Renewable Energy — Landfill Gas

As communities grow, the demand for renewable energy is increasing. Waste Management is helping to fill this need by using waste from homes and businesses across North America to generate electricity. Currently, Waste Management produces enough electricity to power more than 400,000 homes through a source of renewable energy called landfill gas. Today's modern landfill uses advanced engineering to dispose of waste and protect the environment. At more than 80 Waste Management sites, renewable energy plants produce enough electricity using naturally occurring landfill gas. The process begins when waste is collected. One person produces an average of 4.5 pounds of trash every day. While some waste can be recycled, a portion is taken to a landfill for safe disposal. Once inside the landfill, waste decomposes to produce methane. Landfill gas, comprised of about 50% methane is collected by using an underground network of pipes and wells. From this network, the gas is drawn to a renewable energy facility's compression system where the gas is de-watered, pressurized, and filtered to make it clean.

When landfill gas first enters the system, it passes through a filter which removes any large pieces of debris and some liquids that may have become mixed with the gas. After initial filtering, it enters a compressor, which raises its pressure until it's high enough for the gas to be used as a fuel. During compression, the temperature of the gas rises and must be cooled down by an after-cooler. Inside the after-cooler, the temperature of the gas is lowered which allows for any remaining moisture to be condensed. The gas is then filtered a second time to remove the condensed moisture. At this stage, the gas is reheated to prevent any further condensation and is ready to be used as a renewable energy fuel. The whole process from start to finish takes seconds. Waste Management renewable energy facilities use either an engine or a turbine to generate power.

Both follow the same basic principle to produce electricity. An engine that runs on landfill gas really isn't that different from a car engine. It's equipped with pistons, an air filter, exhaust, radiators, and even batteries. Landfill gas enters the engine and is combusted, causing the pistons to spin a drive-shaft. The drive-shaft is connected to a generator, which converts the power into electricity. The electricity is then sent to state-of-the-art control systems, which ensure that the plant is meeting the needs of the utility. Control systems direct electricity to transformers located on-site which either raise or lower the voltage. Low voltage electricity is used to power equipment within the renewable energy facility. While high voltage electricity is exported to the utility grid to supply energy for communities and businesses. With new plants appearing every year at Waste Management landfills, the amount of renewable energy we provide is positioned to grow for years to come. From the design of the plant to the training our employees receive, safety and environmental protection are our highest priorities.

Warning signs are posted throughout the facility. We advise everyone, even experienced employees, to always be on alert for potential hazards. Pipes are also labeled to show where gases and liquids are flowing. Throughout the facility, a methane detection system monitors for leaks of landfill gas. If a leak were to occur, the plant is programed to automatically ventilate, and then if necessary, shut down. In addition to methane monitoring, plant fire detection and security systems are also monitored to facilitate a quick response from local emergency agencies. Employees can also shut down the plant manually should the situation call for it. Additional safety equipment includes an emergency shower, emergency eyewash, air vents, first aid equipment, safety blankets, flame-retardant storage units, portable gas meters, fall protection equipment, and fire extinguishers all help to protect our workers and the environment. Employees working at the site continuously inspect and perform preventative maintenance on all equipment to ensure operational excellence and environmental compliance.

Coolant oil and air filters are routinely changed to maintain peak performance. It's crucial for every worker to wear the necessary personal protectant equipment on the job. Parts of the plant can be noisy. That's why we require hearing protection for employees working around loud machinery. Safety glasses, protective footwear and proper uniform are also required when working in the plant. To ensure safety around high-voltage equipment, employees are provided with additional resources, such as electric arc suits, testing equipment, gloves, and training. For times when a worker is alone, Waste Management has a call-in system in place to monitor employee's safety. At some sites, man-down devices, which are sensors attached to the belt, will signal an alarm if an employee doesn't move for a short period of time, alerting our security center of a possible emergency. Lock-out, tag-out is a job critical requirement to ensure work-place safety.

Employees are trained to use special locks and tags to prevent equipment from accidentally being turned on while they're being repaired. No one should work on equipment without following lock-out tag-out procedures. Most people forget about their trash as soon as it leaves the curb. At Waste Management, our goal is to be the industry leader in finding innovative uses for waste, whether it's through recycling, composting, or creating renewable energy. Waste Management is committed to using trash as a resource to help communities meet their energy needs..