In many ways, renewable natural gas is the ultimate form of recycling. The energy industry has been using it to generate electricity or fuel vehicles for decades, but here’s a new concept: injecting RNG into pipelines for direct use in our homes and businesses. It’s happening here—and around the world—and the sources are closer than you think. By Edward Remington
When it comes to natural gas, the word “fossil” might no longer be accurate to describe the natural gas flowing through pipeline networks.
For years, some utilities have been capturing greenhouse gas emissions from decaying organic material in landfills, wastewater treatment plants, farms and other sources and using it to generate electricity and fuel vehicles rather than letting it simply float into the atmosphere or be flared.
Now, as the world moves to reduce greenhouse gas emissions and energy users strive to reduce their carbon footprint, utility companies in the United States and worldwide are taking a closer look at injecting renewable natural gas into pipeline systems for direct use by consumers, providing the same fuel needs that geologic natural gas sources have long supplied.
An American Gas Foundation study projects that RNG has the potential to serve about 50 percent of the U.S. residential market and 10 percent of the total natural gas market. In order to get there, said Donald Chahbazpour, National Grid’s climate change compliance director, there needs to be a paradigm shift.
“People think natural gas has a static carbon footprint,” Chahbazpour told American Gas. “Geologic natural gas has the lowest carbon footprint already, and [by] using renewable natural gas, we can lower that even further. [For example] there is so much methane produced from the dairy sector. If you capture that, the renewable natural gas from that feedstock actually has a negative carbon footprint.”
National Grid, whose U.S. gas and electric operations serve New York, Massachusetts and Rhode Island, is one of the pioneers among U.S. utility companies to add RNG to its pipelines. Through one of its legacy companies, Brooklyn Union, it has been capturing gas from the Staten Island landfill for pipeline delivery since the 1980s.
“The biggest driver of renewable gas is greenhouse gas reduction, but what makes renewable gas more compelling is that it also enhances diversity of supply while providing a solution for using local waste resources to produce renewable energy,” reports a 2010 white paper from National Grid, Renewable Gas—Vision for a Sustainable Gas Network.
It’s important to note, however, that “renewable natural gas” is not just another name for biogas or landfill gas. For safety and quality reasons, pipeline operators and utilities have very specific standards on the composition of gas entering their systems.
“We don’t consider biogas ‘natural gas’ until it meets pipeline quality or transportation fuel standards,” said David Cox, co-founder of the Coalition for Renewable Natural Gas, a nonprofit national trade group that advocates for increased development, deployment and use of RNG.
Added Chahbazpour: “RNG means it’s pipeline quality. We take the biogas, remove the CO2 and clean it up. You do not inject biogas into the pipeline.”
North America has an ample supply of geologic natural gas. But it’s a different story in Europe, where countries have been importing most of their natural gas for years.
Many Western European countries are seeking to reduce their reliance on Russia, one of the continent’s major gas providers. For that reason, and because of the environmental benefits, there is strong interest in Europe in capturing biogas and converting it to renewable natural gas, also referred to as synthetic natural gas or Bio-SNG.
As in the United States, much of the RNG produced in Europe has been used as transport fuel in countries including Italy and Sweden. In addition, like their ally across the Atlantic, European countries are working to add more RNG into pipeline systems.
For example, JV Energen of Dorchester, England, was the first commercial plant to inject “green gas” into the existing United Kingdom gas network via the Rainbarrow Farm Anaerobic Digester Plant, earning a number of industry awards in 2013.
Other recent projects include:
With the UK’s and the European Union’s aggressive carbon and greenhouse gas reduction goals, substantial progress on RNG in Europe and around the globe can be expected in the years to come.
National Grid is using the knowledge it has gained from its Staten Island project, along with its company commitment toward sustainability, to capture more renewable gas, this time from New York City’s massive Newtown Creek wastewater plant.
The Newtown Creek plant treats more than a billion gallons of wastewater per day. Officials say the public-private partnership involving the city, National Grid and Waste Management will reduce the amount of organic waste sent to landfills, produce enough reliable clean energy to heat 5,200 homes and improve air quality by reducing the vehicle emissions equivalent of 19,000 cars.
For years National Grid was one of the few utilities to source RNG for its pipeline system, but more companies are now adopting the process.
On the West Coast, both Southern California Gas Co. and NW Natural have plans to capture biogas, upgrade it to RNG and inject it into pipelines for use by their customers. As in National Grid’s case, the burners on the end users’ systems won’t be able to tell the difference between the renewable and the traditional, fossil-based natural gas that has been flowing through the network for generations.
“We live in one of the most environmentally aware parts of the country—and one that does not produce natural gas,” Bill Edmonds, NW Natural’s director of Environmental Management and Sustainability told American Gas. “So we have been very sensitive to concerns our customers and community may have about [hydraulic fracturing] and about methane emissions all along the natural gas value chain.”
Responding to that concern, NW Natural and the City of Portland, Oregon, jointly announced an RNG partnership in April ahead of Earth Day. NW Natural will take renewable natural gas from Portland’s largest wastewater treatment plant for injection into NW Natural’s pipeline system and to fuel part of Portland’s heavy-duty vehicle fleet.
City officials say the project, Portland’s single largest climate action project, will cut greenhouse gas emissions by 21,000 tons per year. It will generate more than $3 million in annual revenue for the city and replace the use of 1.34 million gallons of diesel fuel with clean RNG—enough to run 154 garbage trucks for an entire year.
The Portland partnership is NW Natural’s first foray into putting RNG into its pipeline system (other than some short-lived pilot projects in the 1980s, when technology and conditions were not as favorable as today). But NW Natural customers have supported biogas projects at Pacific Northwest dairy farms since 2008 through Smart Energy, a voluntary program that enables residential and business customers to offset emissions from their own natural gas usage. NW Natural works with The Climate Trust, a nonprofit that funds greenhouse gas reduction projects, such as farm biodigesters, in exchange for carbon credits that are then purchased by Smart Energy customers.
“The typical cow produces 120 pounds of manure per day,” NW Natural’s Smart Energy website explains. “Methane emitted from cow waste is 21 times more potent than CO2.”
Biodigesters capture the methane from dairy cow manure and use it to produce biogas. Some farms also use it to generate electricity that they sell to local electric utilities.
“The captured methane is a renewable and on-demand energy source,” Edmonds explained. “Heat generated in this process can also be reused. Byproducts such as fertilizer and animal bedding help close the resource loop, reducing waste, protecting air and water quality and creating more sustainable revenue streams for our region’s farmers and communities.”
Meanwhile, SoCalGas and waste management company CR&R Environmental announced in March that RNG from an anaerobic digestion facility in Perris, California, is being used to fuel CR&R’s waste-hauling trucks. SoCalGas built a 1.4-mile pipeline to bring the carbon-neutral RNG into its distribution system.
While it’s the first time that RNG supply has been directly interconnected with and piped into the SoCalGas system, company officials say it won’t be the last. “We’re exploring several different approaches to bringing more renewable gas into our system and delivering it to customers,” said Lisa Alexander, SoCalGas’ vice president, customer solutions and communications.
“This is exciting because it reduces short-lived climate-pollutant emissions—the methane from dairy manure and food waste and green waste—while creating a renewable fuel for our customers. California aims to reduce those short-lived climate pollutant emissions by 40 percent by 2030.”
Alexander said SoCalGas is also assisting biogas producers in cleaning up their raw biogas to convert it to pipeline-quality RNG.
“We regularly meet with several potential producers, ranging from wastewater plants and landfills to dairies and organic waste diversion project developers, to educate them on connecting to our system,” she added.
Cox, of the Coalition for Renewable Natural Gas, said there are about 40 projects injecting RNG into pipelines in the United States—a number that is sure to grow as more people and businesses realize the benefits of adding renewable fuel to the existing pipeline mix.
He and Johannes D. Escudero founded the Coalition for Renewable Natural Gas six years ago, when they worked to change an obscure California law that outlawed gas originating from landfills to be injected into pipelines in the state. While working on the legislation, it quickly became clear that many utilities and pipeline companies saw the economic and environmental potential for capturing RNG and using it as a fuel supply for homes, businesses and vehicles.
Cox noted that many Fortune 500 companies have made a commitment to become carbon neutral or even carbon negative. RNG helps them achieve their goals by lowering the overall carbon intensity of their fuel use.
That desire is “a great opportunity for the natural gas community to embrace renewable natural gas,” Cox said. “The volume we are producing today is relatively small, but as we scale up, I think it will be a huge help to the natural gas industry.”
National Grid’s Chahbazpour calls it a “no-brainer” for natural gas utilities to work to increase the use of RNG as they face increasing pressure to “go green.” And the fact that there is already a substantial natural gas transportation network helps.
“[RNG] can be distributed via the same pipeline network as geologic natural gas, and can be used in the same ways and in the same equipment to generate electricity, heat homes, create durable plastics and power vehicles,” states the Coalition for Renewable Natural Gas’ Fueling America’s Growth with Renewable Natural Gas white paper.
Added SoCalGas’ Alexander: “Our nation has made a substantial investment in this infrastructure, and today we have one of the most robust systems on the planet. In most urban and semi-urban areas, there are pipelines within a reasonable distance that can accommodate renewable gas by building out distribution or transmission pipeline extensions. Conveniently, this is also where much of our organic waste is located.”
But if RNG, like geologic natural gas, is composed of mostly methane (CH4), how can it be considered carbon neutral or even carbon negative? The answer lies in the life cycle of the gas.
“Unlike geologic natural gas, producing and using RNG captures and uses biogases from decomposing organic wastes that would otherwise go directly into the atmosphere, so it emits much less greenhouse gas over its life cycle,” reports the Coalition’s white paper. “The more RNG is produced and carried by natural gas infrastructure, the more it contributes to positive impacts and sustainability goals of the natural gas industry as a whole.
“The U.S. generates over 70 million tons of organic waste per year across every city, town and rural county in America. That includes 1,750 large landfills, 8,000 large farms and dairies, and 17,000 wastewater treatment facilities. And the advantage of capturing gas from these facilities, besides reducing greenhouse gas emissions into the atmosphere, is that these natural generators of gas are everywhere communities are, not just in deep, million-year-old geologic formations.”
“Policymakers think of wind and solar as the only source of renewables,” said National Grid’s Chahbazpour. “We have to raise awareness. People don’t realize this opportunity exists.”
After all, as the Coalition for Renewable Natural Gas’ white paper points out, developing local RNG sources is “like discovering an inexhaustible gas well in a community’s backyard.” Added Cox, “We absolutely believe that long term, every community can have their own source of renewable natural gas.”
