How is electricity produced for Mercer Island?

Puget Sound Energy (PSE) provides electricity to around a million people, primarily in Western Washington.   For Mercer Island, PSE provides both electricity and natural gas service.  PSE is the the largest utility in the northwest region and is one of three investor-owned utilities in Washington.

How is PSE electricity generated?

Thanks to a state law passed a decade ago, it’s fairly easy to find out.   The Department of Commerce produces an annual report detailing energy sources and types of fuel used by all sixty-four electricity utilities in the State.

I was rather surprised to learn that 32% of the power delivered by PSE to customers in 2009 was produced by burning coal.   That seems surprising because the Pacific Northwest is well known for its abundant hydroelectric capacity, yet over half of the electricity consumed for Mercer Island is produced from fossil fuel sources!

How does PSE stack up against neighboring utilities?   Seattle City Light and Tacoma Power supply electricity produced from hydroelectric sources by a wide margin.   In Seattle it’s 86%, and in Tacoma it’s 82% hydroelectric.  Over 2% of Seattle’s electricity supply was produced from wind sources in 2009, while PSE reported no wind production at all in the same period.  (Click for a larger image.)

Overall, 61% of the electricity consumed in Washington State is produced in hydroelectric facilities.  According to the PSE website, the company owns and operates two wind facilities in Eastern Washington, including the Wild Horse Wind Farm, making it the largest utility producer of renewable energy in the US, and the second-largest investor-owned generator of wind power.  But,

“PSE has elected to sell the green attributes from its wind facilities that are in excess of its current needs to other entities across the nation and therefore does not include the energy from these facilities as “renewable” energy in its fuel mix as reported to the state of Washington.”

So in principle, the average home or business on Mercer Island won’t be consuming wind-generated electric power, unless, perhaps, the company’s “Green Option” is selected.  More on that shortly.

View from State Highway 39: Cottonwood Drive and power plant, 1985. From the book "Colstrip, Montana" by David T. Hanson, published by Taverner Press, distributed by D.A.P. © 2010 David T. Hanson. Used with permission.

Now let’s consider the coal-generated portion of Mercer Island’s electricity consumption, which is about 1/3 of what we consume.  PSE has partial ownership in four coal-fired plants in Colstrip, Montana (population 2,375).  All of PSE’s coal-generated power reported in 2009 was produced in Colstrip, and that production represents 50% of all coal-generated power consumed in Washington State.  (The Northwest Power and Conservation Council has produced a brilliant map showing the location and type of all regional generating stations.)

The Colstrip plants have a generating capacity of over 2,000 megawatts and were built in the 1970s and 1980s.  According to the PPL Montana website, operator of the plants,

“The Colstrip facility is the second largest coal-fired project west of the Mississippi. It uses one rail car’s worth of coal every five minutes…”

The facility employs some 360 people and claims a rosy environmental record:

“Low-sulfur coal and state-of-the-art scrubbers restrict sulfur dioxide emissions to less than levels required by both Phase One and Phase Two of the Clean Air Act. The plant also meets Environmental Protection Agency standards for nitrogen oxides emission.”

The City of Colstrip is in southeastern Montana just north of the Northern Cheyenne Reservation.   Residents of the Reservation itself endure grinding poverty, according to some press reports, due to unwillingness to allow development of extensive coal deposits.  Residents in town, however, are relatively better off.  According to the city,

“Although nearly 20% of persons in Rosebud County are below the poverty line, Colstrip enjoys a fairly high relative per capita income at $29,094 and a median household income of $74,473.”

View of working mine and pit, 1984, from the book, "Colstrip, Montana" by David T. Hanson, published by Taverner Press, distributed by D.A.P. © 2010 David T. Hanson. Used with permission.

Coal for the Colstrip generating plants comes from the adjacent Rosebud strip mine operated by Westmoreland Mining LLC, producing some 12 million tons of coal per year.  Coal is supplied to two of the four Colstrip plants via a 4.2 mile long series of conveyor belts which deliver 36,000 tons of coal per day.  Altogether, the four Colstrip plants consume 10 million tons of coal per year from the mine.  The remaining production is delivered to customers elsewhere by rail car.  The mine employed 438 people in 2007.

The Rosebud mine is extracting a sub-bituminous coal deposit 24 feet thick covered by 100 feet of soil.  Each year some 250 to 350 acres of land are “disturbed” by mining (their term), and an equal amount of land is restored with vegetation for use by livestock.  The operator of the mine has documented a fascinating model land reclamation procedure designed to meet regulatory requirements.

Water for steam in the power plants, and for the city of Colstrip, is drawn from the Yellowstone River some 30 miles distant, transported in a 26” underground pipe and stored in nearby Castle Rock Lake (formerly known as a “surge pond”).

The coal mine and power generation facility deliver a much-needed livelihood for Colstrip, but for Jim McRae, a rancher living in nearby Rosebud Creek, there is an unwelcome side, as outlined on the Northern Plains Resource Council website:

“For 40 years, the citizens of southeast Montana have been repeatedly asked to absorb the impacts of natural resource extraction. We have done our part. We have sacrificed the loss of water, land, property, and quality of life for others to enjoy electricity at the flick of a switch.”

Photographer David T. Hanson exhibited a series of photographs on Colstrip at the Museum of Modern Art in New York in 1986.  A trove of 87 of images taken in the 1980’s was published in book form last month. Some of the photos can be viewed on the Amazon.com website.  The Telegraph, a UK newspaper, wrote a story announcing the publication of the book with commentary highlights from Hanson.

PSE customers consumed about 28% of rated capacity of the Colstrip facility in 2009, and Mercer Island consumed just a fraction of that.  That sliver, however, made up 32% of electricity consumed on Mercer Island.

For its part, Puget Sound Energy has plans to gradually reduce electricity deliveries from Colstrip over the next 17 years.  Until that time has elapsed, when you flick that light switch on Mercer Island, keep a mental picture of coal from a Montana strip mine and water drawn from the Yellowstone River as resources being used, and smokestack gases and coal ash as byproducts.

Natural gas is also used to produce electricity for Mercer Island.  PSE owns eight natural gas-fired generating facilities in Cowlitz, Pierce, Skagit, Klickitat and Whatcom counties.  In addition, a handful of co-generation plants are in place that produce electricity from natural gas and products from a nearby petroleum refinery.  An example is the March Point plant adjacent to the Shell Puget Sound Refinery in Anacortes.

Where does PSE acquire natural gas?  Half comes from the Canadian provinces of British Columbia and Alberta, the other half comes to PSE by pipeline from Rocky Mountain states.

Hydroelectric energy sources include an important contribution from the Rocky Reach Dam in Chelan county and many other dams in the Columbia Basin.  PSE owns three hydroelectric facilities on the Baker, Snoqualmie and Puyallup Rivers.   Other power is purchased through various mechanisms, including the Bonneville Power system. A total of fifteen hydroelectric sources were used in 2009.

PSE has a very good overview on its website outlining details of each of the power sources owned and operated by the company.

Now that we know the sources of Mercer Island’s electrical energy, curiosity is satisfied.  This begs the next question: are there personal choices that can influence the resources you consume to enjoy the benefits of electricity?  The answer is yes.

The first step is to conserve where possible and to use efficient lighting and electrical appliances.  The next step is to consider PSE’s Green Power program.

Participation in the program enables PSE to purchase power on your behalf using a revised mix of sources to cover all or part of your electricity use.  Contracted sources in 2009 and the projected portfolio for 2010 are listed below:

An average home consuming 1000 kilowatt-hours in a monthly billing cycle would pay about $12 more to use electricity sources from the chart above.  To my way of thinking, that’s a small price for the pleasure of no longer having to think of that strip mine in Colstrip, Montana!