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):
Neutron energy (4.89E+13 kJ/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
or
an average UK household for 725 years
or
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 (≈25,000 kJ/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 (≈48,000 kJ/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.
Whilst petrol is currently the most efficient fuel for motor vehicles, today's policy of diluting it with ethanol reduces its energy capacity, for example;
petrol (789 kg/m³) contains 48 MJ/kg
ethanol (749 kg/m³) contains 26 MJ/kg
E10 petrol (10% ethanol) contains 45.8 MJ/kg making it 5% less fuel efficient than pure petrol.
E85 petrol (85% ethanol) contains just 29.3 MJ/kg making it 44% less fuel efficient than pure petrol.
Not only is vehicle performance reduced by mixing petrol with ethanol, fuel consumption rises.
Because any two same vehicles travelling between A & B using the same performance will require the same energy for the journey, irrespective of the fuel source …
… the E10 driven vehicle will consume 5% more fuel (volume) for the journey than that using pure petrol.
… the E85 driven vehicle will consume 44% more fuel (volume) for the journey than that using pure petrol.
Ethanol is also harmful to polymers, which means that we must be careful when using E-Rated petrol; too much ethanol will destroy those polymer parts not designed for it.
Moreover, an ethanol and petrol mixture will separate after about three months, which means that constant refuelling with a half-full tank may mean that the lighter ethanol may settle at the top of the tank. Ethanol develops a fungus after a few months and can cause serious problems to your vehicle if it is subsequently drained, burning pure ethanol.
And because CO₂ is not a pollutant, there is no environmental benefit to diluting petrol with ethanol. The land used for its production, would be put to better use growing food crops.
Natural gas (≈43,000 kJ/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} (≈45,000 kJ/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 (≈40,000 kJ/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 (≈45,000 kJ/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 (≈141,800 kJ/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 (<25.441846700545 kJ/kg (lithium-ion battery))
This calculated energy capacity assumes 100% efficient charging and discharging circuitry, which is impossible.
Moreover, batteries are;
a) not a source of energy; they are nothing more than electronic fuel-tanks, that deteriorate with every replenishment, and the faster they are replenished, the faster they deteriorate. It is expected that 'fast charging' will kill most batteries within 5 years, making it considerably more expensive than a petrol-tank.
b) impractical; no nation on Earth can supply its own electricity needs, even without relying on electricity to power its vehicles.
c) inefficient; 0.053003847% energy per unit weight compared to a petrol-driven vehicle, and less than a quarter of its range.
d) inefficient; more than a quarter of its energy is spent transporting its own weight, making battery-driven vehicles less than 0.04% efficient when compared with a petrol-driven vehicle.
e) polluting; metal mining leaves huge swathes of land and water polluted with toxic chemicals and metals.
f) polluting; apart from mining see 'e' above, the cost of recycling in terms of energy, currency and waste is greater than any product other than nuclear fuel rods.
g) expensive; a battery pack cost more than 2079 times per unit currency per Joule per year than a petrol tank, and electricity generation costs almost 4.5 times more than it costs to recover and refine petrol.
h) inconvenient; batteries take approximately 20-times longer per joule of energy to charge than a petrol tank see 'a' above.
i) inconvenient; in order to prolong the life of a battery, it is necessary to fully discharge and fully charge (condition) at every replenishment.
j) uneconomic; due to 'i' above, an additional power source (such as a petrol driven engine) is required to ensure that battery life and condition can be maintained.
k) uneconomic; the cost of electricity is rapidly becoming the most expensive of all forms of energy generation (Joules per pound-Sterling); it will soon be impossible for the general public to afford their current freedom of movement.
All of which means batteries can never be claimed to be practical, convenient, efficient, economic, clean or safe.
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.