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NRG Mandalay Natural Gas Power Plant in Oxnard, California. Photo by Kyle Field, CleanTechnica.

Clean Power

“Renewable Natural Gas” Is the Ultimate Red Herring

There are three fossil fuels we must stop burning if we are to save our planet: coal, oil, and methane (aka “natural”) gas. Coal is declining precipitously. Scientists think we hit peak coal in 2013, and American use of coal has fallen by over 50% in the last 10 years (though, we need to quickly nail this coffin closed considering how dirty and polluting coal is). Oil is seeing the writing on the wall as major automakers commit to electric vehicles. Many think 2019 may have been the year we hit peak oil, and EVs are expected to make the internal combustion engine a “historical technology” by 2040. The faster we historicize petroleum, the better, so please buy that electric car or e-bike today. 

Natural gas (aka methane) now comes into sight as the next fossil fuel we need to banish in the quest to rescue ourselves from the most catastrophic climate catastrophe. Burning methane is currently responsible for nearly 25% of all carbon emissions in the US, and its use is growing. Methane is also deeply embedded in many of our homes, and this will make it a challenge to extricate. We aren’t anywhere near hitting peak natural gas usage on our current trajectory.

But, as of recently, some American cities, mostly in California, have recognized the need to eliminate gas and slowly get us off the fossil sauce. In 2019, these leading cities did something that had never been done in the history of our species — they started banning future use of methane in new construction. The idea has been to stop digging a hole that we have to quickly climb out of, so they legislated that no new homes or buildings should be built with methane hookups. This will avoid costly retrofits later. The city-led ban began in California, has reached over 50 cities, and is spreading up the West Coast like a good kind of wildfire. 

Enter “Renewable” Natural Gas

Any entrenched industry will fight with all its might not to disrupt revenue streams, regardless of the effects of their products on humanity (see: oxycontin and tobacco). So, it is to be expected that methane peddlers will spend the next crucial decades resisting efforts to ban their product. They’ll use lots of arguments to slow humanity’s inexorable push towards a fossil fuel future. The most ingenious/insidious one that we must quickly debunk is that their carbon polluting fuel is actually clean or has the potential to become so.

Enter, stage right, “renewable natural gas,” or RNG, a brilliant buzzword for a product that companies are counting on consumers to believe in, to continue with business mostly as usual. Renewable natural gas is methane that comes from biological sources like human and cow sewage or landfills. It differs from current methane, which is fracked from the earth’s interior, some of which escapes through pipes, while the rest is burned, adding to our dangerous warming blanket. RNG harnesses methane being created anyway and thus, doesn’t add new layers to our greenhouse problem. A group of nonprofits in my region just released an in-depth look at renewable natural gas and the numbers aren’t good. 

How to Make Renewable Natural Gas — Anaerobic Digestion and Gasification

Before we can examine how much RNG our society will be able to realistically produce, let’s briefly talk about the two ways to make renewable natural gas. Even though, as we’ll shortly see, RNG won’t come remotely close to meeting our current gas demand, it still has the potential to be an important, lower-carbon tool in reducing the emissions of hard-to-decarbonize applications (like industry). 

The first way to make RNG is through anaerobic digestion technology. This is a process where bacteria eat waste in an atmosphere that doesn’t contain oxygen (anaerobic). Sewage treatment plants and pig farms use this process. They gather fecal matter, bring bacteria to a specific temperature, do a lot of other magic in pipes, and out comes methane gas. Landfills are another source of this methane as wasted food and other fun stuff are eaten by bacteria underground and methane is created as a byproduct.

The second way to make RNG is through thermal gasification, which “uses energy to turn agriculture and commercial forest harvest residues” into something called Syngas. Syngas can then be converted to methane with more processing. According to a large survey by the State of Oregon, “There are currently no commercial-scale thermal gasification plants in the United States that convert biomass into methane. The existing plants produce syngas, which is burned and used to generate heat and electricity.” So thermal gasification is a potentially important, but unproven technology that should not make us believe that we can simply keep burning gas in our homes. 

How Much Renewable Natural Gas Could We Conceivably Produce?

In the 2018 Oregon study cited above, (which had many gas industry officials involved in its writing) researchers looked at what we could optimistically hope for from RNG production. The numbers aren’t good. The potential for anaerobic digestion is 4.6% while the potential for thermal gasification is 17.5% of current natural gas usage in the state. So RNG could potentially cover 20% of the methane gas we use today, assuming significant investments in technology and distribution systems that do not exist today – in other words and not anytime soon.Think about it. We could work our tushies off over the next couple, crucial decades, to try to decarbonize natural gas pipes, while the planet is heating up and wildfire smoke is crossing our country coast to coast, and after crucial time and work, we’d still be using 80% fracked, fossil natural gas. If that’s not backing the wrong horse, then I don’t know what is. 

Oregon’s numbers are similar to national numbers. Another study found that, nationally, we could hope for about 16% renewable natural gas, and again, this is far in the future and only if we invest heavily in RNG.

Compare that to electricity as a fuel, and you’ll see a stark difference. Right now, the national electric grid gets 20% of its power from renewables and 20% from nuclear, making electricity 40% carbon free. Biden wants to get to 100% by 2035. Oregon recently passed a law to get to 80% clean electricity by 2030 and 100% by 2040. Wind and solar are carbon neutral and are the cheapest and most installed forms of new energy generation. We have the roadmap and the tools to completely decarbonize electricity over the next 10–20 years and are doing so faster than anyone expected. Clean electricity is real, proven, happening and the horse we should be backing. 

Electrifying our house and capping our natural gas pipe was one of the best things my family has done for the climate.

Other problems with renewable natural gas

There are other significant problems with renewable natural gas which are highlighted in depth in this brilliant article by Laura Feinstein and Eric de Place. Renewable natural gas isn’t even zero carbon. It is true that it often comes from existing sources of methane, but often those sources of methane could be avoided. Take landfills for example. When we toss food scraps into landfills it creates methane. We could capture that methane to make renewable natural gas or we could compost the food scraps like many cities and nations do, and avoid making that methane in the first place and get the benefits of richer, healthier soil in our communities. Relying on renewable natural gas could thus lock us into wasteful, inefficient practices when other options exist. 

Another significant problem is that RNG costs a lot to make. A million BTUs of methane gas currently costs $3. The median cost for the equivalent amount of RNG is about 6 times that, at $18. Yipes! Imagine telling consumers that their gas bills are going to sextuple, and you’ll start to see how viable RNG is as a long term solution. 

Scratch the surface, and it’s easy to see how RNG meets the classic definition of a red herring; “something that misleads and distracts us from a relevant or important question.” There won’t be very much of it, and it’s going to be very expensive. Let’s not get sidetracked from real climate solutions. When our local methane suppliers use the word “renewable” to keep pumping fossils into our homes, we need to understand that this is at best a stalling tactic and a greenwash to distract from the dangers of methane gas. Let’s stay focused on more realistic solutions for heating our homes and addressing the climate crisis like electrification.

I’ll be co-hosting a free webinar with Electrify Now on “The Future of Natural Gas” on Wednesday, September 22. Register and get more information here

Check out this in-depth report on methane gas released by a coalition of 62 organizations recently. 

Related: Natural Gas Leaks Deadly For Trees (Video)

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Joe lives in Portland, Oregon, and works for the nonprofit New Buildings Institute, which promotes electric and decarbonized buildings. He also volunteers with Electrify Now because he believes that electrifying everything, from transportation to homes, is the quickest path to an equitable, clean energy future. And of course, Joe and his family live in an all-electric home and drive an EV.


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