Combating the effects of climate change by reducing CO2 emissions is a concept that crops up again and again at a time (the present) when the energy transition is already under way. There is no doubt that renewable energies are key players in this process.
The term renewable refers both to energy obtained from sources already available in nature that are inexhaustible yet still have a limited environmental impact, and energy obtained using processes that themselves constantly regenerate faster than the energy drawn from them.
The fundamental difference between fossil fuel and renewable energy sources is that extraction is no longer concentrated in specific geographical areas. Renewable sources are within everyone’s reach while only a limited supply of fossil fuels is available on the planet and can, as a result, run out.
What are they? All the sources and types
- Hydroelectric power, which uses energy produced by falling or flowing rivers and streams and converted into electricity by pipelines and turbines.
- Solar energy, which can be converted to electricity using devices capable of capturing it, such as photovoltaic panels.
- Wind energy, which is generated when wind turbines and blades are turned by the power of the wind.
- Geothermal energy, which is produced using the Earth’s own heat and that from geysers, hot water sources, etc.
- Biomass energy, which is produced through the natural or induced combustion of animal or plant waste, typically coming from agriculture, forestry or animal husbandry.
- Tidal power is energy produced by the rise and fall of sea levels caused by the tides, and turned into electricity by specialist power plants.
The advantages of green energy
Generating energy using renewable sources has several advantages. For example, they:
- Are inexhaustible – unlike fossil fuels – and do not require mining;
- Produce clean energy, without emitting CO2 and other greenhouse gases into the atmosphere;
- Reduce dependency on fossil fuel imports;
- Deliver savings on energy supply because power plants are becoming increasingly efficient and have lower maintenance costs.
Furthermore, continuous technological development means that using these sources will become even more efficient in the future.
The main renewable energies in Italy and production percentages
According to research carried out by Ember - Agora Energiewende in 2020, renewable sources generated 38% of the electricity used in the European Union, a figure that for the first time exceeded the amount generated by fossil fuels.
According to the Energy Services Manager’s Statistical Report, that year gross energy production in Italy from renewables was 116.9 TWh, the equivalent of 41.7% of total national production. Production calculated under the criteria of Directive 2009/28/CE to monitor EU targets (118.4 TWh, the equivalent of just under 10.2 Mtep) is also up by 2.5%; in this instance, it accounts for 38.1% of gross domestic electricity consumption.
The renewable source that made the greatest contribution in Italy was hydroelectric power (40.7% of the total) followed by solar (21.3%), bioenergy (which includes biomass, biogas and bioliquids, 16.8%), wind (16%) and geothermal (5.2%).
Compared to 2019, solar energy was the fastest growing renewable in the electricity sector, outperforming all of the others both in terms of power plants (+55.748) and overall installed capacity (+784,765 kW, for a total of 21,650,040 kW).
One of the best known renewables: solar energy
In terms of energy potential, solar energy is the biggest renewable source available on Earth. It is clean because it creates neither CO2 nor polluting gas emissions, and is available almost everywhere on the planet. This is why scientists have for many years been focusing their efforts on the most efficient ways to exploit it.
Two types of system for producing energy from the Sun
The main solar power technology is photovoltaic which uses panels comprising silicon cells. Silicon is a semiconductor that can convert solar rays into DC electricity which is then converted to AC using an inverter. This type of system is a key tool in pursuing energy independence goals. As a result, Enel Green Power is now developing a new range of high-performance photovoltaic panels made from recycled plastic which are themselves fully recyclable. When they will be released on the market, these new low-impact panels, which are also cheaper, lighter and self-cleaning, will guarantee greater autonomy in the solar technology supply chain, which is currently dominated by the Asian nations.
Alongside photovoltaics, there’s also solar thermal, which is mainly used for domestic hot water and, to a lesser extent, for heating. The mechanism is still based on a solar panel but, unlike the photovoltaic version, it doesn’t produce electricity: instead it collects solar energy in the form of heat that it transmits to a fluid, which in turn transfers it to domestic water.
Photovoltaic and agriculture: a winning combination
So-called agrivoltaics (also known as agrovoltaics or agrophotovoltaics) is an innovative approach that combines clean energy generation using photovoltaic systems and sustainable agriculture in a synergic relationship that offers tangible benefits both in terms of agriculture and energy.
Essentially, in agrivoltaics, crops and photovoltaic panels share the same physical space in synergy. The crops grow between the lines of panels or even under them as the panels can be installed about two meters off the ground (standard model) or four to five meters off the ground (raised model). In an agrivoltaic system, agriculture and energy production are closely interconnected and this guarantees a wide range of advantages:
- Less soil consumption since the crops and the photovoltaic panels coexist in the same space, no land has to be set aside exclusively for energy production;
- Improved agricultural productivity because when correctly angled, the photovoltaic panels can protect the land from excessive sun exposure, particularly at the hottest times of the day or during particularly warm moments. For many crops this results in higher yields both in terms of numbers and size of fruits;
- Lower water consumption because as the land is partially shaded, it can hold on to moisture for longer and more efficiently, requiring less frequent watering;
- Economic benefits for farmers who can use part of the energy produced by the photovoltaic system and then sell any surplus;
- Both land and local communities benefit because agrivoltaics can be a good way of recovering disused or uncultivated agricultural land. Moreover, the installation and management of these plants can also create opportunities for local businesses and professionals.
Renewable Energy Communities: what are they?
Renewable Energy Communities (RECs) are another effective way of achieving energy sustainability. These are made up of local citizens, businesses and public authorities who come together to generate energy from renewable sources, share it in the community and then sell any surplus at a profit. Renewable Energy Communities are a flexible tool that meets the needs of different types of users. There are, for example, agricultural energy communities, energy communities set up by businesses and local authorities, and even condominium-based energy communities.
Renewable Energy Communities can use virtually any clean energy source but the technology that best lends itself is photovoltaic.
Howto create a Renewable Energy Community and become an energy producer
In Italy, Renewable Energy Communities are regulated under article 42/b of the so-called Milleproroghe Decree 162/2019, which was converted into Italian Law 8/2020. Under this legislation, RECs (CERs in Italian) can be set up by any public or private entity: groups of citizens, commercial businesses, institutions, SMEs, or other types of organization.
To set up a Renewable Energy Community, the interested parties first need to form a legal entity, typically a cooperative or an association.
On an operational level, they also need to find an area to install the production plant that is close to the end consumers. This plant, normally a photovoltaic system, does not have to be owned by the Community. In fact, it can belong to just one member or even a third party.
Incentives and opportunities
Once the plant is up and running, the Community can access incentives which only cover energy shared within the community, i.e., energy produced and used by the members within the same time slot. The Community can apply directly to the Energy Services Manager (GSE) for these incentives or do so through a third party.
When the Renewable Energy Community generates more energy than it uses, it receives payment for the surplus.
Collective self-consumption and energy communities: similar but different
Energy production and sharing are goals both for Renewable Energy Communities and Self-consumption groups. However, there are certain differences between the two types of organization:
• In Collective Self-consumption Communities, the members share the same building which has a renewable energy production system, normally photovoltaic. This means that the energy can be shared only where it is generated. The classic example of this is a condominium but it can also apply to businesses and institutions using the same building.
• Energy Communities, on the other hand, are legal entities which can self-produce energy using plants and systems that are nearby but not necessarily in the same building. These are connected to Virtual Power Plants (VPP) which allow the energy to be shared by the members. This is referred to as virtual self-consumption: energy is shared using the existing grid without any need for new connections.
It is therefore an invaluable tool in accelerating the decarbonization process and supporting electrification by producing clean energy and lowering utility bills.