The Science of Sustainability

How Green is Biomass Energy?

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Almond shells at the West Biofuels biomass test plant in Woodland, California.

When you think of where energy comes from, you might picture a power plant or maybe wind mills. You probably wouldn't think of a pile of 12 tons of almond shells.

California is hungry for renewable energy. Solar and wind power have taken off thanks to the state's ambitious clean energy goals. But there's another way to generate electricity — by using organic material like agricultural and tree waste. It's known as biomass power.

Matt Summers is an engineer with West Biofuels at their test power plant near Sacramento. California, by the way, is the world leader in growing almonds.

"So we've got more almond shells than anybody else. And you know, we know some companies that handle almond shells and they're always looking for somewhere to take them," says Summers.

Listen to the QUEST radio story How Green Is Biomass Energy?

But where some see a waste product, Summers sees an energy source.

"So this is the heart of the West Biofuels process," he says, pointing to a tower of industrial equipment that turns almond shells into electricity. First, the waste, or biomass, is fed into a reactor.

"We call it reforming, so we're re-forming what's biomass, what's almond shells into smaller particles that are gases," says Summers, describing their gasification technology.

The gas that's produced is a lot like natural gas, so it goes to an advanced generator where it's burned to produce electricity.

But this is where biomass is different from other renewables. The generator produces air pollution, unlike, say, a solar farm. So Summers and his team use pollution control technology to meet California's air quality standards.

Still, despite the emissions from biomass plants, many say there are big benefits to using waste as an energy source.

"Waste is pretty green," says Jim Boyd, a member of the California Energy Commission. "There's enough material out there to make thousands of megawatts of electricity."

Matt Summers of West Biofuels stands next to their fuel source.

There are a lot of unused energy sources out there, Boyd says, like construction debris and orchard cuttings. Biomass energy also has one big advantage over other renewables – reliability. Wind and solar power are variable since the sun and wind aren't available all the time.

"And instead of just thinking about building more natural gas plants to fill the void, we could utilize biomass plants because they are seven by 24 once you get them up and running," says Boyd.

But while other renewables are booming, biomass is on the decline in California. After dozens of plants were built in the 1980s, today, only a handful of new plants are being proposed. In 2009, biomass provided about two percent of the state's electricity.

"There's a great infatuation with wind and solar and very rare references to biomass and some of us are trying to turn that around a little bit," Boyd says.

One problem is simply cost. Biomass facilities need tons and tons of material and trucking it in from around the state isn't very economical.

The other issue gets back to the concern of whether biomass energy is really as green as supporters say. There's the problem of greenhouse gas emissions from biomass plants. Another controversy is over one particular fuel source: trees.

All those years of Smokey Bear and fire suppression in California have created very dense forests – which are at high risk for fires. Both private and public land managers have been trying to reduce that fuel load.

"In a lot of cases you'd do thinning operation where you take out some of the trees, usually the smaller trees, the less valuable trees," says Bill Stewart, a forestry specialist at the University of California – Berkeley.

Stewart says most of the material removed from forests is either burned or left to decay. So there's a lot of interest in using forestry waste in biomass plants.

But Debbie Hammel of the Natural Resources Defense Council says, "I think if you're talking about waste, it's important to define what you mean."

"If you take too much of that residue out of the forest, you're going to have an impact on the forest floor, the fertility of the soil, erosion and potentially wildlife habitat."

Hammel says there's a major debate over how much thinning is good for a forest. So, she worries that a larger biomass industry would create incentives to over-harvest forests. That's why Hammel says not all biomass is equal – and why waste like almond shells should be used before forest cuttings.

"There is a role for biomass done right, but it's a smaller role I think than some people imagine," says Hammel.

Looking ahead, Hammel says the next thorny issue is calculating the greenhouse gas emissions from biomass plants, which can be tricky since the fuels come from a number of sources. That's something the federal Environmental Protection Agency is reviewing now.

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About the Author ()

Lauren is a radio reporter covering environment, water, and energy for KQED Science. As part of her day job, she has scaled Sierra Nevada peaks, run from charging elephant seals, and desperately tried to get her sea legs - all in pursuit of good radio. Her work has appeared on Marketplace, Living on Earth, and NPR's Morning Edition and All Things Considered. You can find her on Twitter at @lesommer.
  • Brent

    CO2 is taken out of the atmosphere to create the almond shell, then it is broken down. No net change of carbon in the system. CO2 released for the "reforming" of almond shells would make this technology carbon neutral. This is fundamentally different than burning fossil fuels where carbon was sequestered millions of years ago and is now being reintroduced into the system.

  • Dario Abisali

    I was a young researcher in biomass technology. And I've been using biomass combustion technologies in the industry in Indonesia. Our technology is very effective, very low cost, very low smoke, low power, very easy operation, very easy maintenance, and capable of producing heat up to 1400 Celsius. We need your support to campaign for this technology to the world. that we are able to produce the maximum enertgi renewable and very stable.

    for further information please contact us at:

    dananekocahyono@yahoo.com.sg
    Santosorising.blogspot.com
    0857.360.180.37

    Ide tersebut diatas sangatlah cocok dan sangatlah bagus bila diterapkan di indonesia. Biomass sangat banyak tersebar, belum lagi kalo kita bicara Limbah kertas dan Limbah sawit. Luuuuuaaarrrrr biasa banyak dan dapat digunakan sebagai sumber bahan bakar terbaharukan secara kontinyu. Alangkah sayangnya bila pihak Usahawan dan Pemerintah tidak memperdayakan sumber bahan bakar ini.

    Kami telah melakukan riset panjang dan telah diuji cobakan di industri. Hasilnya sangat Luar Biasa. Untuk Aplikasi energi pembangkit listrik pun sangat Mumpuni. Kami Mengundang Para Investor untuk mengaplikasikan teknologi ini agar menjadikan Indonesia yang terdepan dalam pengolahan Energi Biomass, dan Pembangkit Listrik Tenaga Biomass. Jadi Ide bukan hanya hidup di dunia mimpi dan Khayalan namun harus sebagai kunci untuk membuatnya jadi nyata.

    Untuk teknologi Aplikasi yang kami sudah aplikasikan bisa di lihat di daftar blog kami dibawah ini (Terima kasih Sudah Berkunjung, Jangan lupa beri Komentar)

    Usulan Pemecahan Masalah untuk Pengolahan limbah sludge di PT Adiprima Suraprinta di : http://santosorising.blogspot.com/2012/01/usulan-pemecahan-masalah-untuk.html
    Usullan Pemecahan Masalah di PT PINDO DELI PULP & PAPER MILLS di : http://santosorising.blogspot.com/2012/01/sludge-kertas-sebagai-sumber-bahan.html
    Perbandingan Biaya Konsumsi : http://santosorising.blogspot.com/2012/01/perbandingan-biaya-konsumsi.html
    PERBANDINGAN PENGGUNAAN BBM DAN BIOMASS Tahun 2006 di : http://santosorising.blogspot.com/2012/01/perbandingan-penggunaan-bbm-dan-biomass.html
    System Kerja Biomass Furnace di : http://santosorising.blogspot.com/2012/01/system-kerja-biomass-furnace.html