Oregon Public Broadcasting

The last feature story in OPBs energy series "The Switch" is, quite literally, about the end - waste.

Some Oregon farms are turning waste into an energy source called "biogas."

The state estimates biogas weighs in at a competitive market rate of only a few cents per kilowatt hour. But as Rob Manning reports, the costs, complications, and the benefits, can vary, based on the kind of waste you're using.

What’s a hamburger, like this one, on the grill at Mike’s Drive-in in Portland, have to do with energy, and climate change?

A lot, actually.

When you flip the switch, where does your power come from? And what will power Northwest homes and businesses in the future?We're asking these questions and more for our special series The Switch.

Cows burp and poop, a lot. That produces a lot of the gas, methane. Scientists say that methane is at least twenty times as intense a greenhouse gas as carbon dioxide.

But methane also flows into many Oregon homes as the prime ingredient in natural gas.

This summer, the state’s largest dairy near Boardman began work on a project to turn troublesome cow methane into usable power.

With the help of the utility, Northwest Natural, the Three Mile Canyon Dairy will soon run one of the state’s largest biodigesters to create biogas.

Bill Edmonds is with Northwest Natural.

Bill Edmonds: ”Biogas is exciting for our customers in that it turns what is a bad, this is waste product, in this case a waste product on a farm, into a good – which is a renewable gas.”

Just a few weeks ago, the city of Portland and Multnomah County published their draft action plan for climate change. It asks Portlanders to think about the carbon footprint of that sizzling burger, or the cheese on top of it.

But for those not ready to go vegan quite yet, biodigesting could help cut the carbon impact of eating meat.

City sustainability manager, Michael Armstrong, says national studies show biodigesters can cut up to 50 percent of a dairy’s carbon load.

Michael Armstrong: “It’s both food choice, in terms of what you choose to eat, but it’s also how what you choose to eat has been grown, processed, and distributed, all up and down the food chain. And manure management is a pretty big opportunity in there.” 

Farmer Bernie Faber is the grandfather of biogas in Oregon. He’s been turning manure into biogas – and then into electricity – since 2001.

Faber says the waste that’s left after the manure’s gone through the digester makes pretty good fertilizer. It also helps with environmental problems like methane gas. But the part Faber says his neighbors always ask about is how they can produce power, too.

Bernie Faber: “How much electricity can I produce, how long will it take me to produce… my comment has always been, you should probably invest your money in something else.”

Bill and Karla Chambers

Faber produces about 30 kilowatts when his digester and generator are at capacity. But another farm family - the Chambers - get 50 times that, or about 1.6 megawatts.

Bill Chambers: “This biogas plant was not about pollution control at all – it was all about energy production for the farm.”

Bill and Karla Chambers come from a long line of Oregon farmers. They started Stahlbush Island farms in the 1980’s, growing pumpkins.

Karla Chambers: “But today, we grow spinach, broccoli, marion and blackberries, boysenberries, black raspberries, super-sweet corn.”

They don’t have any cows or other livestock. But one thing they have in common with Bernie Faber, is that they are also running a bio-digester that turns waste material into electricity. On this day, it’s digesting spinach.

Bill Chambers: “What we’re looking at is feeding of plant waste product into a mix tank, and what’s happening in the mix tank is we’re creating the soup that feeds the digester.”

From there, just like on Faber’s dairy farm, the methane produced is piped to a generator, where it’s turned into electricity. Chambers says the farm uses every bit of energy it can from the generator. The steam blanches vegetables. The heatdries pumpkin seeds.

Bill Chambers: “If you take the whole year and net it together, production against use, we’ll produce about two times the amount of electricity we’ll consume. Not quite, but pretty close.”

The $10 million project got help from the Energy Trust of Oregon, as well as from business and farm producer tax credits. But Chambers cautions that if you want to sell power back to the utility, it takes time and money.

Bill Chambers: “The utility process does not move at the rate of which entrepreneurs would like to see it move.”

Biogas supporters say it packs a lot more energy punch than ethanol or biodiesel. It’s not perfectly clean - but the carbon dioxide produced is considered better than methane.

Such energy debates are not what Karla Chambers expected when she and her husband started Stahlbush 25 years ago.

Karla Chambers: “We’ve always thought of our families as farmers, and since 1990, as food processors, but this is just a huge leap into energy production. But we will be as much in the energy markets moving forward as we are in the food markets, and that’s really a revolutionary step for our family business.”

The biodigester has had its hiccups. One part of the process was down the day I visited. And a vendor hadn’t delivered an odor control device – and its absence was hard to miss.

The Chambers, and other farmers aren’t the only ones learning as they become energy merchants.

Alan Johnston is a civil engineer at the wastewater treatment plant for the city of Gresham.

Alan Johnston: “The waste gas that these digesters produce get ran into this enginre, and it runs purely off that gas.

Rob Manning: “And it’s not running right now?”

Alan Johnston: “It’s not running right now. Right now, we’ve been averaging about 95 percent up time, since November 2005, when it first started up.”

The biodigesters outside, though, are working, pulling methane off of biosolids, from the Gresham area’s wastewater.

Rob Manning: “It gets cleaned, heated, cooled, etc.”

Alan Johnston: “And by the time it hits the engine, it’s what you’d call pipeline quality gas.”

The generator produces 400 kilowatts of electricity, which is about half of what it takes to run the treatment plant.

It’s not as efficient, as the Chambers’ biogas facility. 

Like Bernie Faber’s dairy, a wastewater plant is dealing with material that’s already been digested once, so most of the energy has been used. But Johnston has a plan to improve the energy output. He wants to add animal grease.

Alan Johnston: “The amount of energy per gallon of fats, oils and grease waste, I don’t know what the exact factor is, but it’s quite a bit more than the energy content of the domestic waste. So it might be a little volume, but it’s going to be a lot more than the energy content of domestic waste that goes into the digester.”

And where would Johnston get those fats, oils, and greases?

That’s right, from the grease catchers at places like Mike’s Drive-in.

Various ways of turning waste into power are catching on in Oregon.

Landfills are getting in on the act, too. In the last two years, the number of landfills producing biogas has doubled -- and three more landfills may soon follow. 

And across Oregon, landfills, sewage, and manure currently produce about 30 megawatts of power - enough electricity to light more than 20,000 homes.