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Abstract(s)
O objetivo deste estudo é compreender a viabilidade técnica e económica da
instalação e operação de uma central de desalinização para fornecer água a um processo
de eletrólise de água de larga escala (GW). A central de produção de hidrogénio deve ser
alimentada por fontes renováveis tais como energia eólica e solar fotovoltáico. A divulgação
de investimentos significativos na produção de hidrogénio na região de Sines torna
importante a análise detalhada da operação deste tipo de sistema que acarreta desafios
relativamente às reservas de eletricidade e água. Água, em particular água doce, é um
recurso escasso na zona sul de Portugal e a instalação de uma indústria que usa grandes
quantidades de água nos processos pode causar pressão considerável nas reservas
existentes.
Dada a proximidade da região ao Oceano Atlântico, é relevante avaliar a instalação
da central de desalinização e analizar o impacto geral dessa opção na produção de
hidrogénio.
A operação da unidade de desalinização é analizada do ponto de vista técnico, ao
considerar que é necessário produzir água para fornecer as necessidades instantâneas do
eletrolizador. Isto é feito ao dividir um ano em intervalos de uma hora e estimar a quantidade
de água a produzir em cada hora, considerando a eficiência da dissociação de água do
eletrolizador. A unidade de desalinização é ajustada para utilizar o máximo dos excessos de
produção de eletricidade das fontes de energia renováveis que alimentam o eletrolizador.
Do ponto de vista económico, dois parâmetros foram analizados. Primeiro o custo
nívelado de água desalinizada é estimado e comparado com o custo de água da rede.
Verificou-se que o custo nívelado de água desalinizada é inferior ao custo de água potável
fornecida às indústrias locais pelo serviço municipal de águas de Sines (Águas de Santo
André).
Segundo, o impacto no custo nivelado de hidrogénio é analizado. Verificou-se que a
instalação e operação da unidade de desalinização aumenta o custo nivelado de hidrogénio
por menos de 1%.
Desalinização de água do mar demonstra ser uma alternativa tecnicamente e
economicamente viável para produzir água para uma central de eletrólise de larga escala
que poderá aliviar a pressão de fontes locais de água doce.
The goal of this study is to understand the technical and economic feasibility of installing and operating a seawater desalination plant to supply water to a GW-scale water electrolysis process. That hydrogen production facility should be powered by dedicated renewable energy sources such as wind and solar photovoltaic. The announcement of significant investments in hydrogen production in the Sines region makes it relevant to perform a detailed analysis of the operation of this type of system that will present challenges with regards to the electricity and water supply. Water, in particular freshwater, is a scarce resource in the south of Portugal and the installation of an industry that uses large amounts of water as feedstock can place considerable pressure on existing reserves. Given the proximity of the region to the Atlantic Ocean, it is appropriate to evaluate the installation of a desalination plant and analyze the overall impact of that option on hydrogen production. The operation of the desalination unit is analyzed from a technical point of view, by considering that water must be produced to provide the instantaneous needs of the electrolyzer. This is done by dividing one year in one-hour slots and estimating how much water must be produced each hour, considering the water dissociation efficiency of the electrolyzer. The desalination unit is adjusted to make the best use of the excess electricity production of the renewable energy sources that feed the electrolyzer. From the economic point of view, two parameters are analyzed. First the levelized cost of desalinated water is estimated and compared to the cost of grid water. It has been found that the levelized cost of desalinated water is lower than the price of potable water supplied to the local industries by the Sines municipal water service (Águas de Santo André). Second, the impact on the levelized cost of hydrogen is analyzed. It is shown that the installation and operation of the desalination unit increases the levelized cost of hydrogen by less than 1%. Seawater desalination is shown to be a technically and economically viable alternative for producing the water feedstock for a GW-scale electrolysis facility that could alleviate pressure on local freshwater sources.
The goal of this study is to understand the technical and economic feasibility of installing and operating a seawater desalination plant to supply water to a GW-scale water electrolysis process. That hydrogen production facility should be powered by dedicated renewable energy sources such as wind and solar photovoltaic. The announcement of significant investments in hydrogen production in the Sines region makes it relevant to perform a detailed analysis of the operation of this type of system that will present challenges with regards to the electricity and water supply. Water, in particular freshwater, is a scarce resource in the south of Portugal and the installation of an industry that uses large amounts of water as feedstock can place considerable pressure on existing reserves. Given the proximity of the region to the Atlantic Ocean, it is appropriate to evaluate the installation of a desalination plant and analyze the overall impact of that option on hydrogen production. The operation of the desalination unit is analyzed from a technical point of view, by considering that water must be produced to provide the instantaneous needs of the electrolyzer. This is done by dividing one year in one-hour slots and estimating how much water must be produced each hour, considering the water dissociation efficiency of the electrolyzer. The desalination unit is adjusted to make the best use of the excess electricity production of the renewable energy sources that feed the electrolyzer. From the economic point of view, two parameters are analyzed. First the levelized cost of desalinated water is estimated and compared to the cost of grid water. It has been found that the levelized cost of desalinated water is lower than the price of potable water supplied to the local industries by the Sines municipal water service (Águas de Santo André). Second, the impact on the levelized cost of hydrogen is analyzed. It is shown that the installation and operation of the desalination unit increases the levelized cost of hydrogen by less than 1%. Seawater desalination is shown to be a technically and economically viable alternative for producing the water feedstock for a GW-scale electrolysis facility that could alleviate pressure on local freshwater sources.