Feasibility of a Medium Scale Biogas Technology in a Solid Waste Treatment Plant

Transcription

1 Feasibility of a Medium Scale Biogas Technology in a Solid Waste Treatment Plant BioGaSolutions José Andrés Hernández Máximo Fernández Chapter 1: Project description The proposed project will be located in the following area: Country Region Guatemala San Jorge la Laguna is a town of Sololá in the west of Guatemala. The most important hydrographic accident is Lake Atitlán which is one of the main economic sources of the department as well as the town. The lake is a very attractive tourist centre and serves a lot of commercial support. There is no industry in San Jorge la Laguna because its terrain is very small and the surface quite broken. Due to the varied climates, soil types and topography of Sololá, aside from the use that is given to the land to urbanize and build, its inhabitants sow great diversity of annual crops, permanent or semi-permanent, including cereals, vegetables, fruit trees, coffee (legumes and tuber seeds), etc. In addition to the qualities of the department, some of its inhabitants are dedicated to the breeding of various kinds of cattle, such as beef cattle, sheep, horses, goats, etc., devoting part of these lands to the cultivation of various pastures that serve as food to them. The existence of forests, whether natural, integrated management, mixed, etc., composed of various tree species, shrub or creeping give the department a special touch in its ecosystem and environment, converting it in one of the typical places to be inhabited by visitors not only national but also foreigners. It is in this way you get an idea of how in this department the use of land is sometimes exploited intensively and in others in a passive way. Coordinates Latitude: Longitude: Project Type Short description about the socio economy of the region Biogas Medium Technology Implementation San Jorge la Laguna is a mayan-cakchiquel community with an estimated population of 4,226 inhabitants. Since there is no industry and barely arable lands, must of its inhabitants are forced to look for jobs in other lands, in the tourism industry near lake Atitlán or in the construction industry.

2 Since there is no industry in the town the energy consumption is low and limited to the day to day life of the inhabitants. The town has access to electricity, and they use gasoline and diesel for vehicles. For cooking the fuel par excellence is wood. Actually there is a Solid Waste Treatment Plant installed in San Jorge la Laguna which could have a huge potential to generate income for the town through waste management for the area, compost selling and biogas production. This could mean that they would generate income in their town by selling compost for the agriculture activities of the region, generate energy for cooking and offer a service of waste treatment for other communities. Picture No. 1 San Jorge la Laguna location

3 Picture No. 2 Solid Waste Treatment Plant Chapter2: Defining of business model Project The project focuses on evaluating the feasibility of improving the actual process in the solid waste treatment plant, through the installation of a plug-flow digester in one of the 8 aerobic digesters the plant has. Even though they have the plant, the community doesn t have much counselling regarding the process of aerobic or anaerobic digestion. They also focus only in composting the organic waste (primarily food) and don t compost any other of organic waste. By implementing a plug-flow digester, they will be able to produce and capture biogas and use it for they own consumption. The compost and the digested by-products can be used as fertilizers and sold around the region which has high agriculture activity. The town already classify its garbage and separates organic from inorganic waste, which lowers the labour needed in the process. There are several institutions such as AMSCLAE (Autoridad para el Manejo Sustentable de la Cuenca del Lago de Atitlán y su Entorno) and Universities that provide support through donations or know how. The inhabitants show real interest in the subject and are willing to work to obtain a better community, with less contamination and more productivity through recycling.

4 Each composter has estimated dimensions of 5m x 2m x 2m (LxWxH), providing enough space for at least 16 cubic meters with a 20 % safe volume. The plant receives the organic waste in bags, (since the weight depends on the solid that is carried, we will use volume for estimations). The approximated volume of each bag is 0.04 cubic meters, and the plant receives 150 bags each week, equal to 6 cubic meters of organic waste each week. According to the maximum amount of solids that a plug-flow digester can handle (13 % of solids), the amount and the maximum volume the composters can handle, the amount of solids needed to feed the anaerobic digester is 2.08 cubic meters of organic waste. Picture No. 3 Aerobic Composter of the Solid Waste Treatment Plant

5 Chapter3: Cost of the project Calculation of cost The following are the CAPEX and OPEX of the project: CAPEX The following are the estimated CAPEX for the adaptation of an aerobic composter to a plug-flow digester: Description Unit US. $ Conditioning of the project site - $1, Bio filter system 1 $1, External gas storage tank 1 $2, Polyethylene bag 120 m roll $ Plug-flow digester construction and installation - $4, Piping system 15 m $ Biogas Stoves 10 units $ Screen bag for organic compost (estimated for one year of operation and bag recycling) 2,500 units $2, Total CAPEX $12, OPEX Also think about required resources, labour for operation and maintenance, and rent for buildings. In case that you want to take the loan, consider the interest. Description Fixed Costs (salaries) US. $/per year Transportation 0.00 Waste separation 0.00 Processing (minimum wage for 1 person in Guatemala) $4, Distribution 0.00 Variable Costs Maintenance equipment $ Tools $ Total OPEX $4,862.00

6 Total annual costs The CAPEX is only incurred on the first year of the project therefore; Cost incurred in the first year are: CAPEX + OPEX = $17, Cost incurred from the second year onward: OPEX only = $4, Chapter4: Calculation of revenue Revenue of the project Revenue The main income will be the selling of compost. There is an estimate of 3,242 hectares cultivated in Sololá (Macario, 2008), and from every cultivated hectare the average consumption of fertilizer is 5.33 bags of fertilizer. Assuming a coverage of 15 % of the market, will mean sales of 2,500 bags of compost per year. On the other hand, the project will have avoided payments on the purchase of wood for cooking since the biogas will be used for this purpose. The expectations are to sell around 2,500 bags of compost at $3 per bag. That will $7,500 per year. The first year, the project will buy the bags for the compost but the bags are going to be reused and on the next year, a person that wants to buy compost will have to take the reused bag to receive a new one. In Guatemala, it is estimated that 65.8% of the population uses firewood as an energy source. In San Jorge, there are more than 800 families that could benefit from the biogas produced. These families consume around 7, m 3 of wood to cook which they buy at $/m 3. This is equivalent to an avoided payment of around $560 per year. On the next table, we have the total revenue of the project: Total annual revenue Description $/per year Total income for sold compost $7, Savings on purchases of firewood and gas $ Total $ 8,060.

7 Chapter 5: Applying important methods of capital budgeting Calculation of payback period, NPV and IRR Analysis and financial modelling To determine the feasibility of the project, we calculated the NPV, IRR and the return of investment of the project. In the next tables, you can see the calculations made: Cash Flow Assumptions for cash flow Cost per sold of bag of compost ($/Bag) 3 # Bags of compost sold per year 2,500 Annual income for sold compost $7,500 Annual savings on purchases of firewood $560 Project life time 15 years Rate 6.25 Año Año Año Año Año Año Año Año Año Año Año Incomes Annual savings on purchases of firewood $ $ $ $ $ $ $ $ $ $ Expences Annual income for sold compost $7, $7, $7, $7, $7, $7, $7, $7, $7, $7, Initial investment -$12, Operation and maintenance (O&M) Subtotal $0.00 $8, $8, $8, $8, $8, $8, $8, $8, $8, $8, $4, $4, $4, $4, $4, $4, $4, $4, $4, $4, $4, Seguro $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 Administración y otros $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 Costos de distribución de energía (peajes) $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 Subtotal -$17, $4, $4, $4, $4, $4, $4, $4, $4, $4, $4, Net cash flow -$17, $3, $3, $3, $3, $3, $3, $3, $3, $3, $3,198.00

8 USD Projection on 15 years $30, $20, $10, $0.00 -$10, $20, Year With the calculations, we can see the following results: Results NPV $ IRR 12.70% ROI (years) 5.5 With a payback time of 5.5 years, a NPV of $511 and an IRR of 12.7%, we can see that the project is feasible.

9 Chapter 6: Summary Project and business model summary The proposed plug-flow digester can be adapted to an actual composter of the San Jorge la Laguna Solid Waste Treatment Plant, allowing the inhabitants of the community to improve their compost production by implementing a continuous process and benefit from the biogas production for cooking. Lowering significantly the consumption of wood for cooking. The main waste treated in the community is organic waste, mainly food scraps. By implementing the anaerobic digester, they could even start treating their waste water. One of the main incomes of the process would be the organic fertilizer produced as a by-product of the digestion process. The proposed system would be adapted to one of the aerobic composters. Will manage a 6.83 m 3 /day of waste, generating m 3 /day of biogas. Providing the inhabitants of San Jorge la Laguna, an alternative to wood. After a thorough analysis we conclude that the project is feasible and that many people of the community can benefit from it. The use of biogas instead of wood will improve life quality of the people in San Jorge as well of selling high quality compost for the community.