How Different Alternative Fuels React in Cold Temperatures

Though spring is technically here, if you’re in the Midwest, you know that winter lingers longer than we may like it. As alternative fuels react differently from one another in cold weather—while some are more resilient in winter, others require some preparation and knowledge to keep the vehicle operable—knowing how different alternative fuels function in cold weather is still important at the beginning of spring. Read on to learn about each alternative fuel’s performance in winter and how to keep your alternative fuel vehicle up and running in the harshest temperatures.

How biodiesel reacts in cold temperatures

As aforementioned, petroleum diesel also faces challenges in cold weather. Biodiesel performance in cold weather varies based on the blend ratio, feedstock, and characteristics of the petroleum diesel used.

Despite the misconception that biodiesel struggles in low temperatures, fleets have successfully operated in freezing conditions using blends up to B20. For example, No. 2 diesel and B5 (containing up to 5% biodiesel) typically exhibit similar cold-weather performance. Both biodiesel and No. 2 diesel contain compounds that can crystallize in extreme cold. To prevent engine power loss, CFPP should remain above expected winter lows.

Higher blend biodiesels, however, are more prone to gelling or freezing, much like diesel. As temperatures drop, gelled fuel can cause a loss of power by clogging filters and fuel lines, eventually leading to engine failure. This makes understanding and mitigating cold-weather risks essential for reliable performance.

Something to keep in mind when using biodiesel and operating a vehicle is knowing whether the biodiesel is distilled or undistilled. Distillation removes minor components, such as steryl glucosides, which can cause cold-weather issues. A distilled B10 blend will perform better in cold conditions than an undistilled B10 blend with the same cloud point.

Additionally, winter fuel additives are essential for cold-weather operability. Additives help lower CFPP and improve fuel flow for both diesel and biodiesel blends in freezing temperatures. Additives should be applied before the fuel reaches its cloud point. While No. 1 diesel (kerosene) has traditionally been used to improve cold-weather performance, it has a lower British Thermal Unit (BTU) value than diesel and can reduce fuel economy. Instead of using kerosene, additives are often more cost-effective and just as effective.

Diesel fuel’s cold-weather properties can be measured through various tests. Two key cold-weather performance measures are cloud point (CP) and cold filter plugging point (CFPP). CP is the temperature at which wax crystals begin to form, causing fuel to appear cloudy. CFPP is the temperature at which these crystals grow large enough to clog the fuel filter. CFPP generally represents the lowest operational temperature for a vehicle. Simulated distillation assesses fuel volatility over a temperature range. Cloud point and pour point testing often help estimate the cold filter plugging point, which determines whether fuel will flow properly through an engine.

Water contamination is the leading cause of fuel filter plugging in winter. When temperatures drop below 32°F, water in the tank can freeze and restrict fuel flow. Water accumulation can also lead to microbial growth, a more frequent issue since the introduction of ultra-low-sulfur diesel (ULSD) in 2006. Sulfur previously acted as a natural antimicrobial, and its reduction has made microbial contamination more common. Preventing water from entering fuel tanks reduces cold-weather complications. Keeping tanks full minimizes condensation, securing fuel caps prevents moisture intrusion, and inspecting hoses and gaskets helps identify leaks. Underground storage tank sumps and spill containers should also be kept clean and dry.

If water is present in a storage tank, testing for microbes is recommended. Biocides can treat contamination, but in severe cases, tanks may require draining and cleaning.

To ensure biodiesel performs well in cold weather, several strategies can be used. Seasonal fuel testing before winter can help predict performance under colder conditions. Fuel additives, such as cold flow improvers, can prevent crystallization. Regular testing of bulk storage tanks for water and contaminants is essential to prevent issues, as water contamination can accelerate fuel degradation. Proper tank maintenance practices can further reduce the risk of water infiltration.

Storage plays a key role in biodiesel performance but does not change a fuel’s cloud point. However, cloud point does influence storage best practices. All fuel, whether petroleum diesel or a biodiesel blend, should be stored above its cloud point. For distilled biodiesel blends, a few degrees above cloud point is sufficient. If the biodiesel is undistilled or its quality is uncertain, maintaining storage temperatures at least 10°F above the cloud point of the final blend is recommended to prevent operability issues.

Furthermore, choosing the right blend for a fleet depends on storage conditions and fuel consumption rate. Keeping diesel vehicles in heated garages when not in use or using engine block heaters can improve cold-start performance, and fleets with above-ground storage tanks that use fuel quickly are less affected by air temperature since the fuel doesn’t sit long.

Storage decisions shouldn’t be based solely on air temperature—fuel that turns over in a week at five degrees Fahrenheit may perform better than fuel stored for 30 days near its cloud point. The longer fuel remains near or below its cloud point, the higher the risk of fuel components separating. Working with a fuel provider to select the appropriate blend for local conditions, implementing winter maintenance best practices, and conducting routine fuel testing can help ensure reliable performance throughout the colder months.

For vehicles in operation, proper blending, handling, and additives are essential. When done correctly, biodiesel blends can be used reliably in cold weather. Many truck stops and travel centers continue offering biodiesel blends throughout winter, often adjusting to lower blends on the coldest days. Drivers may already be using biodiesel blends in winter without realizing it.

How renewable diesel performs in winter

It is important to understand the difference between biodiesel and renewable diesel. Renewable diesel remains stable in freezing temperatures and resists gelling due to its chemical similarity to petroleum diesel, though cold weather can negatively impact fuel economy. Biodiesel, on the other hand, is more susceptible to gelling in cold conditions, which can hinder engine performance.

Renewable diesel meets the same American Society for Testing and Materials (ASTM) standard as petroleum diesel but behaves differently in cold conditions. Unlike conventional diesel, renewable diesel can freeze solid when stored near its cloud point, which can be as low as -10°C. To mitigate this risk, the Freezing Point test helps determine appropriate temperature limits for storing and handling renewable fuels.

The Cloud Point of renewable diesel depends on how much the producer isomerizes the paraffins during production. Each manufacturer’s production method affects the final fuel’s Cloud Point, leading to variations in performance. Most renewable diesel producers in the U.S. follow commonly accepted pipeline specifications and seasonal guidelines for Cloud Point, but standards vary. As more producers enter the market and pipeline regulations remain inconsistent across regions, customers should be aware that the Cloud Point of renewable diesel may differ based on location and season.

Blending biodiesel with renewable diesel is becoming increasingly common. Research shows that blending renewable diesel with high-quality, low-cloud-point biodiesel lowers the Freezing Point, creating a 100% renewable fuel that remains stable at lower temperatures compared to renewable diesel alone. Some blends of renewable diesel and biodiesel leverage the lower Cloud Point of renewable diesel while incorporating key benefits of biodiesel, such as enhanced lubricity and reduced emissions, which renewable diesel alone does not provide.

How ethanol reacts in cold temperatures

Ethanol is an effective coolant and antifreeze agent, helping to keep the engine running cool and preventing coolant from freezing in subzero temperatures. As an alcohol, ethanol doesn’t freeze, making it an excellent antifreeze for gasoline, especially since it’s typically present in higher concentrations than the amount of gasoline antifreeze in a tank.

Ethanol is blended into fuels like E10 (87 octane gasoline), E15 (88 octane gasoline), E85, and other mixtures and significantly lowers carbon dioxide, ozone-forming pollutants, and evaporative emissions, helping to reduce poor air quality, especially during the winter months. 

However, ethanol’s presence in fuel increases the volatility (vapor pressure) of gasoline, meaning ethanol requires more energy to vaporize. This increased volatility makes it harder for ethanol to vaporize in cold temperatures, meaning it takes longer for ethanol to vaporize compared to gasoline. As a result, cars running on E85 might not perform as well or idle smoothly in cold weather until the engine warms up.

According to the Department of Energy, ethanol content is adjusted seasonally to improve cold-start and warm-up performance, which is why winter blends of E85 are available. These blends typically contain less ethanol, and you can also mix in some gasoline to further reduce the ethanol content. With some gasoline mixed into the E85, you won’t need to worry about cold starts, even in winter.

According to the Department of Energy, ethanol content is adjusted seasonally to improve cold-start and warm-up performance. For example, in Minnesota, the ethanol content of E85 ranges from 51-83% depending on the season, ensuring your vehicle is ready to go year-round, no matter the weather. All cars from model year 2001 or newer are approved to use E15 (88 octane).

If you’re concerned about starting your vehicle in cold weather, there are a few steps you can take to ensure smoother cold starts with flex fuel. Parking inside a garage, if available, can help as it provides a warmer environment than outdoors. Using an engine block heater is another option; it’s a small electric heater that attaches to the engine and warms it before starting, making cold starts easier.

You can also add gasoline to your fuel tank—around 10% or more of gasoline will lower the ethanol content significantly. Maintaining your engine is crucial, so make sure to check spark plugs and ignition components before winter. Additionally, installing an eFlexPlus or eFlexPro kit allows you to adjust the cold start settings for your vehicle via a smartphone app or software. These kits were designed in Finland, where freezing temperatures are common, ensuring they are effective in helping vehicles start in cold conditions.

How compressed natural gas (CNG) performs in winter

Cold weather can significantly impact the performance and starting of natural-gas vehicles (NGVs), much like diesel engines. Extreme cold weather can impact the starting and performance of compressed natural gas (CNG) vehicle engines. When temperatures drop below freezing, issues such as low fuel pressure and cold air intake into the engine become common. While weather conditions cannot be controlled, proper preventative measures can help ensure that CNG vehicles operate smoothly, even in harsh winter conditions.

In freezing temperatures, CNG vehicles can experience several problems if not properly winterized. Ice can form and thaw, leading to condensation that may damage engine sensors. The fuel pressure regulator diaphragm can freeze, causing improper regulation. Fuel and filters can become contaminated with moisture, ice, or debris. Additionally, the fuel regulator may not be properly warmed due to a lack of circulating coolant and fill receptacles may leak if O-ring seals shrink. Moreover, the engine throttle plate can stick or fail to move freely, the secondary fuel pressure regulator may malfunction, and the intake manifold pressure/temperature sensor could become contaminated. Charge-air coolers may prevent proper warm-up and the throttle plate may not function smoothly.

There are multiple ways to keep your natural gas vehicle properly running in winter. To keep CNG fleets running efficiently in cold temperatures, monitor fuel quality. Moisture and compressor oil can contaminate the system, affecting engine sensors and other costly components. Collaborating with fuel suppliers to verify that their stations are adequately prepared for winter and that their fuel quality meets or exceeds engine manufacturer guidelines is crucial. 

Refueling in cold temperatures also requires extra vigilance, as ice can prevent the fill nozzle from properly connecting, potentially causing leaks. If this occurs, inserting and removing the nozzle multiple times can help clear the ice. Persistent issues may indicate frozen O-rings in the fill receptacle, which often reseal themselves as temperatures rise. If leaks continue, replacing the O-rings or contacting the station operator is recommended.

Leak testing can be challenging in cold weather because detection solutions may freeze. Using a leak detection solution, which works in temperatures as low as -54°F (-48°C), is helpful. Keep the container in a hot water bath to extend the effectiveness of the solution. Always check for leaks quickly and avoid chipping away ice from fuel system parts, as this can cause damage. Instead, melt the ice using a stream of water from a hose or bucket.

Maintaining the high-pressure fuel filter is also vital for winter operation. The high-pressure filter traps particulates and removes moisture from the fuel. If not cleaned regularly, it can restrict fuel flow and cause damage. Draining and replacing low-pressure filters as per engine manufacturer recommendations is also essential to prevent contaminants from entering the engine.

Using the correct engine oil viscosity for winter temperatures ensures proper lubrication and reduces strain on the starter. Low-viscosity oil approved for natural gas service helps engine components move freely in cold conditions. Installing engine block and battery heaters further assists in ensuring proper startup in extreme cold.

Frost or ice on fuel-carrying components could indicate a leak and reduce fuel flow. Frost should never form on the fuel pressure regulator, which relies on engine coolant for warmth. If frost appears, inspecting and repairing any coolant leaks in the hoses connected to the regulator is necessary.

Another way to keep your natural gas vehicle, like CNG, operating well in winter is to park vehicles indoors when possible, with proper ventilation. Liquefied natural gas (LNG) vehicles should never be parked indoors.

Additionally, allowing the engine to warm up before driving is essential since the fuel pressure regulator depends on warm engine coolant to function properly. The engine has reached its optimal operating temperature once the heater begins producing warm air.

Winterizing CNG systems with specialized kits can also improve performance in cold weather. These systems use engine coolant to increase fuel temperature and boost pressure, enhancing engine functionality. Regular maintenance and prompt repairs are key to ensuring reliable operation throughout the winter season.

As domestic U.S. production has increased over the past decade, freeze-offs have become more frequent, highlighting the vulnerability of newer production sources to extreme cold. Regional freeze-off forecasts have helped predict these disruptions, aligning closely with expected scenarios.

The cold weather surge in January 2024 demonstrated the critical impact of freeze-offs and storage challenges. Many market participants struggled with these issues, prompting the introduction of a new freeze-off model that accurately forecasted freeze-offs by region two weeks in advance. This model proved highly accurate, with storage estimates showing less than a 1% error during the third-largest withdrawal in U.S. history.

How propane performs in freezing temperatures

Propane is a versatile fuel commonly stored in pressurized cylinders, where it remains in liquid form. Propane has a freezing point of -306.4°F, while it transitions back to its liquid form at -44°F, so it is very unlikely that your propane vehicle will freeze under normal winter conditions.

However, while propane itself won’t freeze in typical temperatures, it can still be impacted by extreme cold. Propane contracts in low temperatures, and when it gets very cold outside, the volume of propane inside your fuel tank will shrink, leading to a drop in pressure. When the pressure gets too low, it can cause a couple of issues, such as inaccurate readings, giving you a false impression of how much fuel you have left. If the pressure drops too much, the propane may not be able to reach the other parts of the engine. To maintain proper pressure in your tank, keep roughly 30% of the tank’s capacity filled with propane.

However, major temperature fluctuations, like in early spring, can significantly impact propane storage and usage, particularly in propane-powered vehicles. As temperatures rise, the liquid propane expands, increasing the internal pressure of the tank. In cold weather, this can become a safety hazard, especially if a propane-powered vehicle with more than 80% fuel in its tank is brought into a heated building. The sudden temperature increase raises the tank’s pressure, and if overfilled, the safety relief valve will activate, releasing propane gas. This released gas can ignite if there are any nearby ignition sources, leading to a potentially dangerous situation. 

To verify the liquid fuel level, park the vehicle on a level outdoor surface, away from potential ignition sources. While wearing neoprene gloves, disconnect the fuel line and briefly open the tank valve. A properly filled tank will produce an audible hiss but no white fog. If white fog is present, it indicates an overfilled tank. In such a case, do not bring the vehicle indoors until the liquid propane level drops below 80%. Running the vehicle can help reduce the fuel level safely. Before moving the vehicle inside, recheck all valves, especially the pressure relief valve, for leaks.

Before bringing a propane-powered vehicle indoors, it is crucial to ensure the propane system is leak-free. In warmer temperatures, a soap and water solution can be used to inspect connections, valves, and lines for leaks. In colder conditions, a commercial leak detector solution from a safety supply store or a combustible gas indicator calibrated for propane is recommended.

When performing indoor servicing or repairs on a propane-powered vehicle, ensure the fuel lines are free of propane. Fuel lines should only be charged when the engine requires propane. To safely charge the fuel lines, first turn the tank valve clockwise to close it, then allow the engine to run until it shuts down due to lack of fuel. Once repairs are complete, slowly open the fuel line valve to refill the lines with propane. If the excess flow valve engages, shut off the tank valve, wait 10-15 seconds for it to reset, and then reopen it gradually.

In the event of a propane gas release inside an enclosed area, immediate action is necessary to ensure safety. Evacuate the area immediately, as propane vapors are heavier than air and will settle at floor level. Eliminate all potential ignition sources, including torches, water heaters, pilot lights, and cigarettes. If possible, close the leak source and ventilate the area by opening doors. Do not restart any ignition sources until the propane odor has completely dissipated. If there are any uncertainties, consult the manufacturer or propane distributor for guidance. By adhering to these best practices, propane-powered vehicle operators can ensure a safe working environment and avoid potentially hazardous incidents.

How hydrogen performs in winter

A key advantage of fuel cell vehicles is their ability to operate reliably in all weather conditions, including extreme cold. Hydrogen’s extremely low freezing point of -259.14°C (-434°F) ensures that outdoor temperatures, even in harsh winter conditions, will remain far above this threshold. This makes hydrogen-powered vehicles, including buses and trains, particularly well-suited for cold-weather operations.

A U.S. study on hydrogen-powered buses found that battery-powered buses experience a 37.8% range reduction when temperatures drop from 50-60°F to 22-32°F, while hydrogen buses only experience a 23.1% reduction. This highlights that hydrogen-powered vehicles are more resilient in colder climates, although frequent refueling may be necessary in extreme conditions. Additionally, fuel cell buses offer an emissions-free alternative for transit operators without compromising on the performance and utility of conventional diesel buses. Hydrogen-powered trains follow a similar principle, maintaining functionality despite colder temperatures, although the impact may vary slightly depending on the specific model.

One reason for hydrogen fuel cell vehicles’ resilience in cold temperatures is the heat generated by the fuel cell during operation. For example, when the hydrogen fuel cell bus is parked and not in operation, the fuel cell stops consuming fuel and generating heat, causing the internal temperature to gradually drop. Even when the ambient temperature drops below 0°C, this heat prevents system freezing, enabling operation in temperatures as low as -30°C. Additionally, this heat can be used to warm the cabin or battery compartment, ensuring passenger comfort and optimal system function. 

For short downtime periods, the fuel cell’s insulation and mass retain heat for several hours, allowing the bus to restart without additional warm-up time. If internal temperatures approach freezing, the system automatically purges water from the fuel cell lines and dries critical components, ensuring freeze protection. In this dry state, the fuel cell can endure freezing conditions without damage.

Winter maintenance for hydrogen fuel cell vehicles is relatively straightforward compared to traditional combustion engines. Since fuel cells have no moving parts, the need for repairs is minimal. However, regular inspections, such as annual fuel cell stack checks, hydrogen tank assessments, and upkeep like tire rotations and brake servicing, are important, particularly in cold weather. Preventive maintenance is key to ensuring reliable operation during winter months. Key tasks include checking cabin filters and replenishing windscreen fluid, in addition to keeping the fuel cells in optimal condition.

Something to be aware of is that In freezing weather, water vapor is released into the air, like human breath on a cold day, avoiding accumulation on road surfaces. Fuel cell systems, like those in Toyota’s fuel cell hybrid vehicles, are designed to manage water vapor emissions effectively, similar to traditional combustion engines. Even in temperatures as low as 3°F, Toyota’s fuel cell hybrid vehicles start without issues, achieving up to 300 miles of range with the heater running at full blast. However, not all fuel cells are created equal and owners of a fuel cell vehicle should consult with the manufacturer.

Fuel cell systems have been tested in some of the coldest cities and towns in Canada and in Alaska, where deployments have proven reliable in sub-zero conditions. Fuel cell buses have already operated for over 150 million kilometers in extreme climates without issues. These buses are designed to operate in temperatures as low as -30°C, with heat generated by the fuel cell preventing the system from freezing.

Overall, fuel cell technology offers significant advantages for cold-weather transportation. With improved infrastructure, rising adoption, and continued advancements in cold-weather performance, hydrogen-powered vehicles are set to become an important part of the transportation mix in regions with harsh winter climates. As the technology evolves, maintaining awareness of its capabilities and upkeep requirements will be essential for ensuring its long-term success.

To restart a frozen fuel cell, the internal temperature must be brought above freezing. Several cold protection options are available to facilitate immediate start-up at temperatures as low as -20°C. If parked near a utility power outlet, an optional plug-in freeze protection system can maintain the necessary temperature for immediate start-up. Alternatively, if no external power source is available, the bus battery can supply energy to keep the fuel cell above freezing. Depending on conditions, maintaining the module at -20°C requires approximately 250-800W of power.

Looking ahead, hydrogen fuel cell vehicles are expected to play a major role in cold-weather transportation, with market projections forecasting growth to US$207 billion by 2044. The technology’s cold-weather performance, combined with faster refueling times and government incentives, is expected to drive adoption.

How electric vehicles perform in cold temperatures

While winter presents challenges for electric vehicles (EVs), it’s important to remember that traditional internal combustion engine (ICE) vehicles also face their own set of problems in cold weather. Warming up the car, dealing with frozen fluids, and struggling with dead batteries are all familiar inconveniences for drivers of gas-powered vehicles, but many have come to accept these as part of the winter routine. The same goes for electric vehicles.

One common misconception about EVs in cold weather is that they might die in extreme cold. However, Consumer Reports clarifies that EV batteries don’t lose range because of how cold weather affects the battery itself, but because cold temperatures increase the power demands of operating the vehicle. The chemical reactions inside the battery slow down, reducing its capacity to hold a charge and, consequently, the vehicle’s range. Additionally, using the heat and defroster places extra strain on the battery.

Consumer Reports testing also has shown that EV range can drop by 25–50% in winter, with shorter trips and frequent stops experiencing even more significant declines. However, for comparison, gas-powered cars can experience up to a 24% reduction in fuel efficiency when temperatures dip below 20°F.

While this may seem discouraging at first, it’s important to put things into perspective. Most people don’t drive hundreds of miles every day. In fact, the average American drives just 37 miles a day, and the average range of new EVs sold in the U.S. is nearly 300 miles, meaning many drivers will still have plenty of range even in colder conditions.

Another common concern for EV owners who park outside is that the vehicle might be difficult to start in the winter. However, many EV owners report no issues, even when parking outside overnight, though charging does take longer in the cold. 

In addition to these challenges, EVs have some advantages in winter driving. EVs tend to be heavier than gas-powered cars due to their battery packs, which provides better traction on snow and ice.

To improve winter performance, EV and hybrid owners can take several steps. Parking in a covered or indoor space helps maintain battery efficiency, while a heated garage can further improve performance and speed up charging. Additionally, many newer EV models are equipped with heat pumps, which are much more efficient than older, resistive heaters. EVs with heat pumps lose around 20% of their range in extreme weather, while those without can lose up to 40%.  Moreso, preconditioning your EV by running the heater while it’s plugged in is one of the best ways to preserve battery life. Many models even have battery preheating options to help preserve driving range in cold weather.

Instead of heating the entire cabin, consider using localized options like seat heaters and a heated steering wheel, which consume less energy. It’s also important to ensure the battery is fully charged before use, especially for longer trips, to offset energy loss from the cold. Using winter tires improves grip on icy roads, and regularly checking tire pressure reduces rolling resistance. Additionally, using manufacturer-recommended cold-weather oil can enhance efficiency.

When charging outdoors, protect the charging connector from freezing with a magnetic cover or bag, particularly during heavy snow or sleet. It’s also a good idea to carry a charging cable to ensure access to charging points throughout the day. Combining trips can help reduce time spent driving with a cold engine, eliminating the need to precondition the car multiple times.

Finally, smooth driving techniques can help preserve battery life. Avoid rapid acceleration, use regenerative braking when possible, or switch to Eco mode. Additionally, try to avoid towing cargo, as it places additional strain on the battery.

While winter weather does present some challenges for EVs, there are plenty of ways to mitigate the effects. By taking proactive steps, you can maximize the performance of your EV or hybrid, even in the coldest conditions. With the right care and attention, you’ll be able to continue enjoying the benefits of your EV, no matter the weather.

In winter, the key is preparation

As with ICE vehicles, the most important thing to remember when owning and operating an alternative fuel vehicle is to be prepared for fluctuating and extreme temperatures. Since alternative fuels react differently to cold weather—some handle it with ease while others require preparation—understanding their performance in low temperatures remains essential even as the seasons change. To read our entire blog on EV maintenance and tips for winter, read our blog. 

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