FLOATING SUSTAINABILITY: THE CASE OF AQUATIC PHOTOVOLTAIC PLANTS

This innovative technology offers interesting advantages in term of space and optimization of aquatic resources.

Author: Luis Sánchez Torrente

The search of energy solutions with no social and environmental impact is still one of the main challenges of the sustainable agenda. The field of renewable energies and their dizzying expansion over the last decades has implied great progresses in reducing the carbon footprint and dependence on fossil fuels, but it is clear that none of the available technologies offers an outcome 100% free of adverse effects for the environment and the coexisting communities. Let’s think, for example, about how the photovoltaic energy, one of the cleanest power generation options and increasingly cost-efficient, can entail an important challenge especially for countries with high rates of population density or limits in land availability for their installation. Small scale implementation solutions, such as the use of self-consumption panels for housing and public buildings, contribute to mitigating this constraint, but with respect to greater scale generation projects, the photovoltaic energy is still a high impact option due to the large plot areas required for their installation.

However, one of the brighter proposals of the last years in this field opts for mitigating this impact through the use of underused water bodies for the installation of floating solar panels. This is a technological option already tested and successfully implemented in countries such as China and India, and with perspective to be considered as a strategic priority in the development of photovoltaic projects, thanks to the important advantages it can involve. Because, indeed, this is not only about reducing the affectation of the territory in terms of occupied lands, but this technology also offers important environmental co-benefits which makes it a truly attractive option. Thus, the permanent contact with water reduces the solar panels’ temperature and consequently improves their yield efficiency. At the same time, the aquatic surface bearing the photovoltaic modules is less exposed to evaporation, which implies important savings in the availability of water.

Obviously, to make this technological option feasible from a technical and environmental point of view, the aquatic surfaces hosting them must fulfill a series of requirements, mainly in terms of turbulences and variability of the water level, which makes artificial dams, dedicated to irrigation or hydroelectric production, the main candidates to host this kind of projects. Also, the existence of alternative usee of reservoirs has to be compatible with the presence of solar modules, which can generally be settled through a partial coverage of the aquatic surface. This is particularly important in reservoirs where leisure and/or fishing activities exist, to the extent that aquatic excessively shaded ecosystems could involve the disappearance of organic matter that feeds the fish stocks present in the water, hence altering the ecological balance and triggering possible socio-economic affectations. Likewise, the use of aquatic surfaces that, despite their artificial origin, have developed a high landscape value or a touristic potential should be avoided. In such a case, the different strategic options should be assessed as a result of a cost-benefit analysis.

Another strategic option aimed to develop photovoltaic energy without territorial affection is the installation of solar panels over the path of irrigation canals. In this case, it would not be a floating technology, since the modules would be installed by means of canal top structures anchored on the canal’s embankments, but it would definitely be an alternative way to avoid evaporation of irrigation water. At the moment, this strategic option has been implemented on an experimental basis in densely populated rural areas of India, with the aim to be developed on a larger scale.

Even if a better comprehension of the possibilities and effects offered by this technology is necessary, it is undisputable that the search of fully sustainable ways to produce energy has found an important and interesting candidate.

This post has been written for the Blog New Ways Sustainability