Biogas is one of the most common sources of renewable energy. It can be produced by the anaerobic fermentation of wood or agricultural or urban waste. Coherent management of solid urban waste in landfill sites involves the artificial elimination of the gases that accumulate inside the landfill as a result of the actual fermentation of the waste. There aremany advantages to using the biogas generated in Bilbao from urban waste – it is safe, its production generates a considerable profit, it is clean energy, jobs are created, and it contributes to technological development.
Bilbao, located on the estuary of the River Nervion, with a population of more than 400,000, is the administrative capital of the Spanish province of Vizcaya (Biscay).Since the 1974 crisis, the tertiary sector has taken over from the city's traditional industries. With the creation of the Guggenheim and the new metro, the city's appearance is changing as it takes on a new identity. Weather information: Hours of sunshine per year: XXXX hrs Average yearly temperature: XX°C
Coherent management of Solid Urban Waste (SUW) in landfill sites involves the artificial elimination of the gases that accumulate inside the landfill as a result of the actual fermentation of the waste. Aware of the problem this poses, the Bilbao municipal authorities, in conjunction with the company operating the landfill site ("Fomento de Construcciones y Contratas, S.A."), inearly 1984 devised an ambitious project to assess the possibility of using the biogas generated at the municipal landfill site at Artigas as a source of energy. The project on this started later that year, with the creation of six shafts and the fitting of a flare stack with a view, initially, to flaring the biogas generated. Work also began on studying the volumes and the physical and chemicalcharacteristics of the Artigas biogas. It was not until 1988 that the Bilbao municipal authorities, in conjunction with the Basque energy authority ("Ente Vasco de la Energía" – EVE), considered making industrial use of this biogas, which had until then been flared. A feasibility study was carried out, taking into consideration all the possible uses that could be made of the biogas – sale toindustries close to the landfill site, direct use in a furnace to incinerate hospital waste, direct transformation into electricity, etc; the study reached the conclusion that this last alternative was the most viable in technical and economic terms.
THE BILBAO EXPERIENCE
In order to carry out the project, the Bilbao municipal authorities, inconjunction with the Basque energy authority, decided to set up the company BioArtigas S.A. The company has been entrusted with construction of the site and its operation; its object is to produce energy from the waste, both for external use and for the landfill site's own installations, and to provide third parties with technical advice on producing energy at landfill sites. The installation startedoperation towards the end of 1992. Characteristics of biogas The Biomass Unit of the CIEMAT Institute of Renewable Energies carried out a thorough study in order to collect as much information as possible on the physical and chemical characteristics of the biogas generated at the landfill site. The main concern was to have available full preliminary specific information not only on the calorific orenergy value of the fuel but also on the presence in the biogas of potentially corrosive compounds that could cause irreparable damage to motors. Various analyses were carried out in order to determine both calorific value and levels of methane, VOCs (volatile organic compounds), hydrosulphuric acid and water vapour. These compounds are highly corrosive and their presence in substantial...