CoalCoal is ranked by its degree of transformation or maturity, increasing in carbon content from... is the second source of primary energyAll energy sources that have not undergone any conversion process and remain in their natural state.. in the world (nearly 30%), behind oil and ahead of gas, and the leading fuelFuel is any solid, liquid or gaseous substance or material that can be combined with an oxidant... for powerIn physics, power is the amount of energy supplied by a system per unit time. In simpler terms, power can be viewed as energy output... generation (about 40%).
An Energy Resource that Continues to Grow, Albeit at a Slower Pace
While coal still plays an important role in the global energy mixThe range of energy sources of a region., growth in coal use has slowed dramatically. According to the latest International Energy Agency (IEA)An independent, intergovernmental organization founded within the framework of the OECD... report, published in December 2015, the annual increase in global coal use is expected to stand at less than 0.8% in 2020, compared to 3.3% in 20101. In other words, global coal consumption will total 5.8 billion metric tons in 2020, representing a decline of 500 million metric tons from previous IEA forecasts.
There are two main reasons for the drop in coal consumption:
- In the industrialized nations belonging to the Organisation for Economic Co-operation and Development (OECDFounded in 1960, the OECD promotes policies that will improve the economic and social well-being of people around the world...), particularly Europe and the United States, coal use is declining as natural gas and renewable electricityForm of energy resulting from the movement of charged particles (electrons) through a conductor... generation increases, a trend encouraged by carbon taxation and renewable energyEnergy sources that are naturally replenished so quickly that they can be considered inexhaustible on a human time scale... subsidies.
- China, which is still the world's biggest coal consumer, is in the midst of a sharp economic slowdown. In addition, the country is taking measures to reduce the hazardous level of pollution in some of its cities, due primarily to particulate emissions from coal-fired power plants. Initiatives include a number of far-reaching nuclear, wind and solar energy programs.
India, which continues to rely heavily on coal, is expected to become the world's second-largest coal consumer, ahead of the United States. The share of electricity generated from coal in the U.S. has dropped due to the development of shale gasShale gas is found in deeply buried clayey sedimentary rock that is both the source rock and the reservoir for the gas... (see Close-Up: The U.S. Shale Oil and Gas Revolution). On the other hand, U.S. coal exports to Europe and Asia have risen. In recent years, some countries have increased their consumption of coal because of a combination of lower prices and local circumstances: Germany is phasing out nuclear power, Japan is turning to coal in the wake of the Fukushima accident, and India and several Southeast Asian countries areas undergoing rapid economic development.
0.8%: The projected annual increase in global coal use in 2020 (compared to 3.3% in 2010)
Abundant Reserves, but a Serious Environmental Threat
Coal reserves are still plentiful. It has been estimated that there are roughly 909 billion metric tons of proved coal reserves left worldwide, or enough to last more than 150 years at current rates of extraction2.
While coal offers many advantages from an economic standpoint, it has an enormous environmental footprint. Apart from the ecological risks posed by mines, coal-fired plants are a major source of greenhouse gases. Although certain compounds can be removed from the flue gas, the carbon dioxide that is released into the atmosphere still poses a major problem for the environment. To give an example, a large 1,000 - megawatt coal-fired power plant releases about six million metric tons of CO2See Carbon Dioxid per year, equivalent to the tailpipe emissions from two million cars. According to the IEA, coal combustion accounts for around 60% of the increase in global CO2 emissions since 2000.
A 1,000-megawatt plant releases as much CO2 as two million cars.
Is Clean Coal Possible?
The future of coal depends equally on technological innovations to make coal cleaner and policy decisions that promote energy efficiencyIn economic terms, energy efficiency refers to the efforts made to reduce the energy consumption of a system... or put a price on carbon through a carbon tax.
The clean coal concept covers two different approaches:
- The development of innovative pollution control solutions to reduce nitrogen oxide and sulfur emissions and particulates during coal combustion.
- The improvement of power station performance to reduce the amount of coal being consumed and thereby curb carbon emissions (see Close-Up: What is “Clean Coal”?).
The process of capturing carbon dioxide and storing or using it to enhance oil recovery is a highly efficient solution but expensive and difficult to implement (see Feature Report: Carbon Capture and Storage).
New promising technologies to convert coal into gas or liquid are also developing rapidly (See Close-Up: Coal in Power Generation, Iron and Steel, and Coal Chemistry).