The project, located at the Doña Juana Landfill in the Bogotá, Colombia, is one of the largest Clean Development Mechanism projects in Latin America. It involves landfill gas (LFG) capture, flaring, and utilization for energy production on-site or in nearby industries. The landfill is used for the disposal of around 2 million tons of municipal solid waste generated by the 7.3m inhabitants of Bogotá each year.
The landfill gas-to-energy project collects, processes and uses the gas generated at the landfill. In 2007, the Bogota local government awarded a concession to “Biogas Doña Juana S.A. E.S.P.*” to build and operate the project for a period of 23 years plus one month. During the initial steps of the contracting process, the city requested the input of the Clinton Climate Initiative, an aligned partner of the C40 Cities Climate Leadership Group, who later became key supporters of the project. *Source: Personal communication with UAESP. May 2011.
PROGRESS TO DATE
Tests and LFG characterization for the plant design began in 2009. Construction started on the project on September 22, 2009. Infrastructure was completed in 2010.
LFG extraction started in the "newer" areas, Zone VIII and Zone II Area 3 (150 hectares), which contain 16,320,895 and 465,807 tons of waste, respectively. The estimated gas extraction rate from these areas is 13,000 m3/h and 1,100 m3/h respectively. Together this represents 60-70 percent of the total potential gas that can be produced from the landfill.** Extraction will be expanded to Zone VII (40 ha) and to the future zones within the perimeter of the landfill site. **Source: Personal communication with Mr. Sergio Arteaga, field manager of the biogas concession (May 17, 2011).
HOW DOES IT WORK?
Horizontal drains under the garbage piles feed the gas into vertical pipes or “stacks”; vacuums and blowers then force the gas and direct it into a processing plant where it can follow one of two paths:
Path I – The LFG can be flared in a process called “controlled thermal destruction” at an average temperature of 1,000 °C with a 0.3 seconds retention time ensuring methane destruction rates close to 100 percent. Emissions are recorded in real time. The methane content of the LFG is continuously monitored to ensure that it is above 50 percent concentration. If this condition is not fulfilled, the LFG does not enter the plant.
Path II – The LFG can also be used to generate electricity using internal combustion engines. For those, the LFG needs to be cleaned to reduce concentrations of BTEX, NH4, H2S, silicates, etc. The produced electricity is used on-site to power blowers, pumps and other on-site equipment required for final flaring.
The excess LFG can be sold to industries for fuel (coal or fuel oil) replacement. This will become soon a third path.
A permanent monitoring system measures methane destruction rates so that the Clean Development Mechanism verification could take place.
CO2 EMISSIONS REDUCTIONS
The chart below shows the estimated GHG emission reductions over the project life (22 years). The decrease in reductions starting in 2024 reflects the year when LFG coming from areas under extraction will be exhausted and a decommissioning process will take place.
Graphic 1. GHG emission reductions over the project life (22 years). Source: UAESP, 2011.
In total, the project is expected to reduce emissions by 14.8m tons of CO2 equivalent. New waste disposal areas equipped with infrastructure for biogas extraction could increase this figure.
The project has been verified and validated under the Clean Development Mechanism (CDM) and authorization/issuance of Certified Emissions Reductions (CER) credits for 564,233 tons of CO2 equivalent is pending.
The project has been developed by a private consortium under a concession contract; the investment is coming from private loans totaling €13m (US$18.6m), which are expected to be repaid through the revenues obtained from the sale of CERs.
- Expanding the LFG extraction network to achieve extraction rates of 16m3 per hour
- Closing deals with industries to replace coal or fuel oil with LFG
- Evaluate LFG use for the operation of the landfill’s leachate plant
Doña Juana Landfill Gas-to-Energy Project is significantly reducing greenhouse gas emissions from the landfill by flaring LFG, generating electricity for its own consumption and soon selling this fuel to nearby industries.
This project has become a model providing a learning opportunity for other Colombian cities as well as C40 Cities in Latin America and Asia.
Beyond reducing greenhouse gas emissions and being registered as a CDM project, the city will keep more than 24 percent of the CERs and more than 2 percent of the energy sold by the LFG concessionaire during the project life. This income is invested in social projects agreed upon by the communities surrounding the landfill, such as parks, water and wastewater projects, recreation and sports centers. In 2011 investments in these social projects exceeded US$1.2M.
The project also improved the technical operation conditions of the landfill with the following benefits:
- Increased geotechnical stability of the waste mass.
- Reduced LFG and odor emissions
- Development and implementation of new technologies
The project has also had positive effects on:
- Increased support for industrial development in Colombia
- Increased technology know-how and skilled labor
- Improved environmental conditions of the neighboring communities