The amount of generating capacity from natural gas-fired, combined-cycle (Ngcc) power plants in 2018, surpassed coal-fired plants as the technology with the most electricity generating capacity in the U.S.
As of January 2019, U.S. generating capacity at NGCC power plants totaled 264,000 megawatts, compared with 243,000 MW at coal-fired power plants, the Energy Information Administration reported.
Different forms of gas-fired technologies
Total capacity for generating power in the U.S. across all types of natural gas-fired generating technologies surpassed coal as the primary capacity resource more than 15 years ago, Kallanish Energy learns.
However, different natural gas-fired generating technologies are used differently.
Steam turbines (which can also be powered by oil or coal) combust fuel to generate steam, which is used in a steam turbine to generate electricity.
Combined-cycle units heat fuel and use the fuel-air mixture to spin gas turbines and generate electricity. The waste heat from the gas turbine is then used to generate steam for a steam turbine that generates additional electricity.
Natural gas-fired combustion and steam turbines are less efficient and more expensive to run, so they are typically used only during periods of peak electricity demand.
Burn coal to generate steam
Almost all coal plants (except integrated gasification units, which are rare) burn coal to generate steam, with little opportunity for efficiency improvements.
As of the end of 2018, Ngcc power plants accounted for roughly 50% of all U.S. natural gas-fired generating capacity, but they provided almost 90% of total natural gas-fired generation.
Capacity factors for Ngcc plants, which reflect their actual output as a percentage of their capacity, are nearly equivalent to those of coal plants and are typically in the 50% to 60% range, while natural gas combustion and steam turbines are much lower, at roughly 10%.
Ngcc net capacity keeps rising
Since the beginning of 2015, roughly 40,000 MW of coal-fired capacity have been retired, and no new coal capacity has come online in the U.S.
During that same time period, Ngcc net capacity has grown by roughly 30,000 MW. The electricity generation from these Ngcc capacity additions, as well as output from new wind and solar generators, has largely offset the lost generation from coal retirements.
Ngcc plants have recently begun providing more electricity than coal plants. Electricity generation from Ngcc power plants first surpassed coal-fired generation on a monthly basis in December 2015, and again in the first half of 2016, during times of relatively low natural gas prices.
Higher natural gas prices reversed the crossover until February 2018, when Ngcc generation again surpassed coal generation, according to EIA. As more Ngcc plants continue to come online and coal plants contimnue to reture, Ngcc-powered electricity generation should consistently rank as the most prevalent source of electricity generation in the U.S. for the foreseeable future, based on EIA projections.
This post appeared first on Kallanish Energy News.