With low investment, it’s possible to produce almost all energy needed in a household with solar modules. Learn how the solar autonomous energy grid works

Soon, living in a 100% clean renewable energy home won’t be just a dream of environmentalists concerned with the planet’s future. Transition from the conventional electric power supply model, on grid and based on large power plants, is already a reality in some parts of the world. And the best part: in addition to being eco-friendly, the solution is cheaper and ensures power to citizens even during a supply crisis.

One living in a big Brazilian city like São Paulo, for example, may notice the economic benefits from power autonomy since the first moment of use. For a two-story house with four people, installing a photovoltaic solar energy system costs around BRL 15 thousand (US$ 4,000). The impact on electricity bill is immediate: estimation for the first month of use is a reduction by 90%. So, within seven years, the investment would be paid off. And the product’s lifespan is 25 years, at least. After this period, the panels’ production capacity, due to time, declines to 80% of total.

“It’s not an expensive technology, rates are competitive,” says Rodrigo Sauaia, CEO at Absolar (the Brazilian Photovoltaic Solar Energy Association).” From 2010 to date, photovoltaic solar energy cost has become 83% cheaper. Meanwhile, the electric power supply bill went above inflation. Today, generating renewable power is cheaper than buying it,” he completes.

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California: the world’s fifth economy will be 100% clean

California has undertaken two ambitious sustainable commitments. By 2045, all electricity consumed in the American state will come from sources free of greenhouse gas emissions, especially from sustainable matrices such as solar and wind. Last year, Hawaii promised to do the same. In the short-term, from 2020 every 3-floor or higher new house and building will, forcefully, have solar energy modules installed on their rooftops.

A package of measures for generation of green energy in sunny California has been endorsed by politicians and artists such as former USA vice-president Al Gore (Democrat), and the state’s former governor Arnold Schwarzenegger (Republican), and actors Leonardo DiCaprio and Chris Hemsworth, among others. “We have to be a leader. We have to show what can be done. If we can get to 100 percent renewables, others will as well,” said Assemblyman Bill Quirk (Democrats) at the law signature event, sanctioned by governor Jerry Brown (Democrats).

California leaders’ bold decision is likely to inspire other states and countries. California is the fifth largest economy on the planet and the transition from mixed energies (especially fossil fuels) to household solar energy from 2020 should reduce generation of greenhouse gases by 53% – equivalent to 700 thousand tons or 115 thousand fewer fossil fuel-driven cars on the streets.

Energia produzida em casa. Crédito: Riccardo Annandale/Unsplash

In addition to photovoltaic solar systems, new households are required to meet high energy efficiency standards. Among elements listed in the Californian law are the use of building materials and techniques that promote thermal insulation, illumination that takes advantage of natural light and that uses mostly LED technology, as well as air ventilation optimization systems. According to the California Energy Commission (CEC), the cost of a medium-sized household will increase US$ 9.5 thousand, but cost-efficiency estimated is US$ 19 thousand within 30 years. Those on mortgage will pay an extra US$ 40/month, while US$ 80 will be the average discount on the electric power bill.

“With this adoption, the California Energy Commission has struck a fair balance between reducing greenhouse gas emissions while simultaneously limiting increased construction costs,” said Dan Dunmoyer, California Building Industry Association’s president and CEO. “Under these new standards, buildings will perform better than ever and contribute to a reliable grid,” completes Andrew McAllister, CEC Commissioner.

My home, my power plant

No wonder California is known as the sunny state. Sun incidence is so abundant in the state that, according to the Energy Commission, houses installing high-technology sensors may generate more power than they consume. The California state as a whole generates so much solar and wind energy that sometimes production has to be halted or electricity needs to be sold to neighboring states to avoid grid overload.

The following scenario is forming: instead of being a consumer, the average Californian citizen can become a supplier of energy – and earn for that. “This is a very large market expansion for solar,” explained Lynn Jurich, founder of solar installation company Sunrun, in an interview with the New York Times. “It’s very cost effective to do it this way, and customers want it. There’s also this real American sense of freedom of producing electricity on my rooftop,” he completed.

Fontana community, on east Los Angeles, is at the center of this potential energy revolution. There, the American Electric Power Research Institute observes how a society in which energy production and consumption are so well-balanced works. The 20 residences of the community show zero net energy and proved that these practices may work at scale.

The behavior models seen showed that capacity limits of transformers were not exceeded, as there is great oscillation in energy consumption habits, reducing intensity of peaks. Other conclusion drawn from the Fontana experiment is that the option for solar batteries has limitations. According to the report, battery technology has not matured enough to be a cost-efficient solution. The recommendation is to invest in grid distribution and organization – the model that has been expanding around the world.

Self-sufficient energy: independent, but on-grid

Solar autonomous production may be comprised of two models: ‘on-grid’ and ‘off-grid’. The basic difference between both is that on-grid means the house or building is connected to a power distribution grid, and off-grid means the power is stored inside internal batteries.

Today, according to Absolar (Brazilian Photovoltaic Solar Energy Association), a fraction inferior to 1% of photovoltaic solar energy systems operates on battery in Brazil.” The point, whether home or corporate, is connected to the utility grid. When energy production is higher than consumption, this energy is introduced into the grid and goes to the community. When demand is higher than production, the energy available on this grid is used,” explains Rodrigo Sauaia, at Absolar. “Those supplying more than consuming will be awarded with energy credits – and they can’t be exchanged with money [credits are valid up to 60 months],” he added.

Besides direct cost-efficiency seen on the electricity bill, power self-production promotes some independence to power policy oscillations of a country, state or municipality. Variables such as petroleum and natural gas rates and climate changes (drought, for example, may reduce production under hydropower distribution) are less sensitive – and this makes a huge difference for small farmers, especially, those in the fields.

Propriedade rural com energia solar. Crédito: Anggit Rizkianto/Unsplash

A report from Absolar shows that, to date, there are 747 farmers registered as generators of solar electric power. Altogether, they account for 12.2 Megawatts of distributed power, or 5.4% of all installed solar potential in the country. Basically, using all power produced in their properties, these farmers reduced their monthly bills by 95%.

“In Brazil, this scenario is still under development. Distributed generation grew 75% last year, and to date 38 thousand generating units have been registered. However, advances in smart grids are needed, as well as bigger decision-making power, as the expansion of free market and their implementation demand response,” ponders Rui Altieri, president at the Electric Energy Trading Chamber (CCEE) Board of Directors.

Solar power as strategy for economy and sustainability

In the USA, California leads the way regarding energy. In 2017, 16% of all state electricity came from photovoltaic modules. This industry alone accounts for the employment of 86 thousand Californians – more than any other power industry. And this is not just a sector-specific event. According to the Renewable Energy and Jobs annual report, photovoltaic solar energy is the one that most employs in sustainable power-oriented business: 3 million jobs or 25 to 30 workers for each installed MW.

A survey published by Absolar points out that industrial warehouse and storehouse industry in Brazil has an estimated total area of 12 million square meters and that such surface represents an investment potential of BRL 6.8 billion (US$ 1.8 billion) in production of solar power. If half of that amount were applied, 500 thousand residences would be supplied with solar power and 30 thousand new jobs would be generated.

The survey also claims that, with this investment, electricity production would be 1.7 thousand MW/hour a year, which is equivalent to saving BRL 900 million (US$ 242 million) in the country’s power expenditure, and also a reduction of greenhouse gas emissions of 132.7 tons a year. That is, the investment would be paid off in 7.5 years, not to mention the environmental gain.

Pai e filho caminham em estrada de painéis solares. Crédito: Aswin Sreenivas/Unsplash

The leading countries in solar energy installation are Germany, Japan, China and other nations from the European Union. In Brazil, this matrix is growing – in 2017, investments were 18% higher than last year -, but still not enough. The generation installation of photovoltaic solar energy is 1 gigawatt hour and Aneel (National Energy Agency) forecasts 3.2 GW or so by 2024 – Germany has 41 GW installed.

“Great nations are setting goals. It’s important that Brazil keeps up with global trends to become part of that and even turn into a leader, by leveraging its huge energy potential,” says Rodrigo Sauaia. Brazil’s solar incidence is 5.4 kilowatt-hour per square meter, superior to China’s and Germany’s.

A survey conducted by DataSenado states that 85% of the Brazilian population believes the country should invest more in renewables, and 68% agree that the Government should require companies to do the same. “It depends on political will and social engagement. Brazil is in a good position and it’s one of the best places in the world to generate solar, wind, water and biomass energy – when combined, the country is ahead of most. As a nation, we can lead this renovation,” asserts Absolar’s CEO.

Content published in November 28, 2018

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