International Sun Day 2023

Celebrating Sun Day: a limitless source of renewable, clean and affordable energy

In addition to being the enormous star around which our entire planetary system orbits, the Sun is the powerful source of energy that makes life on Earth as we know it today possible. Throughout history, we have benefited from its heat and light in many ways, and our agricultural and food production systems, among others, depend on it. Today, it is up to us to exploit this continuous and inexhaustible radiation in an increasingly efficient way, as a universally accessible, renewable and  clean energy source that is key to the energy transition towards a sustainable system. 

International Sun Day

The sun's energy, or photovoltaic energy, has been and will always be essential for our economic and social development, which is why the solstices and equinoxes are traditionally celebrated in all cultures as a symbol of the earth's fertility. It is because of these millenary roots that the United Nations General Assembly recognised 21 June 2019 as the International Day for the Celebration of the Solstice, or Day of the Sun, as a Universal Cultural Heritage.

21 June is a key date in the calendar of all those interested in astronomy. In the northern hemisphere, it is the longest day and the shortest night of the year, as well as the official start of summer. Meanwhile, the southern hemisphere experiences just the opposite: the shortest day, the longest night and the beginning of the winter season. 

These phenomena are the result of the tilt of the Earth's north-south axis (23.4º) with respect to the Sun, which means that during the year it takes our planet to go around the Sun, different regions receive different amounts of sunlight and with different intensity depending on the time of year. Thus, the opposite effects of the June solstice are experienced on the solstice of 21 December, when winter begins in northern countries and summer in southern countries.

Sun Day celebrations

Historically, the sun has been praised, celebrated and, to a certain extent, also feared by all the great ancient civilisations. It is not in vain that plant and, therefore, animal life depended and still depends on it. These are some of the most famous ancient ceremonies or monuments addressed to the King Star and the solstice:

•  The Incas and Inti Raymi 
  The Inti Raymi ("festival of the sun" in Quechua) of the austral winter solstice was one of the two major festivals celebrated by the Incas in honour of the Sun and represented the rebirth of the star to start a new annual cycle, as well as the mythical origin of the Inca kings (sent to Earth by the Sun). The celebration lasted 15 days, during which there were dances, ceremonies, offerings and sacrifices.

•  The Greek festival of Cronia 
  On this peculiar holiday in Greek mythology, coinciding with the solstice, social hierarchy was completely forgotten in favour of a day of total festivity. The celebration was meant to emulate the golden age of Kronos, when humans were said to live in peace and did not have to work for their livelihood.

•  The pyramids of Egypt
  On 21 June, at Giza, as the sun sets, the light is framed between the pyramids of Cheops and the pyramid of Chephren in perfect line with the Sphinx. These famous funerary constructions were erected with an almost perfect alignment and with their faces facing the cardinal points; another way of venerating the sun that illuminates us and the great knowledge they had of it.

•  Stonehenge monument 
  This megalithic monument in present-day England is understood to be an ancient site of sun worship and is one of the world's best-known astronomically oriented monuments. The stones forming the semicircle are aligned to mark sunrise and sunset during both solstices. Thus, on 21 June, the sun's rays pass through the megalithic circle and fall directly on the so-called "heel stone".

In today's society, despite the fact that we no longer pay so much attention to nature and its cycles in our daily lives, we still maintain some of these ancient celebrations, many of them renamed and appropriated under the Catholic festival of St. John. Thus, it is customary in many countries to have bonfires on the night of the solstice, for example, as well as to participate in meals, regional dances and various courtship rituals among the young.

Find out, thanks to the collaboration of Iberdrola, on any of the following platforms (audio in Spanish): 

 SpotifyExternal link, opens in new window.,  Apple PodcastExternal link, opens in new window.,  iVooxExternal link, opens in new window.,  Google PódcastEnlace externo, se abre en ventana nueva. and  Amazon MusicExternal link, opens in new window. 

Luis Martín Blázquez, head of Solar Engineering at Iberdrola Renovables, tells us in this special episode of the Mindfacts podcast for the Day of the Sun in what stage of technological development is solar photovoltaic energy at and what we can expect from it for our daily lives in the future.

Photovoltaic solar energy

The energy obtained by converting the sun's rays into electricity, using a technology based on the photoelectric effect, is called photovoltaic solar energy. In the process, certain materials present in solar panels are able to absorb photons (light particles) and release electrons, generating an electric current.

At Iberdrola we are convinced of the important role of solar energy as a tool within everyone's reach that will facilitate and accelerate the energy transition towards a system based on renewable energies and a decarbonised economy.

 SEE INFOGRAPHIC: ADVANTAGES OF PHOTOVOLTAIC SOLAR ENERGYEnlace externo, se abre en ventana nueva. 

This type of renewable energy obtained from the sun has enormous exploitation potential and multiple advantages, such as its storage capacity and its possible scale production according to needs.

• It is inexhaustible, therefore unlimited, and non-polluting, as it does not consume fossil fuels or generate waste. 

• It can be obtained anywhere in the world and is available 365 days a year, without being dependent on any conditioning factor.

• Allows the installation of batteries to store surplus electricity for later use.

• It can be produced in modular installations, ranging from small generators for self-consumption to large photovoltaic plants or solar fields.

• It is an optimal system for rural or isolated areas, where the power lines do not reach or are difficult to install, or for geographical areas where the climate allows many hours of sunshine per year.

• It contributes to the creation of green jobs and to boosting the local economy with cutting-edge projects.

Photovoltaic self-consumption

An increasingly widespread way of harnessing the sun's energy, while becoming more energy self-sufficient, is photovoltaic self-consumption. That is, when individuals or companies consume energy produced by themselves in photovoltaic generation installations close to the point of consumption.

Self-consumption through solar collection is on the rise, both in private homes and neighbourhood communities as well as on farms. This form of consumption not only saves on electricity bills, but also contributes to curbing climate change by using 100 % renewable energies.

Technological advances, lower prices for the elements that make up the installation and the smoothing of administrative procedures are some of the reasons why more and more people are opting for this way of taking advantage of an excellent source of energy that accompanies us every day without us hardly realising it: the sun.