Embodied energy and carbon footprint comparison in wind and photovoltaic power plants

This work aims to evaluate comparatively the environmental impact of solar photovoltaic and wind power plants. The conceptual design and the initial preliminary design steps in the material selection process were considered. The assessment was made using two different metrics, embodied energy (EE) and carbon footprint (CF). Five different configurations of wind power plants and a set of photovoltaic panels in a power plant were evaluated. In the wind power plants, the generator, the materials, the height, and the tower type were varied. For manufacturing the towers, the following parameters were considered: material, height, and generator power. The photovoltaic power station can provide up to 1.5 MW. The materials selected for embodied energy and carbon footprint assessment followed two criteria: the greatest mass percentage participation and the greatest value of embodied energy and carbon footprint of each material used. For the calculation of distances travelled from suppliers of raw materials and components used in the photovoltaic panels and wind power plants, the considered destination was the city of Viana do Castelo (north of Portugal), one of the regions with tradition in wind power production and installations. The result is favorable to the concrete column, which achieved the best result of EE and CF. The Oebels 1.5 MW tower with an 80-m concrete column showed an EE of 0.0150 kWh/kWh (19.71% a 3.0 MW 120-m concrete column) and a CF of 4.77 gCO2/kWh (21.90% of the Rocha 3.0 MW 120-m concrete column). Comparing the 1.5 MW photovoltaic plant with the concrete column 1.5 MW wind power, the result is favorable to the concrete column. Taking into account that the values of the photovoltaic power plant are EE of 0.0638 kWh/kWh and a CF of 16.21 gCO2/kWh, the concrete column 1.5 MW represents 23.51% of the EE and 29,43% of the CF. This advantage of the concrete towers repeats for the other columns. The results show that the best configuration is the wind power plant with a concrete column. For further studies, a comparison between concrete and truss tower at the same work conditions is suggested.