Electrification is a big focus in the changing energy landscape and for good reason. Battery-powered equipment can play a significant role in reducing emissions. With all the attention paid to electric solutions, it’s easy to overlook this truth: electrification isn’t the only path forward. And it may not be practical for every customer’s application. 

Alternative fuels can offer another route to lower emissions and support sustainability goals. In some cases, they can complement or serve as a bridge to electrification — particularly when electric equipment isn’t yet available or feasible for the job. 

At Caterpillar, we’ve been building engines that run on different fuels for more than 90 years. (Fun fact: We converted our dozers to run on propane and butane back in the 1930s.) Today, we’re expanding that legacy with investments in products that can run on a range of alternative fuels, so our customers have the flexibility to choose what works best for their applications. 

Thinking about making the switch? Here are a few things to keep in mind as you evaluate your options. 

Google “alternative fuels” and you’ll get millions of results — from vegetable oils to synthetic molecules and everything in between. It can be overwhelming. To help simplify the conversation, here are five of the most relevant options for those who operate Cat^® equipment today: 

1. Biodiesel is a renewable fuel made from animal or plant-based materials, typically blended with diesel (like B20) or used on its own (B100). It’s widely available, but may degrade over time, high blend ratios are not compatible with low emissions engines, and it usually presents challenges in cold weather. 
2. Renewable diesel (RD, R100) is another fuel made from animal or plant-based materials. It’s a drop-in replacement for diesel with a long shelf life, but it can be harder to find and more expensive due to demand. 
3. Methanol is an alcohol-based fuel primarily used in marine applications today. Conventional methanol is fossil-fuel based, but bio and e-methanol versions can offer more than a 90% reduction in lifecycle greenhouse gas emissions*. Accessibility can be limited inland. 
4. Ethanol is another alcohol-based fuel widely used in parts of the Americas and often blended into gasoline. It’s also being explored as a renewable energy carrier for power generation. 
5. Hydrogen is a gaseous fuel that can be used in internal combustion engines or fuel cells. When produced using renewable sources, hydrogen offers the potential for low or near-zero CO₂ emissions, but infrastructure, storage and cost remain key challenges. 

Also, don’t overlook e-fuels — like e-diesel and e-methanol — which are produced using renewable electricity and captured carbon. While still in the early stages of development, they represent a promising long-term option with some of the lowest lifecycle carbon intensities. 

*Source: 2121 IRENA & Methanol Institute Report 

No single fuel checks every box. The best choice depends on your region, your application and your sustainability goals. As you explore the options, consider how each fuel stacks up in three key areas: 

• Availability: Fuel access can vary significantly by location and industry. Ethanol and biodiesel are widely distributed in many areas. Others like HVO, methanol and hydrogen may be more localized or emerging. Logistics matter, too. Consider how easily a fuel can be stored, transported and dispensed at your site, particularly if it’s temperature-sensitive or requires special handling. 

• Cost: Upfront price is only part of the picture. Think about your total ownership costs, which might include fuel transport, storage infrastructure, handling protocols and even operational efficiency. Some fuels command a premium today, especially those in early development or high demand. Others may offer cost parity with diesel, especially in regions with incentives or mandates. 

• Carbon intensity: Are you aiming to reduce emissions at the tailpipe or across the full lifecycle of the fuel? Biodiesel and HVO, for example, may lower lifecycle emissions even if tailpipe output remains similar to diesel. Options like hydrogen and e-fuels can offer significantly lower lifecycle carbon intensity when produced from renewable sources, but those benefits depend on how the fuel is generated. 

You might be searching for a quick drop-in replacement for your current fleet. Or you might be looking for a lower-emissions solution to support electric charging or site power where grid access is limited. Either way, you’ve got options — and they’re already in use today. 

At Caterpillar, we’re actively supporting operations across the globe as they evaluate and apply alternative fuels including biodiesel, HVO, hydrogen, methanol and ethanol in Cat equipment, engines and gensets. We’re also collaborating with customers and industry groups to define fuel specifications, adapt engines for fuel compatibility and validate performance in real-world environments. 

For us, flexibility isn’t just about fuel type. It’s about giving you more options to keep working, support your sustainability goals, and prepare for what’s next.