County officials continue to weigh an application by Republic Services to expand their regional landfill located north of Corvallis – this last Tuesday they heard an argument for keeping the dump open. At center, it’s about pumping biogas into homes.
“I’m really hopeful that we could bring this facility into a place where Benton County would not want to close it,” said Connor Reiten of PNGC Power.
The Benton County Board of Commissioners set aside 45 minutes to hear Reiten’s presentation, the remark came at the end.
Today, PNGC produces electricity from the dump’s biogas emissions. They would like to expand their operation and transition to selling gas to NW Natural.
The current operation
Since 1995, PNGC has had the contract to capture the biogas at Coffin Butte. Landfills produce substantial amounts of methane and CO2, and then smaller amounts of a few other gases. In 2008, the company expanded its capacity at Coffin Butte, and has been producing 5.65 megawatts of electricity, enough to power between 4,000 and 5,000 homes.
We will get into how they want to expand all that, but first you’ll want some information about the company.
Based in Oregon, PNGC Power generates and transmits electricity. They are a cooperative owned by 25 smaller Northwest utility cooperatives that in turn sell electricity directly to customers. One of those cooperative member-owners is Philomath’s Consumers Power Inc.
PNGC says they serve 431,943 accounts, have 57,336 miles of transmission lines, and are backed by over $2 billion in owner-member assets. They operate in seven states.
Expansion at the landfill
PNGC is seeking to expand its biogas capture capabilities at the landfill, processing the gas for resale to NW Natural instead of producing electricity. In essence, the company told Benton County’s Commissioners last Tuesday that conversion to electricity was best practice back in 1995, and that is longer the case.
Nowadays, according to Reiten, the idea is to convert the biogas to RNG, or renewable natural gas, which is chemically the same gas folks use in their homes, or in LNG fueled vehicles. The difference, Reiten says, is that producing RNG is less carbon intensive than traditionally produced gas.
He also told the commissioners that the dump is producing more biogas than it used to – so much, that his firm’s current processing machinery can’t keep up.
The current contract between PNGC and Republic runs until 2074, according to Reiten. But PNGC is currently renegotiating with the landfill so it can produce RNG instead of electricity – they’re looking at a 25-year production period to make the numbers work.
If the landfill closed, biogas emissions would continue past the landfill’s closure but diminish over time to a point where conversion to RNG would no longer be viable.
On Tuesday, Reiten’s said his goal was to inform the commissioners. PNGC hasn’t submitted a formal application to the County quite yet.
The arguments
One primary argument for RNG observes that so long as there’s landfills and gas stoves, they’re both going to emit – and that capturing the emission from one for later use in the other reduces the net total of emissions making their way into the atmosphere. Natural gas is extractive, and renewable natural gas is, well, renewable, goes the argument.
Counterpoint: Renewable natural gas may sound green, but it’s not an antidote for climate change
by Emily Grubert, Assistant Professor of Civil and Environmental Engineering, Georgia Institute of Technology
Natural gas is a versatile fossil fuel that accounts for about a third of U.S. energy use. Although it produces fewer greenhouse gas emissions and other pollutants than coal or oil, natural gas is a major contributor to climate change, an urgent global problem. Reducing emissions from the natural gas system is especially challenging because natural gas is used roughly equally for electricity, heating, and industrial applications.
There’s an emerging argument that maybe there could be a direct substitute for fossil natural gas in the form of renewable natural gas (RNG) – a renewable fuel designed to be nearly indistinguishable from fossil natural gas. RNG could be made from biomass or from captured carbon dioxide and electricity.
Based on what’s known about these systems, however, I believe climate benefits might not be as large as advocates claim. This matters because RNG isn’t widely used yet, and decisions about whether to invest in it are being made now, in places like California, Oregon, Washington, Michigan, Georgia and New York.
As someone who studies sustainability, I research how decisions made now might influence the environment and society in the future. I’m particularly interested in how energy systems contribute to climate change.
Right now, energy is responsible for most of the pollution worldwide that causes climate change. Since energy infrastructure, like power plants and pipelines, lasts a long time, it’s important to consider the climate change emissions that society is committing to with new investments in these systems. At the moment, renewable natural gas is more a proposal than reality, which makes this a great time to ask: What would investing in RNG mean for climate change?
Marketing video from Southern California Gas Co. promoting renewable natural gas as a climate-friendly energy option.
What RNG is and why it matters
Most equipment that uses energy can only use a single kind of fuel, but the fuel might come from different resources. For example, you can’t charge your computer with gasoline, but it can run on electricity generated from coal, natural gas or solar power.
Natural gas is almost pure methane, currently sourced from raw, fossil natural gas produced from deposits deep underground. But methane could come from renewable resources, too.
Two main methane sources could be used to make RNG. First is biogenic methane, produced by bacteria that digest organic materials in manure, landfills and wastewater. Wastewater treatment plants, landfills and dairy farms have captured and used biogenic methane as an energy resource for decades, in a form usually called biogas.
Some biogenic methane is generated naturally when organic materials break down without oxygen. Burning it for energy can be beneficial for the climate if doing so prevents methane from escaping to the atmosphere.
In theory, there’s enough of this climate-friendly methane available to replace about 1% of the energy that the current natural gas system provides. The largest share is found at landfills.
The other source for RNG doesn’t exist in practice yet, but could theoretically be a much larger resource than biogenic methane. Often called power-to-gas, this methane would be intentionally manufactured from carbon dioxide and hydrogen using electricity. If all the inputs are climate-neutral – meaning, for example, that the electricity used to create the RNG is generated from resources without greenhouse gas emissions – then the combusted RNG would also be climate-neutral.
So far, RNG of either type isn’t widely available. Much of the current conversation focuses on whether and how to make it available. For example, SoCalGas in California, CenterPoint Energy in Minnesota and Vermont Gas Systems in Vermont either offer or have proposed offering RNG to consumers, in the same way that many utilities allow customers to opt in to renewable electricity.
Renewable isn’t always sustainable
If RNG could be a renewable replacement for fossil natural gas, why not move ahead? Consumers have shown that they are willing to buy renewable electricity, so we might expect similar enthusiasm for RNG.
The key issue is that methane isn’t just a fuel – it’s also a potent greenhouse gas that contributes to climate change. Any methane that is manufactured intentionally, whether from biogenic or other sources, will contribute to climate change if it enters the atmosphere.
And releases will happen, from newly built production systems and existing, leaky transportation and user infrastructure. For example, the moment you smell gas before the pilot light on a stove lights the ring? That’s methane leakage, and it contributes to climate change.
To be clear, RNG is almost certainly better for the climate than fossil natural gas because byproducts of burning RNG won’t contribute to climate change. But doing somewhat better than existing systems is no longer enough to respond to the urgency of climate change. The world’s primary international body on climate change suggests we need to decarbonize by 2030 to mitigate the worst effects of climate change.
Scant climate benefits
My recent research suggests that for a system large enough to displace a lot of fossil natural gas, RNG is probably not as good for the climate as is publicly claimed. Although RNG has lower climate impact than its fossil counterpart, likely high demand and methane leakage mean that it probably will contribute to climate change. In contrast, renewable sources such as wind and solar energy do not emit climate pollution directly.
What’s more, creating a large RNG system would require building mostly new production infrastructure, since RNG comes from different sources than fossil natural gas. Such investments are both long-term commitments and opportunity costs. They would devote money, political will and infrastructure investments to RNG instead of alternatives that could achieve a zero greenhouse gas emission goal.
When climate change first broke into the political conversation in the late 1980s, investing in long-lived systems with low but non-zero greenhouse gas emissions was still compatible with aggressive climate goals. Now, zero greenhouse gas emissions is the target, and my research suggests that large deployments of RNG likely won’t meet that goal.
Counterpoint by Emily Grubert, Assistant Professor of Civil and Environmental Engineering, Georgia Institute of Technology. Grubert’s piece first appeared in The Conversation. Local coverage by Advocate staff.
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