Landfill Powers Thousands of Seattle Homes

By Dave Unger, director of renewable energy for Waste Management

When most people think of Seattle they think of gray skies and rainy days. However, when I picture the city I often think of something totally different – energy. After all, Seattle is where Seahawks fans push the boundaries of how loud a stadium can go. It’s where the triple shot espresso is as common as water at every street corner coffee shop, and it’s where renewable energy – including from our landfill - is finding a welcomed home.

That’s right, it may come as a surprise to some, but one of those forms of renewable energy providing electricity for Seattle originates from our Columbia Ridge Landfill, which handles some of the disposal needs for the surrounding area. At this facility, we house a plant that uses methane gas, produced during the decomposition of waste, to generate electricity. This power is delivered to Seattle City Light, the utility provider for the city.

For years, Columbia Ridge has generated about 6.4 megawatts of electricity, enough to power around 6,000 homes. However, following the plant’s expansion (expected to be ready for commercial operation later this month) the capacity will grow to about 12.8 MW — enough to power approximately 12,000 homes.

It’s another classic example of a sustainable closed loop, where:

• Seattle produces waste that’s disposed of at a landfill
• Through a process called landfill-gas-to-energy, waste is used to produce electricity
• That energy is then used to help meet Seattle’s electrical needs

So, how are we doing this? How does landfill-gas-to-energy work?

Included in this blog are all sorts of visuals and a video that shows how it’s done. Basically, the process works by collecting gas from the landfill and then using machines to filter and compress it. Following that, the gas goes to generators, which then use it as a fuel to produce electricity.

Although this process may seem new, it’s been around for a long time and is something Waste Management has pursued at its landfills for years. In fact, we currently have more than 120 beneficial reuse sites – where we find alternative uses for landfill gas -- across North America that (when combined) create enough electricity to power upwards to 470,000 homes. It’s one way we can ensure that nothing – even items that get left at the curb – goes to waste.

Thanks, Seattle, for being a welcomed home for this form of energy! While it may not be as loud as a stadium or as invigorating as a triple espresso, the energy produced is something clean, green and reliable (even on rainy days)!