying diesel, which can be interrupted in times of drought, which requires that the diesel plants in some towns have large fuel storage tanks. In addition, many localities with access by dirt roads suffer difficulties during the rainy season, which requires greater fuel reserves, as is the case of the locality of Oiapoque shown below, which has a storage capacity of 1. 5 million liters of fuel, with a range of 45 days.
In recent decades, attempts to reduce the share of diesel generation in isolated Amazon riverside villages and towns have been unsuccessful. PPIs prefer to cling to the diesel generator sets they know so well, under the comfortable shelter of subsidies designed many decades ago to provide energy access, energy security and service reliability. Meanwhile, many renewable energy technologies (RETs) have experienced price reductions and have established themselves in terms of reliability and utilization of locally available natural resources. In this context, RETs such as biomass, solar and wind have been evaluated to assist in the Amazon Energy Transition, and a comprehensive analysis is presented here.
Biomass : Only a minority of communities in isolated systems have sufficient capacity to generate energy by producing biomass from the residues of the regions main crops, such as cassava, açaí, corn, plantain and sweet potato, among others. The production of energy through the burning of wood residues, obtained from sawmills that have a sustainable management plan and international certification of their product is something rare in the region, which is found in only one site (Itacoatiara - AM) that operates in the Amazon (www.itacoatiara.com.br).
Wind : The Amazon region has a low average annual wind speed (less than 4 m/s), which, together with the difficult access and lack of scale in these isolated communities, makes wind power generation uncompetitive in the region.
Photovoltaic : The solar radiation resource is abundant and uniform throughout the Amazon; the average annual global horizontal irradiation is greater than 1700 kWh/m2.year. Solar energy is a modular solution that is easy to install and low maintenance, but the technology has a major drawback, which is the large area required. For the implementation of solar plants in the Amazon, three options are possible: i) centralized photovoltaic plants, mounted on the ground, ii) floating solar photovoltaic plants, and iii) small distributed photovoltaic systems (rooftops or on the ground, including agrivoltaics).
Among the three potential RETs suitable for the Amazon energy transition, biomass and wind power face considerable technical and economic constraints, but solar PV offers great potential to help replace diesel generation, which currently enjoys subsidies for worth $2.5 billion a year and is well established among local PPIs.
The option of centralized installation on the ground and in large areas runs into an important limitation, which is the availability of suitable areas for the installation of large-area solar photovoltaic plants without further suppression of the forest. The Amazon jungle is very dense in tall trees, and this is the main bottleneck of this technical solution, since in many places there are no cleared areas of this order of magnitude. Agrivoltaics can play an important role here, associating photovoltaic energy production and sustainable land use.
Another option is floating photovoltaic systems, which could be installed on the banks of the rivers near which a large part of the isolated communities are located. Floating photovoltaics is widely used in places with high population density and low availability of land, such as Singapore and Japan, and is usually installed in lakes or reservoirs, places with calm waters, with water movement only associated with the local wind. The technical feasibility of installing floating photovoltaic systems along the mighty Amazon rivers faces great resistance and skepticism from the leading and most experienced manufacturers of floating systems.
The third option for photovoltaic generation is the distributed rooftop solution, so common in urban areas, with more than 2 million installations in operation in the Brazilian interconnected power distribution system. Analyzes carried out by the Brazilian National Institute for Space Research (INPE) show that the number of existing rooftops in these isolated communities can guarantee a high percentage of service for these isolated systems. The option also has important social aspects, since PV integration into a large number of systems would require a considerably large local workforce for installation and subsequent maintenance.
Typical residential housing in these low-income communities uses low-cost fiber cement shingles, mounted on fragile wooden structures that cannot support the additional 20-25 kg/m2 load imposed by the typical PV module + aluminum structure used. in rooftop photovoltaics. To allow photovoltaic integration on roofs under these conditions, one of the largest manufacturers of fiber cement tiles in Brazil has developed photovoltaic fiber cement tiles, which are in the final phase of resistance and reliability tests at the Solar Energy Laboratory of the Federal University of Santa Catarina. The additional weight of the 1/6 cut solar cell bands in the final tile is negligible, and the replacement of several of these photovoltaic tiles on existing roofs is simple. The expected costs are lower than for a traditional rooftop PV system, but it is necessary to scale up to access PV cells at competitive costs.
In this assessment of scenarios for a sustainable and resilient energy transition in isolated systems in the Amazon, a part of the PV generators should be installed centrally to guarantee a central system of high performance, availability and reliability without cutting down more forest areas, while another significant part of the generators should be installed distributed on rooftops and in agrivoltaic systems. |
