The Properties of Fuels

References are indicated thus: ⁽¹⁾ refers to note 1 at the bottom of this page
For those of you unfamiliar with the words 'lorry' and 'lorries' this means the same as 'truck' and 'trucks' respectively

The following is a brief summary of the principal energy generation systems and sources available today (comparative approximate calorific values are provided for fossil fuels):

The Future

Neutron energy (4.89E+13kJ/kg) is the same as that released in nuclear power stations. But whilst nuclear power stations rely on dangerous (radioactive) materials and are less than 0.0001% efficient, neutron energy, if released correctly is more than 2,000,000% efficient. Moreover, it is safe, everywhere in the universe and it is free.

The primary benefit of neutron energy is that its fallout is hydrogen (proton-electron pairs); it is clean, and there is an inexhaustible supply here on Earth.
We can acquire all the energy we need from neutrons within the earth’s crust. And you may use any element or combination of elements available (rock or even soil); they do not need to be radioactive because we need not rely on critical mass to release it.
Whilst batteries, solar cells, wind turbine generators and power stations are, dirty, expensive, unreliable and extremely inefficient (<10%); neutron energy is clean, safe, reliable, eternal, massively efficient (>231,000,000%) and free (it can be extracted from anything).
1m of the earth’s crust contains enough energy to supply today's needs for more than 10¹⁴ years
For example, the neutron energy in 1kg of iron will ...
run an average car for 500 years
an average UK household for 725 years
a Jumbo Jet for 10 million miles
Given that the human race is unlikely to survive beyond 1E+09 years (at the very outside); we have an unlimited source of energy available to us; and everybody can access it cheaply. Or, if by some miracle we manage to survive longer than this, another metre of crust will provide a further 7E+14 years.


Coal (≈25,000kJ/kg) is probably the dirtiest and most damaging fossil fuel used on earth today. It needs a great deal of expensive cleaning and filtering to remove all of its harmful by-products and should therefore not be burnt in large quantities.

Petrol (≈48,000kJ/kg) is now one of the cleanest and most efficient fossil fuels available to the general public as it no longer contains lead⁽¹⁾. The exhaust from a petrol burning engine is largely CO₂ and CO. Catalytic converters convert unburnt hydrocarbon gases and/or CO to CO₂. Catalytic converters work most efficiently when hot.
With modern engine management systems and materials, along with lean-burn and high-compression technologies, petrol engines could become the most efficient and cleanest internal combustion engines available to the masses until hydrogen fuel cells become readily available.

Natural gas (≈43,000kJ/kg) currently heats homes and factories and feeds electricity generating stations. Natural gas creates the same levels and type of pollution as petrol. As a gas, it can be compressed by using a large tank and gravity activated roof (a gasometer) to 'pump' it around 'town'.

LPG {liquid petroleum gas} (≈45,000kJ/kg) powered engines generate the same amount and type of pollution as an equivalent petrol engine. Even though it has about the same calorific value (per unit mass) as natural gas, which is where it comes from. LPG is liquefied for vehicles because, as a liquid, it occupies the same volume as petrol. There is no cost, environmental or practical advantage in burning LPG than there is in burning petrol.

Bio-fuel (≈40,000kJ/kg) is simply burning processed plant life. It has less calorific value and more free carbon than petrol. It is dirtier than petrol and cleaner than diesel. It cannot currently be used on its own to fuel vehicles. There is no cost, environmental or caloric advantage in burning bio-fuel over burning petrol.

Diesel (≈45,000kJ/kg) is a heavy fossil fuel that contains solid particulates. Whilst it is more abundant (easier to extract) than the lighter petroleum (which is older and deeper in the earth's crust), it uses more time and resources to refine. Less refined versions of diesel (e.g. gas-oil, kerosene, heavy fuel oil, etc.) are used to power, heating boilers, aircraft, ships, tractors, and lorries. Diesel engines emit least pollution when operating hot, as is the case for petrol driven engines, but with diesel engines the difference is more marked. Catalytic converters turn unburnt hydrocarbons and/or CO into CO₂ and also work most efficiently when hot. A catalytic converter in a diesel engine will last less than 20% as long as it will last in a petrol engine. The carcinogenic sooty particulates emitted from the exhaust of a diesel engine can only be removed via a micro-filter that will become blocked (and therefore useless) in an average car in less than 15,000 miles. The more time these engines spend running cold the quicker they will become blocked. Diesel engines should only be fitted to vehicles that travel very long distances (spend most of their working time hot) and regularly have their exhaust filters and catalytic converters replaced. The cost of regularly replacing catalytic converters and exhaust filters reverses the small financial gains from slightly improved fuel consumption over similarly powered petrol engines. Most (if not all) national vehicle inspection regimes do not verify the operational condition of catalytic converters and exhaust filters.

Hydrogen (≈141,800kJ/kg) fuel cells would be the least polluting and most efficient means of power for any vehicle today … if they existed. Development of this technology is currently taking a back seat to improved internal combustion engines and battery power.

Batteries (≈20,000kJ/kg) constitute the most expensive and most polluting⁽²⁾ form of energy release today. They involve mining activities that leave huge swathes of land polluted from heavy metals and mercury. The heavy metals are in very few locations on earth where they can be mined economically and therefore have to be transported long distances from the mine to the processing plant, and from there to the battery manufacturer, and from there to the users or distributors. Today's batteries are extremely expensive and require replacement every 5 to 6 years. Moreover, a great deal of their power is used simply by transporting their own weight. They are therefore neither economically nor environmentally viable for powering vehicles on a mass production basis. They are not an energy resource; they are simply an expensive energy storage facility. They should be compared with the petrol-tank in a conventional petrol-driven vehicle. They are the most inefficient form of power release available today; considerably less than -200% efficient.

Solar energy can effectively and efficiently feed low power electronic equipment but requires large expanses of land to accumulate sufficient power to be practical for household or light industrial equipment and only works when exposed to sunlight. It is therefore only really practical for desert regions and suffers from similar pollution issues as the battery (above).

Wind energy is a very expensive and ineffective means of power generation needing massive government subsidisation to make it viable. Wind turbine generators require a great deal of material to manufacture and a lot of energy to erect and maintain and they provide no energy in low wind conditions. When working, a 10kW turbine will produce about 10 thousand kWh/yr, and 1.8MW turbine will produce 5 million kWh/yr assuming they operate all day, every day. If the average household consumes 5 thousand kWh/yr, this means that a 1.8MW turbine will feed over one thousand houses and a 10kW turbine will feed 2 houses. The 1.8MW turbine costs £2million and the 10kW turbine will cost £150,000. It will take 100 years to recover this cost based upon current electricity prices ignoring all installation and maintenance costs and assuming the turbine lasts 100 years. On top of which, should be added the cost of recycling the materials back into a useable form at the end of its life. Given the above, this is not a very cost effective means of electricity generation.

Water energy produces 1000 times more energy than wind for the same velocity but as wind can reach much higher average velocities than ocean currents, and as energy increases with the square of the velocity one would think that wind power will outperform water power quite quickly. At 3mph, however, water produces the same energy as wind at 100mph and a 4.5 knot current produces the same amount of energy as wind at the survival speed of a turbine⁽³⁾. Furthermore, currents are guaranteed to work every day.

Hydro-power is without doubt the cleanest and most cost effective power generation system today, but their creation completely transforms surrounding fauna and flora.

Power generated by fission is extremely cost efficient and clean so long as there is no damage or system leakage and assuming its by-product can be safely converted back into something harmless (for plants and animals), or disposed of in outer-space well away from any potential earthly influence, which it can't. Therefore this energy generation method should not be considered viable until the by-product issue can be resolved.

The fusion requires the input of energy. It does not generate energy.

Wood has not been addressed here as it should not be used as a fuel on a large scale. Its use as a fuel in remote areas where alternative fuels are not available is perfectly acceptable, but burning it on a large scale means killing the forests necessary for converting CO₂ to O₂.


  1. Leaded petrol was withdrawn from garage forecourts in the UK in 2000. The last car manufactured to run on leaded petrol was in 1992
  2. See Pollution > Plants and Animals
  3. Manufacturers quote various survival speeds for their wind turbines (100mph to 145mph) but many have been destroyed in winds less than than 120mph and most of them will not operate safely in winds greater than 80mph throughout their design life