TRANSITION TO RENEWABLE ENERGY SOURCES

1.1. DESCRIPTION Even if the energy needs of buildings or individual materials are reduced, it is necessary that renewable and clean energy sources are used to meet them, so that operations such as the combustion of a fossil source, the extraction, processing and transport of which are among the greatest sources of environmental impact, especially on the air, are not necessary. This is also accompanied by the need to have sources that are non-depletable and that allow the energy to be produced directly at the site of consequent use, with ad hoc plants. 1.2. RELEVANCE FOR CIRCULAR BUILDINGS The installation of on-site renewable energy production systems, both on existing and new buildings, allows for maximum energy circularity, especially with a view to self-production and self-consumption: by generating energy and storing it to draw on when needed, one is able to avoid wasting what is produced and reduce the energy demand from national lines, which mainly use fossil fuels for production. The use of renewable sources in the production of building materials also reduces the associated carbon footprint and thus makes them more circular. Renewable productions are particularly important for achieving energy circularity in existing buildings, as they make it possible to respond to the surplus of energy demand linked to the low performance of their envelopes. 1.3. INNOVATION ASPECTS The integration of renewable energy systems on buildings has been a key topic for environmental sustainability for several years now: innovation for circularity must lie in expanding the scale of application of these systems. More and more technological solutions are being proposed, for example, by solar panel manufacturers: in order for their market not to stabilise, it is necessary to focus on innovative solutions, such as customised panels that can be integrated into any building component, from roofing to walls and window frames; the manufacturers' main commitment must be towards producing panels with local materials, which is impossible today as the market is still dominated by the logic of profit that aims to buy cheap materials in Asian countries: there must therefore be initiatives, including public

2.1. PRACTICAL APPLICATIONS - Installation of photovoltaic panels, with correct orientation, and other plant engineering components necessary for the exploitation of electrical energy, as well as for transferring unused excess to the grid in the absence of batteries - Installation of thermal solar panels on roofs for the production of DHW or for pre-heating water in heating systems - Replacing fossil fuel boilers with (renewable) biomass boilers or heat pumps that make better use of electricity production - Participation in community energy, district heating and district production projects to utilise renewable energy produced in large plants - Adoption of plant solutions based on geothermal heat production, or electricity from wind and hydro power - Plant and renewable source choices according to building needs

3.1. BENEFITS - Possibility of accessing numerous incentives at national or regional level to facilitate this transition to green energy - Significant economic savings on consumption, with even some profit in the case of electricity sales, once the payback period has elapsed - Limitation in the production of CO2 and other polluting particles related to fossil combustion - Possibility of integrating installations from renewable sources even later than the construction of the building, depending on the needs identified - Different options of choice with respect to the renewable energy source depending on needs and the most exploitable resources - Integration into most existing buildings 3.2. COMPLEXITIES - Production of photovoltaic panels concentrated in Asian countries for which transport is long, expensive and polluting - Batteries used for electricity storage are highly polluting, non-reusable and have a limited service life, as do most components of photovoltaic systems - Need for design considerations depending on building configuration - Difficult integration of renewables in historic buildings due to constraints - Considerable waste production due to extensive replacement of existing installations - Large, expensive and space-consuming installations are required for large buildings - Need for maintenance and frequent replacement of components - Production is not constant, requiring grid connections, other back-up generators or storage systems