A National Energy Policy Could Accelerate the Renewable Resource of Biogas

What if the US had a strategic energy policy, defining roles for each energy source and backed by major funding? What might that mean for clean-water plants and biogas?

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The other night I had a dream. I dreamed I woke up one morning to find out that our federal government had adopted a comprehensive energy policy. (OK, I didn’t really have this particular dream, but bear with me.)

This policy was not some hodge-podge of here-today/gone-tomorrow grants, loans and incentives for this or that form of green or sustainable energy. It was an actual policy with defined roles for coal, nuclear, natural gas, diesel gasoline, wind, solar, geothermal and, yes, biogas.

And what a great thing it was. No longer would major energy decisions be based on private companies’ short-term economic considerations — like closing and tearing down a perfectly good, newly refurbished and relicensed nuclear plant near my hometown, because right now it’s cheaper to make electricity with natural gas and coal.

Instead, long-range thinking would apply. In the above example, the federal government would subsidize the nuclear plant’s power to keep it open, since in time we’d need that reliable, clean, greenhouse-gas-free energy, and at some point its price would again be market-competitive.

Rude awakening

But of course I woke up to reality. The nuclear plant was still gone. And as far as the eye could see we’d continue, as a nation, making stupid decisions about energy.

I wonder, if we had an actual energy policy, what that would mean for biogas from the nation’s clean-water plants — those with anaerobic digestion, anyway. This one seems like the ultimate no-brainer. Clean-water plants all over the country have anaerobic digesters that produce methane. Many do not use them to produce energy. What stands in their way? More often than not, it’s the up-front investment in engine-generators or combined heat and power (CHP) systems.

Treatment plants increasingly are recognized as resource recovery facilities. One of their resources clearly is energy. Biogas-to-energy systems, based on what I have seen and read, yield a pretty good return on investment and relatively attractive simple payback times.

Where’s the downside?

It stands to reason that a national energy policy would aggressively encourage biogas-fueled CHP. Digestion of biosolids alone can produce substantial gas and energy. The gas burns clean and in many or most cases would displace power from more-polluting sources like coal-fueled power plants. And once a facility has digesters, it’s natural to feed them food waste, FOG and other high-BOD waste products, yielding even more gas. That brings the extra benefit of keeping those materials out of landfills, with all the cost and environmental risk they can entail.

How much potential is there for biogas-to-energy? How much biogas do we produce today versus what we could produce if the resource was fully developed? Well, a few years ago, the North East Biosolids and Residuals Association (NEBRA) collected data on biogas production at clean-water plants across the United States.

The survey found that 1,238 treatment plants use anaerobic digestion and produce biogas, mostly at larger facilities (flows exceeding 1 mgd). On the other hand, two-thirds of the 3,300 or so plants above that size threshold do not produce biogas. And only a small number of plants with flows below 1 mgd do so.

So only a fairly small percentage of the nation’s 15,000 to 16,000 permanent treatment facilities produce and use biogas. To be fair, some of these are small package plants, but the survey did find some small facilities with anaerobic digestion — plants with flows from 1 to 5 mgd, and even some with less than 1 mgd. Some of these use biogas to generate electricity.

What’s the potential?

Another study, the 2014 Biogas Market Snapshot from XPRT Media, said the United States had the world’s greatest untapped biogas potential, and that from all sources — clean-water plants, farms and others — this country could produce nearly 70 million MWh of electricity per year from biogas.

That won’t solve all the country’s energy challenges, but it does compare to the output from several 1,000 MW utility power plants, and that’s a substantial amount of renewable energy.

So if our country had a real energy policy, maybe we’d see incentives put in place to encourage anaerobic digestion and biogas-to-energy. Such incentives could include low-interest loans structured so that the loan repayment would “cash flow” from the energy cost savings (and revenue).
Then perhaps we’d have this valuable resource on the way to being fully developed. That would be a boon to our energy supply, the environment and our economy — not to mention a dream come true.  



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