The expansion of photovoltaic solar energy in the world is significant. However, its contribution to decreases in greenhouse gases (GHG) is not an absolute guarantee. In this context, it is necessary to evaluate its benefits in advance, considering the structure of the electric energy supply matrix of the country producing the photovoltaic solar system, as well as the country where the technology will be implemented. This study evaluates the adoption of renewable sources for electric power generation in a country with a high share of renewable energy. A life-cycle assessment (LCA) of a set of multi-Si photovoltaic (PV) systems installed in the Brazilian northeast (NE), was carried out. The actual generation data of 10 plants totaling 1.1 MWp installed capacity were evaluated during two years of operation. Energy payback time (EPBT), greenhouse gas emission rate (GHGe-rate), and emission payback time were calculated. The great influence of the electric matrix characteristics of the country manufacturing PV systems was evidenced in the results. The interconnected Brazilian electrical system had a 2020 projected GHGe-rate of 63.9 g CO₂/kWh, while the results of 70% of the photovoltaic solar power plants (PSPS) assessed herein exhibit higher GHGe-rates. Thus, in countries where the electric matrix comprises a high share of renewable sources, such as Brazil, the incentive to use PV systems manufactured in nations whose electric matrix registers high emission factors should be well evaluated in terms of the impacts of GHG concentrations and the promotion of sustainable development, in order to avoid indirect import of significant amounts of carbon embedded in the systems.

The energy sector and electricity generation in particular, is responsible for a great share of the global greenhouse gas (GHG) emissions. World electricity generation is still largely based on the burning of fossil fuels. However, Brazil has already a very low electricity carbon intensity due to the country’s large hydropower capacity. In countries with low grid carbon intensities such as Brazil, the investment in photovoltaic solar systems (PVSS) even if it is cost-effective, might become challenging as any new generation competes essentially against other renewable generation and the carbon offset is not a key driver for investment anymore. This study builds further upon that case to examine if national renewable energy incentives could actually lead to an increase of global net carbon emissions from the installation of PVSS in countries with a low grid carbon intensity. The study presents a life cycle analysis (LCA) of ten photovoltaic systems representative of the different operational conditions in regions across Brazil. It was found that the average energy payback time of the studied PV plants is between 3 and 5 years of operation. This result shows the feasibility and viability of such investments in the Brazilian context. When the LCA was integrated into the analysis though, the results showed that the “local” direct emissions avoidance from two out of ten studied PV plants would not manage to offset their “global” life cycle emissions due to the 2020 projected Brazilian grid emission factor which is already low. It is important to recognize that public policies of unrestricted, unconditional stimulus to photovoltaic systems investment might not help towards reducing global net emissions when the PV systems are installed at countries with a low carbon emission electric matrix. That is also something to consider for other countries as the carbon intensity of their grids will start reducing at levels similar to Brazil’s. It is likely that in the near future, the real net carbon offset achieved by PV systems at the global level will be largely defined by the manufacture procedures and the production’s carbon intensity at the country of origin of the PV panels.

Sustentabilidade do futuro: livro de memórias do Sustentare & WIPIS (978-65-272-0451-0) - Explorando A Técnica Construtiva Do Adobe Através De Citações Bibliométricas

Las certificaciones energéticas son herramientas obligatorias o voluntarias para edificios con diferentes requisitos según los países. Las certificaciones energéticas tienen una fuerte sinergia con los requisitos ambientales de los edificios, ya que varias políticas para mejorar la eficiencia energética se basan en iniciativas para mitigar las externalidades ambientales. Por otro lado, un sistema de certificación energética que no analice en profundidad sus impactos ambientales puede acabar promoviendo la adopción de medidas ambientalmente negativas. Estudios anteriores ya identificaron que, en el caso de la certificación brasileña, es voluntaria, hay un puntaje positivo para los proyectos que adoptan sistemas solares fotovoltaicos, incluso si estos sistemas eventualmente presentan un mayor factor de emisión (kgCO2/kWh) en su ciclo de vida que el sistema interconectado nacional. La UE tiene certificaciones obligatorias para varios segmentos de edificios, lo que hace imperativo analizar críticamente los posibles impactos ambientales negativos de la adopción de estas certificaciones. La primera legislación producida en Portugal es el resultado de la transposición de la Directiva 2022/91/CE del Parlamento Europeo. El objetivo principal de esta directiva era reducir las emisiones de CO2 asociadas al consumo energético de los edificios, lo que obligaba a los estados miembros a garantizar la implementación efectiva de requisitos regulatorios mínimos para el rendimiento energético. En el caso de Portugal, la certificación energética es obligatoria desde 2006. Este estudio tiene como objetivo identificar lagunas en el análisis de las externalidades ambientales de las certificaciones energéticas existentes en vigor en ambos países con el fin de mitigar posibles impactos negativos. La metodología utilizada será un análisis comparativo entre los sistemas de certificación energética y sus formas de bonificación y puntuación. Luego, se presentará una revisión crítica sobre las brechas presentadas en los dos sistemas de certificación, caracterizando los posibles impactos ambientales negativos que se pueden generar. Se identifican debilidades en los sistemas de certificación energética de los países analizados, contribuyendo a profundizar en la investigación de sus impactos ambientales.