ASSESSMENT REPORT. Dhapa Disposal Site Kolkata, India

Transcription

1 ASSESSMENT REPORT Dhapa Disposal Site Kolkata, India Prepared for: Kolkata Municipal Corporation Prepared under the support of: U. S. Environmental Protection Agency Landfill Methane Outreach Program Prepared by: File No April 2010

2 Table of Contents Section Page 1.0 Executive Summary Introduction Purpose of the Assessment Report Data Sources Project Limitations Site Description Waste Disposal Information...4 Annual Waste Disposal Rates...4 Waste Composition Data Landfill Gas Generation and Recovery Projections Background on the SCS International LFG Model Effects of Site Conditions on LFG Generation and Recovery Site Remediation Activities Model Parameters...10 Model k Values...10 Methane Correction Factor...10 Model Lo Values...10 Collection Efficiency Model Results Landfill Gas Project Options Electricity Generation Direct Use Flaring Only and Emissions Trading Other Issues LFG Rights Security and Scavangers Recommendations Site Management Project Implementation Conclusions...20 List of Figures No. Page Figure 1. Leachate Ponding at Dhapa Disposal Site... 4 Figure 2. Waste Pickers at Dhapa Disposal Site... 4 Figure 3. Composting Plant...14 Figure 4. Composting Equipment...14 i

3 List of Tables No. Page Table 1. Waste Disposal Estimates Dhapa Disposal Site... 5 Table 2. Waste Composition Data Dhapa Disposal Site... 7 Attachment A Dhapa Waste Disposal Site Attachment B - LFG Model Results List of Attachments ii

4 ASSESSMENT REPORT DHAPA LANDFILL, KOLKATA INDIA 1.0 EXECUTIVE SUMMARY This assessment report for a landfill gas (LFG) utilization or flaring only project has been prepared by SCS Engineers (SCS) for the Dhapa Disposal Site in Kolkata, India. The assessment was prepared based on the information provided by the Kolkata Municipal Corporation (KMC) and observations made during a site visit on October 20, The disposal site has served the City of Kolkata as an uncontrolled dumping ground since Based on site volume and waste density estimates, the site is estimated to have received approximately 7 million metric tonnes (Mg) of municipal solid waste (MSW) as of the time of the site visit in October 2009, and has the capacity to receive another 4 million Mg of waste, for a total of 11 million Mg at closure. This future capacity estimate assumes a 10 hectare (ha) expansion occurs and that all disposal areas reach maximum height of 40 m (10 m above October 2009 levels). Based on 2009 disposal rates (3,500 Mg per day) and an assumed growth rate of two percent, the site will be full by late At that time, either a new landfill site will need to be ready for use, or disposal will need to continue outside of current disposal area boundaries and/or above reported maximum height limits. Areas of the site targeted for installing LFG collection wells will require closure and remediation prior to development. Site remediation activities are already planned for the 8.1 ha Western Mound, starting in Remediation is assumed to be completed in the Western Mound in 2011 to allow LFG project start-up in that disposal area in Remediation is also assumed to occur in the remaining disposal areas to allow the project to collect LFG from the 13.3 ha Eastern Mound by 2013 and the 10 ha Expansion Area by Because site remediation activities are expected to include grading and slope reduction, additional disposal areas will need to be acquired to accommodate expansion of the waste footprint,. An LFG generation and recovery model was prepared based on the estimated waste disposal rates, waste composition, climate, site conditions, and estimated achievable collection efficiencies. The model assumes site closure occurs in late 2012, followed by completion of site remediation activities for the entire disposal site, and projects that an LFG project could yield a total of about 771,000 Mg of CO 2 -equivalent emission reduction credits (CERs) over a 10-year period ( ). Based on the projected quantities of recoverable LFG and a review of available project options, this assessment report indicates that the Dhapa Disposal Site could be a candidate for an LFG utilization project. A more in-depth analysis would be required to evaluate the economic feasibility of various project options presented in this assessment report. 1

5 2.0 INTRODUCTION This assessment report for the Dhapa Disposal Site has been prepared by SCS Engineers (SCS) for the U. S. EPA s Landfill Methane Outreach Program (LMOP), as part of the Methane-to- Markets Program, an international initiative to help partner countries reduce global methane emissions in order to enhance economic growth, strengthen energy security, improve air quality, improve industrial safety, and reduce emissions of greenhouse gases. 2.1 PURPOSE OF THE ASSESSMENT REPORT The overall purpose of the Dhapa Disposal Site Assessment Report is to perform an assessment of potential LFG recovery rates and a preliminary evaluation of options for the utilization of the LFG. This overall purpose is achieved through the pursuit of the following objectives: Summarize and evaluate available information on the disposal site, including its physical characteristics, site management, and waste disposal data. Evaluate technical considerations for LFG project development, including estimates of the amount of recoverable LFG over the project period. Examine available LFG utilization options, including electricity generation, direct use, and flaring only projects. 2.2 DATA SOURCES The following information which was used in the preparation of this report was (1) based on observations by SCS personnel during the site visit performed on October 20, 2009; (2) provided by Mr. Arun Sarkar, Principal Chief Engineer of the Kolkata Municipal Corporation (KMC) during a meeting on the day of the site visit; (3) provided in a data profile form completed by Dr. Suneel Pandey of KMC; or (4) provided by KMC via (sent April 10, 2010 by Arpita Chatterjee to P.U. Asnani). Estimated site opening date (1981). The size of the areas used for disposal, including a proposed expansion area. Estimated maximum current waste depths. Average waste disposal rates in 2008 and 2009 based on scalehouse data. Waste composition data. Estimate of height to be added to the existing waste mounds. Assertion that the West Bengal Pollution Control Board plans to remediate the western portion of the site ( Western Mound ). Assertion that site closure will not occur before a new site for an engineered landfill is acquired and available for use. 2

6 2.3 PROJECT LIMITATIONS The information and estimates contained within this assessment report are based on the data provided by the Kolkata Municipal Corporation (KMC). Neither the U.S. EPA nor its contractors can take responsibility for the accuracy of this data. Measurements, assessments, and projections presented in this report are based on the data and physical conditions of the landfill observed at the time of the site visit. No warranty, express or implied, is made as to the professional opinions presented herein. Changes in the property use and conditions (for example: variations in rainfall, water levels, site operations, final cover systems, or other factors) may affect future gas recovery at the disposal site. The U.S. EPA and SCS Engineers do not guarantee the quantity or the quality of the available landfill gas. 3.0 SITE DESCRIPTION The Dhapa Disposal Site is located in Kolkata, India in the state of West Bengal. The climate in Kolkata is tropical and rainy. The 24-hour average temperature is 26.6 degrees C (79.9 degrees F). Average annual precipitation in Kolkata is 1,625 mm (64 inches), of which over 95 percent falls in the monsoon months of June through September. 1 The Dhapa Disposal Site is owned by the KMC. The disposal site has been operating as an open dump serving the City of Kolkata (estimated 2009 population of 5 million 2 ) since The site currently accepts waste from both KMC s public waste haulers and private haulers. Little or no soil cover has been applied historically, and waste is deposited in an uncontrolled manner that has resulted in steep, unstable slopes, leachate accumulation within the waste mass, and leachate runoff into nearby water bodies (see Figure 1 below). Besides the creation of environmental hazards, these conditions limit both LFG generation and the potential for efficient LFG extraction. The disposal site property covers 34.2 hectares (ha), of which approximately 21.5 ha consists of waste disposal areas. The site has been divided into an eastern disposal area ( Eastern Mound ), which receives waste from KMC s waste haulers, and a western disposal area ( Western Mound ), which receives waste from private haulers. A composting facility is located between the two disposal areas and receives selected waste loads from organics-rich sources such as food markets. The composting facility is privately owned and covers 12.2 ha of the disposal site property. In addition, there are about 200 waste pickers at the site who scavenge through the waste daily (see Figure 2). A schematic drawing of the site is provided in Attachment A, which shows the areas and relative locations of the composting facility and disposal areas, including a proposed 10 ha Expansion Area. 1. Source: 2. Source: 3

7 Figure 1. Leachate Ponding at Dhapa Disposal Site Figure 2. Waste Pickers at Dhapa Disposal Site 3.1 WASTE DISPOSAL INFORMATION Annual Waste Disposal Rates The Western Mound covers 8.1-ha and reaches a maximum height of 30 meters (m). The Eastern Mound covers 13.3-ha and also reaches a maximum height of 30 m. The volume of waste in place was calculated using a scaled aerial photograph obtained from Google Earth and AutoCADD software to be 2,275,290 cubic meters (m 3 ) in the Western Mound and 3,535,710 m 3 in the Eastern Mound, for a total volume of 5,793,000 m 3. This estimated volume was assumed to reflect the amount of waste in place as of October

8 The in-place waste density is estimated to be 1.2 Mg per cubic meter (Mg/m 3 ) based on waste composition, age, and the estimated volume loss due to waste decomposition over the site s disposal history. This results in an estimated total of approximately 7 million Mg waste in place as of October KMC reported that the site received an average of about 2,500 Mg/day in 2008 and 3,500 Mg/day of waste in 2009, based on scalehouse records. Historical annual waste disposal estimates were developed based on the 7 million Mg total, the reported opening date (1981) and the reported 2008 and 2009 disposal rates (912,000 Mg/year and 1,277,500 Mg/year, respectively). An annual growth rate of 15 percent was required for historical disposal estimates to be consistent with the amount of waste in place, the number of years of disposal, and the reported 2008 and 2009 disposal rates. The resulting historical disposal rates are shown in Table 1. Table 1. Waste Disposal Estimates Dhapa Disposal Site Year Annual Disposal (Mg) Waste In Place (Mg) Year Annual Disposal (Mg) Waste In Place (Mg) ,000 18, ,400 1,170, ,700 38, ,700 1,364, ,800 62, ,800 1,587, ,400 89, ,200 1,843, , , ,600 2,138, , , ,800 2,477, , , ,600 2,866, , , ,000 3,314, , , ,200 3,829, , , ,500 4,422, , , ,400 5,103, , , ,000 6,015, , , ,277,500 7,293, , , ,303,100 8,596, , , ,329,200 9,925, ,400 1,002, ,042,100 10,967,600 KMC estimated that the disposal site has capacity for receiving wastes for another 5 years. This estimate was evaluated by the LMOP Project Team based on waste volume calculations and projected future disposal rates that were developed using the following information and assumptions: KMC projects that there is capacity for an additional 10 m of height on top of the existing disposal mounds. This report assumes that the 10 m of additional height will be applied to all disposal areas (present and future) and will set a limit on the disposal capacity, along with the available area for disposal. 5

9 KMC has allocated an additional 10 ha on the south side of the Eastern Mound ( Expansion Area ) to allow for expansion of that disposal area. KMC will likely continue current disposal practices of piling waste in steep mounds, until the disposal area is closed. LMOP and SCS do not recommend or condone this practice, but recognize that it is likely to continue at the Dhapa Disposal Site. Because the average age of waste deposited after October 2009 will be relatively young at the time of site closure, the average in-place density for future waste is much less than the historical density, and is estimated to be about 0.8 Mg/m 3. Future disposal rates are assumed to increase at a rate of two percent per year starting from the reported 2009 disposal rate of 3,500 Mg/day (1,277,500 Mg). Using the above assumptions, the Project Team performed a volume calculation using a scaled aerial photograph obtained from Google Earth and AutoCADD software. The volume estimates show that there appears to be additional capacity for about 779,000 m 3 in the Western Mound, 929,000 m 3 in the existing portion of the Eastern Mound, and 3,285,000 m 3 in the 10 ha Expansion Area, for a total of about 5 million m 3. Applying the estimated in-place waste density of 0.8 Mg/m 3, there is additional capacity for about 623,000 Mg in the Western Mound, 743,000 Mg in the existing Eastern Mound, and about 2.63 million Mg in the Expansion Area, for a total of 4 million Mg. This provides a final site capacity of million Mg. Applying estimated future disposal rates, there is enough capacity for about three years of waste disposal after October The resulting future waste disposal estimates are shown in Table 1. KMC has indicated that the West Bengal Pollution Control Board is planning to remediate the Western Mound with the financial assistance of the World Bank and the Government of India. The Western Mound holds approximately 39 percent of the total volume of disposed waste. A feasibility study to select the remediation technology had been scheduled to begin in April 2009, and the actual remediation work was to start in April, As of April 2010, the feasibility study has not yet been released, but the remediation project reportedly has been approved and is expected to begin soon. This assessment report assumes that the West Mound will be closed in 2010, with remediation completed before 2012 (assumed date of LFG project start-up). In addition, this study assumes that the rest of the site will eventually be closed and remediated after remediation of the Western Mound is completed. The Eastern Mound is projected to reach the 10 m additional height limit by the end of 2010 and be available for closure and remediation in 2011 and 2012, when waste disposal would move into the 10 ha Expansion Area. This report assumes that the entire site will be closed in late 2012, based on the estimated remaining capacities of the existing and planned disposal areas, which were calculated by setting a maximum height of 10 m above top deck elevations existing in October The actual site closure date will depend on the date that a new landfill is available. KMC has stated in an to Mr. P.U. Asnani that the East Mound and 10 Ha. Expansion area...can only be closed 3. Source: Dhapa Landfill Profile Form filled out by Mr. Arun Sarkar on March, 2008 and West Bengal Pollution Control Board Memo #389/3S-187/2008 6

10 immediately after availability of the land for new Engineered Landfill and the same is ready for operation. At present Kolkata Municipal Corporation has no other alternative but to utilize the East Mound and 10 Ha. Expansion area for waste disposal system within this period. (See discussion of possible impacts of a delay in site closure on LFG recovery in a later section of this report.) Waste Composition Data Waste composition and moisture conditions in a landfill are primary considerations when estimating LFG model Lo and k values. This report applies waste composition data provided by KMC in a completed data form for the Dhapa site. Because the data was grouped into only four waste categories food and garden/park waste combined (50.56%); wood (1.15%); paper and textiles combined (7.94%); and all inert waste (29.60%) details on the breakdown of inert waste categories were developed using waste composition information developed for the Gorai Landfill Assessment Report. 4 The estimated waste composition percentages are summarized in Table 2. Table 2. Waste Composition Data Dhapa Disposal Site Waste Material Estimated % Food Waste 45.5% Garden Waste 5.1% Paper 4.0% Textiles 4.0% Wood 1.2% Plastics 3.3% Construction and Demolition Waste 29.6% Metals 0.5% Glass and Ceramics 0.3% Other Organics 3.4% Other Inorganics 3.4% Total 100.0% Organic Fraction (wet basis) 63.0% Organic Fraction (dry basis) 25.9% Sources: Data form completed by Arun Sarkar, KMC. A breakdown of reported percentages into specific waste materials was estimated based on information provided in the draft Gorai Landfill Assessment Report. 4. Assessment Report Gorai Landfill, Mumbai, India. Draft report submitted December

11 4.0 LANDFILL GAS GENERATION AND RECOVERY PROJECTIONS 4.1 BACKGROUND ON THE SCS INTERNATIONAL LFG MODEL SCS has developed a proprietary international LFG model that employs a first-order decay equation for estimating LFG generation based on annual waste disposal rates, the amount of methane one tonne of waste produces (Lo value), and the rate that waste decays and produces LFG (k value). The model k and Lo variables are based on estimated waste composition and local climate information. Data used for developing model input parameters are discussed in later sections of this report. The SCS International Model uses the same input variables (k and Lo) and is generally similar to the U.S. EPA s Landfill Gas Emissions Model (LandGEM). The most significant difference between the models is the assignment of multiple k and Lo values in the SCS International Model. While the simple (single k and Lo) first order decay equation used in LandGEM is appropriate for modeling U.S. landfills, it is SCS s opinion that LFG generation at sites in developing countries may not be adequately modeled using this approach, primarily due to the significantly different waste composition and site conditions which create different patterns of waste decay and LFG generation over time. The SCS International LFG model employs separate modules with different k and Lo values that separately calculate LFG generation from the different waste components. This multi-phased first-order decay model approach recognizes that the significant differences in the types of waste disposed in developing countries require changes to the model structure as well as to the values of the input variables. A similar approach has been adopted by the Inter-governmental Panel on Climate Change (IPCC), which released a landfill methane generation model in 2006 that applies separate modules for four different waste categories. 5 LFG generation estimates produced by the model are used to project LFG recovery following installation of a collection system based on the estimated collection efficiency. Collection efficiency, defined as the percentage of generated LFG that is recovered by the LFG extraction system, is affected by a number of factors, including: collection system design, extent of wellfield coverage, waste depth, type of liner and cover, leachate management issues, landfill management practices, and collection system operations. 5. IPCC, IPCC Spreadsheet for Estimating Methane Emissions from Solid Waste Disposal Sites. 8

12 4.2 EFFECTS OF SITE CONDITIONS ON LFG GENERATION AND RECOVERY Site conditions at the landfill can impact LFG recovery either indirectly (by their effects on LFG generation) or directly (by their effects on achievable collection efficiency). Site conditions impacting LFG generation and recovery which were considered in the development of the model estimates are summarized below: Moisture conditions. Annual average precipitation was used to evaluate moisture conditions at the site and to estimate appropriate model k values. According to annual average precipitation in Kolkata is approximately 1,625 mm. Landfill management practices. As noted previously, the site has been operated as an open dump throughout its active lifetime. Shallow and/or uncovered waste piles typically experience aerobic conditions near the surface, that are toxic to methane generating bacteria. As a result, dump sites generate significantly less methane than managed landfills that control the size of the active disposal area, compact waste, and apply soil cover on a frequent basis. This effect is accounted for in the model by modifying the Lo values through the application of a methane correction factor (MCF) that is assigned based on the estimated fraction of waste which decays aerobically and does not produce methane. The historically poor conditions at dump sites also tend to contribute to low collection efficiencies. 4.3 SITE REMEDIATION ACTIVITIES Site remediation activities planned for the Western Mound would be expected to include at least the following: waste consolidation, re-grading, intermediate or final cover installation, and construction of stormwater drainage features. Site remediation will lessen environmental impacts of the disposal site, including water pollution from leachate runoff into nearby wetlands. Re-grading of the existing sloped areas to more stable (e.g. 3 to 1) slopes will require a larger area than the disposal area currently occupies. Remediation of nearby wetlands may be required to offset possible expansion of the disposal area. While environmental improvements would be the primary reason for site remediation, site remediation also would make conditions more suitable for the installation and operation of an LFG collection system. Given the existing conditions (no soil cover, steep and unstable side slopes, poor drainage), a properly functioning LFG collection system cannot be installed at the site except in areas that first undergo remediation. For this reason, this report assumes that the entire disposal site will be remediated. Remediation of the Western Mound is assumed to be completed in 2011 in time to allow for installation of the LFG collection system and system start-up by mid Remediation of the Eastern Mound is assumed to occur in 2012 and 2013, and remediation of the 10 ha Expansion Area in 2013 and

13 Disposal areas must first stop receiving waste before beginning remediation activities. Any delays in the assumed remediation schedule due to disposal areas continuing to receive waste past projected closure dates will cause delays in LFG system installation. Even after an area is remediated, the long history of leachate accumulation in exposed waste without proper drainage will likely create leachate problems that can persist for years. Furthermore, the process of waste excavation and re-grading to stabilize slopes will expose buried wastes to aerobic conditions and decrease methane generation. Additional discussion of model inputs and assumptions that reflect the site conditions is provided below. 4.4 MODEL PARAMETERS Model k Values Based on the precipitation rate and estimated waste moisture conditions at the disposal site, SCS assigned the model k values of 0.360, 0.072, and per year for the fast, medium, and slowly decaying organic waste fractions, respectively. Methane Correction Factor Based on an assessment of the effects of historic site management practices and expectations of disposal area re-grading, a MCF of 0.7 was assigned to account for aerobic waste decay. Prior to remediation, waste areas would be expected to generate greater amounts of methane than assumed in the model (i.e., a MCF of 0.8 would be appropriate based on the IPCC recommended value for unmanaged disposal sites less than 5 m deep). However, since all disposal areas are assumed to eventually be remediated before wells are installed, a 0.7 MCF was applied to reflect the impacts of site re-grading on average rates of aerobic decay. The MCF adjustment was applied to the Lo values. Model Lo Values Waste composition data was used to estimate Lo values for the fast, medium, and slowly decaying organic waste categories, based on the dry organic content of the disposed waste (as compared to average U.S. waste) multiplied by the estimated MCF. Separate Lo values were calculated for the different organic waste categories which are as follows (after applying a MCF of 0.7): Fast-decay waste (food and a portion of the garden waste): 51 m 3 /Mg. Medium-decay waste (paper, textiles, and a portion of the garden waste): 136 m 3 /Mg. Slow-decay waste (wood): 129 m 3 /Mg. The fraction of waste consisting of inert materials (e.g., construction and demolition waste, metals, plastics, glass and ceramics) was assigned an Lo value of 0 as it is not expected to contribute to LFG generation. 10

14 Collection Efficiency As discussed above, conditions at the disposal site would be expected to limit the efficiency of the collection system to low levels and would require site remediation before system installation. Three LFG recovery scenarios were developed to reflect a range of achievable collection efficiencies that vary depending on the level of effort and amount of resources available to operate the collection systems. All three scenarios assume that the Western Mound would be remediated in 2010 and 2011, followed by installation of a collection system and system start-up in 2012, and complete system coverage of the Western Mound by Site remediation and system expansion into the remaining disposal areas is assumed to occur from 2013 through Maximum collection efficiency levels will occur from 2015 onwards, when remediation, final cover installation, and collection system installation in all disposal areas are assumed to be complete. Any delays in the assumed schedule for site remediation and system installation (i.e., if the East Mound and/or Expansion Area remain open past projected closure dates), would cause significant decreases in projected collection efficiencies under all scenarios. The three recovery scenarios are described as follows: 1. The low recovery scenario assumes that a moderate level of skill and effort is employed in the operation and maintenance of the collection system (e.g., including wellfield monitoring and adjustment about once per month). Collection efficiency is assumed to be 10 percent in the West Mound in 2012 and 35 percent starting in Collection efficiency in the East Mound is assumed to be 10 percent in 2013 and 35 percent starting in Collection efficiency in the Expansion Area is assumed to be 10 percent in 2014 and 35 percent starting in Using the above assumptions, site-wide collection efficiency is calculated to increase from 2 percent in 2012 to 35 percent in The Project Team considers the low recovery estimates to be conservative and should be employed only if a large margin of safety is needed. 2. The mid-range recovery scenario assumes that a moderately high level of skill and effort is employed in the operation and maintenance of the collection system (e.g., including wellfield monitoring and adjustment 2 to 3 times per month). Collection efficiency is assumed to be 25 percent in the West Mound in 2012 and 50 percent starting in Collection efficiency in the East Mound is assumed to be 25 percent in 2013 and 50 percent starting in Collection efficiency in the Expansion Area is assumed to be 25 percent in 2014 and 50 percent starting in Using the above assumptions, site-wide collection efficiency is calculated to increase from 6 percent in 2012 to 50 percent in The Project Team considers the mid-range recovery scenario to be its best estimates of likely recovery and recommends its use in the economic evaluation. 3. The high recovery scenario assumes that highest possible level of skill and effort is employed in the operation and maintenance of the collection system (e.g., including weekly or more frequent wellfield monitoring and adjustment). Collection efficiency is assumed to be 35 percent in the West Mound in 2012 and 60 percent starting in Collection efficiency in the East Mound is assumed to be 35 percent in

15 and 60 percent starting in Collection efficiency in the Expansion Area is assumed to be 35 percent in 2014 and 60 percent starting in Using the above assumptions, site-wide collection efficiency is calculated to increase from 8 percent in 2012 to 60 percent starting in The Project Team considers the high recovery estimates to be ambitious and attainable only if the maintenance of an optimal LFG recovery system is considered to be a top priority. Note that, in addition to the potential variability in collection efficiency and the level of operation and maintenance, mathematical modeling of LFG is inherently uncertain. The Project Team considered (and tried to account for) this modeling uncertainty in selecting the values for the high and low recovery scenarios when projecting LFG recovery rates. 4.5 MODEL RESULTS LFG generation projections for the Dhapa Disposal Site are provided in Table B-1 and Figure B- 1 in Attachment B. LFG recovery projections under alternative collection system efficiency scenarios (low, mid-range, and high) are provided in Tables B-1 and B-2 and Figure B-1 in Attachment B. As shown in Table B-1, projected LFG generation increases from about 5,250 m 3 /hour in 2010 to a maximum of about 7,000 m 3 /hour in LFG generation is projected to decline steeply thereafter, reaching about 4,100 m 3 /hour in 2015, 1,500 m 3 /hour in 2020, and 820 m 3 /hour in Under the mid-range collection efficiency scenario, LFG recovery is projected to be about 400 m 3 /hour in 2012, and to steadily increase to a maximum of about 2,070 m 3 /hour in 2015 when collection efficiency increases to maximum levels. After 2015, LFG recovery is projected to decline rapidly due to declining LFG generation. Table B-1 also shows that the potential for power generation from LFG is estimated to exceed 1 MW over a 9-year period ( ), and exceed 0.5 MW for a 17-year period ( ), under the mid-range recovery projections. Certified emission reductions (CERs) achieved by this project through the combustion of landfill methane under the mid-range recovery projections are estimated to exceed 770,000 tonnes of carbon dioxide equivalent (CO 2 e) emissions for the 10-year period from 2012 through Section 3.1 noted that the projected site closure date based on remaining volume would not apply as long as an alternative site for an engineered landfill is not available. If waste disposal continues past 2012, LFG recovery would be impacted largely by any changes to the assumed schedule for site closure, remediation, and LFG system development. Unless disposal moves into a new expansion area to allow for closure and project development of existing areas, increases in future LFG generation from ongoing waste disposal in the existing areas would be more than offset by delays in project development in the near future, resulting in significantly lower LFG recovery rates until at least

16 5.0 LANDFILL GAS PROJECT OPTIONS LFG project options examined in this study include: (1) on-site electricity generation; (2) direct use for heating/boiler fuel (medium-btu application), and (3) flaring only for obtaining emission reduction credits (CERs) under the Clean Development Mechanism (CDM). Both utilization options would require construction of new facilities, including an LFG-to-electricity (LFGE) power plant in the case of the electricity generation option and an LFG processing and delivery system (pipeline) in the case of the direct use option. All three options would require operation of the LFG collection and flaring system and are expected to generate revenues from the sale of CERs. The utilization options also would be expected to generate revenues from the sale of electricity or LFG. Capital costs for a GCCS will depend to a large extent on LFG flows, landfill size, and waste depth. A typical range for GCCS costs, including flare start-up and source test and engineering and contingency costs, is about $70,000 to $120,000 (U.S.) per hectare of landfill area. Annual GCCS operation and maintenance (O&M) costs typically average from 7 to 10 percent of capital costs, not including costs of electricity or system expansions. 5.1 ELECTRICITY GENERATION The projected LFG recovery rates under the mid-range recovery scenario indicate that the disposal site could support approximately a 1 MW power plant from 2013 through 2021, and a 0.5 MW power plant from 2012 to 2028, using reciprocating engines. To evaluate whether an electricity generation project is economically feasible, the estimated project revenues, construction costs (capital costs), and operating costs for the following alternatives should be considered: Selling generated electricity to a nearby end-user through a dedicated line. Selling generated electricity to the power grid. Utilizing generated electricity to offset electricity purchases for on-site uses. The revenues produced by these project alternatives should be compared to the estimated project construction and operating costs. Estimated revenues from electricity sales will depend on the quantity of electricity sold and the electricity sales price. Costs associated with an LFGE project at the Dhapa Disposal Site will depend not only on the cost of constructing and operating the power plant but also the cost of the electrical interconnection to the grid. All of the above alternatives will require either a new interconnect or modifications to the existing interconnect. At most sites with LFG generation rates similar to the amounts estimated for this disposal site, traditional electricity generation projects that sell power onto the grid often are difficult to justify on an economic basis. Because small to medium sized electric generation projects typically have higher investment costs when compared to larger facilities on a cost per installed kw basis, these electric generation projects are typically not feasible without some kind of project competitive advantage. The high investment costs result from the following drivers: 13

17 Smaller projects require similar fixed cost investments as larger projects, including electric transmission lines and interconnection infrastructure to the closest substation. Smaller engine-generator units cost more per installed kw and have lower efficiencies compared to larger units. To offset the high investment costs, smaller electric projects typically require some kind of project competitive advantage such as: High on-site electricity usage paying high retail rates which can be offset by the project s electricity generation. Existence of a high electricity tariff, renewable tariff, or renewable portfolio standard, and the existence of markets where the renewable attributes can be sold. Existence of a large electricity user close by paying high retail rates which can directly take the power generated at the facility. Existence of an electric interconnect to the grid nearby which can be utilized with little additional infrastructure investment. The Dhapa Disposal Site has some of the competitive advantages listed above, including the existence of a fairly large electricity user on the site property (composting facility), and the possible existence of three-phase distribution lines suitable for connecting to a small LFGE project close to the disposal site. The composting facility located at the disposal site is expected to have significant electrical and thermal energy needs based on the observed size of the facility. The composting facility may be able to use both electricity and thermal energy from the LFG and would be an excellent facility to approach regarding the use of LFG-based energy, given its close proximity. The composting plant can be seen in Figures 3 and 4. Figure 3. Composting Plant Figure 4. Composting Equipment 14

18 The alternative to selling generated renewable electricity directly to a nearby end-user or utilizing the electricity for on-site load is selling renewable electricity to the electrical grid. This would require an interconnect to the local power grid. During the site visit, a three-phase distribution power line going to the landfill was observed. This line, which was used to supply on-site power to the composting operations, may have adequate capacity to be used to connect the electricity generation project to the grid, but a more detailed interconnect study would be required to evaluate its suitability. If the existing distribution line is not adequate, an assessment of the interconnection options and the suitability of nearby substations to accept the power would be required. Interconnection options may include upgrades to the existing line or constructing a new dedicated line to a nearby substation. Further study also would be needed to evaluate the regulatory requirements for renewable energy sources to connect to the state grid, as well as to sell power directly to a third party end user. The National Electricity Policy of 2005 states that the purchase of electricity from nonconventional sources by distribution companies must occur through a competitive bidding process. The Electricity Act of 2003 also provides guidelines for setting up generation tariffs for renewable-based electricity, including a suggestion to link the generation tariff to the highest power purchase cost (fixed + variable) from the conventional plant in the state. Although the Ministry of New and Renewable Energy (MNRE) 6 has stated that LFG is a source of renewable energy, to date no renewable energy tariff has been announced for waste-to-energy projects, which include LFG recovery projects. However, the MNRE does offer financial assistance to waste-to-energy projects. For LFG recovery projects, financial assistance would be provided under the scheme of demonstration projects for power generation from MSW through new technologies, and the project would receive financial assistance of up to 50 percent of the project cost or a maximum of 3 million Rupees per megawatt of capacity. In the State of West Bengal, the West Bengal Electricity Regulatory Commission (WBERC) has determined the tariffs for electricity from renewable sources in the regulations for Cogeneration and Generation of Electricity from Renewable Sources of Energy. 7 This regulation establishes that distribution companies in the State of West Bengal have a quota of electricity to be purchased from cogeneration and renewable sources expressed as percentage of their total consumption of electricity in a year. The quota varies depending on the established licensee and increases on year by year basis. The regulation recommends that the tariff for the purchase of electricity from cogeneration and renewable sources is agreed mutually between the licensee and the supplier at a level not above the price cap for each type of source of energy specified in this regulation. The price cap for renewable energy from MSW is $4.50 Indian Rupees per kwh (U.S. $0.097 per kwh) 8 and will remain fixed for a period of five years, which started when the regulation came into force in March 25, Furthermore, the generating entity has open 6. Formerly the Ministry of Non-conventional Energy Sources (MNES) 7. West Bengal Electricity Regulatory Commission (Cogeneration & Generation of Electricity from Renewable Sources of Energy) Regulations, Notification No. 39/WBERC; dated March 25, Using an exchange rate of $US per Indian Rupee as of February 24,

19 access to any transmission company system within the State of West Bengal, once payment has been made for open access, transmission, wheeling, reactive energy, and other charges. Based on an estimated electricity sales rate of $0.097 per kw-hr, and assuming a 93 percent capacity factor (percent of plant operating time) and a 7 percent parasitic load (percent of generated electricity required to run the power plant), a 1 MW plant could generate revenues of approximately $730,000 per year. Based on the estimated construction and operating costs per kw of facility capacity, construction costs for a 1 MW LFGE facility at the Dhapa Disposal Site will likely exceed $2 million, and facility operating costs will likely exceed $175,000 per year. These construction cost estimates do not include the cost of an electrical interconnect to a local substation, which could range substantially depending on the availability and suitability of nearby distribution lines and/or substations. 5.2 DIRECT USE The sale of LFG for direct use at a nearby industrial facility can generate significant revenues while requiring less initial facility costs than an electricity generating facility. The projected LFG recovery rates under the mid-range recovery scenario indicate that the disposal site could support a 1,000 m 3 /hr direct use LFG project from 2013 through 2018, and a 400 m 3 /hr direct use LFG project from 2012 through Project feasibility is largely determined by distances to end users. Unless the direct use client is located at a very short distance from the disposal site, an LFG transmission pipeline will be required. If the direct use project requires transporting the LFG a significant distance to the end user, it typically requires a gas compression and treatment skid (filter, compressor or blower, de-hydration unit). LFG treatment requirements also are driven by the equipment that will utilize the LFG. Gas compression and treatment skid costs will be about $500,000 to $1 million, depending on the volume of LFG treated, distances to end users, and end user delivery pressure requirements. Pipeline construction will be about $100,000 per km (assuming open trenching and not including payments for right-of-way easements). Annual O&M costs are estimated to be approximately $35,000 to $55,000 per year, depending on the project size and labor costs. The Dhapa Disposal Site is located in an isolated area, and no industries were observed near the disposal site during the site visit, other than the on-site composting facility. Unless other facilities can be identified that are located nearby and could serve as potential end-users of LFG, an off-site direct use project does not appear to be a feasible option. The only potential option for utilizing recovered LFG appears to be on-site uses that do not generate revenues (only potential cost savings). As discussed above, the potential for using LFG as a source of thermal energy at the composting facility should be explored. Another potential on-site use for recovered LFG could be combustion in a leachate evaporation system. The economic viability of a leachate evaporation project will be driven primarily by the all-in cost incurred by the landfill to treat and dispose of its leachate. In sum, the viability of a direct use project will be driven by the following key factors: (1) the end user s distance from the landfill; (2) the quantity and timing of the end user s demand for thermal energy (i.e., a large and steady demand would be best); (3) the end user s cost of current 16

20 fuel; (4) complexity and cost to convert existing systems to utilize LFG; and (5) quality of LFG required by the end user for its processes. 5.3 FLARING ONLY AND EMISSIONS TRADING It is now possible to account for, and transfer, the reduction in greenhouse gas emissions resulting from activities that reduce or capture any of the six main greenhouse gases. Because methane generated from solid waste disposal on land is one of the major sources of greenhouse gas emissions, its capture and oxidation to carbon dioxide results in an environmental benefit. This benefit may be measured and traded under a number of different emission reduction trading schemes world wide, including the sale of CERs under the CDM. In order to qualify for trading of emission reductions, normally a project must be able to prove that there is no requirement under law, or mandated by waste disposal licenses or other regulations, to control the emission of the particular greenhouse gas relating to the project. This appears to be the case at the Dhapa Disposal Site. While flaring is the normal method for thermal oxidation of LFG, any process which prevents the emission of methane to the atmosphere would also qualify for tradable emission reductions. The carbon dioxide created by the thermal oxidation of methane is considered to be "short cycle" and the product of the normal carbon cycle, and therefore does not need to be accounted for under the current methodologies. If electrical energy production is also included, and that power is either exported to the local distribution network or used to displace other usage of electricity generated by the combustion of fossil fuels, it is possible to gain additional emission reductions as a result of the displacement of fossil fuel use. Although not a utilization option, flaring collected LFG would therefore produce significant environmental benefits and potential revenues from the sale of CERs. Because CERs are typically the only source of revenues from a flaring only project, prices received for the emission reductions will largely determine economic feasibility. A flaring only project would likely produce lower revenues than the other project options but may be more economically feasible to develop due to much lower capital investment costs. In addition, a flaring only project does not preclude a landfill from subsequently developing and implementing an LFG utilization project. A phased approach can reduce project risk by allowing for the proving of LFG quantities that the landfill can produce, recover the cost of the LFG collection system (and thus not burden the utilization project with having to fund the capital for the collection system), and provide a revenue base to help support the development and financing of the utilization project. It is very important that the concept for a second phase LFG utilization project be included in any project design document (PDD). Even if all the details are not known, a general concept should be introduced to allow for the modification of the PDD in lieu of a complete PDD resubmission. 17

21 6.0 OTHER ISSUES 6.1 LFG RIGHTS For any LFG project to occur, the ownership of the gas rights needs to be clearly defined. Potential disputes over gas rights need to be settled before there can be decisions regarding proceeding with a project, contract negotiations, or revenue sharing. 6.2 SECURITY AND SCAVANGERS The Dhapa Disposal Site currently does not block public access to the site, and a large number of scavengers work the active disposal areas on a daily basis. To prevent theft and vandalism, LFG extraction equipment can only be installed in secured areas. Thus, security fencing will need to be installed to protect any areas that are to be developed. 7.0 RECOMMENDATIONS This section presents general recommendations aimed at improving the chances of developing a successful LFG utilization or flaring only project. 7.1 SITE MANAGEMENT Site Closure Plan. In order to develop a realistic plan for the implementation of the LFG recovery system, the site should first prepare a closure plan. The following considerations should guide the preparation of the site closure plan: Closure plan: A site closure plan will give more certainty to the schedule for implementing the LFG project and expanding the collection system to cover all disposal areas. This plan also will provide information to determine how the system coverage can be maximized through the life of the LFG project. Current uncertainties regarding the closure dates for the Eastern Mound and the Expansion Area make developing a closure plan for the Dhapa Disposal Site difficult at present. Side slopes: Side slopes should be at grades that are stable while providing adequate drainage of stormwater. Historical disposal practices at the site have resulted in steep, unstable slopes that exceed 1:1 (horizontal to vertical) ratios in many places. Side slopes of approximately 3:1 are generally recommended, but a slope stability analysis should be performed to determine grading requirements. Currently, there is a conflict between the need to expand the waste footprint to provide proper slope grading, and the limited amount of area available. KMC will need to address this conflict by acquiring additional land adjacent to the existing disposal areas. 18

22 Access roads: Access to all areas of the site must be provided for heavy equipment such as drilling rigs, backhoes, etc. potentially needed during the construction of the LFG system. Active Disposal Area. The active disposal area should be minimized. Considering that stormwater that infiltrates through the active disposal area becomes leachate, the smaller the active disposal area the less leachate will be generated. Stormwater Management. The site does not have any soil cover and does not use tarps to prevent stormwater that falls on the landfill surface to infiltrate into the waste and turn into leachate. The site remediation process should include final cover installation and provide adequate slopes and runoff features (ditches, benches, etc.) to avoid ponding of water and excessive erosion. Leachate Management. All landfills considering an LFG project must implement a leachate management system that evacuates leachate from the waste mass, limits additional rainfall infiltration, controls leachate runoff, and properly treats generated leachate. The site has no bottom liner or leachate drainage system. High rainfall rates in the region and the lack of cover have caused leachate accumulation within the waste and leachate runoff into nearby water bodies. Leachate accumulation problems often are the primary cause of LFG project underperformance. Final cover installation and site remediation should help limit future leachate generation and provide drainage, but dewatering of the site will likely take years to complete. 7.2 PROJECT IMPLEMENTATION The following are recommended next steps for implementing an LFG utilization or flaring only project: LFG Rights: To clarify any potential uncertainty regarding the rights to the LFG, legitimate stakeholders should work together to equitably share the benefits and document any agreement. As a general guideline, we recommend that any benefit received resulting from the LFG should be commensurate with the level of risk incurred. For example, the entity responsible for addressing environmental liabilities (including incurring the costs of site closure and remediation) should also receive benefits from the LFG. Solicit Offers: The project owner should solicit offers to develop the LFG utilization project and/or a flaring only (GHG reduction) project. If the successful bidder is obligated to put up significant capital, then the LFG rights will most likely have to be transferred to the successful bidder in return for some kind of benefit (typically a payment based on the amount of LFG available or used). Other Considerations: If the project is to be implemented first as a flaring only project and later expanded to a utilization project, make sure the possibility of an LFG utilization project is preserved. Include the concept for a second phase LFG utilization project in 19