Fossil fuel power
Crude Oil.
Unique properties.
Joule.
Energy density.
Batteries.
Alkanes.
Fuel.
Biofuels.
Carbon dioxide.
Fossil fuel replacement.
Crude oil is a mixture of hydrocarbons and other organic compounds.
It is found in geological formations deep below the Earth’s surface.
Crude oil is liquid at ambient temperatures.
Unlike natural gas, this makes it easier for storage and transportation.
The bulk of crude oil comprises of long hydrocarbon molecules.
This can be converted into a variety of shorter alkanes and alkenes, which are more useful.
The process of refinement is called cracking.
It involves boiling the oil, to produce an array of products, with different properties.
Petrol, diesel, kerosine, plastics, pharmaceuticals etc., are byproducts of crude oil.
It is only since the invention of the internal combustion engine,
that we have woken up to its potential.
Oil fuels about 90% of transportation energy needs.
Oil plays a big part in agriculture also.
Fertilisers, pesticides and herbicides use oil as a raw material.
All plastics are derived from oil.
It is no wonder, that oil has become central to our economy and lifestyle.
Oil is extracted from the ground as an oil-in-water emulsion.
It is then chemically separated using de-emulsifiers.
Some oil is released into the atmosphere.
The burning of oil produces large quantities of carbon dioxide.
Oil along with coal is the biggest contributor to the increase in atmospheric carbon dioxide.
This in turn is a primary contributor to global warming.
The environmental cost of oil and coal is enormous.
Unfortunately current economics do not factor in this cost.
Oil prices are likely to keep increasing.
In the U.S. 50% of the households spend 24% of their total net income for energy bills.
Rising fuel prices hit the poorest members of society most.
We need to urgently find an alternative to oil, gas and coal,
even before we exhaust the planet’s resources.
Oil has several unique properties which made it an essential part of our life.
The joule is the SI unit of energy.
It is named after James Joule.
Joule researched how much energy could be extracted from a given source.
Joule was able to discover the mechanical equivalent of heat.
He established that motion and heat are mutually interchangeable.
A given amount of work will generate the same amount of heat.
Joule’s work resulted in naming the unit of energy after him.
Joule later worked with Lord Kelvin, to develop the absolute scale of temperature.
The Joule is the energy expended in applying a force of one Newton,
through a distance of one meter.
It is also the energy of a current of one ampere,
passed through the resistance of one Ohm for one second.
Electricity bills are calculated in Kilowatt hours, which is equivalent to 3.6 megajoules.
Food is measured in calories.
The calorie is the amount of thermal energy required,
to raise one gram of water by one degree centigrade.
Power is the rate at which energy is converted from one form to another.
We measure this in joules per second or watts.
In a power station, coal is burnt to heat water,
and the steam drives turbines which generate electricity.
Here the potential energy of coal is converted to heat,
then to kinetic energy, and finally to electricity.
The amount generated per unit of time is the power.
Energy density relates to the amount of energy stored to the volume of the storage facility.
Fuels with the lower density have less potential energy.
Because a substance has a high energy density, does not mean that it can be converted efficiently.
For example, butter has a higher energy efficiency than ethanol.
But, this efficiency cannot be easily converted, say to kinetic energy, to run a car.
The energy density of a fuel is expressed as the specific energy.
This is the energy stored per unit mass.
It is expressed as joules per gram.
When an object is in motion it has kinetic energy.
The equation for kinetic energy is E= half m v squared.
E is the kinetic energy.
m is the mass.
v is the velocity.
A bullet has very little kinetic energy, but it is lethal, because it deposits a small amount of energy,
very quickly in a small area.
An astroid moving at 100,000 km per hour has an enormous amount of kinetic energy.
When the moving object comes to an halt, the energy is released.
This is what happens when an astroid collides with a planet.
The astroid that collided with Earth 65 million years ago,
had the energy equivalent of 100 tera tonnes of TNT, or 1 billion atomic bombs.
The specific energy of some materials in kilojoules per gram are:
Car battery 0.13.
TNT 2.7.
Wood 16.
Coal 25.
Petrol 46.
Natural gas or methane 56.
Hydrogen 142.
Uranium 84 million.
Moving objects which have high energy density does not help when it comes to storage.
Batteries are stores of chemical energy.
They draw power from a chemical reaction inside them.
Batteries are convenient to use but they have some drawbacks.
The best rechargeable batteries have only one fifth the energy of gasoline.
A battery loses energy as heat while discharging.
Batteries are filled with expensive chemicals which needs to be replaced after a period.
Batteries are also very expensive.
When we use a battery, to run a car, there are many stages of energy conversion.
In the power station fuel such as coal, is converted to thermal energy.
This is converted to steam.
The steam drives a mechanical turbine.
This generates electricity.
The electricity is transmitted in power lines.
It is stored by recharging batteries.
It is finally used to power a vehicle via a motor.
There is energy losses in each stage.
The biggest advantage of batteries is that emissions are only at the power station.
This gives a better opportunity to manage emissions.
What makes combustible fuels very appealing, is their efficiency.
Combustible fuels take oxygen from the atmosphere.
The amount of oxygen consumed is dependent on the fuel.
For example, one gram of hydrogen reacts with 8 grams of oxygen, to make 9 grams of water.
In this process it releases 142 kilojoules
TNT works in a different way.
It contains the oxygen necessary for combustion within it.
This means the rate it can release the energy,
is not limited by the speed at which it can draw oxygen.
TNT releases all its energy very quickly.
That is why it is used as an explosive, though its energy density is not very high.
A chocolate cookie has 8 times the energy of TNT.
But it takes a very long time to digest and release the energy.
The sudden release of energy due to oxidation is the principle,
behind the internal combustion engine.
A fine aerosol of gasoline is sprayed into the cylinder.
A fine spray maximises the exposure to air and oxygen.
The resulting micro explosion powers the car.
Alkanes are a group of chemicals compounds such as methane, propane, and pentane.
They consume oxygen for combustion.
They produce heat, water, and carbon dioxide.
In these reactions, the carbon-hydrogen bonds are broken.
Carbon-oxygen and hydrogen-oxygen bonds are formed.
For example: CH4 + 2O2 gives CO2 + 2H2O.
All alkanes are chains of hydrogen and carbon molecules.
As the chains get longer, the proportion of hydrogen to carbon gets smaller.
Methane is the simplest alkane, and the proportion is, 4 is to 1.
In ethane it is, 3 is to 1.
In propane it is, 8 is to 3.
In octane it is, 9 is to 4.
In polyethylene it is about, 2 is to 1.
The amount of oxygen consumed as a proportion does not change much.
It is about 80% of the mass involved.
Making the water bonds, creates much more energy than creating the carbon dioxide bonds.
Fuels that produce more water through combustion have greater energy density.
One gram of methane produces 55 kilojoules of energy.
One gram of octane or gasoline produces 48 kilojoules.
Octane requires slightly less oxygen and results in more carbon dioxide.
Choosing a fuel is based not only on energy density, but also on convenience.
Burning 1 gram of candle wax produces roughly the same amount of energy as octane.
But it is not practical to run a car using wax.
Cars work best with a liquid fuel.
There is a large infra structure which gets the fuel to the car tanks.
In principle it is possible to run an internal combustion engine using hydrogen.
There is a double advantage of its high energy density and zero emissions.
Hydrogen is extremely reactive.
There is no natural sources of pure hydrogen.
Water is plentiful.
To extract hydrogen from water, we need to use a process called electrolysis.
This process consumes more energy than it produces.
Hydrogen is very difficult to store and transport.
Liquid hydrogen’s boiling point is minus 252 degree centigrade.
For these reasons, as of now, hydrogen is not a preferred fuel.
Convenience plays a big role in using a substance as a fuel.
Coal is 20 times cheaper than petrol.
However it is not as convenient as a fuel.
Coal could be converted into a liquid fuel, but this involves a cost.
We should hope for ecological reasons, that this is not seen as a solution.
Alternative energy sources need to be more economical than coal.
It is tempting for developing countries to use coal as a fuel.
It is encouraging to note that some of them do not succumb to this temptation.
Brazil has one of the largest fossil fuel reserves.
It produces 40% of its energy requirements from alternative fuels,
compared to the global average of 14%.
Apart from convenience there are other factors which influence the choice of a fuel.
Energy infrastructure, mode of delivery, cost of cleaning up etc, are some of them.
Trains used to run on coal.
Now they prefer using diesel or electricity.
It is more convenient and cleaner.
The automobile was invented when oil was cheap, and perceived as abundant.
The U.S. which had domestic supplies adapted cars as the primary mode of transport.
Europe invested more in public transport.
In the U.S. the wealthy tend to live in the suburbs.
In Europe the affluent districts are in the heart of the city.
The rate at which we are transiting to renewable energy is quite slow.
We can compare this with the transition from biomass to fossil fuels.
In 1890’s the share of biomass energy,
was just below 50% of the world’s total primary energy supply.
Less than 20 ExaJoules of additional fossil fuel energy was required.
By 2010 the global use of fossil fuels was 400 ExaJoules annually.
This means that the energy requirements now to replace fossil fuels is 20 times more.
Our entire fossil fuel infrastructure occupies an area of 30000 square Kilometers,
which is the size of Belgium.
Replacing this with biofuels would require an area of 12 million square kilometers,
which is the size of U.S. and India combined.
This is the land area that would be required to produce 12.5 terawatts of energy.
Bio fuels obviously are not a practical alternative to fossil fuels.
Oil is too convenient and too cheap to replace easily.
The good things about oil is what makes it so dangerous.
It will become all the more difficult to move away from oil.
All this while we will be polluting the environment with carbon dioxide.
Fossil fuels in any form releases carbon dioxide.
This ultimately causes global warming.
We are facing a future with extreme weather events, and rising sea levels.
Summers are predicted to become hotter.
Predictions about future carbon dioxide concentrations vary widely.
It is difficult to predict what exactly will happen in 40 years time.
However we cannot afford to wait for 40 years to take action.
Over the past 600 thousand years carbon dioxide levels have varied very little,
between 200 to 300 parts per million.
The current carbon dioxide levels is higher than what it was in the past 20 million years.
This is projected to double in our life time.
Almost all the glaciers are melting.
The ice in Greenland and polar regions are melting.
This could raise the sea levels by 6 meters.
The acidity of oceans is increasing.
20% of the world’s coral is already bleached.
At this rate they might entirely disappear by the end of the century.
Countless species of fish will become extinct.
Global warming will cause the artic permafrost to melt.
This would release large quantities of methane, which is a greenhouse gas.
This will trap more of the sun’s heat.
The last time this happened, was at the end of the Permian era, 230 million years ago.
Global temperature spiked by 4 to 8 degree centigrade.
This led to the extinction of 90% of all species in the planet.
Decarbonising our energy economy is not an option, - it is essential.
All projections predict that we will need more energy in the future.
Without energy there can be no economic growth.
Over the past 150 years global GDP has been growing at 1.6% per annum.
No country in the world has a policy to inhibit growth.
We cannot expect negative growth in the foreseeable future.
By 2050 the population is expected to be 10 billion.
If we assume energy demand growth rate of 1.5%, we would require 50 terawatts by 2050.
This is three times the current demand.
There is considerable effort to increase energy efficiency.
But this alone will not solve the problem.
Assuming energy efficiency efforts will be successful,
the per capita consumption of energy will be 2 kilowatts.
The energy required to provide a diet of 2000 calories a day, would require 1 kilowatt.
This would leave one kilowatt, for all other facets of modern life.
2 kilowatts per person is an ambitious target.
Currently in the U.S. it is 10 kilowatts, and Europe it is 5 kilowatts per person.
Even with optimistic projections of energy efficiency,
we will need 28 terawatts of energy per year, by 2050.
Natural gas is the least carbon intensive of all the fossil fuels.
Hydraulic fracturing or fracking has had a major short term impact on global energy markets.
We should not use cheap fuels, to fuel a final consumer boom.
This will only accelerate the impact of climate change.
It is clear that we need a replacement for all fossil fuels.
Nuclear technology is another option to produce energy.
It is a scalable form of energy production.
It produces no carbon dioxide.
It generates electricity efficiently and cheaply.
It is also potentially dangerous.
We have to decide whether it is worth taking the risk.