Which types of fuel can be used with a cogeneration plant? The Big Comparison
An engine is only as good as the fuel that drives it. This old wisdom from the automotive industry applies even more to a cogeneration plant, which is designed for continuous operation.
The choice of the right energy source is the first and most important strategic decision for your energy project. It determines not only the emissions and the ecological footprint but significantly influences economic viability, maintenance intervals, and the lifespan of your system.
“Technology is our drive, efficiency is our focus”. Therefore, at PowerUP, we view the fuels for cogeneration plants not just as a means to an end, but as a decisive factor for performance.
In this article, you will learn everything important about fuels for CHP plants.
The Omnivore: Why CHPs are so flexible
The heart of most CHP systems in the commercial and industrial sector is an internal combustion engine. Usually, this is a modified spark-ignited gas engine, or rarely (for diesel) a compression-ignition engine. These engines are technological chameleons: With the right adjustments to ignition, mixture formation, and exhaust aftertreatment, they can burn almost anything that is flammable and gaseous.
We basically distinguish between two categories:
- Fossil Fuels: Offer supply security and clean combustion but are finite resources (e.g., natural gas, propane).
- Renewable Energies: Are carbon-neutral and often cheaper to source (waste products), but place higher demands on engine technology (e.g., biogas, landfill gas, hydrogen).
The Classic: Natural Gas (Pipeline Gas)
When we talk about CHPs in the US, we mostly mean natural gas. It is the standard fuel for utilities, industry, and residential areas. The reason is obvious: The pipeline infrastructure is excellent, and domestic production (shale gas) keeps prices relatively low compared to other regions.
Technically, natural gas is a “grateful” fuel. It burns very cleanly, with almost no residues like soot or sulfur. This protects the engine and ensures long maintenance intervals.
Additionally, very high efficiencies in power and heat generation can be achieved with natural gas CHPs. For operators looking for maximum reliability with minimal effort, natural gas is often the first choice.
The Flexible Alternative: Propane (LPG)
Not every location has access to the natural gas grid. This is where Propane (LPG – Liquefied Petroleum Gas) comes into play. It is stored in a tank on-site and has similar combustion properties to natural gas.
Propane is a valid option, especially for remote manufacturing plants, greenhouses, or farms without a digester. The energy density is high, and the engines run—similar to natural gas—very gently on materials. However, logistics (truck delivery) and storage on the property must be calculated into the investment and operating costs.
The Green Power: Biogas, Landfill Gas & RNG
Here beats the heart of the energy transition—and often the heart of our customers in agriculture and waste management.
Biogas (Digester Gas): Produced by the fermentation of biomass (manure, organic waste) directly on the farm. It is the perfect cycle: The farmer uses waste to produce carbon-neutral electricity and heat.
Landfill Gas (LFG): A massive sector in the US. Waste in landfills decomposes to produce methane. Instead of flaring it, cogeneration plants turn it into revenue.
Renewable Natural Gas (RNG): If biogas or LFG is upgraded to pipeline quality, it becomes RNG. This is highly lucrative due to incentives like RINs (Renewable Identification Numbers) or LCFS (Low Carbon Fuel Standard) credits.
The Challenge: Biogas and LFG are “rough characters”. They often contain contaminants like hydrogen sulfide (H2S) or siloxanes (in landfills), which react to form acids or glass-like deposits in the engine. This attacks components like cylinder heads, spark plugs, and bearings massively.
This is exactly where PowerUP’s expertise lies: We supply compatible parts that withstand aggressive gases, ensuring stable operating hours despite demanding fuels for the cogeneration plant.
Niche and Phase-out: Diesel and Solid Fuels
There are fuels whose time is running out, and those that occupy niches.
Diesel / Fuel Oil: While common for backup generators (standby), diesel plays almost no role for new, continuous-duty CHP plants in the US. Reason: Strict EPA Tier 4 emission regulations require expensive aftertreatment (DEF/Urea), making continuous operation uneconomical compared to gas.
Wood Gas / Biomass: Solid biomass cannot be burned directly in the engine. It must first be converted into wood gas in a gasifier. This technology is fascinating and sustainable but technically highly complex and maintenance-intensive.
The Future: Hydrogen (H2)
Hydrogen is considered the fuel of the future. It burns completely emission-free to form water. Currently, pure green hydrogen is still expensive, but the Inflation Reduction Act (IRA) is boosting production with tax credits.
Modern gas engines are increasingly being delivered as “H2-Ready”. This means they can already handle blends of up to 20% hydrogen in the natural gas grid today and can be converted to 100% hydrogen later with manageable effort. Fuel cells also use hydrogen to generate electrical power and heat, but via an electrochemical path without combustion. For large industrial plants, however, the gas engine remains the dominant technology due to its robustness.
Fuel Choice and Economic Viability
Which fuel is worth it for you? The answer is a calculation comparing acquisition costs, fuel costs, and revenue.
- Natural Gas: Fuel costs fluctuate (market price), but low investment and maintenance. Economical through “Spark Spread” (electricity savings).
- Biogas/LFG: Fuel is “free” (waste) or cheap, but high investment in gas treatment and higher maintenance costs. Extremely economical through incentives and waste utilization.
- Hydrogen: Currently often a pilot project character, but strategically important for companies wanting to reduce their carbon footprint to zero.
A look at our article on costs of a CHP plant shows: The choice of fuel is the biggest lever for running costs (OPEX).
Your fuel determines our service
Whether you use clean natural gas or demanding landfill gas: Every fuel leaves its mark on the engine. Different energy sources mean different wear.
A landfill gas engine needs different spark plugs and intervals than a natural gas unit. We at PowerUP know these differences in detail.
We do not just offer “spare parts”, but solutions tailored to your fuels for the CHP plant and your engine—be it MWM®, INNIO Jenbacher®, or Caterpillar®.
Maximize your efficiency and minimize your downtime. Let us work together to ensure your engine performs at its best with any fuel.
