Adventure in energy (history, present, future)
My presentation at the final exam for the course "History of Science", 17.07.2008
My presentation at the final exam for the course "History of Science", 17.07.2008
*****
My paper for the ERM Alumni Conference on Energy and Natural Resources Policy, Brandenburg Technical University of Cottbus, Germany, 6-10.10.2008
Abstract: The world of fossil fuel – based economy is eventually coming into crisis as these fuels go exhausted. Moreover, the problem is not only the depletion of these fuels, but also many environmental and social issues related such as environmental pollution, climate change, oil wars… Nuclear power cannot be a favourable alternative because of safety and security challenges of the unsolved nuclear waste problem and the nightmare of nuclear weapon proliferation. For a sustainable energy future, we have abundance of renewable energy potential and we should improve more our energy efficiency in all aspects from technology, manufacturing, building to daily life consuming.
1. Introduction
Every living-thing needs energy to maintain their lives on Earth. Everything needs energy to do their works. Every society needs energy to power their social and economic activities. In anytime and anywhere, energy is always essential as a heart of matter. However, most present trends in energy indicate a deteriorating picture.
To some extent, the history of human development has intimately related to the inventions of energy sources. For a long time in human history, people had relied mainly on natural energy sources like sunshine, windmill, water-flow, firewood and animal work. Up until just two recent centuries, along with industrial revolution, fossil fuels have been exploited and have quickly become dominant, accounting for approximately 80% of world primary energy consumption [1]. Pressure of industrialization and population on energy demand has increased dramatically. Within a rather short time of two hundreds years, we human have already burnt out an amount of fossil fuels that nature processes had taken millions of years to form! Obviously, these non-renewable energy sources will run out someday, and according to some estimate, that day will not be so far from now for oil. Actually, we are in the time of Peak Oil, the point when the maximum rate of global petroleum extraction is reached, after which the rate of production enters terminal decline [2]. The time of cheap oil will end soon [3]. Many experts have been warning about the end of our civilization as we know it is today [4], the end of oil age with its catastrophic consequences [5]. The world of fossil fuel – based economy is eventually coming into crisis as these fuels go exhausted. In searching for more energy resources, people even have fought each other in oil wars. The energy matter then has turned into serious political matter. Moreover, the problem is not only the depletion of these fuels, but also many environmental and social issues related to this type of our fossil fuel-based economy, such as too much external-dependent, unsustainable agriculture systems, coal mining risk, offshore oil spillage, pollution from coal-power plants, from transportation and industrial activities…and the most serious one perhaps is the green house effect that leads to global climate change with numerous unpredictable sub-consequences.
Then, recently, the challenge of climate change has brought up again the interest in nuclear energy. But ‘Is nuclear the answer?’ [6], the Sustainable Development Commission in UK conducted eight detailed studies covering safety, waste, economics and climate change and concluded that the advantages of nuclear power as a low-carbon technology are outweighed by disadvantages such as uncertain costs, long-lived radioactive waste and an increased risk that nuclear weapons will proliferate. Also, even when considering nuclear power as an option to meet future energy needs, report from MIT finds: ‘the prospects for nuclear energy as an option are limited by four unresolved problems: high relative costs; perceived adverse safety, environmental, and health effects; potential security risks stemming from proliferation; and unresolved challenges in long-term management of nuclear wastes’ [7]. Another report from Oxford Research Group [8] has raised two main questions ‘How dangerous is nuclear power?’ and ‘Can it help reduce CO2 emissions?’ In the report, the short answer to the first questions is ‘very’ - nuclear power is uniquely dangerous when compared to other energy sources; and for the second question the answer is ‘not enough and not in time’. Therefore, nuclear power is more a problem than a solution. On the other hand, uranium is finite resource; that means ultimately, they will be exhausted someday and thus, like fossil fuels, it can not be a good answer in the long run.
Then, what are the strategies to tackle this global energy crisis, and further, to achieve a sustainable energy future?
2. Saving energy and improving energy efficiency
The first and foremost available solution is energy conservation, through reducing energy waste and increasing energy efficiency. We should recognize the fact that in the mean time alternative energies can not replace fossil fuels at the scale, rate and manner at which the world currently consumes them. Moreover, Fritjof Capra [9] pointed out that the deepest roots of our current energy crisis lie on the patterns of wasteful production and consumption. Therefore, to solve the crisis, what truly matters is not getting more energy, which would only aggravate our problems, but profound changes in our values, attitudes and lifestyle. Energy conservation is our short-term key energy source and will always be a good answer in the long run.
Though Peak Oil can conceive quite catastrophic potential, it also opens some hopeful possibilities, a chance to address many underlying social problems, and the opportunity to return to simpler, healthier and more community oriented lifestyle [3]. The example of Cuba can serve as a positive and instructive model for a world facing Peak Oil on a global scale [10]. Cuba is the only country that has faced such a crisis – the massive reduction of fossil fuels, after the Soviet Union collapsed in 1990. Cuba's transition to a low-energy society has taken place by creating cycling culture, sharing public transportation and turning from a mechanized, industrial agricultural system to one using organic methods of farming and local, urban gardens. Lesson from Cuba’s survival gives us hope in the power of community, and the effectiveness of their strategies, which can be summarize in three words: curtailment, conservation and cooperation [11].
Energy conservation brings many benefits. It is low cost and available at all levels. Using less energy resource also means reducing pollution and environmental degradation, while prolong fossil fuel supplies and buying time to phase in renewable energy. Efficiency improvements efforts include more efficient utilization of both quantity and quality of energy, as well as broader measures such as improved energy management, fuel substitution, and better matching of energy carriers and energy demands [12]. Saving energy can start just right at each individual’s lifestyle. For examples:
- Buy and use energy-efficient devices
- Look for electronics that are rechargeable
- Turn off and unplug lights, TV sets, computers, and other electronic equipment when they are not in use
- Walk or cycle for short trips, consider car-pooling or take public transport for longer ones
- Live as close to work as possible
- Eat lower on the food chains, buy regionally and seasonally produced organic food whenever possible
The list goes on… and every bit can help.
Many measures can also be done on the technical sphere, where there is a lot of space expected for creative innovations. In housing, remarkable energy-saving can be achieved by improved heat insulation or building design which takes advantages of natural elements like sun, wind, plants, trees, green-roofs… instead of using air conditioning. Many intelligent lighting systems with energy-saving sensors have become widely used for hotels, official buildings. In transportation, energy-saving techniques can be attained through increasing fuel efficiency and making vehicles from lighter and stronger materials. Besides, idea of co-generation, producing both heat and electricity from one energy source can be well applied in industry.
In addition, a thoughtful vision is needed for energy policy. Governments should accept a target of phasing out oil and gas use within 50 years, discontinuing all direct and indirect subsidies to the oil and gas industry, at the same time increasing investment in public transport, changing tariff policies to support local consumption of goods produced locally, and encouraging sustainable agriculture [13]. Many policies available to alleviate energy insecurity can also help to mitigate local pollution and climate change, as a “triple-win” outcome [14]. For examples, development in public transportation does not only conserve energy, but also relieve congestion, improve air quality, provide access for all ages, offer mobility for rural areas [15]. On the other hand, organic farming does not only reduce petroleum-based inputs but also improve soil quality, help building healthy land, provide healthy food for community.
3. Developing renewable energies
Eventually, we will use up non-renewable energy resources. From a long-term point of view, renewable ones are what we should rely on. According to the estimation of WBGU (German Advisory Council on Global Change), we have huge potential of renewable energy sources. All together, renewable energy sources can provide 3078 times the current global energy needs, in which solar-power 2850 times, wind-power 200 times, biomass 20 times, geothermal-power 5 times, wave-tidal-power 2 times and hydropower 1 time [16]. Renewable resources, the natural powers that maintain our lives throughout human history, will not run out. The Sun shines for all of us, and the wind blows, free of charge. Although the equipments to collect solar and wind energy, such as solar panels and wind turbines cost money, when considering that the resource is taking for free, the overall cost of using solar and wind energy can make them smart choices. Renewable technology cost trends typically show a steep decline during last decades [17] and that trends will continue to reach reasonable levels in the future as their market’s expansion. Moreover, renewable energy are often clean, such as wind and sunshine, they do not emit smoke or create pollution. Others, such as biomass, almost always cause less pollution than fossil or nuclear alternatives.
Renewable energies would bring a number of benefits to the economy. First, they help increase the diversity of energy supplies, and thus lower the dependency on imported fossil fuels and improve the security of energy supplies. Second, they help make use of local resources to provide a cost-effective energy supply (characterized by mobility, modularity and low operating costs; renewable energies are very flexible in case of upgrade and competitive technologies as decentralized systems) while reducing regional and global greenhouse gas emissions. Since they are often flexible, small-scale designs, which take the advantages of local conditions, they can be located close to the demand. Then, transmission and distribution costs are reduced, as well as losses. Finally, from the social point of view, renewable energies can create more domestic employment. Such benefits have created a strong motivation for pursuing renewable energies in both developed and developing countries. The investment costs of renewable technologies have been reduced remarkably today and this makes renewable energies more attractive, quickly developed and expanded [18].
Solar-power
The Sun has produced energy for billions of years. On average, the energy from the Sun reaches the Earth is about one kilowatt per square meter worldwide. Then, in one day, the sunlight which reaches the Earth produces enough energy to satisfy the world’s current power demands for eight years. Even though only a percentage of that potential is technically accessible, this is still enough to provide just under six times more power than the world currently requires [16]. Unlike other energy technologies, solar energy technologies cause neither noise, nor pollution; hence they are often installed near consumers to reduce construction costs. Solar energy is used for heating water, space, drying agricultural products, and generating electrical energy.
Besides using design features to maximize use of the Sun (passive solar systems), some buildings have active systems to gather and store solar energy as concentrating solar systems (Solar thermal collecting). Solar collectors sit on the rooftops of buildings to collect solar energy for space heating, water heating, and space cooling. Most solar collectors are large flat boxes, painted black on the inside, with glass covers. In the most common design, pipes in the box carry liquids that take the heat from the box and bring it into the building. This heated liquid, usually a water-alcohol mixture to prevent winter freezing, is used to heat water in a tank or is put through radiators to heat the air. Interestingly, because of the cooling effect moist air has when it evaporates, solar heat can also drive a cooling system. By using mirrors and lenses to concentrate the rays of the Sun, solar thermal systems produce high temperatures that can be used to heat water for producing steam to drive an electric turbine or for industrial applications. Additionally, solar power can contribute to domestic water heating, which already requires a lot of electricity. Hotels, schools and hospitals could be equipped with solar water-heating systems.
Photovoltaic (PV, solar cell) systems convert sunlight directly into electricity. To achieve the desired voltage and current, modules are wired in series and parallel into PV array. The flexibility of modular PV system allows designers to create solar power systems that can meet a wide variety of electrical needs, no matter how large or small. Most of the market for solar electric today is concentrated in off-grid homes. Solar cell system is considered as a way to avoid building long and expensive power lines to remote areas. As the cost of photovoltaic systems continues to decline, they will find increasingly larger niches. No other electrical generator is as easy to install or maintain. As PV prices continue to fall, solar power will become a significant source of electricity in the 21st century.
On the other hand, just very recently, solar-power has turned to a new dawn in history as the nanosolar’s thin film technology has been awarded for “Top Innovation of the Year 2007” by Popular Science magazine [19] and “Best Invention of the Year 2008” by Time magazine [20]. This innovation has marked a revolution in solar energy since it utilizes thin sheets of nonsilicon components that reduce the production costs by over 90% and decrease the thickness by 99%. The nanosolar powersheet is thin enough to be rolled and is printable in many versatile forms. Nanosolar is on track to make solar electricity cost-efficient for ubiquitous deployment and mass produced on a global scale [21].
Wind-power
Wind is air in motion. It is produced by the uneven heating of the Sun on the Earth’s surface. Since the Earth’s surface is made of various land and water formations, it absorbs the Sun’s radiation unevenly. Wind power turns the kinetic energy of the wind into mechanical or electrical power which can be used for a variety of tasks. Windmills have been used for pumping water or grinding grain for hundreds of years. Today, the windmill's modern equivalent, a wind turbine, can use the wind's energy to generate electricity. Whether the task is creating electricity or pumping water, the wind offers an inexpensive, clean and reliable form of power. Wind energy does not produce any air pollution. It is completely renewable, and very efficient. It requires minimal maintenance and has low operating expenses.
Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. For utility-scale sources of wind energy, a large number of wind turbines are usually built close together to form a wind plant. Small turbines are sometimes connected to diesel/electric generators or sometimes have a battery to store the extra energy they collect when the wind is blowing hard. As wind speed doubles, power generation capability increases eightfold. Wind speed increases with altitude and over open areas with no windbreaks. Good sites for wind plants are the tops of smooth, rounded hills, open plains or shorelines, and mountain gaps that produce wind funneling. Wind energy is growing fast. It has been the world's fastest growing renewable energy source for more than a decade with an average annual growth rate of about 25% along with rapid decline in turbine manufacturing costs. Wind energy is estimated to grow from 60 GW today (0.5% of global power) to 1000 GW (12-18% of global power) by 2020 [22]. Wind is free so wind energy can provide a stable long-term price for power production.
Bio-energy
People have used biomass energy or bio-energy for thousands of years, ever since people started burning wood to cook food or to keep warm. In fact, biomass continues to be a major source of energy in much of the developing world. Biomass is organic material which has stored sunlight in the form of chemical energy thanks to photosynthetic process of plants. When burned, the chemical energy is released as heat. Biomass burning generates about the same amount of carbon dioxide as fossil fuels, but every time a new plant grows, carbon dioxide is actually removed from the atmosphere. The net emission of carbon dioxide will be zero as long as plants continue to be replenished for biomass energy purposes. These energy crops, such as fast-growing trees and grasses, are called biomass feedstocks.
In addition to firewood, biomass can be fermentated into liquid form or extracted from vegetable oils and used in transportation such as ethanol or biodiesels. Brazil is the leader country in production and utilization of ethanol from sugarcane. These biofuels produce fewer emissions than petroleum. However, land use for those energy crops over food crop planting is still a hard issue, particularly for developing countries, where the need for food, as the basic need in fighting poverty, is more predominant.
Biomass fuels include not only wood, straw, plants, residues from agriculture or forestry, but also the organic component of solid wastes. Even the fumes from landfills, a byproduct of the decay process of organic matter in municipal solid waste, comprised of approximately 50% methane, can be used as a biomass energy source. In fact, landfill gas has emerged as an easily available, economically competitive and proven energy source [23]. Reducing landfill methane emission by utilizing it as a fuel helps capturing a major greenhouse gas 25 times more potent than carbon dioxide. Obviously, this is a very beneficial approach which produces energy without competing with food production while simultaneously solves the problems of waste and protects the environment. Similarly, biogas is considered one of the cheapest renewable energies in rural areas in developing countries. Like landfill gas, it is produced by the action of bacteria on vegetable/organic material in anaerobic conditions. The bacteria slowly digest the material (usually animal dung, human wastes and crop residues) and produce a gas which is roughly 60% methane and 40% carbon dioxide. This gas is combustible and thus can replace other fuels like wood, agricultural residues, and kerosene for use in simple gas stoves and lamps. Biogas is used for cooking, lighting, generating electricity…etc. Production of biogas would not only save firewood but also be beneficial for integrated farming systems by converting manure to fertilizer for crops or ponds for fish and water plants. Other benefits of biodigestion include the reduction of manure smell, elimination of smoke when cooking and the alleviation of pathogens and thereby improving hygiene on farms.
Recently, researchers have brought up a very interesting and good news for future of biofuel. It is algae, a promising oil alternative, a big idea for future energy because of its high potential and efficiency [24]. Since they have simple cellular structure, a lipid-rich composition and a rapid reproduction rate, these tiny aquatic organisms can yield 30 times more energy per acre than land crops such as soybeans, according to the US Department of Energy [25]. Many algae species also can grow in salt water or other harsh conditions. In addition, microscopic green algae (pond scum) can split water into hydrogen and oxygen under controlled conditions [26]. Thus, these green algae have hopeful potential to become microscopic power plants for hydrogen, which is considered one of the energy in the future.
Micro-hydropower
Of the renewable energy sources that generate electricity, hydropower is the most often used. Mechanical energy is derived by directing, harnessing, or channelling moving water. The amount of available energy in moving water is determined by its flow or fall. The most common type of hydroelectric power plant uses a dam on a river to store water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. But hydroelectric power doesn't necessarily require a large dam. Some hydroelectric power plants just use a small canal to channel the river water through a turbine.
Hydropower is almost free, there are no waste products, and hydropower does not pollute the water or the air. However, it is criticized because it does change the environment by affecting natural habitats, especially the ecosystem behind large-scale hydropower dam. So, small-scale micro-hydro system (pico-hydro system), is more favourable. Household-scale micro-hydropower systems have proven particularly important in isolated rural communities that are located far from the national grid but close to suitable water resources. These pico-hydro, with a maximum electrical output of 5 kilowatts (kW), sufficient to power light bulbs, radios, televisions, refrigerators and food processors [27]. Hydro power systems of this size benefit over the larger systems in terms of cost and simplicity of design. Only small water flows are required for pico-hydro systems, meaning that many suitable sites are likely to exist. A small stream or spring often provides enough water. Recent innovations in pico-hydro technology have made it an economic and versatile source of power even in some of the world's most resource-poor and inaccessible places. Well-designed pico-hydro systems have a lower cost per kW than solar or wind power. Pico-hydro equipment is small and compact. The component parts can be easily transported into remote and inaccessible regions. Local manufacture is possible, and the design principles and fabrication processes can be easily learned. The number of houses connected to each scheme is small, usually under 100 households. This eases maintenance and reduces capital requirements. Standard AC electricity can be produced and distributed throughout a village to power electrical appliances, or it can charge large batteries for households.
4. Future Energy Vision
Several years ago, there was a growing interest in developing a hydrogen economy [28], which proposed to solve the problems of our current fossil-fuel-based (hydrocarbon) economy. Hydrogen has been predicted as a clean energy of the future for stationary, mobile and transport applications, especially with the use of fuelcells. The main advantage of hydrogen economy is the elimination of pollution, since the only byproduct from burning hydrogen or combining hydrogen and oxygen gases in fuelcell to produce electricity is water vapor, no harmful gases to environment. In addition, fuelcell-powered vehicles are about twice as efficient as those with internal combustion engine. During last decade, fuelcell-vehicles [29] have been developed by many big players in the world such as Honda, BMW, Huyndai, Toyota, Ford, GM… However, the development of a hydrogen economy has to face up to major barriers [30] of producing, transporting and storing hydrogen. The key fact is that hydrogen is not a source of energy. Like electricity, hydrogen is only an energy carrier. That means, hydrogen is only a way of storing and distributing energy, but hydrogen itself has to be generated from somewhere else. Hydrogen can be produced by electrolysis of water, but we need electricity to do the work. Moreover, hydrogen is not a convenient carrier of energy. Because of its lightness and explosive characteristic, hydrogen containers should be tight enough and quite bulky. Then, for mobile applicants, hydrogen must be liquefied or compressed to increase energy density. Therefore, there are still many difficulties to realize the vision of a hydrogen economy.
On the other hand, since more than fifty years, scientists all over the world have been working to realize the dream of a fusion vision. There are now two remarkable fusion projects, both have been developed under international cooperation: the Joint European Torus (JET) [31] and the International Thermonuclear Experimental Reactor (ITER) [32]. Fusion, which is expected to be abundant, clean and safe, could become the dominant source of electricity on Earth in a century or so. Although it may be a possible source of energy in the distant future, there is still a long way to go.
So, what would be the more realistic and feasible prospect for a sustainable energy future? Lester Brown [33] believes that “the new energy economy will be based much less on energy from combustion and more on the direct harnessing of energy from wind, the Sun and the Earth itself”. Thus, future would belong to the age of Renewable Sources. It is also the scenario described in the Energy [R]evolution report, by the European Renewable Energy Council and Greenpeace [16]. The vision would be made by optimized integration of renewable energy, developing smart consumption, generation and distribution systems and maximizing the efficiency of building through better insulation. Solar façade would be a decorative element on office and apartment buildings. Rooftop wind and solar would be placed so that energy is generated close to the consumer. Clean electricity would also come from offshore wind parks or solar power station in deserts. Electricity would be much more prominent and become the principal source of energy for transportation, replacing gasoline and diesel fuels. Hydrogen can become a way of back-up to store solar, wind energy to use at night or during cloudy days…
Shifting to renewable energy means shifting to more decentralized and diversified systems which maximize the use of locally available, environmental friendly energy sources. “It is encouraging to know that we now have the technologies to build a new energy economy, one that is not climate-disruptive, that does not pollute air and that can last as long as the sun itself” – Lester Brown.
1. Introduction
Every living-thing needs energy to maintain their lives on Earth. Everything needs energy to do their works. Every society needs energy to power their social and economic activities. In anytime and anywhere, energy is always essential as a heart of matter. However, most present trends in energy indicate a deteriorating picture.
To some extent, the history of human development has intimately related to the inventions of energy sources. For a long time in human history, people had relied mainly on natural energy sources like sunshine, windmill, water-flow, firewood and animal work. Up until just two recent centuries, along with industrial revolution, fossil fuels have been exploited and have quickly become dominant, accounting for approximately 80% of world primary energy consumption [1]. Pressure of industrialization and population on energy demand has increased dramatically. Within a rather short time of two hundreds years, we human have already burnt out an amount of fossil fuels that nature processes had taken millions of years to form! Obviously, these non-renewable energy sources will run out someday, and according to some estimate, that day will not be so far from now for oil. Actually, we are in the time of Peak Oil, the point when the maximum rate of global petroleum extraction is reached, after which the rate of production enters terminal decline [2]. The time of cheap oil will end soon [3]. Many experts have been warning about the end of our civilization as we know it is today [4], the end of oil age with its catastrophic consequences [5]. The world of fossil fuel – based economy is eventually coming into crisis as these fuels go exhausted. In searching for more energy resources, people even have fought each other in oil wars. The energy matter then has turned into serious political matter. Moreover, the problem is not only the depletion of these fuels, but also many environmental and social issues related to this type of our fossil fuel-based economy, such as too much external-dependent, unsustainable agriculture systems, coal mining risk, offshore oil spillage, pollution from coal-power plants, from transportation and industrial activities…and the most serious one perhaps is the green house effect that leads to global climate change with numerous unpredictable sub-consequences.
Then, recently, the challenge of climate change has brought up again the interest in nuclear energy. But ‘Is nuclear the answer?’ [6], the Sustainable Development Commission in UK conducted eight detailed studies covering safety, waste, economics and climate change and concluded that the advantages of nuclear power as a low-carbon technology are outweighed by disadvantages such as uncertain costs, long-lived radioactive waste and an increased risk that nuclear weapons will proliferate. Also, even when considering nuclear power as an option to meet future energy needs, report from MIT finds: ‘the prospects for nuclear energy as an option are limited by four unresolved problems: high relative costs; perceived adverse safety, environmental, and health effects; potential security risks stemming from proliferation; and unresolved challenges in long-term management of nuclear wastes’ [7]. Another report from Oxford Research Group [8] has raised two main questions ‘How dangerous is nuclear power?’ and ‘Can it help reduce CO2 emissions?’ In the report, the short answer to the first questions is ‘very’ - nuclear power is uniquely dangerous when compared to other energy sources; and for the second question the answer is ‘not enough and not in time’. Therefore, nuclear power is more a problem than a solution. On the other hand, uranium is finite resource; that means ultimately, they will be exhausted someday and thus, like fossil fuels, it can not be a good answer in the long run.
Then, what are the strategies to tackle this global energy crisis, and further, to achieve a sustainable energy future?
2. Saving energy and improving energy efficiency
The first and foremost available solution is energy conservation, through reducing energy waste and increasing energy efficiency. We should recognize the fact that in the mean time alternative energies can not replace fossil fuels at the scale, rate and manner at which the world currently consumes them. Moreover, Fritjof Capra [9] pointed out that the deepest roots of our current energy crisis lie on the patterns of wasteful production and consumption. Therefore, to solve the crisis, what truly matters is not getting more energy, which would only aggravate our problems, but profound changes in our values, attitudes and lifestyle. Energy conservation is our short-term key energy source and will always be a good answer in the long run.
Though Peak Oil can conceive quite catastrophic potential, it also opens some hopeful possibilities, a chance to address many underlying social problems, and the opportunity to return to simpler, healthier and more community oriented lifestyle [3]. The example of Cuba can serve as a positive and instructive model for a world facing Peak Oil on a global scale [10]. Cuba is the only country that has faced such a crisis – the massive reduction of fossil fuels, after the Soviet Union collapsed in 1990. Cuba's transition to a low-energy society has taken place by creating cycling culture, sharing public transportation and turning from a mechanized, industrial agricultural system to one using organic methods of farming and local, urban gardens. Lesson from Cuba’s survival gives us hope in the power of community, and the effectiveness of their strategies, which can be summarize in three words: curtailment, conservation and cooperation [11].
Energy conservation brings many benefits. It is low cost and available at all levels. Using less energy resource also means reducing pollution and environmental degradation, while prolong fossil fuel supplies and buying time to phase in renewable energy. Efficiency improvements efforts include more efficient utilization of both quantity and quality of energy, as well as broader measures such as improved energy management, fuel substitution, and better matching of energy carriers and energy demands [12]. Saving energy can start just right at each individual’s lifestyle. For examples:
- Buy and use energy-efficient devices
- Look for electronics that are rechargeable
- Turn off and unplug lights, TV sets, computers, and other electronic equipment when they are not in use
- Walk or cycle for short trips, consider car-pooling or take public transport for longer ones
- Live as close to work as possible
- Eat lower on the food chains, buy regionally and seasonally produced organic food whenever possible
The list goes on… and every bit can help.
Many measures can also be done on the technical sphere, where there is a lot of space expected for creative innovations. In housing, remarkable energy-saving can be achieved by improved heat insulation or building design which takes advantages of natural elements like sun, wind, plants, trees, green-roofs… instead of using air conditioning. Many intelligent lighting systems with energy-saving sensors have become widely used for hotels, official buildings. In transportation, energy-saving techniques can be attained through increasing fuel efficiency and making vehicles from lighter and stronger materials. Besides, idea of co-generation, producing both heat and electricity from one energy source can be well applied in industry.
In addition, a thoughtful vision is needed for energy policy. Governments should accept a target of phasing out oil and gas use within 50 years, discontinuing all direct and indirect subsidies to the oil and gas industry, at the same time increasing investment in public transport, changing tariff policies to support local consumption of goods produced locally, and encouraging sustainable agriculture [13]. Many policies available to alleviate energy insecurity can also help to mitigate local pollution and climate change, as a “triple-win” outcome [14]. For examples, development in public transportation does not only conserve energy, but also relieve congestion, improve air quality, provide access for all ages, offer mobility for rural areas [15]. On the other hand, organic farming does not only reduce petroleum-based inputs but also improve soil quality, help building healthy land, provide healthy food for community.
3. Developing renewable energies
Eventually, we will use up non-renewable energy resources. From a long-term point of view, renewable ones are what we should rely on. According to the estimation of WBGU (German Advisory Council on Global Change), we have huge potential of renewable energy sources. All together, renewable energy sources can provide 3078 times the current global energy needs, in which solar-power 2850 times, wind-power 200 times, biomass 20 times, geothermal-power 5 times, wave-tidal-power 2 times and hydropower 1 time [16]. Renewable resources, the natural powers that maintain our lives throughout human history, will not run out. The Sun shines for all of us, and the wind blows, free of charge. Although the equipments to collect solar and wind energy, such as solar panels and wind turbines cost money, when considering that the resource is taking for free, the overall cost of using solar and wind energy can make them smart choices. Renewable technology cost trends typically show a steep decline during last decades [17] and that trends will continue to reach reasonable levels in the future as their market’s expansion. Moreover, renewable energy are often clean, such as wind and sunshine, they do not emit smoke or create pollution. Others, such as biomass, almost always cause less pollution than fossil or nuclear alternatives.
Renewable energies would bring a number of benefits to the economy. First, they help increase the diversity of energy supplies, and thus lower the dependency on imported fossil fuels and improve the security of energy supplies. Second, they help make use of local resources to provide a cost-effective energy supply (characterized by mobility, modularity and low operating costs; renewable energies are very flexible in case of upgrade and competitive technologies as decentralized systems) while reducing regional and global greenhouse gas emissions. Since they are often flexible, small-scale designs, which take the advantages of local conditions, they can be located close to the demand. Then, transmission and distribution costs are reduced, as well as losses. Finally, from the social point of view, renewable energies can create more domestic employment. Such benefits have created a strong motivation for pursuing renewable energies in both developed and developing countries. The investment costs of renewable technologies have been reduced remarkably today and this makes renewable energies more attractive, quickly developed and expanded [18].
Solar-power
The Sun has produced energy for billions of years. On average, the energy from the Sun reaches the Earth is about one kilowatt per square meter worldwide. Then, in one day, the sunlight which reaches the Earth produces enough energy to satisfy the world’s current power demands for eight years. Even though only a percentage of that potential is technically accessible, this is still enough to provide just under six times more power than the world currently requires [16]. Unlike other energy technologies, solar energy technologies cause neither noise, nor pollution; hence they are often installed near consumers to reduce construction costs. Solar energy is used for heating water, space, drying agricultural products, and generating electrical energy.
Besides using design features to maximize use of the Sun (passive solar systems), some buildings have active systems to gather and store solar energy as concentrating solar systems (Solar thermal collecting). Solar collectors sit on the rooftops of buildings to collect solar energy for space heating, water heating, and space cooling. Most solar collectors are large flat boxes, painted black on the inside, with glass covers. In the most common design, pipes in the box carry liquids that take the heat from the box and bring it into the building. This heated liquid, usually a water-alcohol mixture to prevent winter freezing, is used to heat water in a tank or is put through radiators to heat the air. Interestingly, because of the cooling effect moist air has when it evaporates, solar heat can also drive a cooling system. By using mirrors and lenses to concentrate the rays of the Sun, solar thermal systems produce high temperatures that can be used to heat water for producing steam to drive an electric turbine or for industrial applications. Additionally, solar power can contribute to domestic water heating, which already requires a lot of electricity. Hotels, schools and hospitals could be equipped with solar water-heating systems.
Photovoltaic (PV, solar cell) systems convert sunlight directly into electricity. To achieve the desired voltage and current, modules are wired in series and parallel into PV array. The flexibility of modular PV system allows designers to create solar power systems that can meet a wide variety of electrical needs, no matter how large or small. Most of the market for solar electric today is concentrated in off-grid homes. Solar cell system is considered as a way to avoid building long and expensive power lines to remote areas. As the cost of photovoltaic systems continues to decline, they will find increasingly larger niches. No other electrical generator is as easy to install or maintain. As PV prices continue to fall, solar power will become a significant source of electricity in the 21st century.
On the other hand, just very recently, solar-power has turned to a new dawn in history as the nanosolar’s thin film technology has been awarded for “Top Innovation of the Year 2007” by Popular Science magazine [19] and “Best Invention of the Year 2008” by Time magazine [20]. This innovation has marked a revolution in solar energy since it utilizes thin sheets of nonsilicon components that reduce the production costs by over 90% and decrease the thickness by 99%. The nanosolar powersheet is thin enough to be rolled and is printable in many versatile forms. Nanosolar is on track to make solar electricity cost-efficient for ubiquitous deployment and mass produced on a global scale [21].
Wind-power
Wind is air in motion. It is produced by the uneven heating of the Sun on the Earth’s surface. Since the Earth’s surface is made of various land and water formations, it absorbs the Sun’s radiation unevenly. Wind power turns the kinetic energy of the wind into mechanical or electrical power which can be used for a variety of tasks. Windmills have been used for pumping water or grinding grain for hundreds of years. Today, the windmill's modern equivalent, a wind turbine, can use the wind's energy to generate electricity. Whether the task is creating electricity or pumping water, the wind offers an inexpensive, clean and reliable form of power. Wind energy does not produce any air pollution. It is completely renewable, and very efficient. It requires minimal maintenance and has low operating expenses.
Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. For utility-scale sources of wind energy, a large number of wind turbines are usually built close together to form a wind plant. Small turbines are sometimes connected to diesel/electric generators or sometimes have a battery to store the extra energy they collect when the wind is blowing hard. As wind speed doubles, power generation capability increases eightfold. Wind speed increases with altitude and over open areas with no windbreaks. Good sites for wind plants are the tops of smooth, rounded hills, open plains or shorelines, and mountain gaps that produce wind funneling. Wind energy is growing fast. It has been the world's fastest growing renewable energy source for more than a decade with an average annual growth rate of about 25% along with rapid decline in turbine manufacturing costs. Wind energy is estimated to grow from 60 GW today (0.5% of global power) to 1000 GW (12-18% of global power) by 2020 [22]. Wind is free so wind energy can provide a stable long-term price for power production.
Bio-energy
People have used biomass energy or bio-energy for thousands of years, ever since people started burning wood to cook food or to keep warm. In fact, biomass continues to be a major source of energy in much of the developing world. Biomass is organic material which has stored sunlight in the form of chemical energy thanks to photosynthetic process of plants. When burned, the chemical energy is released as heat. Biomass burning generates about the same amount of carbon dioxide as fossil fuels, but every time a new plant grows, carbon dioxide is actually removed from the atmosphere. The net emission of carbon dioxide will be zero as long as plants continue to be replenished for biomass energy purposes. These energy crops, such as fast-growing trees and grasses, are called biomass feedstocks.
In addition to firewood, biomass can be fermentated into liquid form or extracted from vegetable oils and used in transportation such as ethanol or biodiesels. Brazil is the leader country in production and utilization of ethanol from sugarcane. These biofuels produce fewer emissions than petroleum. However, land use for those energy crops over food crop planting is still a hard issue, particularly for developing countries, where the need for food, as the basic need in fighting poverty, is more predominant.
Biomass fuels include not only wood, straw, plants, residues from agriculture or forestry, but also the organic component of solid wastes. Even the fumes from landfills, a byproduct of the decay process of organic matter in municipal solid waste, comprised of approximately 50% methane, can be used as a biomass energy source. In fact, landfill gas has emerged as an easily available, economically competitive and proven energy source [23]. Reducing landfill methane emission by utilizing it as a fuel helps capturing a major greenhouse gas 25 times more potent than carbon dioxide. Obviously, this is a very beneficial approach which produces energy without competing with food production while simultaneously solves the problems of waste and protects the environment. Similarly, biogas is considered one of the cheapest renewable energies in rural areas in developing countries. Like landfill gas, it is produced by the action of bacteria on vegetable/organic material in anaerobic conditions. The bacteria slowly digest the material (usually animal dung, human wastes and crop residues) and produce a gas which is roughly 60% methane and 40% carbon dioxide. This gas is combustible and thus can replace other fuels like wood, agricultural residues, and kerosene for use in simple gas stoves and lamps. Biogas is used for cooking, lighting, generating electricity…etc. Production of biogas would not only save firewood but also be beneficial for integrated farming systems by converting manure to fertilizer for crops or ponds for fish and water plants. Other benefits of biodigestion include the reduction of manure smell, elimination of smoke when cooking and the alleviation of pathogens and thereby improving hygiene on farms.
Recently, researchers have brought up a very interesting and good news for future of biofuel. It is algae, a promising oil alternative, a big idea for future energy because of its high potential and efficiency [24]. Since they have simple cellular structure, a lipid-rich composition and a rapid reproduction rate, these tiny aquatic organisms can yield 30 times more energy per acre than land crops such as soybeans, according to the US Department of Energy [25]. Many algae species also can grow in salt water or other harsh conditions. In addition, microscopic green algae (pond scum) can split water into hydrogen and oxygen under controlled conditions [26]. Thus, these green algae have hopeful potential to become microscopic power plants for hydrogen, which is considered one of the energy in the future.
Micro-hydropower
Of the renewable energy sources that generate electricity, hydropower is the most often used. Mechanical energy is derived by directing, harnessing, or channelling moving water. The amount of available energy in moving water is determined by its flow or fall. The most common type of hydroelectric power plant uses a dam on a river to store water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. But hydroelectric power doesn't necessarily require a large dam. Some hydroelectric power plants just use a small canal to channel the river water through a turbine.
Hydropower is almost free, there are no waste products, and hydropower does not pollute the water or the air. However, it is criticized because it does change the environment by affecting natural habitats, especially the ecosystem behind large-scale hydropower dam. So, small-scale micro-hydro system (pico-hydro system), is more favourable. Household-scale micro-hydropower systems have proven particularly important in isolated rural communities that are located far from the national grid but close to suitable water resources. These pico-hydro, with a maximum electrical output of 5 kilowatts (kW), sufficient to power light bulbs, radios, televisions, refrigerators and food processors [27]. Hydro power systems of this size benefit over the larger systems in terms of cost and simplicity of design. Only small water flows are required for pico-hydro systems, meaning that many suitable sites are likely to exist. A small stream or spring often provides enough water. Recent innovations in pico-hydro technology have made it an economic and versatile source of power even in some of the world's most resource-poor and inaccessible places. Well-designed pico-hydro systems have a lower cost per kW than solar or wind power. Pico-hydro equipment is small and compact. The component parts can be easily transported into remote and inaccessible regions. Local manufacture is possible, and the design principles and fabrication processes can be easily learned. The number of houses connected to each scheme is small, usually under 100 households. This eases maintenance and reduces capital requirements. Standard AC electricity can be produced and distributed throughout a village to power electrical appliances, or it can charge large batteries for households.
4. Future Energy Vision
Several years ago, there was a growing interest in developing a hydrogen economy [28], which proposed to solve the problems of our current fossil-fuel-based (hydrocarbon) economy. Hydrogen has been predicted as a clean energy of the future for stationary, mobile and transport applications, especially with the use of fuelcells. The main advantage of hydrogen economy is the elimination of pollution, since the only byproduct from burning hydrogen or combining hydrogen and oxygen gases in fuelcell to produce electricity is water vapor, no harmful gases to environment. In addition, fuelcell-powered vehicles are about twice as efficient as those with internal combustion engine. During last decade, fuelcell-vehicles [29] have been developed by many big players in the world such as Honda, BMW, Huyndai, Toyota, Ford, GM… However, the development of a hydrogen economy has to face up to major barriers [30] of producing, transporting and storing hydrogen. The key fact is that hydrogen is not a source of energy. Like electricity, hydrogen is only an energy carrier. That means, hydrogen is only a way of storing and distributing energy, but hydrogen itself has to be generated from somewhere else. Hydrogen can be produced by electrolysis of water, but we need electricity to do the work. Moreover, hydrogen is not a convenient carrier of energy. Because of its lightness and explosive characteristic, hydrogen containers should be tight enough and quite bulky. Then, for mobile applicants, hydrogen must be liquefied or compressed to increase energy density. Therefore, there are still many difficulties to realize the vision of a hydrogen economy.
On the other hand, since more than fifty years, scientists all over the world have been working to realize the dream of a fusion vision. There are now two remarkable fusion projects, both have been developed under international cooperation: the Joint European Torus (JET) [31] and the International Thermonuclear Experimental Reactor (ITER) [32]. Fusion, which is expected to be abundant, clean and safe, could become the dominant source of electricity on Earth in a century or so. Although it may be a possible source of energy in the distant future, there is still a long way to go.
So, what would be the more realistic and feasible prospect for a sustainable energy future? Lester Brown [33] believes that “the new energy economy will be based much less on energy from combustion and more on the direct harnessing of energy from wind, the Sun and the Earth itself”. Thus, future would belong to the age of Renewable Sources. It is also the scenario described in the Energy [R]evolution report, by the European Renewable Energy Council and Greenpeace [16]. The vision would be made by optimized integration of renewable energy, developing smart consumption, generation and distribution systems and maximizing the efficiency of building through better insulation. Solar façade would be a decorative element on office and apartment buildings. Rooftop wind and solar would be placed so that energy is generated close to the consumer. Clean electricity would also come from offshore wind parks or solar power station in deserts. Electricity would be much more prominent and become the principal source of energy for transportation, replacing gasoline and diesel fuels. Hydrogen can become a way of back-up to store solar, wind energy to use at night or during cloudy days…
Shifting to renewable energy means shifting to more decentralized and diversified systems which maximize the use of locally available, environmental friendly energy sources. “It is encouraging to know that we now have the technologies to build a new energy economy, one that is not climate-disruptive, that does not pollute air and that can last as long as the sun itself” – Lester Brown.
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