Addicted to convenience – energy vs. soil:
What fate awaits composting in an energy-mad world?
The industrialized world is addicted to convenience, and that convenience requires energy. But at what cost? In the energy vs. soil tug-of-war, will recycling organics back to the soil win the day over incineration or burial?
High-rate composting is efficient, economical, and delivers a multitude of benefits beyond basic organics recycling. But that doesn’t seem to dissuade proponents of landfill gas-to-energy (LFGE), the thermal/incineration waste-to-energy (WTE) crowd, and even anaerobic digestion (AD) advocates from making a grab for those organics, ranking the generation of energy above common sense.
Given our reliance on energy, this isn’t surprising. For most people, losing power has immediate and debilitating results. And while everyone waits with bated breath if the electricity so much as flickers, the same can’t be said for composting and compost use awareness.
This places composting in a very tenuous position in everything from funding to feedstocks.
Energy vs. soil — does composting have a future in a power-hungry world?
Modern humans have been around for millennia. We’ve only had access to electricity as a service for about 130 years. But, in that short time, we have become addicted to its convenience.
In most minds, power — whether on or off-grid, centrally produced or generated on a rooftop panel – has been elevated to the realm of necessity.
How can composting and compost use, with its near-invisible influence on how most people live day to day, hope to compete for development budgets and feedstocks? Our insatiable hunger for convenience seems to trump everything, including the environment and economics.
The executive summary for a recent AD study for a county in the U.S. northwest concluded anaerobic digestion of food waste was “… complex and expensive relative to landfilling or composting.” Yet the study went on to fill 100-plus pages with options for making AD a part of the regional waste management landscape.
Why? Because AD can be used to generate electricity.
Yet, according to a March 2018 report from the U.S. Energy Administration, at $102.20/MWh total system levelized cost of electricity (excluding tax credit), biomass is one of the most expensive ways to generate power. It is second only to offshore wind generation ($124.60/MWh), even higher than advanced nuclear ($90.10/MWh).
But addiction isn’t rational or logical. Whether the “drug” is opium, sugar, or electricity, the addict’s got to have it.
So, where does that leave composting in the energy vs. soil competition? Fighting for feedstocks.
In the absence of source-separation and recycling mandates, the bulk of the biodegradable fraction of the waste stream is controlled by municipalities and/or Big Waste and may be unavailable to independent composters.
Organics revenue impacts profitability
In the U.S., compostables make up 40-60 percent of the municipal waste stream. For disposal businesses, organics-derived income can be significant and represent a big chunk of annual revenue to these companies.
Landfills still control the bulk of organics, and fewer than a third of landfills have gas recovery systems. A report on the State of Organic Waste Management in North America estimates 142 million tonnes of organics (~157 million tons) go to disposal in the U.S. while about 66 million tonnes (~72 million tons) are diverted.
Once municipal assets, landfills have shifted from mostly public to mostly private sector ownership. The vast majority, even those publicly owned, are operated by the private sector. Most of the active waste-to-energy facilities are privately owned and/or operated, too.
Since the private sector runs on profits, if landfill and incinerator operators can tack on an energy technology to justify a “green” claim, retain control of those waste streams, and still make money, they’re going to do it. The fact that these systems are inefficient, unnecessary, and more expensive than composting for managing organics doesn’t seem to matter to anyone outside of the composting industry.
Why? Because they’re generating e-n-e-r-g-y … and that leaves composting out in the cold.
But energy recovery costs more and doesn’t close the loop for organics
When augmented with energy systems, traditional disposal does offer marginal improvement over organic waste management practices of generations past. But is it smart to ignore the long-term impacts of these strategies for short-term energy gains?
Landfills, incineration, and even stand-alone AD compete with composting for organic waste. Though loss of topsoil ranks second only to over-population as a global threat, the world’s desperate need to recycle organics back to the soil remains hidden in the shadow cast by energy’s addictive influence.
If just 40 percent of that total waste stream was organic, the 95,023 daily tons of U.S. gross WTE capacity would include about 38,000 tons of organics a day or 11.4 million tons of compostables per year (if operated for at least 300 days a year). If separated from the disposal stream and composted, instead, those organics would have yielded about 5 million tons of compost.
When mixed with 100 pounds of average soil, a pound of compost will hold 33 pounds or 4 gallons of additional water. WTE destruction of those 5 million tons of compost (10 billion pounds) caused about 40 billion gallons of runoff that would have cost combined sewer and stormwater (CSO) cities about $9.2 billion to treat at $.23 per gallon.
Applying the same formula to the wasted organics dumped into the nation’s landfills (157 million tons of raw organics = 78.5 million tons or 157 billion pounds of compost holding 628 billion gallons of water) adds $144.44 billion to that staggering treatment cost, bringing the total to more than $150 billion in unnecessary dollars spent by taxpayers – and that’s assuming an MSW organics fraction on the low end of the typical 40-60 percent generation range.
To put things in perspective, 628 billion gallons is more than two days of freshwater use in the U.S. (306 billion gallons/day).
That wasted $150 billion, if put toward more efficient power generation, could have been used to establish 150,000 1MW solar farms, each generating enough electricity to power 200 households. That adds up to 30 million households, sufficient power for all of California (13.01 million households), Texas (9.62 million households), and most of Florida (7.69 million households).
But for all the hoopla surrounding LFGE and WTE systems, these technologies do nothing to complete the soil cycle. Yet the costs of these negative soil impacts from landfilling or incineration of organics are not factors in energy system assessments, which fail to take in the big picture.
Is energy generation from organics via AD, LFGE or WTE really the way to go? Do we want to feed our power addiction by generating electricity at any cost?
WTE may have a role to play in waste management, but not for organics. And until AD drops into the realm of practicality, let’s back-burner those systems, too.
Instead, expand source separation, build out composting infrastructure, and install solar panels at those facilities. Based on today’s economic realities, that’s the more efficient, affordable, and sensible way to generate electricity from recycled organics.
READ MORE: Urban organics topics Table of Contents
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