Turning landfill waste into energy

Turning landfill waste into energy

Believe it or not, landfills have a key role to play in the transition to renewable energy. Landfills are no longer just disposal points, but rather, they can be the starting points for new energy sources. This article will take a deeper look into how landfill waste is turned into renewable natural gas, and how landfills are becoming valuable energy resources.

Why and how do landfills play a role in the energy transition?

Proper landfill design and management are essential for safe waste disposal. Well-operated landfills are designed to bury trash with minimal negative impact on people and the environment. Special lining systems prevent contamination of nearby ground and surface water. Gas collection systems control and collect the methane and landfill gas released by decomposing waste. This setup provides a protective layer between the waste and the environment, generating a sustainable and creative use of the waste. 

Landfills aren’t all the same – they fall into distinct categories based on the type of trash they collect. For example, municipal solid waste landfills accept mainly household and non-hazardous commercial waste. By contrast, industrial waste landfills only handle industrial plant waste, construction and demolition debris, and site cleanup waste. Bioreactor landfills speed up the biodegradation of organic waste. Lastly, coal combustion residuals and hazardous waste and landfills are strictly regulated due to the nature of the waste they accept. 

Beyond simply receiving garbage, landfills have the potential to be used as renewable energy resources. Organic materials that decompose in landfills produce a methane-rich gas called biogas, or landfill gas. Due to its high methane content, it does increase greenhouse gas emissions. This is why in the United States many landfill operators are required to collect biogas before it is emitted into the atmosphere. Some operators simply flare it or burn it off, but increasingly, the captured biogas is used in a productive way. For instance, it can be used on-site in a generator to produce heat and electricity. It can also be refined into almost pure methane and used interchangeably with natural gas.

Obtaining methane in this manner can be nearly carbon-neutral. Under some definitions, it may even carbon-negative. That’s because when it’s not captured and burned, methane is   released into the atmosphere in methane form, which has a greater global warming potential than CO2.  

Collecting RNG through the “waste to energy” process 

"Waste to energy" techniques are designed to solve two problems at the same time—managing waste and generating energy. The traditional waste-to-energy approach consists of burning garbage, making steam with heat, and generating electricity with steam. This has been done at scale for decades. 

Collecting methane at landfills is a different way to obtain energy from waste. Landfill methane forms when organic waste such as food scraps and other biodegradable material becomes buried in a landfill and undergoes decomposition in the absence of oxygen. Micro-organisms break down organic matter into simpler molecules such as carbon dioxide, methane and other gases. Methane is produced in the largest quantities. These gases migrate through the landfill’s waste layers. Operators who seek to capture them install collection systems consisting of a network of perforated pipes. The collected biogas is then extracted and treated to remove undesirable components. Biogas that is merely burned on-site for heat can be used after a simple moisture removal treatment. Biogas can also undergo more extensive treatments to obtain nearly pure methane. The result -renewable natural gas, or RNG- can sometimes be injected into the local natural gas network.

Landfill availability    

The United States has approximately 2,600 operating MSW landfills according to the U.S. Environmental Protection Agency. Of these, over 530 landfills are currently recovering and using biogas in some way. Another 470 have been identified as potentially well-suited for the adoption of a waste-to-energy solution. This constitutes a large opportunity. Deploying waste-to-energy systems at more landfills would be an excellent way to boost renewable energy production, while also creating jobs and opportunities in less-affluent areas. 

Using RNG to power vehicles    

When biogas is upgraded to RNG, it can be used as a fuel in any vehicle designed to run on natural gas. Chemically, RNG and natural gas are identical. RNG, however, is not obtained from fossil resources and as a result, its use can be carbon neutral.

Numerous businesses and local governments are running their vehicle fleet on RNG. RNG, for example, is commonly used to fuel garbage trucks, showcasing a circular approach to energy usage where waste is converted into fuel, and then used for waste collection. There are approximately 10,000 garbage trucks running on RNG in the United States.

RNG offers an exciting and viable route toward sustainable transportation and power generation. By tapping into the potential of our landfills and other waste sources, we can not only power our vehicles in an environmentally friendly manner but can also contribute to the broader global effort to mitigate climate change. Cummins’ natural gas engines are designed to efficiently operate on RNG, making them an optimal choice for businesses seeking renewable energy solutions.
 

Puneet Singh Jhawar

Puneet Singh Jhawar

Puneet Singh Jhawar is the General Manager of the global natural gas business for Cummins Inc. In this role, he is responsible for the product vision, financial management and overall performance of the natural gas business. Over his 14-year career at Cummins, Jhawar has cultivated successful relationships with a number of Cummins’ largest customers. Jhawar has extensive global experience, with roles based in the Middle East, India, Europe and the US.

Cummins Custompaks are being used for water management as Thailand struggles with its water crisis

CustomPak on site

Water crisis

Sixty Cummins Inc. CustomPaks are in service in Thailand as part of a critical water management plan aimed at easing the country’s water crisis – a crisis that has caused enormous economic and social damage and stirred conflict among communities.

Over the past several decades, Thailand has continually faced water problems caused by severe drought. Water reserves in dams and reservoirs are insufficient while water resources are often contaminated with toxins caused by urban communities and the industrial and agricultural sectors.

Severe flooding is a threat, too, at a time when the realities of climate change are hanging over the country.

As a result, the allocation of precious water resources, which must be shared among various stakeholders including new and existing industry, large and small agriculture, and cities and villages has become a flashpoint.

Kittithanapat Engineering Co. (KTP), has been involved in the water management system since 1996, working closely with authorities such as the Royal Irrigation Department, Department of Water Resources, Bangkok Metropolitan Authority and others.

CustomPaks on site

600 hp CustomPaks

To help KTP meet its often urgent requirements, Cummins DKSH (Thailand) has recently supplied 60 Australian-built CustomPaks – 45 powered by Cummins’ X15 engine rated at 600 hp, and 15 powered by the QSL9 rated at 325 hp. These fully self-contained powerpacks are emissions certified to Tier 3.

The CustomPaks are coupled to hydraulically-driven, large-volume submersible water pumps sourced by KTP from US company Moving Water Industries (MWI); KTP is the exclusive distributor in Thailand for these MWI Hydroflo pumps.

Prior to Cummins’ involvement, KTP was using another diesel engine brand but service support wasn’t up to the standard required.

Long-serving KTP engineer Kittisak Thanasoot says Cummins DKSH’s reputation for technical and aftersales support along with the reliability of the Cummins product were a key reason behind KTP’s decision to specify the CustomPaks for the Royal Irrigation Department.

The ability of Cummins DKSH to respond to short delivery times was also important.

“Supplying large quantities of high horsepower diesel engines for emergency situations such as flash flooding can be a challenge for KTP,” says Kittisak Thanasoot.

“Responding to the needs of the government agencies to manage such problems in a timely manner and with least impact on communities, KTP has found the answer in our partnership with Cummins DKSH.”

Power, pride and passion

Parked semi truck

The switch back to Cummins power has been beneficial for iconic New Zealand company Uhlenberg Haulage. It's all about whole-of-life costs.

Uhlenberg Haulage is closing in on 60 years in business, having been founded in 1966 by Mike and Carol Uhlenberg.

Based in Eltham, Taranaki, in New Zealand’s North Island, the operation is today owned and operated by their sons Chris, Daryl and Tony Uhlenberg.

Describing the Uhlenbergs as “old school family truckies”, Daryl talks about the company’s time-honored journey with a definite tone of pride, especially the work of his parents in laying the foundations for what is today an iconic fleet in its own right.

Cummins Inc. made its debut in the Uhlenberg fleet in 1971 with an NH250 powering a second-hand Kenworth K923 used in logging. A second Kenworth, a new W924 with a Cummins NTC335, followed soon after hauling an LPG tanker.

The Uhlenberg operation today comprises 40 prime movers and a variety of trailing gear to cater for the myriad of a jobs the fleet is involved in.

A number of Peterbilts feature in the fleet although Kenworth is now the brand of choice with six new units to be delivered over the next 12 months to cater for business growth.

Cummins’ X15 Euro 5 engine rated at 550 or 600 hp is the preferred power specification, with 18 red engines currently in the fleet.

Uhlenberg family in front of truck

Whole-of-life support

“The switch to Cummins has been a very good experience for us. We have nothing but praise for the Cummins organization,” says Daryl.

“The whole-of-life picture is the key thing for us and we’ve got that nailed with the support we get from Cummins – parts availability, scheduled maintenance, life expectancy and in-frame rebuilds.

“So the red engines turn up, we run them to life, which is 900,000 to 1.2 million kilometers, and then Cummins does an in-frame overhaul in a timely manner. If there’s an issue, parts and support are close by.

“The support we get from Cummins Palmerston North is fantastic, second to none.”

Daryl recently looked under a Kenworth that was in the workshop for a service and was surprised to see no oil leaking from the one-million-kilometer X15. “I remember when I was a fitter we had to wear a raincoat when working under a truck,” he jokes.

Fuel agnostic

Acknowledging that the push to decarbonize is now “very real”, Daryl likes the idea of Cummins’ fuel agnostic concept where one base internal combustion engine, optimized to run on diesel, can also be customized to run on ultra-low and zero-carbon fuels like renewable natural gas and hydrogen.

“My father was a pioneer of linehaul trucking in New Zealand and he always embraced new technology. He was never scared of it,” he says.

“I tend to be a little more cautious but I can see where a 500 hp natural gas or hydrogen engine would work for us in short haul applications,” he admits. “We’re certainly willing to look closely at these alternative fuel technologies when suitable infrastructure is in place.”

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