ENVIRONMENT GLOBAL WARMING

UNEP - Promoting Cleaner Fuels and Vehicles for Better Air Quality (Video)

European Environment Agency - Use of cleaner and alternative fuels

Promoting Cleaner Fuels and Vehicles Worldwide

CLEANER FUELS

Ethanol-Corn, Sugar, Cellulose

Ethanol, or grain alcohol, can be produced from corn, sugar beets, sugar cane, or other crops primarily by fermentation. Ethanol came onto the scene largely as a means of moving toward energy independence. Brazil currently uses ethanol to meet an estimated 40 percent of its transportation requirements. Presently, roughly 20 percent of the corn grown in the United States is converted to ethanol. Current farming methods use a high percentage of petrochemicals, which to some extent defeats the intent of displacing oil.

Mixtures of ethanol and gasoline (such as 15 percent ethanol and 85 percent gasoline, or E85) are becoming common as an alternative fuel in certain areas of the United States. The energy payback from corn-grown ethanol, however, is marginal. Depending on agricultural conditions, ethanol produces on average only 25-30 percent more energy than the energy it took to produce it. These results in a net energy benefit, with the actual numbers depending on the specific production conditions, including how much carbon dioxide emissions are needed grow, harvest, process, and distribute the ethanol. A higher percentage of ethanol in the fuel blend may require engine modifications. Some automobile manufacturers are now offering flexible fuel vehicles (FFVs) to accommodate either gasoline or higher-percentage ethanol mixes. Because of its chemical structure (carbon–oxygen bonds rather than  the more energetic carbon–hydrogen bonds found in petroleum-based fuels), ethanol delivers about 30 percent less energy per gallon than gasoline. This may not be as noticeable with low-ethanol blends but may become more of an issue when there is more ethanol in the mix.

Since ethanol contains carbon in its chemical structure, it, like any other carbon containing fuel, produces carbon dioxide when burned. For a given amount of energy produced from the same size fuel tank, both ethanol and gasoline produce comparable amounts of carbon dioxide. One difference is that the carbon dioxide that gets released to the atmosphere when ethanol is burned came from the atmosphere through the process of photosynthesis that produced the corn. Ethanol can be thought of as just returning the carbon it removed from the atmosphere. This does not give ethanol a real advantage over gasoline, however, because if the corn wasn’t removing carbon dioxide, presumably some other crop would be there in its place. Growing corn to produce fuel requires farmland that otherwise could grow food crops. This could introduce price pressure on food at a time when increasing flood and drought conditions might diminish the usefulness of some agricultural areas around the world.

The process of producing ethanol involves a fermentation step that produces carbon dioxide. For every 0.51 kg of ethanol produced, 1 kg of carbon dioxide is produced. Capturing this carbon dioxide would improve ethanol’s effectiveness in terms of greenhouse gas reduction. Additional carbon dioxide is released when ethanol is burned, but it is made up of the same carbon atoms that were removed from the atmosphere to grow the feedstock to produce the ethanol.

Brazil has pioneered the use of ethanol. The government mandated 25 percent use of ethanol as a means toward energy independence. Government support, available agricultural acreage, and a climate conducive to growing sugar beets helped to promote this effort. Whether or not other countries can replicate Brazil’s experience with ethanol, the experience today does serve as a success story in implementing a change in a country’s approach to energy production and use. While achieving the twin goals of energy independence and pollution reduction, it is questionable whether ethanol can make much of a dent in the level of carbon dioxide emissions in the short term. Potential efficiency improvements in the ethanol growth and production cycle may improve this situation, this especially if organic farm wastes such as corn stalks, grasses, wheat and rice straw, leaves, and other agricultural leftovers (called lignocellulosic materials) are used as a starting material.

Cellulosic crops are attractive because they have higher yields than high carbohydrate crops such as corn and sugar beets. They grow more easily in areas that are not suitable for grains or other food crops without the need for extensive fertilization. They do not necessarily compete with crops grown for human or animal consumption. The cellulosic materials can provide some of the process heat needed to separate the ethanol after the fermentation process, avoiding the need for consuming additional fossil fuels in the process. At this point, substantial more research is needed to make this a commercial option.

Biodiesel

When Rudolph Diesel introduced the engine that now bears his name at the 1900 World’s Fair in Paris, he used peanut oil as its fuel, which by today’s standards could be considered biodiesel rather than petrodiesel. Thus the current resurgence of interest in the use of organic sources of fuel for diesel engines brings us full circle. Diesel engines are 30-40 percent more efficient than the more common internal combustion engines that use a spark plug to ignite a gasoline-air mixture. A diesel engine uses the heat generated by compression of the fuel mixture to produce the combustion that drives the engine. Diesel engines are far more popular in Europe today than in the United States, where they are used commonly in buses and trucks. Throughout their life cycle, biodiesel fuels produce 60-75 percent less carbon dioxide than an equivalent amount of gasoline.

One of the things that makes biodiesel attractive in a way that does not apply to ethanol is that biodiesel can be made from recycled oil that has been used for cooking. The amount of waste oil available for this purpose, however, would be insignificant compared with the amount needed. Biodiesel appears less promising, however, than cellulosic ethanol in terms of cost and potential for commercialization. In general, biofuels are limited by the amount of farmland around the world that can be dedicated to energy crop growth and by the availability of agricultural waste streams that can be converted to biofuels.

Hydrogen

From the point of view of global warming, hydrogen is perfect as a fuel. Hydrogen fuel produces no carbon dioxide and releases only water to the environment. Whether the hydrogen is burned in an internal combustion engine or reacts chemically in a fuel cell to produce electricity, it is by far the cleanest fuel imaginable.

Three things need to happen to make hydrogen fuel a reality:

1. An efficient and cost-effective method to generate hydrogen must be developed. The source is no problem. Hydrogen can be produced by passing an electric current through water. However, if the energy used to separate the hydrogen comes from a coal-fired electrical power plant, it defeats the purpose of using hydrogen in the first place. Use of a renewable form of energy such as wind or solar electricity would result in a net reduction of carbon dioxide emission. (Another way to produce hydrogen is to separate the hydrogen atoms in methane.)

2. Hydrogen would need to be transported to where it is to be used. If, for instance, gasoline trucks are used to bring the hydrogen from a separation plant to a “hydrogen fi lling station,” as much carbon dioxide might be to the atmosphere as might have been saved by using hydrogen in the first place. Local generation of hydrogen close to its point of use is a better option but one that would requiring modifying the way gas stations work today.

3. Finally, an infrastructure of filling stations would need to be established throughout the transportation system. Technical problems would need to be addressed, such as the fact that hydrogen leaks much more easily than other gases such as natural gas and would need more robust containment and distribution systems.

Hydrogen-powered vehicles, including cars and buses, have been developed and have been proven to be technically feasible. They are ideal for the environment. However, the best estimates for the infrastructure to support a hydrogen economy are decades away. A lot of carbon dioxide will be generated in the next several decades in the meantime.

Land Use

IPCC estimates put carbon dioxide emissions from deforestation, including decomposition following logging operations, to be between 7 and 16 percent of the world’s contribution in 2004. Natural contributors to greenhouse gas production and sinking are larger than the added contributions from fossil fuel combustion and other human activities. Every year, a large amount of carbon dioxide (roughly 100 billion metric tons) is removed from the atmosphere and stored in plants and soil. Removal and release of carbon dioxide are roughly in balance worldwide. The U.S. Department of Energy estimates that plants absorbed 17 percent of the carbon dioxide produced by burning fossil fuels in 1992.

Forests hold an enormous reservoir of carbon. The U.S. Forest Service estimates that forests in the United States hold 56 billion metric tons of carbon, equivalent to nearly 40 years of emissions from fossil fuel combustion. Overall, U.S. forests, just as those in other countries, have been a net carbon sink in recent years.

Methane

Natural gas. Methane emissions come from several natural and human contributed sources. Reducing the human component centers on several industries. Since methane is the main constituent of natural gas, greater care during the production, processing, transmission, and distribution of natural gas will result in a lower level of emissions.

Petroleum. Crude oil production releases methane through venting from storage tanks and other equipment. This presents an opportunity to reduce emissions. Since methane is a fuel, if it can be captured in useful quantities, it could offset in part the cost of collecting it. Each molecule of methane that burns (completely) releases one molecule of carbon dioxide, which, as we know, is also a greenhouse gas. However, the ability of the carbon dioxide molecule to absorb energy is far less than the methane molecule. For this reason, given the choice of burning methane or releasing it, it is preferable to burn it.

Coal. Venting and possible reuse of methane captured from underground or surface coal mines is a way to reduce methane emission.

Agriculture. Improved feeding practices, such as using concentrates to replace foraged food and adding oils to the diet of livestock, can cut down on the methane produced on farms.

Landfills. Reducing the amount of waste that is brought to landfills is a good step toward reducing the release of methane. Collecting the methane generated and using it as a fuel, if possible, or burning it, if necessary, would cut down on methane release from landfills.

Steps Toward a Solution

It is inevitable that greenhouse gas emissions will continue to rise over the next several decades as the world grapples with an appropriate response. The question is the point at which the emissions are stabilized. Robert H. Socolow and Stephen W. Pacala suggested that doubling of the carbon dioxide above preindustrial levels would be a reasonable “boundary separating the truly dangerous consequences from the merely unwise.”

They define two scenarios:

1. Emission levels continue to grow at current rates for the next 50 years, reaching 14 billion tons of carbon by the year 2056.

2. Emission levels are frozen at 7 billion tons a year for the next 50 years (and then reduced by half over the next 50 years).

One way to define an effective solution is to identify actions that will bring the world from the first scenario above to the much more benign condition represented in the second scenario. This gives us a better idea of what it will actually take to have a meaningful impact on the problem of global warming. To stabilize carbon dioxide emissions at current levels, it would be necessary to emit 7 billion tons a year less than current levels for the next 50 years. Such an action likely would stabilize greenhouse gas concentrations well below 560 ppm (anticipating substantial absorption of the increased emissions by the oceans). Each of the following actions independently would prevent the release of 25 million tons of carbon if phased in over the next 50 years. One or two of them alone is not enough; it will take seven of these steps (or their equivalent) worldwide to stabilize greenhouse gas levels. Any seven of the actions (or combination) from the following list would result in that stabilization.

1. Increase average automobile mileage from 30–60 mpg-for 2 billion drivers.

2. Reduce average automobile driving distance from 10,000–5000 miles per year-for 2 billion cars.

3. Reduce worldwide electricity use by 25 percent.

4. Improve the efficiency of at least 1600 large coal-fired electricity generating plants by from 40-60 percent.

5. Replace 1400 large coal-fi red plants with natural gas-fired plants.

6. Install carbon capture and storage systems at 800 large coal-fired electricity-generating plants.

7. Install carbon capture and storage systems at coal plants that produce hydrogen for 1.5 billion vehicles.

8. Install carbon capture and storage systems at coal-to-syngas plants producing 30 million barrels of syngas daily.

9. Double the amount of nuclear-generated electricity to replace coal.

10. Increase the use of wind-generated electricity by a factor of 40 to replace coal.

11. Increase photovoltaic power generation by a factor of 700 to replace coal.

12. Generate enough hydrogen by increasing wind-generated electricity by a factor of 80 to produce hydrogen for cars.

13. Drive 2 billion cars on ethanol (Note: using one-sixth of the world’s farmland and assuming substantial reductions in the carbon footprint of producing and transporting ethanol compared with ethanol produced today from corn).

14. Stop all deforestation.

15. Expand conservation tillage to 100 percent of cropland (growing crops without first tilling the soil).

These steps include a broad range of options that will stabilize and potentially reverse the climate changes that have been set in motion. To stabilize greenhouse gas concentrations below 500–600 ppm, substantial reductions in carbon dioxide emissions from coal generated electricity generation and internal combustion engines will be needed. This will not be achieved by a series of well intended gestures on the part of individuals. Instead, the world must fundamentally rethink how it produces and uses energy.

Hybrid Cars - Explained

Hybrid Electric Vehicles

Solar Heat

As long as the sun is going to the trouble of heating up the earth, we may as well take advantage of its efforts wherever we can. Solar heat, or solar thermal energy, reduces the demand for fossil fuels or electricity generated by fossil fuels. There are three main methods for doing this:

1. Passive solar energy for buildings. By planning to use available incoming solar energy, a building can reduce its heating requirements significantly without much added cost. Passive solar design includes use of south-facing windows and overhangs that are sized to allow sun to enter the building in the winter but that will block the summer sun. Use of high-heat-capacity materials in the area where the sun strikes provides some storage of heat during the most intense periods of sun and minimizes the likelihood of overheating. Passive solar design usually makes the most sense in new construction and is most effective in well-insulated structures.

2. Active solar energy for buildings. Commercially available solar heating systems that circulate a fluid (usually water or air) through solar collectors mounted on roofs or in yards can contribute to the heating needs of a building. The fluid is driven by a pump or fan, with heat either going directly into the building or warming a storage medium such as rocks or water. For many parts of the world, this will be a supplement to a primary system that does not use solar energy. China currently leads the world in making use of solar heating, with an estimated 80 percent of all installations worldwide. The Chinese solar heating panels are made from evacuated tubes rather than the fl at-plate designs used elsewhere.

3. Hot-water heating. Domestic hot-water heaters are probably the simplest and most widespread application of solar energy. These are well suited to warmer locations, where added costs are not needed to provide for freeze protection.

Geothermal Energy

Geothermal energy refers to producing heat from the earth. Theoretically, this potential resource alone can supply all the world’s energy needs if fully exploited. Some geothermal sites are near the surface and are readily accessible. Other sites require drilling to the layers of heated rock 10 km (6.2 miles) or more beneath the earth’s surface. At least 20 countries around the world are using geothermal energy, including Iceland, the United States, Italy, France, New Zealand, Mexico, Nicaragua, Costa Rica, Russia, the Philippines, Indonesia, China, and Japan. Kenya will soon be able to provide close to one-quarter of its electrical requirements using geothermal energy.

Geothermal electricity is generated by steam produced from underground heat turning a turbine. If the underground heat is not hot enough to produce steam on being brought to the surface [182°C (360°F)], the water in the geothermal reservoir is passed through a heat exchanger that transfers the heat to a separate pipe containing fluids with a much lower boiling point. Systems using this form of heat exchange (known as binary-cycle plants) have the advantages of lower cost and increased efficiency. Most geothermal power plants planned for construction are binary-cycle plants.

An interesting tradeoff to explore is whether it is more cost-effective to retrofit an existing coal-fired electricity plant to run off geothermal power rather than to go to the effort of capturing and storing the carbon dioxide emissions.

The temperature of the earth slightly below its surface is close to 55ºF (13ºC).

Geothermal energy also can be used for heating homes directly, as is being done in about 30,000 locations in Canada. Use of an underground heat sink (instead of colder winter air) enables electric heat pumps to be much more efficient.

This approach also can be used for cooling in parts of the world where it is needed.

Transportation-The Problem with Oil

AUTOMOBILE EFFICIENCY-HOW MUCH OIL

IS REALLY NEEDED TO MOVE JUST ONE PERSON?

One-quarter of the greenhouse gases generated throughout the world are a byproduct of transportation. In the United States, each person consumes, on average, 1.3 gallons of gasoline each day. This is 10 times greater than the average for the world. America continues to exhibit an infatuation with the automobile. Just as adolescents in industrialized countries count the days until they are able to drive, a similar interest in becoming mobile exists, and understandably so, throughout the emerging world.

Today, more than 7 out of 10 people in the United States own cars. In Europe, this number ranges from between 2 and 5 people out of 10. In the rapidly developing countries of China and India, that number is much less than 1 person out of every 10. If the rest of the world consumed gasoline at the rate that it is consumed in the United States, 10 times the current amount of greenhouse gases would be generated. Standard spark-ignition internal combustion engines today are perhaps 35 percent efficient under ideal conditions and 10–20 percent efficient in typical urban driving.

Considering that in today’s cars roughly 300 pounds of people and gear are moved through traffi c in a vehicle that is 10 times that weight, the overall efficiency of the fuel in performing its primary function is only about 1–2 percent. From this, we can take heart in how much room there is for improvement.

GENERATING LESS CARBON DIOXIDE

Gas–Electric Hybrids

Hybrid vehicles have two motors-an electric motor powered by a battery and a significantly downsized gasoline engine. The battery is charged by the operation of the gasoline engine and by regenerative braking, which recaptures mechanical energy that otherwise would be lost during braking.

Hybrid designs save energy in the following ways:

• They use the electric motor to provide power during acceleration. This enables the gasoline engine to be much less massive.

• When the vehicle brakes, the energy is recovered as electrical energy, which is then stored in the battery.

• Shutting down the engine when the vehicle is stopped eliminates waste.

This is especially true during city driving, where there can be a lot of unproductive idling time in traffic.

• Use the electric motor instead of the gasoline engine at slow speeds eliminates engine operation when it is least efficient.

• Power steering and other accessories can be shifted to more efficient electrical operation.

Transmission improvements also reduce loss of power. Use of nickel–metal hydride batteries similar to those used in satellites instead of lead–acid batteries increase the amount of energy a battery can hold and enhances its performance. A hybrid, such as the Toyota Prius, just about doubles the fuel economy of comparable nonhybrid cars, with even better numbers under congested urban conditions.

How much will this help? Let’s assume that 2 billion cars are expected to be on the world’s roads by the middle of the twenty-first century and that all achieve 60 miles per gallon (mpg) instead of the 30 mpg or so that is typical of today’s cars. This will prevent 1 billion tons of greenhouse gas emissions each year.

 Of course, there are differences in how automobile gasoline mileage is measured. More “realistic” driving conditions result in lower numbers. Still, the best-performing gas–electric cars such as the Prius show a factor of 2 improvement over comparable cars that do not have an electric motor. Moreover, improvements in how much energy can be stored in a given battery mass (called the specific power of the battery) can be expected to translate directly to improved hybrid car performance.

Plug-in Hybrids—Producing Much Less Carbon Dioxide

How about taking a hybrid car and putting in an even higher-performance battery that can be charged when the vehicle is not in operation? A supersized battery would reduce the need for the gasoline engine substantially. Basically, this would be an electric car with a small gasoline motor to supplement the power of the electric motor the small percentage of the time that greater acceleration is needed.

The gasoline motor also would extend the range of the vehicle so that it could continue back home or to the nearest place to recharge the battery if the battery runs out. Mileage approaching 100 mpg is reasonable to expect from this approach and since most car owners drive less than 35 miles (16 km) per day recharging overnight may be very feasible. Mileage in the range of 100 mpg can be accomplished on some current commercially obtained hybrid cars by using a precharged lithium ion battery rather than the standard nickel-metal hydride battery (http://auto.howstuffworks.com/100-mpg-news.htm ).

In a Prius “hypermileage” marathon, a team drove 1397 miles along a 15-mile course on 12.8 gallons in just under 48 hours. The result: an average 109.3 miles per gallon setting an unofficial world record. 120.6 mpg was established on the best segment of the course. The improved mileage came from driving techniques that minimized the amount of time that the engine runs and minimizes power fl owing to and from the battery. Although these techniques are not practical for most driving conditions, it serves as a proof of concept that significantly higher mileage is possible.

While operating by the electric motor, plug-in hybrids would not generate any greenhouse gases or any form of pollution, for that matter. However, since plug-in hybrids get some of their energy from the electrical power grid, the opportunity to reduce greenhouse emissions depends on the sources of the electricity used to charge the battery. If the electricity comes from a coal-fi red electrical power plant that does not capture and store its carbon dioxide emissions, the benefit t of the cleaner operation of the plug-in hybrid would be greatly diminished. If the electricity is produced without carbon dioxide emissions, the impact of the plug-in vehicle can be significant in addressing the transportation part of this problem.

Automobile designs that use precharged batteries (such as plug in hybrids) contribute to reducing global warming only to the extent that the electricity they use to charge their batteries does not generate greenhouse gases.

Tour of Nuclear Power plant

How Nuclear Reactors Work

Lighting Efficiency-How Many Scientists Does It Take to Screw in a More Effi cient Light bulb?

A little over one-third of all energy is used to produce electricity. Slightly more than one-fifth of all electrical energy is used for lighting. Incandescent light bulbs are extremely inefficient, wasting over 95 percent of the electrical energy by producing heat rather than light. What makes matters worse is that heat generated by light bulbs constitutes a significant part of the cooling load for office buildings.

Fluorescent bulbs, including the screw-in type compact fluorescent bulbs, are five times more efficient than incandescent bulbs. Light-emitting diodes (LEDs) are, in a way, comparable with a solar cell in reverse. They convert electrical energy to light energy. LEDs have the potential to achieve 10 times better efficiency compared with incandescent and twice the efficiency of fluorescent bulbs. LEDs of various colors are now used commonly for electronic component indicator lights, outdoor displays, and automobile brake lights. White-light LEDs emit ultraviolet light on a phosphor that produces a mix of visible colors that people see white light.

This technology has made inroads in initial markets such as high-efficiency flashlights and solar-powered walk lights. Several companies (including GE and Phillips) have been actively pursuing commercialization of white LED light bulbs (also referred to as semiconductor lighting). This represents a significant opportunity to conserve electrical energy and reduce greenhouse gas emissions.

ALTERNATIVES TO COAL-GENERATED ELECTRICITY

Coal is not the only game in town. Coal currently may be one of the most convenient ways to produce electricity, but from a long-term environmental perspective, it is clearly not one of the best. At present, one-third of the world’s electricity is generated by hydroelectric (water) power and by nuclear power. Neither is a source of greenhouse gases.

Hydroelectric

Hydroelectric (or water) power is a nonpolluting, non-greenhouse gas–generating source of electricity that currently is providing 16 percent of the world’s electricity. Its application is very site-specifi c, and many of the good sites have been taken, with the balance of sites that remain to be exploited located in developing countries. The largest site in the world is the Three Gorges Project located on the Yangtze River in China. On its completion, it will generate nearly 20,000 MW of power. By comparison, the Hoover Dam in the United States and the Aswan Dam in Egypt have about 2000 MW of capacity. Two other major sites in South America have over 10,000 MW of capacity. According to some estimates, there is enough potential to increase the installed capacity of hydroelectric generating sites by a factor of 3 or 4. Opportunities also exist for smaller hydroelectric sites. Concerns with impacts on wildlife and water resource management make it increasingly difficult to expand hydroelectric power to new sites. Hydroelectric power will be part of the mix, but it may not grow as rapidly as other renewable sources of power.

Exploitation of the energy from the oceans, both from wind-driven waves and ebb and flow of tides, represents a huge and mostly untapped potential renewable nonpolluting source of electricity. Ocean thermal electric conversion (OTEC) systems extract energy from the oceans by taking advantage of the temperature difference between the top surface and cooler water at depths below 1000 m (0.62 mile).

Nuclear

A nuclear power plant produces electricity by converting heat generated by splitting atoms into steam, which turns a turbine. Since nuclear power does not involve the combustion of a fuel, it does not produce greenhouse gas emissions. There are 438 operating commercial nuclear reactors throughout the world. These are located in 30 countries. The United States has 104, followed by France with 59, Japan with 55, and Russia with 31. China has 11 reactors. Dozens of new reactors are currently being planned by China, India, and Russia. Several countries are currently exploring building their first nuclear reactor. Since 2000, more than 20,000 MW of nuclear capacity has come online throughout the world.

Nuclear power provides nearly one-sixth of the world’s electricity, with larger percentages in some countries, such as France (78 percent), Belgium (54 percent), Sweden (48 percent), Hungary (38 percent), and Germany (32 percent). Nuclear power provides 20 percent of U.S. electricity requirements. Despite hitting the early speed bumps of Three Mile Island in the United States and Chernobyl in the former Soviet Union, nuclear power has been reliable and efficient for the past several decades. According to the U.S. Energy Information Administration, nuclear reactors are now operating at nearly 90 percent of design capacity. This represents a significant increase from 1980 during which the operating capacity was only 56 percent.

No firm orders have been placed for new nuclear reactors in the United States for decades based mostly on concerns about waste management and maintaining costs. However, in the Far East, new nuclear power plants capable of providing 2000 MW of electrical power are coming online. Finland has taken the lead in setting up a site for its high-level nuclear wastes at an underground storage facility a half a kilometer underground. This is expected to be functioning by 2020. Most other countries are still seeking ways to store and, more important, secure spent nuclear materials. The United States has not started construction on a new nuclear plant for three decades. The last new reactor to come online in the United States was the Watts Bar 1 in eastern Tennessee, which began operation in 1996. Construction had started on this site 23 years earlier. NRG Energy, Inc. recently submitted an application to build two new nuclear reactors in South Texas.

Nuclear power presently accounts for 16 percent of the world’s electricity and 20 percent of the electricity in the United States. To promote nuclear power as a possible way to alleviate greenhouse gas emissions, in 2005, as part of the Energy Policy Act of 2005, the United States introduced new financial incentives (a credit of 1.8 cents per kilowatt hour) for new nuclear power plants during their first 8 years of operation. This may help nuclear power, which have an average electricity cost of 6.7 cents per kilowatt hour, to be more competitive with coal-powered plants, which have an average electricity cost of 4.2 cents per kilowatt hour. The nuclear industry conceivably would continue to benefit from economic incentives if carbon emissions are assigned a cost.

Nuclear power plants require cooling water to condense and reduce the temperature of steam that drives the turbines. This cooling water raises the temperature of the body of water into which it is discharged and has been described as thermal pollution. Typically, the maximum temperature of the discharged water is regulated. Site licensing delays have required resolution of this and other environmental impact issues. As climate change reduces available water resources in some areas, including those that will evolve toward greater drought conditions, nuclear power plants in those water-challenged areas will have a more difficult time operating. During the European heat wave of 2003, nuclear power plants in France were forced to shut down because of water restrictions. Nuclear plants in the United States and Japan have already had to limit operations because of water conditions that were not fully anticipated when the power plants were built. This came at a time of peak electrical demand from air-conditioning loads during the summer months.

There have been no major accidents since the two most severe accidents affecting this industry: Three Mile Island in the United States in 1979 and Chernobyl in the former Soviet Union in 1986. However, this growing technology has had numerous minor incidents that have not led to more serious problems. Since nuclear power plants have a 40- to 50-year design life span, the industry will have to address issues of component and structural breakdown and the economic costs of removing nuclear power from service.

Although nuclear power can be considered part of the solution to the global warming problem, it does place an enormous burden on those operating the nuclear power plants to keep the nuclear materials safe and out of the wrong hands. Needless to say, nuclear materials must be secured throughout the world regardless of whether the nuclear industry expands from its present level. Because it is a non-greenhouse gas–producing source of energy, we can expect nuclear power to continue to grow. The challenge will be to balance this growth with the need for nonproliferation of weapons that can be made from even small quantities of nuclear waste material.

Wind

Today, wind energy provides only about 0.5 percent of the world’s electricity. But wind power has found a niche in parts of the world and has been growing at an average rate of 28 percent per year worldwide since 2000. In 2005, there was with a record increase of 40 percent in the use of wind-generated electricity owing to cost reductions and government incentives. Wind electric generators are two- or three-bladed propeller systems that are often clustered together in wind farms. One possible silver lining of climate change is that higher average wind speeds are expected in some places, allowing wind-generated electricity to become more competitive. The trend over the last 25 years has been toward larger wind turbines. In the early 1980s, systems typically produced fewer than 50 kW. Today, the largest commercially available wind turbine has a rotor diameter of over 120 m (394 ft) and generates around 5 MW. The average today is in the range of 1.6–2 MW. (A megawatt is 1 million watts, which can provide the electrical power for roughly 1000 homes in the United States and a larger number of homes in other countries.)

Wind accounted for 18.5 percent of the electrical energy in Denmark, using installations such as shown in Figure 8-5, giving Denmark the highest usage per person anywhere in the world. (Western Denmark is setting the wind energy use record by producing 25 percent of its electrical power from the wind.) Wind energy provides roughly 15 percent of the electrical energy in Spain.

On good sites, well-designed systems can produce electrical power for around 3 to 5 cents per kilowatt-hour (in terms of U.S. currency), which is competitive head to head with fossil fuel-generated electricity. Wind-generated electricity can be used to produce electricity independently, to offset fossil fuel–generated power by utilities, or connected to the power grid and sold to utilities. “For farmers, one wind turbine can rake in about $5,000 a year in rent, compared with $300 for corn or soybean farming.” Opposition to more widespread use of wind is in some locations can be impeded by aesthetic or other environmental concerns that result in a not-in my-backyard syndrome.

Not all but many other selected locations around the world have an opportunity to cut their carbon dioxide emissions using wind energy (or “airtricity,” as it is called by some people). A global study of 7500 sites showed an average wind speed at 80 m above the ground of 6.9 m/s. The greatest potential was found in northern Europe, the southern tip of South America, the Great Lakes Region, and the northeastern and western coasts of Canada and the United States. If fully exploited, wind power could provide five times the anticipated global electrical requirement in 2005. Much of the growth in wind power is expected to provide power to meet growing demand rather than to displace fossil fuel-generated electricity. Major investments in wind energy have occurred in Europe, Japan, China, the United States, and India.

Wind energy can be intermittent, with occasional periods when electrical output stops entirely. Connecting wind farms to a larger power grid enables utilities to use electricity generated by the wind when it is available without the need for dedicated storage.

Solar Electricity (Photovoltaics)

Enough energy from the sun strikes the earth in 1 hour to provide all the energy consumed by the earth’s entire population in 1 year. In most places, sufficient sunlight strikes the earth’s surface to power an (energy-efficient) home and support a plug-in hybrid car. Solar energy stands out as an opportunity that overshadows all the other renewable energy sources and fossil fuels combined. Today, only a small fraction of this vast potential has been exploited.

Solar cells were developed (by accident) at Bell Labs and have been used to power most satellites launched since the 1950s. The development of terrestrial (earth-based) solar electricity began in response to the oil crisis of the early 1970s. Solar cells, or photovoltaic energy, convert energy from the sun into direct current electricity. There are no moving parts and no greenhouse gas emissions.

Photovoltaics are used to power nearly every satellite in orbit and have become a common source of energy for many calculators. It is a proven and reliable technology. Much of the commercial interest in photovoltaics over the past several years has been for remote power, such as to power roadside signs, call boxes, and buoys at sea.

Since an initial push in the 1970s, solar power found a niche to provide electricity where it was otherwise inconvenient, too expensive, or impractical to connect to existing power lines. Photovoltaics power refrigerators in remote villages to keep vaccines cold. They provide a small voltage to inhibit corrosion of pipelines and run irrigation pumps. Many of the photovoltaic installations over the past few decades were used to provide new power rather than to replace electricity generated by fossil fuels.

Today, the fastest-growing market for photovoltaics involves grid-connected applications that use an electronic component (called an inverter) to convert the direct current that the panels generate to alternating current. The power generated can be used to meet electrical needs of a home or business. If a solar array produces more power than is needed at a particular time, that power can be delivered to the power grid for distribution to other customers by the local utility. Individual producers of solar-generated electricity can (legally) run their electric meters backwards and be compensated for that power. Figure 8-6 shows a home in California that produces electricity using photovoltaic panels on its roof.

Although power purchased by utilities is regulated at the state level, it can provide a benefit to the utilities by providing power during peak-demand periods. During the hottest part of the day, when air-conditioning loads are greatest, local grid connected photovoltaic systems can help utilities to avoid firing up their more costly supplemental natural gas–fired turbines. It also can reduce the need to add capacity just to meet peak demand.

During the past decade, photovoltaic installations have increased by 30 percent annually, with the trend going from isolated stand-alone applications to grid-connected systems. In 1994, 60 percent of the photovoltaic market was remote power. Eighty percent of the systems installed in 2004 were of the grid-connected type. Much of the growth of this technology is the result of financial incentives provided by Germany, Japan, and states in the United States, including California, Arizona, and New Jersey. Today, nearly 50 percent of the new photovoltaic installations have been in California. The total installed capacity is approaching 4000 MW worldwide.

The major obstacle to widespread use of solar electricity is its greater cost relative to fossil fuels. Presently, photovoltaics are about three times more expensive than they need to be to compete in today’s energy market with fossil fuel-generated electricity. There are three main types of solar-cell technology:

1. Silicon wafers. Most commercial solar cells use silicon as the base material that absorbs light energy and converts it to electricity. The silicon can be either crystalline (as is used in Silicon Valley electronic applications) or a slightly less perfect but less expensive semi crystalline form. Silicon wafers represented more than 90 percent of the solar-cell market in 2004. Solar cell manufacturers have been making use of excess or slightly off-grade silicon wafers intended for the semiconductor electronics industry. As a result of the surge in photovoltaic sales, the industry must cope with a shortage in silicon. Other approaches are to produce silicon in fl at sheets to avoid the expense of cutting.

2. Thin film. Certain materials such as cadmium telluride, copper indium gallium diselenide, and noncrystalline (amorphous) silicon absorb sunlight using very little material. This provides a potential cost savings, but often at the expense of performance. Often there is a large gap between best laboratory proof-of-concept results and actual performance achievable in the field. Thin-fi lm photovoltaics represent just under 10 percent of the solar electric market today.

3. Concentrating photovoltaics. This technology focuses the incoming sunlight onto small areas of high-performance solar cells. Since the focusing materials can be much less expensive than the active solar-cell area, use of concentrating solar system represents another approach to cost reduction. The diffi culty is that concentrating systems often need a way to at least partially track the sun, which adds to the complexity and cost of the system. Concentrating solar systems remain an area of active interest but have not achieved commercial status yet.

Achieving cost targets for solar electric systems requires reducing the cost not only of the solar cells but also of other aspects of the system. Although the system contributes much to the overall cost of photovoltaics, the cost of the solar cell is a closely watched metric as to its commercial readiness. Currently, electricity generated by solar cells (averaged over the useful lifetime of a system) costs in the range of $6 per watt. Bringing the cost down to $4 per watt is seen as the goal to make photovoltaics competitive on their own. In some situations, development is needed in the other “stuff,” or the balance-of-system costs. This applies to concentrator systems that have greater cost in components that focus or concentrate light to enable a much more expensive but state-of-the art solar cell. When a cost study indicates that the photovoltaic system is not cost-effective, even with zero-cost solar cells, it becomes clear that the next effort needs to go into overall system costs. Opportunities exist to reduce cost in all aspects of the system over its useful life.

The industry has been following a learning curve that has resulted in a decline of 20 percent in the price of photovoltaics for every doubling of worldwide production. In the mid-1950s, when the fi rst commercial solar cell came out, it sold for nearly $1800 (in 1955 dollars). It was 1000 times more expensive than fossil fuels. In the 1970s, costs had come down, but photovoltaics still were 100 times more expensive than conventional electricity. Today, the difference is in single digits, with the playing field being leveled by the support of governments around the world.

Assigning a cost to carbon dioxide emissions may close the gap in commercial markets to allow solar electricity to continue to play a greater role in the future. At present, worldwide photovoltaic generating capacity is expected to exceed 1 GW, or enough to power several hundred thousand homes.

Why "Global Warming" Failed & Why Climate Change is Real

Global Warming: News, Facts, Causes & Effects

Resetting the Earth’s Thermostat-Solutions

The inhabitants of the earth are now at a crossroads. The choices-whether they are made deliberately or by default-are where and when we stabilize the level of greenhouse gases and how we respond to the possible consequences of not having done that soon enough. We will explore actions that can help to mitigate the changes that have been set in motion. We also will deal with the options that are available to adapt to the climate changes that will occur regardless of what actions we take. The two major sources of greenhouse gases: coal-burning electricity-generating plants and petroleum-burning vehicles. Together these contribute 80 percent of the heat-absorbing gases we are loading into the atmosphere. Solutions are available, but most assuredly they will require a departure from doing business as usual.

Electrical Power: The Problem with Coal

WHAT’S NOT TO LIKE ABOUT COAL

Coal is cheap and plentiful. It fueled the industrial revolution in Europe and then in the United States. The emerging countries still see coal as providing the same opportunity for growth and prosperity that it afforded the developed nations. China is a leading producer of coal worldwide, meeting almost one-third of the world’s demand in 2005, followed by the United States and India (British Geological Survey). The United States (as well as other countries) has an abundant supply of coal, enough to last at least a century, providing a major component of America’s long-sought energy independence.

Coal plants work by burning coal, which, in turn, boils water. That water turns to steam, which turns a turbine, which turns a generator, which produces the electricity.

There is no doubt that coal will continue to play a major role in producing the world’s electricity for years to come. Electrical power companies in the United States are expected to add 280–500 megawatt power plants by 2030. By that time, the newly installed electrical power plants throughout the world may very well have added as much carbon dioxide to the atmosphere as was added during the entire industrial revolution. China is on pace to construct the equivalent of one large coal fired electricity-generating plant each week. It is inevitable that coal will continue to be used to provide the lion’s share of electricity around the world in the near future. To come to terms with global warming, it is necessary to squarely confront the challenge faced by emissions from coal-fired electrical power plants.

CARBON CAPTURE AND STORAGE-SEQUESTRATION

There is no way to prevent coal from producing carbon dioxide when it burns. However, it is possible to prevent the carbon dioxide that is generated from being released into the atmosphere. In this scenario, carbon dioxide is separated from the exhaust gases, moved, and then stored. The process is called capture and storage (CSS) or geologic carbon sequestration. Possible storage methods under consideration include injection in stable underground geologic formations, dissolution in the ocean depths, or binding in solid form as chemical carbonates.

The idea of removing products of combustion from a power plant smokestack is not entirely new. Since the Clean Air Act of 1970, power plant operators have installed equipment that removes particulates and the oxides of sulfur and nitrogen before the waste gases are released into the air. In a similar manner, carbon dioxide also can be removed from the output of the smokestack. Similar capture technology is used extensively throughout the world in the manufacture of chemicals such as fertilizer and in the purification of natural gas.

Storage in underground reservoirs is the most mature and probably most likely sequestration approach. A similar technique is used by the petroleum industry. Carbon dioxide is injected underground to help force the last drops of oil out of fields that are nearly empty.

The Intergovernmental Panel on Climate Change (IPCC) estimates that there are sufficient locations throughout the world to capture all the carbon dioxide that is likely to be generated from all fossil fuel–consuming plants operating through the twenty-first century. The closer the reservoir is to the power plant, the lower is the cost of capturing and storing its carbon dioxide emissions. A study by Hawkings et al., 2006 estimates that capture and storage would add an extra 1.6 cents to an average cost of 4.7 cents/kWh for coal-generated electricity. This would make coal-generated electrical power that is free of carbon dioxide approximately 25 percent more expensive. Carbon captured from coal-burning plants can be transported economically to sites that require carbon dioxide to enhance oil recovery. If this occurs, much, if not all, of this extra cost can be offset.

Approaches to sequestration include the following:

Geologic sequestration. Captured carbon dioxide is stored underground in sites such as depleted oil and gas fields, coal seams, and brine fields. Injection of carbon dioxide into coal seams has the added potential benefit of producing methane, which could be extracted as a fuel. Geologic sequestration is effective only if the containment is secure over the long term. Any leak of carbon dioxide over time defeats the purpose of storing it in the fi rst place.

Chemical sequestration. Carbon removed from smokestacks could be secured by forming stable minerals such as calcite (CaCO3) or magnesite (MgCO3). This parallels the weathering process that results in the formation of natural minerals and may be less likely to trigger unforeseen ecologic consequences. The minerals could be expected to be stable for millions of years, so concerns about leaking can be put to rest. Also, the chemical process of forming the minerals is exothermic, so the heat generated could be put to use and contribute to the overall energy efficiency of the operation. Since the ash leftover from coal combustion contains calcium and magnesium (chemical constituents of the stable minerals), experiments are underway to incorporate this into sequestration tests.

Biologic sequestration. This involves fixing the carbon dioxide in biomass such as algae (described later in this chapter). The biomass can be used as a fuel or a food source. As with other biomass solutions, the carbon ultimately is released to the atmosphere.

Some new power plants, however, are being configured as “sequestration ready,” anticipating the possible move toward its implementation.

BURNING COAL MORE EFFICIENTLY

Standard coal-fi red electricity-generating plants burn the coal in air, which consists of nearly 80 percent nitrogen gas. The heat generated produces steam, which turns a turbine, which turns a generator. Removal of the carbon dioxide from the gas stream is difficult because of the large amount of nitrogen gas that is also coming out of the smokestack.

A more advanced approach to burning coal is called integrated gasification combined cycle (IGCC). In this approach, the coal is first treated with steam. The coal is partially oxidized to produce carbon monoxide and hydrogen gas. This combination is known as synthesis gas, or syngas. The syngas then is burned and further treated, resulting in a much higher concentration of carbon dioxide. The carbon dioxide then can be removed much more easily at lower overall cost.

Capture and storage processes will compromise the overall efficiency of the process of converting coal to electrical energy. As a result, conventional coal-fired plants may need to consume 30 percent more coal, and IGCC plants may require 20 percent more coal. The benefit will be a reduction of carbon dioxide emissions in a way that actually could benefit rather than hurt the coal industry.

To accomplish capture and storage of carbon dioxide from coal-generated plants, electric utility bills may need to be more than 30 percent higher than at present.

USING LESS COAL-CONSERVATION OF ELECTRICAL ENERGY

Coal burning is a major source of carbon dioxide. It is often said that the least expensive source of energy is conservation. The less electricity we use, the less coal we need to burn to provide it.

Electrical Energy-How Much Do We Need?

The United States has the highest use of energy per person of any other country in the world. The typical home in the United States has an average power consumption of about 1 kW (1000 W) of electricity. This is the equivalent of having ten 100-W light bulbs burning all the time. This creates a typical annual energy requirement of 8000-10,000 kWh for each home. There are many opportunities to reduce this requirement. Other high-wattage appliances, such as toasters and hair driers, do not consume very large amounts of electrical energy because they are used only for short periods of time. Laptops use less energy than desktops. Power-saving options on computers save energy for either type of device.

Measuring Electrical Power and Energy

Electrical power is measured in watts (W). If you are dealing with a lot of watts, it may be easier to refer to kilowatts (kW): 1000 W make up 1 kW. Power is not the same as energy. Energy is how much power you use for a given amount of time. Electrical energy is measured in kilowatt-hours (kWh). If you burn a 100-W light bulb for 10 hours, you consume more energy than if you keep it on for only 1 hour.

Standby Power

Some studies have shown that the typical American home constantly wastes 20-60 W of electrical power. This is like never shutting off one small-wattage bulb. These phantom appliances include an average of 10 unneeded electrical devices on at any given time, including battery chargers, inkjet printers, DVD players, garage door openers, and ready-mode sound and video systems. Cable and satellite set-top boxes often consume more power than the television set they serve. A simple rule of thumb is that if it feels warm when it is presumably off, it is consuming power.

This wasted power adds up to $3.5 billion annually and accounts for the generation of almost 1 percent of total carbon dioxide emissions. Eliminating all this parasitic wasted electricity would save the average household 5-10 percent of its energy costs, resulting in a savings of about $400 annually per household (S. Hoffman, ElectricNet, www.electricnet.com). One simple way to eliminate much of this waste (besides unplugging unneeded devices) is to use a switchable power strip.

Although most of this waste is occurring in the United States, much of the electronic equipment involved is manufactured in developing countries. Since this is potentially a global problem, countries throughout the world can play a role in reducing this source of wasted electricity. Eliminating this phantom standby power represents the low-hanging fruit, but there are many other areas in which electricity can be conserved (as well as overall).