|Written by Isaura Daniel|
|Wednesday, 15 July 2009 05:51|
Brazilian merchant Lizete Araújo da Silva, 51, has worked for approximately ten years in a variety store in Perus, one of the farthest neighborhoods from the center of the city of São Paulo. She commutes from the adjoining city of Franco da Rocha and, since 2003, the air as she comes off the bus, Perus, is better for breathing.
The reason is that nearby, large volumes of methane and carbon dioxide have ceased to be emitted into the air and now have a nobler purpose: generating energy.
The Perus neighborhood houses one of the projects for generating energy from waste in São Paulo. The site was not chosen at random. There used to be an active landfill named Bandeirantes operating there. Now, the landfill no longer receives trash, but the material that was disposed of at the site for approximately thirty years, now in decomposition, produces the gas needed for electric energy production.
In the past, it used to go into Lizete's lungs, and into the lungs of other men and women who live nearby, making the air of those living nearer the site foul, and collaborating to destroy the ozone layer.
In addition to the Bandeirantes landfill, São Paulo also generates energy from waste at another landfill, named São João and located in the São Mateus neighborhood. Together, they enabled the São Paulo City Hall, which is in charge of the projects, to reduce its emissions of environmentally harmful gases by 20%, and to make money as well.
The initiative results in carbon credits that have already been traded at two auctions, in 2007 and 2008, generating 71 million Brazilian reais (US$ 35.6 million). The funds are used in projects for the communities that live in the surroundings of the landfills.
The Bandeirantes landfill is Latin America's largest in terms of household residue, with an area of 1.4 million square meters, and the piping in its power plant receives 150,000 normal cubic meters of gas per day, according to information supplied by Biogás, the company in charge of energy generation.
Counting in the São João landfill, whose plant is also managed by Biogás, the project answers to 59% of carbon credits traded worldwide from waste energy generation.
Biogás took over the Bandeirantes landfill in 2003, and of São João in 2006. Half the carbon credits obtained belongs to the city hall, and the other half belongs to Biogás. All of the electric power, in turn, is Biogás'. As a result of an agreement signed early on between Biogás and the Unibanco bank, the electric power - 20 megawatts per hour - is used at the banking institution's branches.
As a matter of fact, what the bank does, explains Antonio Carlos Delbin, technical director at Biogás, is transfer all of the energy to the grid of the National Electric Energy Agency (Aneel) in exchange for its electricity bills.
Delbin says that 4.5 million carbon credits have already been captured. Seemingly, it is all very simple. Suction pipes are installed at the landfill, and the gas goes through them and into the plant, where it works as an engine for generating energy.
That, however, requires investment that is not always profitable. So much so that the São Paulo City Hall has designed energy generation projects for four other landfills. Only two of them received proposals from companies interested in operating the plants.
If a landfill is too far removed from the energy grid, explains Delbin, then investment in gas transport is not worthwhile. At the Bandeirantes landfill, for instance, Biogás invested from 3 to 4 million reais (US$ 1.5 to US$ 2 million) for that. At São João, investment totaled 30 million reais (US$ 15 million).
The cost-to-benefit ratio is pointed out as one of the reasons for the small number of initiatives for generating energy from waste in the country. The technical director claims that each individual landfill must be assessed to determine if applying for carbon credits and generating electric energy is worthwhile.
This type of project is in fact criticized by environmentalists and energy industry professionals. Holding a doctorate in Science from the University of São Paulo (USP), Sabetai Calderoni, whose environmental studies are known worldwide, believes that this is not the best solution for waste, and that in a best-case scenario landfills would not be made.
Calderoni, however, claims that for landfills that already exist, it is a good measure. "Methane gas is twenty times more pollutant than carbon dioxide," says the Doctor.
In Calderoni's opinion, the best thing would be to have the waste sorted. Afterwards, materials that cannot be reused and have heat-generating power, such as construction waste and wood, would be placed into gasification equipment to then generate energy.
Different from the landfill, which has a short lifespan in terms of energy generation - it is capable of generating energy for 15 to 20 years after it stops receiving waste -, this other type of initiative can be permanent, which makes it economically more interesting as well.
As long as projects along those lines are not a reality, however, generating light and carbon credits from waste is one of the initiatives in the environmental field that earn praise worldwide. The municipality of São Paulo received international acclaim for its landfills-energy factories.
The projects were presented at the summit of the C40, a group of the world's largest cities turned to finding ways for a more sustainable planet, held in Seoul in May. As a result of the environmental work, São Paulo may host the C40 summit in 2011.
"Cities and urban settings answer to 75% of carbon dioxide emissions," says the joint secretary of Foreign Relations of the São Paulo City Hall, Flávio Goldman. He recalls, though, that the solutions to environmental issues are also in the cities, by means of policies for urban management, residue management, rational energy use, and incentive to collective transport, among others.
With a mayor (Gilberto Kassab) who is concerned with the environmental issue, the city of São Paulo has implemented a series of actions in recent years, such as the 100 Parques (100 Parks) program, by which the municipality, which now has 58 parks, should have 100 parks by 2012.
Another such initiative is the Projeto Solar (Solar Project), which makes it mandatory to install water heating systems using solar energy in new buildings, and vehicle inspection, which measures emissions by automobiles, among others. The city has also created a set of municipal laws regarding the environment.