Comparing Diesel to Gasoline, Natural Gas, and Coal for Quality, Utility, and Availability

There are three categories of fossil fuels: solid, gas, and liquid. Of all the solid fossil fuels; the gas fossil fuels; and the liquid fossil fuels, diesel has the highest energy-production-to-low-emissions ratio of any. In fact, diesel fuel produces fewer emissions than gasoline and does far less damage to the atmosphere than natural gas. 

Diesel is the gold standard of fossil fuels. 

There are two primary measures by which to gauge the value of a fossil fuel. The first means of determining the value of a fossil fuel is fuel density. Fuel density is the number of fuel molecules — hydrocarbons — in a fuel on a volume or weight scale. 

The second means of determining the value of a fossil fuel are lifecycle emissions. Only accounting for combustion emissions is extremely misleading. The entire life cycle of a fossil fuel must be taken into account. By doing so, it becomes apparent that some fossil fuels that combust cleanly can be in the ranks of the dirtiest fossil fuels available. 

Likewise, fossil fuels that do not combust as cleanly as other may, in fact, be much cleaner overall. Diesel, for example, was traditionally considered a “dirty” fossil fuel, but it may, in fact, be one of the cleanest. 

And in addition to fuel density and emissions, diesel fuel is extremely stable which gives it a high utility factor. Utility is a factor in transportability, safety, and ease of use. 

Fuel Density of Diesel Fuel in Relation to Other Fossil Fuels

Determining the fuel density of a liquid fuel requires little more than a graduated cylinder and a scale. Determining the fuel density of a gas fuel requires more complex instruments and formulas. But, neither liquid fuel density nor gas fuel density are particularly complex concepts to understand.

Fuel density is important for one reason, it determines the volume or weight of fuel required to produce a required sum of energy. Fuel density is simply the ratio of mass to volume. “The greater the fuel density, the greater the mass of fuel that can be stored in a given tank and the greater the mass of fuel than can be pumped from a given pump.” A smaller quantity of high-density fuel generates more energy than the same quantity of low-density fuel. 

Diesel fuel has an extremely high energy density in relation to most other fossil fuels.

The fuel density of diesel is higher than any gas fossil fuel as the density of gas fuels is exponentially lower than that of liquid. The fuel density of diesel is higher than every liquid fossil fuel with the exception of residual oil aka, “bunker fuel.” No coal produces more megajoules per kilogram than diesel. 

Fuel Density and Fuel Economy: “Gas Mileage”

Fuel density determines the space necessary to produce a required amount of energy. That means fuel density plays a critical role in fuel mileage, another space for energy measure. Because of the energy density of diesel, per gallon, diesel-powered vehicles get much better mileage than petroleum powered vehicles of comparable size. 

“Over the diesel’s operating range, the average thermodynamic efficiency—how much work the engine produces from the fuel—is in the mid 30 percent range, at least 15 percent better than a gas engine. Not even close, right?”

Broken down simply, if a gasoline-powered vehicle gets 21 miles to the gallon, a diesel powered engine will get 30. It is fair to say, diesel is a much better fuel than gasoline with respect to fuel economy. 

Fuel Density and Gas-State Fuel Vehicles

Natural gas-powered vehicles are never likely to gain any traction in the automobile market. The fuel density of methane is so low that natural gas-powered vehicles require an oversized tank to drive relatively short distances. Natural gas vehicles are extremely expensive. And, the cost of fuel is also very high because it takes so much methane — again, a super low-density fuel — to power a vehicle.  

According to Forbes Magazine, “Natural gas vehicles are saddled by a number of drawbacks. They get worse mileage than regular gas cars. Reviewers, in general, say they are relatively uninspiring to drive. And the economics are not terrific: Honda’s CNG Civic costs more than the regular Civic.” 

Propane powered vehicles have many of the same problems as natural gas-powered vehicles including a limited range, low power and torque, and the fact that both are extremely volatile fuels. Additionally, propane is considerably more expensive than natural gas. 

The fuel density of diesel assures two things: a smaller tank is necessary for the same amount of mileage or hours of operation and per gallon or liter, diesel gets better mileage: fuel economy.

Emissions from Fossil Fuels

There are two common mistakes a person can make when discussing fossil fuel emissions. The first is to think of greenhouse gases and pollution as only products of combustion. Doing so makes some dirty fossil fuels seem clean and some clean fossil fuels appear dirty. In order to properly assess the greenhouse gases and pollution generated by a fossil fuel, the entire life cycle of that fossil fuel must be taken into account. 

The second mistake also pertains to combustion. Measuring the sum of greenhouse gases and pollution produced per unit of volume or weight is also misleading. Just because one fossil fuel generates more greenhouse gases per gallon or pound does not mean it is a greater polluter. 

Diesel is a victim of this kind of indolent analysis.

Diesel Emissions Versus Gasoline

Instead of measuring emissions per gallon, a much more indicative means of measuring emissions is the sum generated over distance or time. According to the U.S. Energy Information Administration, “About 19.64 pounds of carbon dioxide (CO2) are produced from burning a gallon of gasoline that does not contain ethanol. About 22.38 pounds of CO2 are produced by burning a gallon of diesel fuel.” 

That does not mean, however, that diesel produces more emissions. Again, diesel has a much higher energy density than gasoline. So while each gallon of diesel produces about 12 percent more carbon dioxide per gallon, per mile diesel produces far less. If a car gets 21 miles per gallon, then it produces .935 pounds of carbon dioxide per mile. That is almost a pound of carbon dioxide per mile. 

On the other hand, a comparable diesel engine gets about 30 miles per gallon. That diesel engine — at 22.38 pounds per gallon — only produces .746 pounds per mile. In other words, gasoline produces 21 percent more carbon dioxide per mile than diesel. 

Talking about the cleanliness of a fuel or how dirty it is based on emissions per gallon is misleading. Claiming diesel is a greater polluter than gasoline is irresponsible. 

Diesel Emissions Versus Natural Gas

Natural gas, up until the last few years, was considered the “cleanest” of fossil fuels. The thought was since natural gas produces the smallest amount of carbon dioxide during combustion of almost all fossil fuels that it must be clean. The problem is, natural gas is anything but natural and the opposite of clean.

Natural gas is almost exclusively methane and while methane burns cleanly, in its natural state, methane is among the most potent and damaging of greenhouse gases. Before it begins to break down, for the first 20 years it is in the atmosphere, methane has a global warming potential 86 times that of carbon dioxide. Over a 100 year span, methane has a global warming potential of 30 times that of carbon dioxide. 

Not only is methane a terribly destructive greenhouse gas, leaks are so commonplace in the industry that there are concerns we are accelerating global warming at rates so dramatic that the effects will be irreversible. And the biggest problem is fugitive gas.

Each year, the oil and gas industry releases huge sums of methane into the atmosphere. Some escapes by accident and some methane are simply allowed to float into the atmosphere through venting. “Emissions reached 9.8 million metric tons in 2014, up 11 percent from four years earlier. That’s enough methane to meet all of the natural gas fuel needs of a state the size of Pennsylvania, instead vented to the atmosphere.”

According to Forbes Magazine, fugitive and vented methane sums reached 3.6 trillion tonnes in 2014 alone and continue to rise each year. 

The Utility of Diesel Fuel 

While overlooked as one of the values of fossil fuel, its utility is one of the most important characteristics of diesel. Diesel is extremely stable. Unlike gasoline and natural gas — both of which are extremely volatile, diesel does not easily combust. The stability of diesel fuel makes it easier to store and transport than other fossil fuels used in the transportation sector. 

Drawback of Diesel Fuel 

Ironically, the same characteristic of diesel fuel that makes it so exceptionally valuable is also its biggest drawback, fuel density. Like all high-density fossil fuels, it is difficult to combust diesel. More to the point, it is difficult to burn diesel fuel completely. While 100 percent combustion is not possible for any fossil fuel — a complete burn is a theoretical concept our technology is currently incapable of achieving — the more energy-rich a fuel, the lower the percentage of that fuel that burns completely.

The reason diesel fuel does not burn completely is because the big hydrocarbon molecules in diesel have a charge. As a result, the hydrocarbon molecules cluster together in bundles. When this occurs, oxygenation of the individual molecules is partial as opposed to universal. Poor oxygenation means an incomplete burn. 

Oxygenating Diesel Fuel for a More Complete Burn with the Rentar Fuel Catalyst

The Rentar Fuel Catalyst is a pre-combustion device that mounts on the fuel line between the tank and the engine. Like a catalytic converter, a fuel catalyst is made of noble metals that function as catalysts. Catalysts are metals that can generate a change without themselves being changed. In the case of a fuel catalyst, the noble metals generate a change in the hydrocarbon molecules which makes the fuel burn more completely.

A simple explanation of what the noble metals in the Rentar Fuel Catalyst do is: neutralize. The Rentar Fuel Catalyst neutralizes the positive charge between hydrocarbon molecules that cause them to cluster together. Once the charge disappears, the fuel molecules in diesel separate which means they oxygenate at a higher rate. A higher oxygenation rate means a more complete burn and a more complete burn means two things: greater fuel economy and lower emissions. 

And, the increase in fuel economy and the reduction of emissions from the Rentar Fuel Catalyst are significant. For over the road vehicles, the Rentar increases fuel economy by between 3 percent and 8 percent. So significant are the fuel savings that the Rentar will pay for itself in less than one year. For heavy equipment, the savings can reach as high as 12 percent. For furnaces and boilers, the Rentar Fuel Catalyst can save up to 30 percent. 

And with respect to emissions, the Rentar is equally — if not more — impressive. The Rentar Fuel Catalyst reduces black smoke by 44 percent. It reduces greenhouse gas emissions — NO, NOX, and SO2 for example — by up to 19.2 percent and particulate matter by the same sum. 

Fossil fuels, hydrocarbons, are the most important energy source found on Earth. And of all the fossil fuels, none are more important than diesel. Diesel produces more energy while generating fewer emissions and doing less damage to the environment than any other fossil fuel. 

With the Rentar Fuel Catalyst, diesel produces even more energy and even less emissions.