Coal is the largest source of carbon dioxide and other harmful emissions produced by generating electricity, but that doesn't mean it will go away any time soon.

While coal's deleterious environmental effects are well known, certain economic factors could ensure its continued role as fuel for electricity generation for years to come.

DON'T MISS: Natural Gas Continues To Replace Coal: 'Bridge' Fuel To Lower-Carbon Energy

This is particularly true outside the U.S., in countries that are just establishing large-scale energy infrastructure, says the Brookings Institute in a new report on coal.

Coal-fired generation is on the decline in the U.S., but it could rise in other countries, analysts suggest.

Electric power plant outside Ithaca, New York

Electric power plant outside Ithaca, New York

In "emerging markets," access to cheap, coal-powered electricity is often viewed as vital to economic development.

Economic development, in turn, is viewed as a more important short-term goal than preserving air quality, let alone reduction of greenhouse-gas emissions.

The result is epic smog, as seen in most Chinese cities today, with attendant public-health costs and environmental degradation.

MORE: EPA's Coal-Plant Emissions Rules: This Will Be The Big Fight (Jun 2014)

Coal exemplifies the difficulty in balancing "tradeoffs among the environmental, economic, and energy-security" goals of policy, the report says.

By 2040, the report's authors expect Australia, China, India, and Indonesia to account for 70 percent of world coal production.

In comparison, Brookings cites data from the U.S. Energy Information Administration (EIA) showing that coal's share of total U.S. electricity generation dropped from 44 percent in March 2011 to 34 percent in April 2012.

Two BNSF locomotives hauling coal trains meet near Wichita Falls, Texas

Two BNSF locomotives hauling coal trains meet near Wichita Falls, Texas

The EIA predicts that coal's share of U.S. generation will decline to 32 percent by 2040--seemingly a conservative goal.

With continuing declines in the price of photovoltaic solar panels, some analysts suggest that some types of solar and wind generation plants are now cost-competitive with new generating plants--even those fueled by natural gas.

Utilities, meanwhile, must worry about the costs of having to maintain a power grid while more homes adopt solar power and slash their purchases of the electricity carried over that grid.

Much of the current decline in coal use is due to newly-abundant natural gas, which not only produces fewer greenhouse-gas emissions, but is also now cheaper than coal.

The Environmental Protection Agency (EPA) is also in the process of introducing tougher emissions standards for power plants.

U.S. Capitol Building

U.S. Capitol Building

The rollout of these regulations highlights another factor that extend the longevity of coal: entrenched opposition to any policies proposed by the Obama Administration in the short term, and to any policies related to climate change in the longer term.

The New York Times notes that Senator Mitch McConnell [R-KY]--whose state is a leading coal producer--is orchestrating a large-scale lobbying effort against what he calls a "war on coal."

While McConnell has limited ability to thwart the new EPA rules in Congress, he is targeting the state-level officials who are responsible for creating each state's plan for compliance with the new regulations.

McConnell's office, the Times reports, has distributed a legal blueprint showing states how to stop implementation of the EPA rules.

As always--whether for economic or political reasons--the battle over coal shows once more that change doesn't come easily.


Follow GreenCarReports on Facebook, Twitter, and Google+.