Landfill Gas to Medium Btu Gas
The simplest and often most cost-effective use of LFG is as a medium-Btu fuel for boiler or industrial process use (e.g., drying operations, kiln operations, and cement and asphalt production). These projects pipe gas directly to a nearby customer where it is used in new or existing combustion equipment as a replacement or supplementary fuel. Only limited condensate removal and filtration treatment is required, however some modification of existing equipment may be necessary. Before LFG can be used by a customer, a pipeline must first be constructed to access the supply. Pipeline construction costs can range from $500,000 to $1,000,000 per mile, therefore, proximity to the gas customer is critical for this option. Often, a third party developer is involved in the project who will assume the cost of installing the pipeline. The customer's gas requirements are also an important consideration when evaluating a sale of medium-Btu gas. Because there is no economical way to store LFG, all gas that is recovered must be used as available, or it is essentially lost, along with associated revenue opportunities. Therefore, the ideal gas customer will have a steady, annual gas demand compatible with the landfill's gas flow. For customers with larger energy needs, LFG may still be used to supply energy for specific equipment or burners dedicated to LFG.
As general guidance when comparing boiler fuel requirements to LFG output, approximately 8,000 to 10,000pounds per hour of steam can be generated for every one million metric tons of waste in place at a landfill.
Equipment modifications or adjustments may be necessary to accommodate the lower Btu value of LFG, and the costs of modifications will vary. Costs will be minimal if only boiler burner retuning is required. However, boiler burner retrofits are typically customized, and total installation costs can range from $120,000 for a 10,000 lb/hr boiler to $300,000 for an 80,000 lb/hr boiler.
Operation and maintenance costs associated with using LFG in boilers, kilns, dryers, or other industrial equipment are typically equivalent to costs when using conventional fuels. In general, operation and maintenance costs will depend on how well the equipment is maintained and how well the gas collection system is controlled.