Food waste carries a heavy social, environmental, and financial cost, but with the right technology, it can become a stable, low-cost, high-return source of electricity.
Taiwan generates an estimated 16.5 million tons of food waste a year. That’s enough to ﬁll 182 Olympic-size swimming pools every day all year, year-in and year-out. For most people, it’s out-of-sight, out-of-mind – at worst, someone else’s problem.
In reality, food waste costs Taiwan taxpayers billions of dollars a year. It is a significant source of air and water pollution and Taiwan’s already oversized greenhouse gas emissions. Soil contamination from food waste reduces our limited farmland every year.
But it doesn’t have to be that way. With the right technology, converting food waste to energy epitomizes the circular economy. More to the point, it could provide Taiwan much more electricity than it now gets from nuclear power and provide a practical, low-cost / high-return incentive for inbound foreign investment and the retention of local manufacturing.
Taiwan truly is a global leader in solid waste recycling. Only Korea and Sweden do it better. However, when it comes to handling food waste, Taiwan punches well below its weight class.
In 2017 – more than a dozen years after government mandated the separate collection of home kitchen waste – less than 19% of the 3 million metric tons of the food waste reported by the Environmental Protection Administration (EPA) was recycled as compost and pig feed. That’s down 40% from the peak in 2013.
The remaining 2.45-plus tons of unwanted produce, past sell-by date processed food, uneaten buffet and plate scrapings were burned at a taxpayer cost of almost NT$6.1 billion (US$200 million) and a very high environmental price.
Also, it is hard to say how or where the many private contractors get rid of the much greater volume of school, hotel, restaurant, night market, supermarket, convenience store, and wet market food waste they are paid to haul away.
Arguably, much of that food never should have been thrown away in the first place. But old habits die hard. Bottom-line: Taiwan’s current approach to food waste disposal is expensive, inefficient, and inadequate to process the huge daily volume generated across the entire length of the food chain from plow to plate.
There is a better way. Food waste is a practical, low-cost/high-return source of truly renewable energy – a modern consumer society “co-product,” not a “by-product” – when you apply the right technology: namely state-of-the-art anaerobic fermentation.
Food waste to electricity using anaerobic biological treatment already is commonplace in Europe, Australia, Canada, the United States, and Korea. David O’Keefe, chief scientist for U.S. waste technology leader PurposeEnergy™ described the upside for Taiwan. “Anaerobic conversion of food waste to energy and organic fertilizer turns waste to wealth, the circular economy at its best,” he noted. “There always will be food waste. Rather than burning or burying it or for slopping hogs, we can best use it to cleanly and efﬁciently power homes, offices, and factories as well as reinvigorate farm land.”
This process eliminates harmful methane and run-off now released from compost and landfill sites. Likewise, it avoids the toxic airborne emissions, bottom ash, and energy wastage from incineration. It also helps reduce Taiwan taxpayer-funded government waste disposal subsidies, illegal dumping, and the island’s oversized carbon footprint.
“Food waste to electricity is ideal for Taiwan to replace nuclear power,” O’Keefe added. “Why burn more coal or sacrifice farmland for solar when a clean, low-cost alternative not only is available locally but now is being thrown away?”
With the right anaerobic digestion technology, Taiwan’s food waste could generate an estimated 33 Gigawatt hours of electricity a year – over 1.2% of Taiwan’s total electricity output in 2016. That’s over 15% of the electricity we now get from nuclear power. The cost per kilowatt hour is lower than wind, and it’s cheaper to install than both wind and solar. The payback period is as short as 3-6 years.
There also are strategic competitiveness implications for the Taiwan economy. Food waste to electricity and thermal power deliver the large-scale, sustainable green energy supply demanded by global investors and strategic partners central to Taiwan’s tech economy like Apple, Microsoft, and Google. It also can play a role in providing energy security for local tech pillars like Taiwan Semiconductor Manufacturing Co. (TSMC), which otherwise might need to move production offshore.
To its credit, Taiwan has plans for anaerobic biological treatment centers for food waste in Taipei, Taoyuan, and Taichung. However, the proposed scale is small – only 200,750 tons a year, less than 7% of the food waste the EPA collected in 2017. Notably, the target electricity output from those projects is far less than more advanced systems can generate, opening the door to inferior technology and poor return on taxpayer investment.
The right technology
Energy from garbage has been around for centuries, as simple as sticking a pipe in buried waste and collecting the raw biogas. Today’s high output anaerobic digestion systems are far more efﬁcient, combining advanced microbiology with sophisticated chemical and mechanical engineering.
In anaerobic digestion, bacteria in an oxygen-free tank digest organic waste and convert it to biogas, water, and organic solids. A generator converts the biogas to electricity and thermal energy. The leftover solids are used for compost and organic fertilizer; the water can be reclaimed for industry.
Anaerobic digestion of organic waste was introduced to Taiwan in the 1990s, but has yet to gain market traction. Industry experts agree that lack of popularity is mainly an issue of having chosen the wrong digestion technology for the job, resulting in unappealing returns on investment for users.
For example, land-intensive, “low-rate” systems common on large EU and U.S. hog farms are designed more for converting manure to liquid fertilizer for use on those farms’ adjoining corn and soybean fields, not for high-efficiency electricity generation. Those farms also rely on expensive mechanized manure collection to preserve the biogas potential. These basic system-design assumptions simply do not align with Taiwan hog farming practices.
Traditional “high rate” bioreactors found at food and beverage factories cannot digest undissolved solid waste. Since solids typically contain much more biogas potential than liquid waste, the resulting electricity output is disproportionately lower. To complicate matters, the factory must engineer a second process to separate and dispose of the solid waste. Taiwan manufacturers who have chosen these systems use them only for wastewater treatment, not energy production.
Additionally, these systems frequently require high-volume use of expensive chemicals, which increases operating costs. Likewise, they need the chemical composition of the feed-stock to remain stable, impossible when dealing with widely variable types of food waste.
For industrial-scale processing of food waste, the system must be able to process both liquid and solid waste, as well as withstand “shock loading” surges from more volatile waste like restaurant grease, dairy products, yeast, and sugary drinks. It also should need little, if any, pretreatment or use of pH stabilizing chemicals and have no moving mechanical parts in the bioreactor itself that require regular service shutdowns.
That’s where U.S. innovators outperform the traditional European systems and can turn the problem of Taiwan food waste into a productive asset. PurposeEnergy™ of Boston is a prime example. The company’s revolutionary TriBrid-Bioreactor™ has the world’s highest biogas conversion efficiency, and thus generates more energy. They are extremely robust, very low maintenance, and occupy very little land.
As a result, the company is turning highly polluting food, farm and factory waste into electricity, compost, and fertilizer, and reclaiming water from Vermont to Hawaii. Planning for a project in Taiwan to generate power from raw vegetable waste already is well advanced.
The time is long past when Taiwan could afford the luxury of letting nature slowly take its course with food waste and ignore the strategic role it can play in national energy security.
Today, Taiwan faces an energy crunch, chronic freshwater shortages, and worsening air pollution. Local manufacturers need energy supply security or will move offshore. Foreign buyers and investors increasingly demand renewable energy-powered supply chains, lest they take their business elsewhere.
Although the government’s renew-able energy policy rhetoric is inspiring, actual progress in upgrading the energy sector and growing the renewable power supply to replace nuclear energy has been slow. Meanwhile, Taiwan tax-payers pay billions of dollars a year for the privilege of food waste poisoning their air, water, and farmland.
Food waste to energy presents a generational opportunity for Taiwan – an opportunity to both meet the challenge of reducing the heavy social, ecological, and ﬁnancial burden of food waste as well as the fast-track rollout of a truly low-cost, high-return, high-volume renewable energy source. It’s time to put the right resource to work in the right place and tap the enduring green power of food waste with superior U.S. technology.