Solar panels at home: how they work, how much they cost to install and how much you save on electricity per year

It may seem strange in these days of paper-colored skies, but the reality is that behind this sheet that covers and cools the horizon is, about 150 million kilometers away, a star whose light travels this distance in 8 minutes and 20 seconds. It’s called the sun.

This luminosity, in addition to allowing the existence of practically all forms of life on our planet – as well as the fact that you can show a fascinating tan in summer -, also serves to produce what is called solar energy. .

A more or less simple definition would say that the radiation, light and heat coming from the sun are exploited by a series of technologies to generate electrical energy. But that’s not the only thing: that is, when you hang your clothes and let them dry in the sun, strictly speaking, you are also using solar energy.

It may sound very modern, and it certainly is on a massive, domestic level, but as early as 400 BC, the Greeks were making their windows out of glass to trap sunlight in their homes. In addition, they built greenhouses to capture heat and allow the growth of exotic plants or seeds.

This being the case and knowing the water crisis from which there seems to be little return, it is not a bad idea to start investigating the options available to adopt this type of energy in the home. This is not a minor investment, but in addition to bringing medium-term economic benefits —such as a considerable reduction in the electricity bill—the immediate gain is the reduction of our environmental impact. Something that, in times as apocalyptic as these, is no small thing.

Tomás Steinacker, founding partner and commercial director of the photovoltaic energy company city ​​light enthusiastically explains that, according to information from the Global photovoltaic potential According to the World Bank, the northern and central-northern zone of Chile has the maximum values ​​of solar resources and photovoltaic energy potential on the planet.

Miguel Valenzuela, technical director of THREE60 clarifies and warns that although there the conditions for solar energy are indeed optimal, “this is not the case in the south, where the conditions are less favorable due to the latitude and the cloudiness that exist in this territory”.

“In summary”, he says, “the solar radiation conditions do not correspond to the country but to the geographical area where one lives”.

But just as we must apply sunscreen even on cloudy days – because the radiation always reaches our skin – Raul Arce, chief engineer of the project of the solar panel company lifeenergy assures that currently the solar panels “deliver yields that allow to obtain excellent results, even in sectors as remote or “little sunny” as Patagonia, which was unthinkable a few years ago”.

A fact stands out: “Cities in southern Chile such as Valdivia, Puerto Montt or Puerto Varas have a higher average solar radiation than leading cities in terms of photovoltaic solar energy, such as Frankfurt, in Germany, or Amsterdam, in the Netherlands. Down “. Steinacker says Ciudad Luz has developed projects “from Arica to Los Lagos, so we can safely say that most of Chile is suitable for exploiting this technology.”

Is it possible today to consider having a house running entirely on solar energy? According to Valenzuela, with “a well-dimensioned system, considering the geographical area where the house is located and its consumption, I do not see any problem in making it feasible”. However, he believes the best option for now is to consider “a hybrid system, which uses solar power when available and, when it runs out, turns to power from the common electric grid. “.

But Arce assures that current solar technology can supply 100% of the energy consumed by any home, regardless of its size or energy demand. “We are talking about lighting, heating, domestic hot water and any additional equipment for common use. In addition, the different solar technologies provide access to a quality power supply where the common electrical service does not reach or where the cost of implementation is more expensive than that of a solar system.

“For places that already have a connection to the utility grid, it makes much more sense to think about photovoltaic systems working as a supplement,” Steinacker says. “This is achieved through the use of grid-connected equipment – connected to the traditional grid – and the Net Metering Act or Citizen Generation Act, which allows everyone to produce their own energy in a clean and safe on the roof of her house. Houses”.

And what happens if, between that which arrives through the poles and that which is generated on the roof, I find myself with a surplus of energy? When this hybrid system produces more electricity than needed, it can be “sold” to distributors. “These injections are generally seen as discounts to the next month’s account, which reduce the charges generated in months with less sunshine.”

He assures that Ciudad Luz is already developing several subdivision projects that directly consider not having an electricity grid and being powered only by solar energy. “For people who cannot connect to the electricity grid, so-called off-grid systems are installed, which include batteries where energy is stored.”

Maria Luisa del Campo is a researcher and director of Kipus, a technology center of the Faculty of Engineering of the University of Talca specialized in energy efficiency.

From there, it analyzes the advantages and disadvantages of implementing solar energy as a medium in the home. “The biggest benefit is the environmental contribution, as it uses renewable energy and a free and generous resource in many parts of our country.”

“Another advantage, he explains, is that it requires very little maintenance: all you have to do is clean the panels with water to optimize solar capture.

For Miguel Valenzuela, the positive point of this sustainable energy is that once implemented “it has a low maintenance cost and is respectful of the environment”. Arce also highlights the reduction of energy costs, obtaining autonomy and access to electricity in places where the normal supply does not arrive or it is very expensive to rent it. But the main thing seems to him to be the “significant contribution to the environment through the reduction of the carbon footprint of the energy we use, which allows users to actively contribute to the mitigation of climate change”.

Now the stupid part: the cons. Valenzuela begins by acknowledging that “these systems require a high initial investment and may require a lot of space to implement if the energy demand is high”. Depending on the area and the energy demand, he launches as a reference that “an average system can oscillate between 5 and 7 million pesos”.

Arce seconded him. “For the reduction of a ballot of about 50,000 pesos, the investment can be about 4 million pesos, which in many cases represents an unattractive return.” However, he clarifies, “there are different types of financing aimed at reducing or amortizing the initial investment, allowing the same savings generated to pay part or all of the loan”.

Researcher Del Campo takes her calculator, does the math and shows. Depending on the consumption and the type of house, the installation of a solar panel system “would save between 300 and 550,000 pesos per year, so the investment is recovered in about 10 years”.

Steinacker gets serious. He assures that from a financial point of view, “the panels are an excellent investment, which pays for itself between 5 and 10 years and lasts around 25 years”.

She recognizes, yes, that this level of investment “is a brake on the massification of these systems, since everyone cannot invest 4 million pesos”.

So he pulls an ace up his sleeve. ‘In Ciudad Luz we offer an alternative with our model’No initial investment ”. From the savings that the photovoltaic system generates on the cost of electricity, we charge a monthly fee, which is calculated to be lower than these savings. Thus, and without investing a lot up front, people reduce their monthly electricity consumption by up to 30% and also get clean energy”.

You’ve done the math, and after weighing the pros and cons, you come up with the idea of ​​turning your house into a solar-powered one. And now what?

Attention, because the list of Miguel Valenzuela, of Tres60, is a little long. “The first thing is to determine the energy expenditure required by the house and the autonomy time required by the battery bank. Then, you have to size the solar system that will be needed, the installed power that it must have and the capacity of the battery bank. And then evaluate the implementation with an authorized installer and process the authorization of the certificate issued by the Superintendence of Electricity and Fuels (SEC)”.

But it is not strictly necessary that you take care of all this yourself. Enerlife’s project manager, Raul Arce, says it’s best to seek advice from a company experienced in the industry and able to provide warranty and lifespan for installed equipment. “These are facilities that should be in operation for the next 25 to 30 years, so this point is crucial,” he said.

In Ciudad Luz, the procedure is as follows: “The first thing is to have an up-to-date copy of the electricity account. With it, the monthly consumption, the connected power of the domestic connection and the subscribed tariff will be checked. With this data you can enter to our website the team to propose an ideal equipment. Then, in the field, the feasibility of the installation is checked. Where possible, initial engineering, in-house installation, and filing with the SEC and distribution company are performed. Once the flow is finished, the start-up of the photovoltaic system is carried out and, if agreed, the subsequent maintenance of the installation,” explains Steinacker.

Raul Arce says it is essential to require the installation company to have a service contract that includes clear responsibilities and deadlines, with guarantees, implementation dates and after-sales service deadlines. “This step will definitely help ensure a successful return on your investment,” he notes.

The other option, much simpler and cheaper, and a good starting point to get to know the subject, is the one offered by Valenzuela. “Acquire one of the solar power kits sold on the market , which are already sized to deliver a previously defined installed power. In this case, it will be enough to calculate the necessary consumption and buy the kit”.

The third way is to just keep hanging clothes on the clothesline and be content with whatever fancy idea you do. sun drying .