The main benefit sought by including hydrogen in the alternative fuels mix is emissions reduction – eventually by 100%. However, in the near term, there is an objectionable cost differential between fossil fuels and hydrogen. Hydrogen costs are proportional to hydrogen energy, which may be expressed as a percentage of the energy consumed by the baseline energy system (i.e. a non-hydrogen vehicle fleet). The ratio of percent emissions reduction to percent hydrogen energy, relative to baseline conditions, is a measure of the effectiveness of hydrogen utilization called the leverage factor. Hydrogen leverage is defined as the ratio of [%Emissions Reduction]/[%Baseline Energy Supplied as Hydrogen].

Imagine a fleet of 100 natural gas buses. The bus fleet agency wants to reduce emissions by buying hydrogen-powered buses but cannot afford to convert the entire fleet. What is the best way to reduce emissions using the least hydrogen? In the simplest example, a few of the buses are replaced with hydrogen internal-combustion engines with the same fuel economy as natural gas. These hydrogen-powered buses can have near-zero exhaust emissions, so if 7 of the 100 total buses run on hydrogen, there will be a 7% reduction in emissions. In this case, there is no leverage – the emissions reduction compared to the amount of hydrogen energy used is a ratio of one. By taking advantage of the unique properties of hydrogen, it is possible to improve the typical one-to-one relationship between emissions reduction and hydrogen use.

Consider another example, using Hythane®. As before, there is a fleet of 100 buses, but now 7% hydrogen by energy is blended with natural gas and used over the whole fleet. Both laboratory and real-world experience shows that a natural gas engine with a calibration optimized to reduce NOx emissions with 7% hydrogen in natural gas will cut emissions by about 50%, for every bus in the fleet. In this example, Hythane® reduces emissions 50% with 7% hydrogen by energy, so the hydrogen utilization leverage factor is 50% / 7% = 7.1, or more than 2.5 times better than the most generous fuel cell bus scenario.

In addition, the Hythane® example above is much more realistic. Although the expense of the hydrogen refueling infrastructure cost was not considered for the sake of simplicity, this cost is currently much more significant than the hydrogen fuel costs over the life of the vehicle. In contrast, there are only minimal costs associated with changing the natural gas engine calibration and pre blending the Hythane® fuel. The existing natural gas refueling compressors, storage tanks, and fuel dispensers can be utilized, while the vehicle engine and fuel system do not require any hardware changes. No other costs are incurred by switching the fleet from natural gas to Hythane®; there is only a 20% maximum vehicle range penalty for the same volume of compressed gas fuel tanks. Many years of research have proven that only 5% to 7% hydrogen by energy is all that is necessary to minimize emissions and significantly stabilize the combustion of natural gas. Hythane® is the next step on the path to an ultimate hydrogen economy. The only practical way to utilize hydrogen in vehicles with today’s technology is through the use of Hythane®, which provides leveraged benefits to justify infrastructure investment even before hydrogen vehicle technology becomes economically feasible. By providing widespread vehicle refueling stations with developed hydrogen sources, Hythane® eliminates the infrastructure issues that could be a barrier to future pure-hydrogen applications, in a way that is maximally useful today.