Costs for geothermal generation at some facilities have decreased to half the original price per kilowatt hour of power in 1980 , compared to when the first independent geothermal plants were installed. (10) Their cost falling at a faster rate than coal over this same period. The current price for extensions onto existing projects can be competitive with polluting coal-fired plants. While geothermal’s costs have steadily decreased throughout the years, those of natural gas have increased, often experiencing boom and bust type cycles that can negatively impact the economy.