Edited sentence: About 98 percent of the Porto Alegre's residents are connected to the power grid.Brazilian investment group Central Termoeletrica Sul (CTSul) has plans to invest US$698 million in a 650MW coal-fired power generation plant in Cachoeira do Sul, located in Rio Grande do Sul.In 1999, a natural gas pipeline from Bolivia to Brazil was completed, with its terminus in Porto Alegre.In Brazil there are also a few coal-fired plants, fuel-oil fired plants and one nuclear facility.Increased utilization of natural gas and other sources is planned in order to reduce Brazil's overdependence on hydroelectric power.Infiltration into the soil is prevented by the double-walled construction of a clay layer and a high-density polythene geo-membrane, the lowering of the water table and the draining off and treatment of any effluent.Once sorted, the waste is compressed and baled up to be sold as raw material to recycling factories.Organic waste is used to generate thermal energy and to make compost.Porto Alegre was one of the first cities in Brazil to develop a recycling program and has been acknowledged as having the best management practices in the country.Since 1990, household waste already separated by residents has been collected in all neighbourhoods on a weekly basis.Since 1997, all non-recyclable waste has been disposed of in landfill sites.The city produces about 900 tonnes of household waste per day.The forecast is that energy generation will begin at the beginning of 2007.The largest wind energy park in Brazil, which is being built east of Porto Alegre in Osório, will add 150 megawatts (MW) to the Brazilian energy matrix.The production represents 5 percent of the energy consumed in the state of Rio Grande do Sul and would be sufficient to meet two-thirds of Porto Alegre's energy demands.The project is part of the Alternative Energy Sources Program (Proinfa) from state-owned Eletrobrás, which will purchase the energy produced for the next 20 years.The units are managed by autonomous cooperatives with directors elected every two years.The vast majority of the city's power comes from hydroelectric sources, at 94 percent of grid output.Waste is sorted in recycling units, which are large sheds containing crates for the unsorted waste and benches for manual sorting