The cable-stayed bridge of Hortolandia, a symbol of the modernization of this southern Brazilian city, alongside tall buildings and the city’s extensive tree cover, which has made it a model of sustainable urban development. Credit: Mario Osava / IPS

By Mario Osava
HORTOLANDIA, Brazil , Feb 26 2025 (IPS)

Almost everything seems new or under construction in the southern Brazilian city of Hortolandia, from its wide avenues and cable-stayed bridge to its large buildings and riverside parks.

Even the city hall itself, the Palace of Migrants, will celebrate its first anniversary on May 29, and its main parking lot is still under construction, but already bears the city’s new hallmark: solar panels on its roofs.

A municipality of 240,000 people located 110 kilometers from São Paulo, Hortolandia seized the opportunity presented by cost-effective technology and legal incentives to generate its own electricity for public sector consumption.“We want to grow, but also preserve. The city must care for its environment, seek new ways to think about energy, water, and consumption”: Donizete Faria.

The 21 photovoltaic plants built since 2023, some in the final stages of completion, will save 80% of the city hall’s electricity costs, according to Fernanda Candido de Oliveira, director of the Lighting Department of the municipal Public Works Board.

The remaining 20% will be covered by the energy efficiency program, which began earlier and has already replaced all old urban lighting with LED lamps. In this way, the city will become self-sufficient in electricity, limiting expenses in this area to distribution network usage fees and maintenance costs.

In addition to the 26,500 public lighting points, the self-generation system will power 200 municipal service locations, saving approximately 4.5 million reais (US$ 800,000) annually, which will be reinvested in various sectors of local administration.

Fourteen schools, four health units and a sports stadium have their roofs covered with solar panels. In total, 5,000 panels are already generating energy, and others already installed will soon begin operation.

The city hall will house three photovoltaic plants, one on its roof and two in its parking lots, one of which is still under construction. In total, it will have 1,800 panels.

The plant for the new social events center, which is nearing completion, will have 1,568 solar panels already visible from the cable-stayed bridge, whose two parallel decks of aerial cables are suspended by three horizontal connecting columns, a structure that symbolizes Hortolandia’s modernization.

The parking lot of the Hortolandia city hall, still under construction, features photovoltaic panels on its roofs, one of the 21 solar plants that will generate 80% of the electricity consumed in the 200 municipal offices and public lighting systems. Credit: Mario Osava / IPS

Economy and Environment
The primary goal of the program is economic, saving resources for other areas, but it also benefits the population, Oliveira noted. “The energy efficiency of LED lamps allowed us to grant a 10% reduction in residents’ electricity bills,” she explained.

“We were the ugly duckling of the Campinas metropolitan region,” which includes 20 municipalities and a total of 3.5 million inhabitants, but “now we are a unique case in these innovations,” a reference point, she proudly stated.

“Solar energy hit the mark, an extraordinary achievement,” said Dirson Pereira da Silva, the receptionist at the Santa Clara Ecological Park, which features a lagoon at its center.

After 36 years living in a city that “buried all its streams,” Araraquara, 170 kilometers away, he returned to his hometown and his passion for the lagoon in 2023.

The seven parks in Hortolandia, most of them designed to protect watercourses, confirm its environmental vocation, which also underpins its commitment to solar energy.

The municipality has identified over 50 springs and strives to conserve or restore them as needed, according to Eduardo Marchetti, Secretary of Urban Planning and Strategic Management. This requires maintaining or expanding riparian forests.

Hortolandia is a “tree city” recognized in 2023 by the international Arbor Day Foundation, a nonprofit organization based in Washington that seeks to reforest the world.

An ecological park around the Santa Clara lagoon, where residents and students stroll and visit the Environmental Observatory, an important center for nature preservation located in Hortolandia. Credit: Mario Osava / IPS

Trees Against Floods

The city used to suffer from floods caused by the overflowing of the Jacuba stream, with frequent losses for riverside residents and businesses. This was overcome by building four reservoirs and caring for the springs and riparian forests, recalled Marchetti, who has lived in the municipality since birth.

Trees are also a requirement for financing from international banks. For example, to build the cable-stayed bridge, the Development Bank of Latin America and the Caribbean (CAF) required the planting of 120,000 trees as a condition for its soft loan.

“Maintaining green parks has its costs. We lost 30,000 trees due to lack of care, such as removing weeds that take their nutrients,” Marchetti noted.

Hortolândia was founded in 1991 after separating from Sumaré, a municipality of 280,000 inhabitants. Its territory is small, covering 62.4 square kilometers.

“In the 1970s, we were a rural area that received many industries, especially in the 1980s. This led to a population explosion, accompanied by high violence, reaching 102 murders per 100,000 inhabitants,” recalled Josemil Rodrigues, a journalist who advises Mayor José Nazareno Gomes.

Fernanda Candido de Oliveira, director of public lighting, with the engineer and systems analyst who control the electricity generation system of Hortolandia’s city hall. Credit: Mario Osava / IPS

Planning for Transformation
The development of the new city received a significant boost starting in 2005 under Mayor Angelo Perugini, “a visionary” to his supporters.

In 2005, sewage coverage was limited to 2% of wastewater; now it reaches 98%, with 100% treatment. Only 40% of the streets were paved; now 99% are, and homicides have dropped to 13 per 100,000 inhabitants, according to data provided by the journalist.

“Long-term planning was key. Hortolandia’s vocation is to be a smart and sustainable city,” he stated. Solar energy is part of this goal and has made the city a national reference, Rodrigues emphasized.

The photovoltaic panels are a logical consequence of the environmental vision of the city’s leaders. The current mayor, Gomes, was the Environment Secretary under his predecessor, Perugini, who was elected four times starting in 2005 and died of COVID-19 in 2021, at the beginning of a new municipal term.

Additionally, environmental education is a priority in the “political-pedagogical project” of all municipal schools, observed Donizete Faria, director of the Department of Pedagogy and Continuing Education at the Education Secretariat.

Eduardo Marchetti, Secretary of Urban Planning and Strategic Management of Hortolandia, where seven ecological parks and forests protect the southern Brazilian city from floods and improve local quality of life. Credit: Mario Osava / IPS

Solar energy is too recent to assess its impact on education, but energy efficiency has been a permanent topic in schools for many years, including through visits to ecological parks and the Environmental Observatory, a specialized center located in Santa Clara Park.

The fact that 14 schools have solar plants on their roofs will help “children take ownership of the photovoltaic panels, see them, and have hands-on lessons about renewable energy and consumption,” Faria hopes.

“We want to grow, but also preserve. The city must care for its environment, seek new ways to think about energy, water, and consumption,” he concluded.

The operation and maintenance of the photovoltaic network installed in the city cost little. Systems analyst Alessandro Alves monitors everything from his computer connected to all the plants, and electrical engineer Renan Queiroz intervenes if repairs are needed.

Since the plants have a guaranteed lifespan of 25 years and the inverters last 10 years, there will be no pressing concerns, such as equipment disposal or recycling, for many years, Queiroz reassured.

Hortolandia’s urban master plan has an environmental focus, due to flooding and the need to manage water resources, Marchetti explained. Water reuse, green roofs, and solar energy are part of the tax incentives for property owners.

The new plan, already approved, maintains the focus on the environment but adds technological innovations. “We are a technological city,” with several IT and pharmaceutical companies, concluded the Secretary of Urban Planning.

In Egypt, some families are turning to bio-gas digesters that convert organic waste into methane for fuel. Credit: Cam McGrath/IPS

By Cam McGrath
CAIRO, Jun 12 2013 (IPS)

The bio-gas digester on the roof of Hussein Farag’s apartment in one of Cairo’s poorest districts provides a daily supply of cooking gas produced from the kitchen waste his family would otherwise discard in plastic bags or empty into the clogged sewer below his building.

Constructed of two large plastic tubs and mostly recycled materials, the zero-emissions bio-gas unit saves his family about LE 20 (three U.S. dollars) a month in gas bills. And in the ramshackle Darb El-Ahmar district where Farag lives, that works out to nearly a day’s wage.

Farag’s bio-gas digester converts organic waste fed into its 1,000-litre plastic tank into methane gas that can be used to heat water or cook food. Ordinary kitchen waste – everything from food scraps, to stale tea and mouldy bread – is soaked overnight in water to soften, then poured into the tank’s bacteria-rich soup to decompose. A pipe carries the methane gas produced to the family’s kitchen stove.

“I just empty my kitchen waste into it, but anything organic will work as feedstock,” Farag told IPS.

The digester produces about two hours of gas a day in the summer, and slightly less in the cooler winter months, according to Farag. Every week he drains a few litres of dark effluent from the tank.

“I bottle the residue and sell it as organic fertiliser to garden shops,” he explains.

Farag says the unit, which he built for less than LE 1,000 in 2008 (180 U.S. dollars at the time), requires virtually no maintenance, as it has no mechanical parts.

“Egypt needs a system like this, because there is a lot more organic waste now that all the pigs are gone,” he says, referring to the nation-wide pig cull that the Egyptian government carried out in April 2009 in a knee-jerk reaction to the swine flu pandemic."Most families produce enough kitchen waste each day to produce enough gas to meet all their cooking and water needs."
--Hanna Fathy

Pigs were the linchpin of Cairo’s traditional waste management system, consuming up to a third of the 20 tonnes of daily waste produced by the city’s 18 million residents. Without them, the volume of “wet” waste has swollen, clogging sewers and landfills and piling high in city streets and empty lots.

The rotting heaps of organic rubbish attract flies and rats, creating vectors for disease.

Farag says initial support and funding for building bio-gas digesters came from Solar CITIES, a non-profit initiative to develop sustainable energy solutions for low-income families. The non-governmental organisation (NGO) helped build more than half a dozen bio-gas units in Cairo, as well as rudimentary solar water heaters constructed from local recycled materials, before its funding dried up.

In Manshiyet Nasr, another low-income Cairo district, Solar CITIES coordinator Hanna Fathy constructed his own bio-gas digester in 2009. He has since travelled extensively instructing residents of poor and off-grid communities on how to achieve energy independence through home bio-gas production.

“Most families produce enough kitchen waste each day to produce enough gas to meet all their cooking and water needs,” Fathy says.

Fathy, currently working on environmental projects outside Egypt, says the government’s energy subsidies discourage Egyptians from investing in sustainable energy solutions. Recovering the initial capital cost of a bio-gas digester can take up to ten years but would take just one year if subsidies were dropped.

“The government doesn’t provide incentives for families to switch to clean energy, so they stick with the cheapest short-term solution, which is to buy gas cylinders,” Fathy told IPS in an earlier interview.

More than 12 million Egyptian households rely on butane cylinders, which retail for LE 8 (1.15 dollars). The tanks last about two weeks and are not without problems.

Apart from the enormous burden the heavily subsidised gas cylinders put on the economy, shortages of imported butane have resulted in long queues at distribution outlets. Disputes over cylinders have even led to fatalities.

The poorly maintained gas cylinders also have an alarming tendency to explode, resulting in catastrophic kitchen fires and injuries.

Electrician Mohamed Rageb, whose wife was severely burned when the gas cylinder she was cooking with exploded in 2010, says the accident pushed him to consider switching to a bio-gas digester. Using a design he found on the Internet he plans to build a compact unit on his balcony.

“I think they are safer, and save time [spent queuing for gas cylinders],” he says.

While instalment plans are available for purchasing energy-consuming kitchen appliances and air conditioners, no credit facilities exist for families switching to green energy bio-gas. Rageb must borrow the full amount to buy the parts for his homemade digester. It could take years to recover the costs, but he is confident his gas bill savings will grow as Egypt’s cash-strapped government phases out energy subsidies.

“Without subsidies, a gas cylinder would cost about LE 100 (14 dollars) to fill,” he points out.

Rageb maintains that if the government would subsidise clean energy technologies instead of unsustainable conventional energy use, price-conscious low-income Egyptians would be the first to make the switch.