The human demand for energy began long ago when apes metamorphosed into the first of what after another million years of evolution would become homo-sapiens. Survival was tough in the beginning, but things changed after fire was harnessed. This resulted in an extension of the domain of the human race on this planet. The invention of agriculture around 10,000 years ago finally led to human settlements and civilizations, which flourished due to a steady source of nourishment.

As the process of agriculture and farming came to be automated, rural populations began moving towards growing cities. Almost 60% of the human population worldwide now resides in urban areas. With high urban population densities, the energy use steadily increased due to the swelling energy consumption. Wood and hay, the most common sources of energy till the beginning of the 19th century gradually lost out to coal. The abundance of wood wasn’t much of an advantage as compared to it being too unmanageable for storage and transportation.

Coal dictated the energy markets for a considerably long time. Coal had widespread use in steam locomotives and heating systems. With the advent of the internal combustion engine, coal had to give way to the source of energy that would rule the roost in the years to come. Coal became too heavy and bulky to carry in order to fuel the newer, lighter and efficient machines. Oil has higher energy density compared to coal along with the advantage of providing high levels of mobility.

Consumption of oil has grown since then to the current rate of around 100 million barrels per day. Oil has faced stiff competition from the likes of bio-fuels and environmentalists who argue the world’s addiction to oil. The most recent oil-spill in the Gulf of Mexico has resulted in a renewed pitch for increased use of renewable sources of energy.

In “Power Hungry: The Myths of Green Energy and the Real Fuels of the Future”, Robert Bryce states his position about why it’s impossible to shake oil from its top perch and why “green” energy is still a myth. Over the past six decades, billions of dollars have been spent on renewable energy programs such as solar energy, wind energy, biofuels and electric cars, but to no avail. The reason renewables seem to have lost out to coal, oil and natural gas is that the latter three can provide more energy per given unit volume, area or mass.

Building a wind farm to produce a comparable amount of power as a thermal or nuclear power plant would require almost 40 times the land mass and far greater amounts of building materials than conventional power plants. Wind also has a major disadvantage of being highly seasonal. Thus, to meet constant and growing demands for electricity without regular blackouts, wind-farms will need to have traditional power plants as back-up.

People living in rural regions depend largely on wood, which results in deforestation and destruction of wildlife habitats. The fastest way to avoid this is to provide the locals with fuel derivatives of oil so that they stop burning wood. As Mr Bryce says, “If oil didn’t exist, we’d have to invent it”. Oil is now an indispensible resource. The many problems caused by the oil business also cannot be denied. Oil drilling, both onshore and offshore have had terrible environmental consequences. But when the costs related to drilling, processing and transporting oil are compared with those of fuels that might replace oil, such as biofuels and corn-ethanol, oil wins hands down.

Corn-ethanol, which was being touted as a replacement to petroleum, lost out in its developing stages due to its really low power density. Ethanol may only be a poor substitute for petroleum. Substituting ethanol for petroleum will not reduce oil imports, since oil refineries will still need crude oil to produce its various by-products. Crude oil not only provides petroleum and diesel, but also kerosene, propane, butane and other by-products which are used in building materials and laying roads.

One of the most abundant elements on our planet is hydrogen, which is now being heralded as the clean fuel of the future. But in order to obtain hydrogen in a form that can be used as a fuel, a lot of energy needs to be used up. The process isn’t simple either. Hydrogen does have a high energy-density by weight but at the moment, the hydrogen fuel cell is only technically, not economically, more efficient than the internal combustion engine.

What the world needs right now is energy that is as cheap and abundant as possible. The world also needs to increase energy efficiency and reduce contamination and pollution related to the use and production of these sources of energy. Fortunately, technology is advancing to a level in order to achieve the above mentioned goals. To completely switch to renewable sources now would mean replacing high power-density, reliable and low cost sources with low power-density, expensive and highly variable sources of energy. The major disadvantage of the so called ‘green’ energy sources is that they can never provide power as and when we demand, in the vast quantities we need, at the prices that we can afford. Renewable technologies haven’t reached a level of efficiency to make them useful in large-scale power applications.

In view of the worldwide dependency on oil and coal for power, it is difficult to see how any of the world’s leading countries could let go of these sources without damaging their economies. The requirement of energy is at an all-time high at present and policy makers should stress the need for adaptation of efficient technologies without hindering economic development. But with most energy policies there is a good mix of politics and self-interest in the plans, which can only be avoided if we have more engineers and scientists and fewer lawyers and politicians making policies on energy.