Renewable energies are energies that come from natural sources and have a faster replacement rate than their consumption rate. In other words, they are virtually inexhaustible. This concept, coined by the United Nations, came into use in the 1970s, a result of the oil crisis that revealed the finite nature of fossil fuel reserves. Fifty years later, the leading concern is not exhaustion of reserves, but rather global change caused by greenhouse gas emissions (GGE) from these fossil fuels. For this reason, we now tend to use other terms. We do not only consider the renewal rate of the natural resource used, but also the energy generation process and the impact of its use. This is where the concept of clean energies arises, which goes beyond renewable energies, and seeks for energy production to generate fewer GGEs and potential associated impacts.
At the same time, the development of both renewable and clean energies, like wind and solar, is taking firm strides forward, diversifying formats and improving efficiency and profitability on a day-to-day basis. With good reason, one of the EU’s goals to move toward cleaner energy is, by 2030, for 42.5% of energy consumed in the EU to come from renewable sources.
One of the most recent solutions to encourage the roll-out of clean energies is to implement them on water surfaces. This has advantages, like using the resource where it is most plentiful, non-competition with other land uses, and improved efficiency.
Thus, in the case of sea wind energy, also called offshore, we use the most powerful and constant high-seas air currents, along with larger wind turbines than can be used on land. The first sea wind farm was installed in 1991 in Denmark. In Spain, we are already defining our first specific projects, especially in the area of the Canary Islands. The Ministry for the Ecological Transition and the Demographic Challenge (MITECO) has drawn up a Roadmap to develop this technology, which sets forth installation capacity targets, identifies the areas with the greatest potential for implementation, and regulates concessions.
In the case of floating solar energy, for now in our country, development has only been regulated for reservoirs and artificial bodies of water. Regarding solar on land, constant cooling and dust reduction improve efficiency. In turn, there are other benefits for bodies of water, such as reduced evaporation and spread of algae. Leaders in this technology are China, the United States, and Japan, but we already have good examples in Spain, like the Flotante Sierra Brava in Cáceres, with 3,000 solar panels and 1.3 MW peak power output, directly connected to the grid.
In the Madrid region, we also have an interesting floating solar pilot project executed by Canal de Isabel II in the lower tank at the hydroelectric plant in Torrelaguna, with 3,770 panels and 1.7 MW power output. This project is a good example of the hybridisation of two renewable energies (hydroelectric and solar) and is a fundamental part of the Canal’s Solar Plan which, along with another thirty facilities, seeks energetic self-sufficiency for activity.
In order to be considered a good example of clean energy, all wind and solar development on water surfaces should guarantee that there are no notable effects on the environment where they are located (ocean or inland waters). To this end, the utmost environmental safeguards and studies to help modulate and mitigate possible impacts on the landscape and biodiversity are essential.
Under this premise, water can act as a powerful mid-term platform to roll out clean energies, which are crucial to reach our climate neutrality goal in the European Union.
