Renewable energies in Europe
What they are, how they work, and how the EU institutions are aiming to make them increasingly popular given their strategic independence and the achievement of the goal of zero impact on the environment and climate by 2050
Wind, solar, hydroelectric, ocean, geothermal, biomass, and biofuels. These are renewable energy sources that are alternatives to fossil fuels and help reduce greenhouse gas emissions, diversify energy supply and reduce dependence on volatile and unreliable fossil fuel markets, especially oil and gas.
The EU, with the Green Deal and the Climate Act, has taken the step from awareness of climate change and global warming to action, aiming for a transformation that will eventually see the Old Continent at zero impact by mid-century. But it is also, and above all, from Ukraine invaded by Russia that comes the warning to act quickly and focus on renewables because the issue of energy independence of the Twenty-Seven has emerged as an urgent one.
EU legislation on the promotion of renewable energy has therefore evolved significantly over the past 15 years. In 2009, EU leaders set a target of a 20% share of energy consumption from renewable sources by 2020. In 2018, a target of a 32% share of energy consumption from renewable sources by 2030 was agreed upon. In July 2021, in light of the EU’s new climate ambitions, it was proposed to the co-legislators to raise the target to 40% by 2030. The future policy framework for the period after 2030 is under discussion.
This is the kinetic energy produced by the movement of air over the earth’s surface, between areas of high and low pressure. Capable of making a significant contribution to a carbon-neutral future, wind power is in constant development: if current growth trends are confirmed, this green energy could cover 20% of global electricity demand by 2030, with a consequent reduction in CO2 emissions of over 3 billion tonnes per year.
Wind turbines take kinetic energy from the wind and transform it into mechanical energy. In a wind turbine, the blades are connected to the rotor, which in turn is connected to the shaft in the pole, which sends the rotational energy to the electric generator located at the base of the structure. The wind turns the blades, which turn the generator, which transforms mechanical energy into electrical energy using a dynamo. Depending on its location, the wind farm can be on-shore or off-shore. Onshore wind farms are installed on land, in areas where there is usually a certain amount of wind movement. Offshore wind farms, on the other hand, are located directly on the sea.
Solar energy is the type of renewable energy that is growing proportionally more than the others (+24% per year in the IRENA 2019 report), in step with technological development, which makes it possible to build increasingly efficient solar power plants.
At the heart of a photovoltaic field are solar panels. The semiconductor material they are made of, such as silicon, is sensitive to light and creates electricity when hit by solar radiation. The panels are mounted on special support structures, which ensure the correct tilt and orientation to maximize light exposure. All solar panels in a photovoltaic field are connected to an inverter, a machine that transforms the direct current produced by the modules into alternating current, which is easier to transport and use in all homes. A control system monitors the operation of the system and connects it to the grid so that the electricity produced is available.
Renewable and clean come from water. Hydroelectricity is energy that uses large masses of water moved by gravity or conveyed in dams, locks, canals, and bridges. Either a natural reservoir exists upstream or an artificial reservoir is built with a dam, which forms a barrier and prevents the flow of water from going downstream. Through penstocks, the water is conveyed at high speed downstream where a plant containing hydroelectric turbines and an alternator is located. It is here that the kinetic energy, generated by the rotation of the turbines, is converted into electrical energy by the alternator. Hydroelectric plants can be run-of-river (located on the watercourse), reservoir (the water is collected in a basin), or storage (the water is brought upstream with the help of pumps).
Ocean energy comes from the sea and is also known as pelagic energy. The technology that harnesses it is fluid-dynamic, i.e. it draws power from waves, tides, and currents to produce electricity.
There are different types of ocean energy, such as that generated by sea currents, which can move blades and create mechanical energy, like the wind that wind turbines use. Ocean energy can also be harnessed from the tides, especially where tidal power stations can be installed. In these plants, water enters a turbine that produces energy when the tide rises or falls. Tidal energy can be used in several ways, using an oscillating water generator, with water jumping, or with systems based on wave amplitude.
Another type of ocean energy is thalassotherapy, which exploits the difference in temperature between the surface of the sea and its depth. It is little used because there are very high costs to install the plants. Finally, we have sea salt energy, which is based on osmosis between membranes that separate the saltwater from freshwater. It is an environmentally sustainable system that only produces brackish water as waste, so it does not pollute.
Geothermal energy uses the heat present in the planet’s crust and subsoil to produce electricity and is a stable source from which constant energy can be obtained. Geothermal heat is the result of nuclear decay processes of radioactive elements (uranium, thorium, and potassium) within the earth’s core, mantle, and crust. The thermal energy stored underground escapes to the earth’s surface via fluid carriers such as water and steam. There are three types of geothermal power plants. Dry steam plants, in which steam is extracted from fractures in the ground and used to drive a turbine. Flash power plants, transform hot, high-pressure water into cooler, low-pressure water. And binary, in which a fluid with a lower boiling point than water is run alongside boiling water, which turns the fluid into steam to drive a turbine.
A clean source of energy that reduces dependence on fossil fuels, biomass is organic matter generated by plants and animals that have been specially treated for use as biofuel in power plants. Firewood residues, waste from the agro-food industry, municipal organic waste, green shoots from forestry and agriculture, seaweed and livestock waste, and effluents are the organic-vegetal materials from which energy is produced. When biomass is burned, it releases heat and emits a quantity of carbon dioxide similar to that emitted in nature during an ordinary photosynthesis process. Biomass power plants produce electricity using steam generated by burning agricultural, industrial, and municipal waste. The materials are burned in a combustion chamber, producing the heat needed to turn the water in the thermodynamic circuit into steam. The steam turns a turbine, which in turn drives the rotor of an alternator that produces an alternating electrical current. The alternating current is sent to a transformer which raises the voltage before it is fed into the system. The water vapor at the outlet of the turbine is transformed into the water by a condenser and finally sent to the storage tank.
By definition, a biofuel is a fuel whose energy is obtained through the process of biological carbon fixation. As the term itself suggests, the word is made up of two terms: “Bio” and “Fuel”. Let us look at each of these two words in detail. A biofuel is a hydrocarbon that is produced by a living organism and that humans can use to power equipment, buildings, and much more. In practical terms, any hydrocarbon fuel that is produced from organic matter (living or formerly living) in a short period (days, weeks, or sometimes months) is considered to be a biofuel. Biofuels, therefore, stands in stark contrast to fossil fuels, which take millions of years to form, and other non-hydrocarbon fuels, such as nuclear fission. Biofuels can also be produced by controlled chemical reactions carried out in laboratories or industrial plants, which use organic matter (biomass) to produce fuel. The only two requirements for a biofuel to qualify as such are the presence of carbon dioxide, which is present at the beginning of the process and is fixed by a living organism, and the timing of the production of the final fuel, which must be within a short time.
Offshore renewable energy
In November 2020, the Commission presented its Offshore Energy Strategy, in which it aims to boost the capacity and use of offshore energy technologies, including floating offshore wind farms, ocean energy (wave and tidal energy) installations, and floating photovoltaic installations, use of algae to produce biofuels.
Developing this sector and connecting the huge potential of wind energy to the European grid will not only benefit the environment by reducing emissions from energy production and helping to protect biodiversity but will also create opportunities for investment and growth, including in coastal areas.
Hydrogen, when produced from renewable energy sources, does not emit carbon and therefore contributes to the decarbonization of the economy. Hydrogen is seen as the energy carrier of the future, able to help decarbonize high-emission sectors such as energy-intensive industries and transport.
The Commission adopted its hydrogen strategy in July 2020 and identified hydrogen as an investment priority in the EU recovery plan. It launched the European Clean Hydrogen Alliance, bringing together industry, civil society, and national and regional authorities, to support investment and stimulate demand in the energy sector.
In its conclusions of December 2020, the Council recognized the important role played by hydrogen, in particular, that produced from renewable sources, in achieving the EU’s de-carbonization targets; in achieving economic recovery in the context of Covid-19; and in contributing to the EU’s competitiveness on the global stage.
Integration of the energy system
To become climate neutral by 2050, Europe needs to radically transform its energy system into an integrated energy system with high shares of renewable energy and significant energy efficiency improvements. System integration is about linking energy sectors with each other and with end-use sectors such as buildings, transport, and industry. An integrated system is more economically and technically efficient and counteracts heat loss.
In its strategy for energy system integration, the European Commission has proposed to build a more circular energy system focused on energy efficiency. This would help provide more and greener electricity to sectors such as transport and industry and promote low-carbon fuels, including hydrogen, for sectors that are more difficult to decarbonize.
Trans-European Energy Networks (TEN-E)
The Trans-European Energy Networks (TEN-E) policy, launched in 2013 and currently under revision, supports cross-border projects to connect Member States’ energy networks and promote the integration of renewable energy.
The aim of the Commission’s proposal for a revised TEN-E Regulation is to modernize, decarbonize and interconnect the EU’s cross-border energy infrastructure to help achieve the EU’s 2050 climate neutrality targets. The regulation is also intended to continue to ensure market integration, competitiveness, and security of supply.
Biomass and biofuels
The Renewable Energy Directive (Directive (EU) 2018/2001) currently in force includes a target of 3.5% by 2030 and an intermediate target of 1% by 2025 for advanced biofuels and biogas in the transport sector. Although the current 7 % cap on first-generation biofuels is maintained in the road and rail transport sector, an EU-wide obligation for fuel suppliers to provide a certain share (6.8 %) of low-emission and renewable fuels is introduced, as well as an extension of the scope of the EU sustainability criteria for bioenergy (including biomass and biogas used for heating and cooling and electricity production).
In January 2014, the Commission published a communication entitled “Blue Energy: Realising the ocean energy potential of Europe’s seas and oceans by 2020 and beyond”. This Communication sets out an action plan to support the development of ocean energy, including wave, tidal, thalassotherapy conversion, and salt gradient energy.
Giulia Torbidoni – PFE