Transportation is another sector that has increased its relative share of primary energy use. This sector has serious concerns as it is a significant source of CO2 emissions and other airborne pollutants, and it is almost totally based on oil as its energy source. An important aspect of future changes in transportation depends on what happens to the available oil resources, production and prices. At present, 95% of all energy for transportation comes from oil. (more…)

Following the recent completion of three nuclear power plants, there is now some 9.6 GW of nuclear capacity in the United Kingdom. The nuclear share of electrical output, which has stood at around 13% for many years, should rise to around 20% when this capacity is in full operation. A further two reactors are currently under construction which will increase the British nuclear capacity to more than 12 GW by the late 1980s, which could bring the nuclear share of electrical output to around 25%. (more…)

Federal Excise Taxes placed on specific energy sources tend to reduce energy demand for these energy sources in both the short and the long run. The federal government imposes excise taxes on almost all petroleum products (including petroleum additives) and coal (see Table 1). The federal government also imposes federal excise taxes on many transportation uses of methanol, ethanol, natural gas, and propane and imposes a fee on electricity produced from nuclear power plants and nuclear power electricity. (more…)

A combination of legislation and technology has helped clean up many of the world’s coal-burning plants. Both developed and developing countries have adopted increasingly stringent environmental regulations to govern emissions from coal-fired power plants. In the United States, all coal-fired power plants built after 1978 must be equipped with postcombustion cleanup devices to capture pollutants before they escape into the atmosphere. Cyclones, baghouses, and electrostatic precipitators filter out nearly 99% of the particulates. Flue gas scrubbers use a slurry of crushed limestone and water to absorb sulfur oxides from flue gas. The limestone reacts with the sulfur dioxide to form calcium sulfate, which may be used to produce wallboard. Staged combustion and low-NOx burners are used to burn coal to minimize NOx formation. Another strategy, selective catalytic reduction, reacts ammonia with NOx over a catalyst to produce nonpolluting nitrogen and water vapor.

Conventional coal-fired power plants capture pollutants from the flue gas after it leaves the boiler. Circulating fluidized bed (CFB) combustors capture most of the pollutants before they leave the furnace. Crushed coal particles and limestone circulate inside the CFB combustor, suspended by an upward flow of hot air. Sulfur oxides released during combustion are absorbed by the limestone, forming calcium sulfate, which drops to the bottom of the boiler. The CFB combustor operates at a lower temperature (14001F) compared to pulverized coal (PC) boilers (27001F), which also helps reduce the formation of NO x .

Precombustion coal cleaning is another strategy to reduce sulfur emissions by cleaning the coal before it arrives at the power plant. Sulfur in coal is present as pyrite (FeS2 ), which is physically bound to the coal as tiny mineral inclusions, and as ‘‘organic sulfur,’’ which is chemically bound to the carbon and other atoms in coal. Pyrite is removed in a coal preparation plant, where coal is crushed into particles less than 2 inches in size and is washed in a variety of devices that perform gravity-based separations. Clean coal floats to the surface, whereas pyrite and other mineral impurities sink. Additional cleaning may be performed with flotation cells, which separate coal dust from its impurities based on differences in surface properties. Precombustion removal of organic sulfur can be accomplished only by chemical cleaning. So far, coal combustion emissions and chemical cleaning has proved to be too costly, thus flue gas scrubbers are often required to achieve near-complete removal of sulfur pollutants.

The tightening of environmental regulations is likely to continue throughout the world. In the United States, for example, by December 2008, it is anticipated that coal-fired power plants will have to comply with maximum emission levels for mercury. Emissions of mercury and other trace metals, such as selenium, are under increasing scrutiny of coal combustion emissions because of suspected adverse effects on public health.

Coal is sometimes combusted with waste material as a combined waste reduction/electricity production strategy. The disposal of waste from agriculture and forestry (biomass), municipalities, and hospitals becomes costly when landfill space is limited. Some wastes, particularly biomass feedstock, are combustible, but their low energy density (compared with coal) limits their use as an electricity production fuel. Blending coal with these fuels provides an economical method to produce electric power, reduce waste, and decrease coal plant emissions. Most wood wastes, compared to coal, contain less fuel nitrogen and burn at lower temperatures. These characteristics lead to lower NO x formation. In addition, wood contains minimal sulfur ( o 0.1% by weight) and thus reduces the load on scrubbers and decreases scrubber waste biomass.

Numerous electric utilities have demonstrated that 1–8% of woody drying biomass can be blended with coal with no operational problems. Higher blends may also be used, but require burner and feed intake modifications as well as a separate feed system for the waste fuel. Cofiring in fluidized bed boilers may avoid some of these drawbacks, but the economics of co-firing are not yet sufficiently attractive to make it a widespread practice.

Coal use today is no longer evocative of dirty power plants with polluting black smoke billowing from their smokestacks. Many of these plants have been transformed through technology to operate more efficiently and with significantly lower emissions. Some fire coal with other waste materials and others produce both electric power and heat transmission. Cases of plant retrofits and their new performance statistics are documented by various institutions, including the Energy Information Administration (http:// www.eia.doe.gov) and the World Coal Institute (http://www.wci-coal.com). The following examples highlight clean coal use throughout the world: (more…)

Gasification is a thermo chemical process that has been exploited for more than a century for converting solid feedstocks to gaseous energy carriers. The first gasifier patent was issued in England at the end of the 18th century and producer gas from coal gasification was mainly used as lighting fuel throughout the 19th century. At the turn of the 20th century, the main use of producer gas, obtained essentially from coal, switched to electricity generation and automotive applications via internal combustion engines. The use of producer gas was gradually supplanted by the use of higher energy density liquid fuels and as a result confined to areas with expensive or unreliable supplies of petroleum fuels. (more…)

At present, in the United States and worldwide, motor vehicles are fueled almost exclusively by petroleum based gasoline (or reformulated gasoline) and diesel fuels. Since the first oil price shock in 1973, efforts have been made to seek alternative fuels to displace gasoline and diesel fuels and achieve energy and environmental benefits. Some of the alternative fuels that have been researched and used are liquefied petroleum gas (LPG), compressed natural gas (CNG), liquefied natural gas (LNG), methanol (MeOH), dimethyl ether (DME), Fischer– Tropsch diesel (FTD), hydrogen (H 2 ), ethanol (EtOH), biodiesel, and electricity. Production processes associated with gasoline, diesel, and each of these alternative fuels differ. (more…)

Energy exists in many forms. Some of energy forms are simple to use and identify as energy. But other forms of energy can not be seen until the energy released. Some forms of energy like light and sound, they carry energy from one place to another. There are also vibrating objects that carry the kinetic energy that makes the sound. The energy passes through the wave where the wave was originated. The higher the wave, it gives more energy. Light is also one form of energy. A light beam or light ray brings out energy from where there was light. This energy is often referred to as radiation energy. (more…)

The energy that people use every day comes from many different sources. The resources are divided into two main groups: renewable energy and nonrenewable energy. Renewable energy sources are those that can be used again and again. Renewable energy resources have unlimited supply. (more…)

Nuclear energy has some distinct advantages in strengthening the external dimension of energy supply security. These include:

• Nuclear power plants produce electricity domestically. Their capital and labor inputs are also provided domestically. With more than 90% of its inputs in terms of value sourced domestically, it can be considered a largely domestic source of energy and electricity.

• Of course, a majority of OECD countries import part or all of their requirements of uranium plutonium. (more…)