Posted in GreenBiz
April 4, 2022

Anaerobic digestion: Turning America’s food waste into RNG


This article is sponsored by Bioenergy Devco.

As the climate crisis accelerates and the need to decarbonize using independent energy sources grows increasingly urgent, governments and industry must cooperate in developing clean and renewable energy options. There is no silver bullet to solve climate change, but anaerobic digestion (AD) is a critical piece of the puzzle. AD is next-level composting. Inside closed tanks, we turn organic byproducts — such as meat and food scraps, used cooking oil or spoiled produce — into carbon-negative renewable energy. This eco-friendly process has been prevalent across Europe for over 20 years, so why isn’t AD more common in the United States?

First, let’s delve deeper into how AD works. Unlike aerobic digestion, the open-air process behind composting, anaerobic digestion happens when microbes break down waste inside environments without access to oxygen — creating methane that can then be captured and transformed into clean energy such as renewable natural gas (RNG) or green hydrogen. The solid byproduct is a nutrient-rich soil amendment that is superior to regular compost as it’s cleaned of all contaminants that might otherwise pollute fields and waterways. Microbes have played a role in naturally decomposing organics for almost 4 billion years, and now we can harness AD on a large scale to produce clean energy and healthy soils.

People are often surprised to hear that food scraps, fats, oils and spoiled products are among the most economical and environmentally responsible energy sources, and they wonder why this organic material is not recycled into renewable energy in the United States. Instead, most food waste in this country today is incinerated or tossed into landfills, where the material decomposes and releases methane into the air. 

The beauty of AD technology is that it achieves decarbonization in two ways: the production of renewable energy and the reduction of harmful practices such as landfilling, incineration and the land application of excess organics on fields. Decades ago, digesters emerged and were widely deployed in Europe because of the continent’s lack of space for landfills. In the United States, we have the capacity and created more landfills; the land that once felt limitless to many in the United States has been covered by toxic landfills polluting our air, land and water. There is a massive opportunity to deploy AD at scale in the U.S., and it’s beginning to happen.

The United States stands to gain much from deploying AD. The American Biogas Council estimates the AD market has the opportunity to build as many as 13,500 new projects, producing enough energy to power 7.5 million homes and cut emissions equivalent to removing 15.4 million automobiles from the road. Digesters could account for $40 billion in capital deployment to create 335,000 short-term and 23,000 long-term jobs. Of the 103 million tons of food we waste annually in the U.S., 53.5 million tons go to landfills or incinerators or are land-applied. Diverting organics to anaerobic digesters would reduce harmful greenhouse gas emissions, odors and groundwater pollution — creating renewable, carbon-neutral energy in the process. 

Bioenergy Devco (BDC) has been developing AD facilities for over 20 years; we have built over 250 enclosed AD facilities and operate more than 140 worldwide. But these facilities are primarily in Europe, where AD is a well-recognized green energy solution. As a waste-agnostic company, BDC has built digesters alongside prominent food and beverage companies, helping them create circular waste management processes and reach their sustainability goals. In the United States, we’re developing commercial AD centers in multiple cities. 

For example, adjacent to the Maryland Food Center — a hub for dairy, meat, seafood and produce processors and distributors — we’ve built the state’s first utility-scale AD facility, generating renewable natural gas that will power local homes and businesses. This facility will manage more than 115,000 tons of excess organics each year and produce upwards of 265,000 metric million British thermal units (mmBtu) of RNG, enough to power 4,800 homes annually. All in all, the facility will stop 26,000 metric tons of carbon dioxide from going into the atmosphere each year, which equals the same environmental benefits of a forest 56 times the size of Central Park. 

Of course, one or two AD facilities are not enough to make a meaningful impact. For AD to play a significant role in decarbonization, there must be thousands of AD facilities across the country. It begs the question: why aren’t we doing this all over the United States right now? 

For the moment, the main roadblock to large-scale AD rollouts is mostly inertia; it’s easy to stick with the current disposal methods of landfilling, land application and incineration, yet these create greenhouse gasses, excess nutrients in soil and waterways and other toxic outputs. The good thing is AD technology needs no special incentives to be an economically viable way to reduce climate change. In most of the United States, the existing tipping fees (the fee that waste haulers pay to dispose of their waste) to landfills and incinerators are equivalent if this organic material was sent to an AD. This means you can send your organic waste to a sustainable and environmentally responsible AD company for the same price it costs to send it to an unsustainable landfill or incinerator. 

The other roadblocks are regulatory and political. Most local and state governments have been slow to press food producers and their partners to use more sustainable organics recycling methods. However, California recently became the first state to legally mandate composting with its sweeping Senate Bill 1383, and several states in the Northeast have passed laws requiring organics to be collected and processed separately from other waste. The next step is to pass legislation requiring organic byproducts to not just be composted but broken down via AD, so they come to life again as renewable energy. Governments can also provide incentives for renewable energy creation and consumption, as they’ve done in Europe.  

The coming years will see many more AD facilities spring up across the U.S., but we cannot scale without partnerships with food producers, utilities, waste management companies, and local and state governments. Organics recycling is not a singular solution to the environmental crisis, but it is an economically viable and critical component in helping us simultaneously achieve energy independence, climate goals and improving our air, water and soil quality. 

April 4, 2022 at 01:09PM

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