Averting energy crunch and global warming

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Syed Fattahul Alim
Energy is what keeps living as well as the non-living world moving. Here the focus, however, will be on the energy need of the world of the living, and more particularly, of the humans and their societies. The growth and development of society have always depended on how it solves and plans its energy use. In the pre-modern era, energy derived from muscle power of both humans and animals and power of the winds and flowing water helped humans to transport themselves and other objects from one place to other. For making fire for cooking and other purposes, they would use wood, twigs, leaves and other kinds of flammable substances available at that time. Small wonder the world of the pre-modern era was slower and less productive than what it is in the modern age.
But how has modern society solved its energy problem? Strangely, it has not really solved anything so far as the use of energy is concerned. Modern man has rather been squandering the fossil energy Mother Nature had kept in its secret reserve for millions of years. With the advent of machine age, underground hydrocarbon reserve in its various forms, for example, coal, petroleum, methane, etc., is being exploited and burnt freely by man to power everything he uses and depends on. In his spendthrift manner, he has now walked up to a very tricky situation. Firstly, the world is now left with a mere fraction of the fossil fuel reserve it had stumbled upon in the beginning. As a result, it is facing the spectre of energy crunch. The technological base on which modern society stands may come to a grinding halt unless it hits upon a new idea of averting the danger. The unrestrained exploitation and use of fossil energy has thrown the world into another kind of predicament. The name of that predicament is what is known as global warming. The carbon dioxide gas emitted from the burning of fossil fuel has created a kind of screen around the planet Earth that traps heat. The heat increases the net temperature of the world. As a result, the climate of the Earth has undergone a drastic change increasing the number and frequency of natural calamities like drought, downpour, hurricanes and cyclones. The glaciers and polar ice caps are melting raising the sea level and thereby threatening the low-lying countries with inundation and floods.
To save the civilisation from the threat of global warming, it is therefore necessary to cut the emission of carbon dioxide into the atmosphere, if it is not possible to stop it altogether.
So, it has become incumbent upon humanity to look for newer, preferably renewable, sources of energy for its survival as well as for continuing the forward march of civilisation.
Excepting fossil fuel what are then its options?
The nuclear option Despite its environmentally unfriendly image, nuclear power is firmly back on the world's energy agenda thanks to the need to cut carbon-dioxide emissions. Scientists are working to make the next generation of nuclear power stations cleaner and more efficient than ever Global warming is rooted in one of the most fundamental ideas of Newtonian physics: there is no action without a reaction. Put simply, we cannot continue to pump carbon dioxide and other pollutants produced from the burning of fossil fuels into our environment without suffering the consequences. Environmental scientists have been highlighting this problem for some time, but only now are governments giving the issue the attention that it deserves. Man-made climate change is one of the greatest threats our planet faces, and is already estimated to be responsible for over 160,000 deaths worldwide each year resulting from heat waves, flooding and crop damage.
Yet in tackling global warming we face a dilemma. Fossil fuels provide at least 85 per cent of our total energy needs, from the electricity that powers our homes to the production of manufactured goods and our food supply. Renewable energy sources, such as those utilizing the Sun, the wind and the waves, can help reduce our dependence on fossil fuels, but their unreliable nature and often low output means that they can only provide a small part of the energy solution. Indeed, most forms of renewable energy have a significant environmental impact of their own - for example by disfiguring the landscape or by endangering wildlife. They also require fossil-fuel power stations to be on standby for when output is low, for example when wind turbines are not generating in still conditions.
Fortunately, there is another option to tackle our looming energy crisis: nuclear power. At the atomic level, the thermal energy released in a fission event is 200 MeV, compared with only a few electron-volts produced each time a hydrocarbon molecule is broken by burning carbon-based fuels. As a result, a single nuclear reactor fuel pellet just 1 cm long can produce the same amount of electricity as 1.5 tonnes of coal. Furthermore, nuclear power produces tiny amounts of waste, as opposed to the vast volumes of pollutants pumped unchecked into the environment by the burning of fossil fuels. Although nuclear waste is much more toxic than these pollutants, it can at least be completely contained.
Nuclear power came to the fore in the late 1950s and 1960s, with the building of many nuclear power stations around the world. However, the environmental hazards associated with nuclear waste have always been an argument against nuclear power. Combined with the Chernobyl accident in 1986 and market forces in the energy sector, the nuclear industry went into decline in the 1980s and 1990s. But the tide now appears to be turning. In May, for example, the UK government signalled its intention to build a new fleet of nuclear power stations across the country, and several other countries, including China, Finland, France, India and Russia, have announced or even begun work on building new reactors.
It is not just the urgent need to combat climate change that is fuelling this nuclear revival. Economic arguments based on spiralling gas and oil prices, plus strategic interests in ensuring individual countries have a stable energy supply, are also major factors. In fact, so strong are these economic and strategic arguments that it now seems impossible to see a realistic solution to our energy needs without nuclear power playing a significant role once again.
If nuclear power has its own potential for hazarding environment with radiation pollution, scientists are also developing cleaner and greener sources of energy. Solar energy is one such option.
Solar power
Nanotechnology could transform solar cells from niche products to devices that provide a significant fraction of the world's energy, as Edwin Cartlidge discusses.
The burning of skin on a hot summer's day, the awesome power of a tornado or the existence of a simple blade of grass all testify to one thing: the huge amount of energy transmitted to us from the Sun. In a single hour the Sun delivers the same amount of energy as consumed by all of humanity in a year - about 5 × 1020 J - and in 36 hours releases as much energy as exists in the Earth's estimated oil reserves. When you combine this with the fact that solar energy is essentially inexhaustible, available to everyone the world over and generates no greenhouse gases or other harmful pollutants, it seems hard to imagine why we do not make greater use of it.
The main reason is cost. Electricity produced by solar (or photovoltaic) cells costs about $0.30 per kilowatt hour (kWh), whereas that derived from wind costs in the region of $0.05 per kWh and from natural gas about $0.03 per kWh. Technologically, the difficulty in deriving energy from the Sun's rays - as opposed to, say, fossil fuels - is that they have a relatively low energy density. The upshot is that in the US, for example, photovoltaic cells generate only about 0.02% of electricity, with the vast majority of the rest coming from coal, gas and nuclear power.
This situation is set to change, however. Gradual improvements to the basic single-crystal silicon solar cells have already reduced the cost of photovoltaic electricity by about a factor of 20 in the past 30 years, and the continuing development of cheaper crystalline materials should see this trend continue. According to a report produced by American scientists George Crabtree and Nathan Lewis for the US Department of Energy in 2005, solar cells will become competitive enough - generating electricity at $0.02 per kWh - to be implemented on a massive scale in about 20-25 years' time.
But some believe that the rise of solar energy could be far more dramatic. Crabtree and Lewis themselves estimate that the widespread use of photovoltaic cells could happen as soon as 2015 if physicists can perfect a new generation of more advanced devices built using nanotechnology. These include cells based on quantum dots or nanocrystals devices, which are potentially both cheaper and more efficient than existing cells. Indeed, such is the promise of these technologies that a report produced for the German government in 2003 predicted that by 2050 photovoltaics could be meeting a quarter of the world's energy needs.
Such a transformation would require huge political will. However, the increasing urgency with which governments are addressing, or at least discussing, the issue of climate change suggests that this will may emerge.
Although the world's emissions of greenhouse gases could be reduced using other non fossil-fuel energy sources, some researchers believe that photovoltaics could take much of the strain on their own. In the United Kingdom, for example, scientists point out that if the country expanded its photovoltaic capacity by 40 per cent each year - which is less than that occurred globally in 2004 - then it could more than make up for the loss of generating capacity caused by the closure of its ageing nuclear reactors over the next 20 years.