How Renewable is Renewable Natural Gas? - Episode 61

Sound too good to be true ? Well , it may be . Today , I'm going to unpack what renewable natural gas is , how it's made , what it's used for , and then we'll spend some time talking about whether this is truly a decarbonization magic bullet for the natural gas industry or a solution that may need some further work to refine . Wait a minute .

It's how long it takes to suns race it , or the amount of time the sun's shown yesterday . Okay , not really , but these winter months are just dark , long and brutal . Let's get it on . We burn a lot of natural gas in the US .

The Energy Information Administration estimates that 36% of our nationwide energy use is through burning methane and , frankly , that's been a good thing , as the usage of natural gas has displaced other , dirtier fossil fuels , such as coal , over the past couple of decades .

But now it's gas's turn to decarbonize , and there's a lot of questions around how best to address this energy source . One of the more prevalent solutions being proposed is in the production of renewable natural gas , or RNG Sounds appealing , right , renewable and natural in the description . Whereas traditional natural gas comes from geologic formations , rng is a biogas .

It's captured from other sources , such as landfills or biodigesters at farms or wastewater facilities . It could be the methane being captured from livestock or organic waste operations .

That renewable gas is gathered up and processed so they can be used as a fuel source and then burned in much the same fashion as traditional natural gas , because it is methane , same as traditional gas . Oh , it has some advantages because it's been processed to get to this point . For instance , rng has fewer particulates and volatile organic compounds .

In fact , the purity of RNG can reach 96 to 98% methane , while normal natural gas may be a bit lower , but it's still methane , which is important for our existing infrastructure .

As companies that are already burning natural gas can now burn RNG with relatively little adjustment to their processes or systems , end users can claim decarbonization goals while not having to overly disrupt their existing operations . But if RNG is just methane in a different package , what makes it a viable decarbonization solution ? The theory here is twofold .

Which kind of work with each other . First , rng is the methane captured from biological material like plants and trees . These are resources that captured carbon in the first place . So the idea is that you're not introducing new carbon into the atmosphere , just carbon that had already been captured , so the process is carbon neutral .

The second argument for RNG being a sustainable solution is that the methane coming from livestock and landfills Well , that's methane that's being released into the atmosphere anyway . If we can capture that and use it in place of traditional natural gas sources . That's kind of like taking an entire methane stream completely off the table .

Whereas before we had two streams of methane , one to burn and one that was going straight into the atmosphere , now we just have the single stream of burning methane . But this is why it gets tricky and why the evolving considerations for RNG are so complex .

Let's take that last point about using captured biogas , processing it and using it as an alternative fuel source for traditional natural gas . From a very valid perspective , we're capturing methane , which is a far more potent greenhouse gas than carbon dioxide is , and we're displacing a traditional natural gas source .

So this is a more climate-friendly solution , but it's not zero carbon . We can't just look at the narrow focus of just the methane capture and claim success . The entirety of the carbon cycle here needs to be considered , because the RNG that we're burning still emits carbon dioxide into the air . Want to do some math with me ?

Think of the original scenario where a herd of cows emit methane into the air and a farm purchases natural gas from their utility to burn in their water heaters . The cows may emit one part methane and the water heaters may emit two parts CO2 .

Now the farm installs a capture system for that methane , processes it up to RNG standards and burns that instead of the gas from the utility . The methane that the cows were emitting is now gone , but the farms still drop in two parts of CO2 into the air . It's just now coming from the biogas .

Now that doesn't mean that capturing the methane and reusing it is a bad idea . We're still removing the potent methane and that's good . It's just that we have to be honest about the full impact .

Or consider the first argument for the renewable nature of biogas , in that biogas from organic material was captured via photosynthesis in the first place and what we're really discussing is kind of a circularity of capture , burn and capture again , looked out in a vacuum .

That circularity suggests that certain biogas can be considered carbon neutral , but while the carbon that's been captured by the plants in the first place could have taken place years or , if not decades ago , the burning of the biogas today puts that carbon out immediately .

There's a time component that needs to be considered here , and if you're familiar with the concept of the time value of money , then think of this as the time value of carbon . Carbon captured today is more valuable than carbon captured in the future . The last concern RNG is expensive .

It's about 50% more expensive than traditional natural gas , and there are fewer than 200 RNG projects operating in the US , which means that even if you want to pay for that type of premium for RNG , it may be really tough to get your hands on the biogas in the first place .

And it's these concerns on whether RNG is truly a clean , renewable energy resource that has divided the industry .

On the one hand , capturing free methane is a good thing for the environment , but RNG doesn't truly meet the standards for full decarbonization , which is why certain states and other entities are starting to pull back from strategies that relied upon RNG as a net zero resource .

For instance , at the end of last year , massachusetts Department of Public Utilities issued a notice that they would no longer recognize RNG nor hydrogen as viable solutions for decarbonizing the state's gas distribution network .

Instead , the DPU will require utilities to develop plans to fully electrify residential heating load through heat pumps and the use of renewable energy , rather than reposition gas networks for RNG . Other states such as New York and California are considering similar restrictions , and this debate has ramifications at the federal level as well .

If we're to get the price of RNG down , we would need to invest billions and billions of dollars into new RNG projects in order to scale up the technology and infrastructure . But if RNG isn't going to fully bring us to the end goal of a net zero economy , well , is that type of investment really worth it ?

Or should we take the path of Massachusetts and simply invest behind full electrification in the first place ? But then what do you do about the methane in agriculture that wouldn't then have had the end market end goal ?

Rng is a tricky subject , but it's a topic that needs to be looked at across the entirety of the carbon life cycle and not easily dismissed as clean energy . I'm Paul Schuster and this has been your 8 Minutes .