ENVIRONMENT GLOBAL WARMING

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).