The energy transition consists of a shift from an energy system based on fossil fuels and nuclear energy to a new system without nuclear power generation or carbon emissions, based on renewable sources (primarily, wind and solar power).
Due to the effects of greenhouse gases, the Earth is overheating. As well as causing glaciers to melt and sea levels to rise, global warming triggers other climate changes, such as desertification and an increase in extreme phenomena, including hurricanes, floods and fires. Climate change could cause incalculable damages. In Spain, three out of every four tonnes of greenhouse gases come from the energy system. The decarbonization of the energy system is a crucial part of the fight against climate change.
The energy transition will mean greater energy efficiency, less pollution at a local level, lower external energy dependence and an improved balance of trade. As well as the environmental benefits this will generate, this will all have a direct positive impact on the general public and the economy.
A key feature of the energy transition involves replacing part of the electricity generation, formed by large dispatchable units that had sufficient fuel in the past (coal, oil, natural gas or uranium), with a large number of uncontrollable distributed generation facilities (wind and photovoltaic power) close to the points of consumption.
The new electrical system paradigm focuses on guaranteeing a reliable, efficient and sustainable supply, based on electricity generation that is unpredictable and, therefore, difficult to control or dispatch.
As a result, storage is a key factor in the success of the energy transformation that we are undergoing.
As well as a renewable generation park capable of meeting the demand for energy, energy storage systems will be required in order to cater for the variability that characterizes a large proportion of electricity generation with renewable energies. The operation of storage technologies has to focus on maximizing the integration of renewable energies and making full use of the excess energy generated at times of a surplus of the renewable resource, thereby ensuring the prevention of any losses through leaks. Storage is essential not only for having access to a large-scale electricity supply, but also for making progress in terms of self-consumption and energy communities.
Not directly. Surplus electrical energy has to be converted into other types of energy that can be dispatched over time (through chemical bonds to batteries, increasing the altitude of a mass of water, raising the pressure of a volume of air, increasing the rotational speed of a spinning mass, charging an electrical capacitor, etc.) to be used later when the reverse process is conducted. It should be highlighted that all these energy transformations involve the expenditure of energy or, in other words, a loss of energy that we cannot use productively.
There are various energy storage systems: mechanical, thermal, electrochemical and chemical. The efficacy of some of these technologies is tried and tested, such as hydro-pumping, while others are still at the development stage. Each method has its pros and cons.
It is a system with two reservoirs at different heights connected by a pressurized pipe. When there is surplus electrical energy (high generation, low demand), water is pumped from the lower reservoir to the higher one. In the opposite case, when more energy is needed in the electrical system, the higher reservoir releases water to generate electricity.
It is an indirect way of storing electrical energy using a physical process in which the altitude of a mass of water is varied. The storage facility or “battery” works in a cycle of filling and emptying reservoirs (loading and discharging), through which the water from the bottom reservoir is transported to the top one (loading the storage facility) and later from the top reservoir to the bottom (discharging the stored energy).
No. An electrical energy storage plant is like a large battery that is charged by surplus green wind and solar energy, which is then used when the mains network needs it. It can never give out more energy than is put in. Therefore, it is not a generating plant, as such plants create a positive energy balance. In fact, in the full pumped storage cycle, around 20% of the input energy is consumed. In other words, if the system takes 100 units of electrical energy that it uses to fill the top reservoir, it will only put around 80 units back into the mains network when the reservoir is emptied.
Compared to other storage technologies currently in development, such as batteries or green hydrogen, hydro-pumping is the most mature, tried and tested storage system. Moreover, it boasts the longest useful lifetime, lasting up to a hundred years, while batteries last a maximum of twenty years. Hydro-pumping can store large amounts of energy and supply high levels of energy for over 8 hours. In addition, hydro-pumping generates other benefits for the electrical system, such as the capacity to help regulate the voltage and frequency of the mains network in order to facilitate the proper working of electrical and electronic appliances.
Pumped storage was first used in 1890 in Italy and Switzerland. Since then, the pumped-storage hydroelectricity plants built have remained in operation. The useful lifetime of a pumped storage plant is estimated to be over 100 years.
No. Gironés-Raïmats forms part of a set of projects identified at a European level as key initiatives for helping to achieve the European Union’s energy policy and climate goals. These projects aim to provide accessible, safe and sustainable energy for the whole population, as well as contributing towards the decarbonization of the economy in the long term.
To be designated as a PCI, a project has to meet certain technical criteria set at a European level by Regulation (EU) 347/2013. One essential condition is that the benefits for society generated by the project must outweigh the costs. Moreover, PCIs have to form part of the European electricity transmission and have the express support of the Member State and the European Commission. To be selected as a PCI, the project also has to go through a strict public participation process on a Europe-wide scale.
PCI projects benefit from a one-stop shop system for administrative procedures, as well as access to specific European funds for development. Moreover, they must comply with the most rigorous European environmental standards and consult a specific public participation process in the initial phase to improve the regional acceptance of the project.
The administrative process for a PCI is regulated by Regulation (EU) 347/2013 and the Spanish sector regulations. It includes a public participation process, the water concession procedure, an environmental impact assessment, the procedure for electric connection and the corresponding adjustments in terms of regional and urban planning.
No. The Gironés-Raïmats reservoirs are not on the main axis of the Ebro River and are located far from it. The water from the Ebro River is only used to fill one of the reservoirs initially. After this, the pumped-storage hydroelectricity operates as a closed circuit between the two reservoirs.
An initial fundamental aspect is the location of the project. A suitable site has to ensure that there is not potential impact on protected natural areas or endangered species of flora and fauna. Any impact or risk to towns or private properties must also be avoided. The electrical connection has to make use of the existing corridors. Landscape integration can be improved through a design that ensures that the project is adapted to the existing terrain as much as possible, underground works and environmental restoration. In some cases, habitat improvement measures are required to compensate for the loss of habitat for certain species.
No, they are complementary. The demand of the residential sector accounts for around 20% of total electricity consumption in Spain. Gironés-Raïmats will provide its services to all consumers, including industry and services, within both the national and European electrical system.
The energy transition will entail a shift from dispatchable energies (coal, gas, oil and nuclear) to non-dispatchable renewable energies (wind and solar). Energy storage will enable us to enhance the security of the system to prevent periods in which the energy supply may fail (cloudy days with no wind). Moreover, at such times, the market price of energy tends to rocket. Energy storage avoids these extreme prices. With the wide-scale penetration of non-dispatchable renewable energy generation within the electrical system, the capacity for storage is absolutely necessary.
Any project of this scale and importance poses implementation challenges, as the general aim is to maximize the regional benefits and minimize the impacts. One of the key challenges in the case of Gironés-Raïmats is to resolve the high technical complexity effectively and, at the same time, ensure that is accepted by the region in order to improve its implementation and designed, through a participative process. With a project of these characteristics, it is essential to progress through the administrative process and mobilize the huge amounts of capital required to get the project up and running.
The closed circuit design of Gironés-Raïmats means that the plant can be operated regardless of changes in the flow of the Ebro River. While the output of conventional hydroelectric plants will be affected by increasingly common droughts, Gironés-Raïmats will provide security and yields for the electrical system, with the ability to operate at full performance under these circumstances.