Water Diesel Emulsion

What is water diesel emulsion?

Water diesel emulsion is a finished fuel that can be used as a direct replacement for conventional diesel fuel without any engine changes or modifications. It contains very fine water droplets suspended in the base diesel fuel. The water droplets are encapsulated within the diesel fuel to ensure they do not come into direct contact with (and potentially damage) the engine or tank. These droplets can account for up to 20% of the fuel. In the engine the water influences the combustion process and reduces the formation of certain pollutants. Since water has no energy value there is a reduction in peak power and torque, which gives a slight (up to 10%) reduction in acceleration, although this is unlikely to cause any difficulties in typical fleet operations.

What are the environmental benefits of using water diesel emulsion?

Water diesel emulsions produce lower NOx and particulate matter emissions than standard diesel due to the lower combustion temperature. Emissions reductions are generally proportional to the water content. Most available emulsion fuels in the EU have water content of 10-15%, these will typically reduce emissions of particulate matter by 25% and NOx emissions by 15% compared to pure diesel. Some trials have also indicated that water diesel emulsion can reduce CO2 emissions by between 3% and 12% compared to diesel, depending on the change in fuel consumption.

How much does it cost to use water diesel emulsion?

We offer Hydorfuel emulsion for less than pure diesel. Water diesel emulsions have slightly lower fuel duty than pure diesel, as water is exempt from fuel duty. This exemption only applies to the water component of the fuel (so for an emulsion with 10% water content, the fuel duty would be 90% of that for pure diesel). Fuel consumption will increase due to the water content of the fuel, but some trials have indicated that fuel consumption has not increased proportionally to the amount of water in the fuel, thereby leading to a small reduction in CO2. There should be no change in maintenance costs when using good quality emulsion fuels as these do not adversely affect engine condition or durability.

Where can I buy water diesel emulsion fuel?

Water diesel emulsion is currently  under the brand name Hydorfuel. It is usually purchased in bulk quantities by fleets with a central fuel tank and is compatible with existing diesel storage facilities.
We also offer fueling containers, fully automated system on the site, where Hydorfuel can be made on-demand.

What else do I need to know about water diesel emulsion?

Operators should check with the vehicle manufacturer and fuel supplier regarding the vehicle’s warranty position in relation to the use of water diesel emulsion fuel. Emulsion fuel will mix readily with normal diesel fuel so there is no need to drain bulk storage or vehicle fuel tanks when converting to emulsion fuel.

Water diesel emulsions have a shelf life of at least one months, which is more than adequate for normal fleet operations.

Other Diesel Fuel Additives and Devices

There are other diesel fuel additives or devices that may be on the market which could have environmental benefits. Operators should ensure that these are assessed using data from a chassis dynamometer (or "rolling road") over an appropriate drive cycle before deciding whether to use them. The Transport Energy Best Practice guide on Fuel Saving Devices gives some useful tips on the things you should look for when considering whether to use these devices or additives.

Using a fuel with a low sulphur content reduces emissions of particulate matter and results in less degradation of the engine and improved performance from emissions reduction technologies, such as particulate traps. At the moment most diesel in US is Ultra Low Sulphur Diesel (ULSD), which has less than 50 ppm (parts per million) of sulphur. Diesel with less than 10 ppm is also available from some fuel suppliers, and is often referred to as ‘sulphur free’. Sulphur free fuels are currently only produced at a very small number of oil refineries, and is not yet widely available.

Water diesel emulsion is a finished fuel that can be used as a direct replacement for conventional diesel fuel without any engine changes or modifications.