Which Power Generation by Source Generates More Greenhouse Gases
- What Are Greenhouse Gases in Power Generation
- Coal Power Generation Produces the Highest Emissions
- Natural Gas Generation Ranks Second in Emissions
- Renewable Energy Sources Offer Near-Zero Emissions
- Comparing All Major Generation Sources
- Real-World Example: Canada's Electricity Grid
- Move Toward Cleaner Energy Sources
- Frequently Asked Questions
Electric power generation is still one of the major sources of greenhouse gas emissions. The emissions per unit of different energy types vary, so the selection of energy is significant. The following article compares major power generation sources based on the emissions associated with each type, expressed as grams of CO2 equivalent per kilowatt hour (gCO2e/kWh).
Coal-fired plants have the largest emissions, at around 820-980 gCO2e/kWh, while gas plants come next at 450-500 gCO2e/kWh, depending on the level of gas leakage. Other sources of energy, such as wind and solar energy, have lower emissions of 11-50 gCO2e/kWh.
What Are Greenhouse Gases in Power Generation
Greenhouse gases trap heat in the atmosphere, contributing to global warming. The production of power is a large contributor in this regard; it is normally pegged at about a third or 40% of total emissions from the energy sector.
Carbon dioxide is the major contributor to the emission of power and constitutes about 75% of the warming effects that result from human activities. Fossil fuels that have been underground for millions of years are emitted as they burn in power stations.
But for methane, it's trickier. In a time span of 20 years, methane has a warming influence 80 times higher than that of carbon dioxide. Leaks in the natural gas distribution chain are high.
Coal Power Generation Produces the Highest Emissions
Multiple environmental agencies confirm coal as the dirtiest major electricity source on a lifecycle basis. Coal plants emit substantially more greenhouse gases per kilowatt-hour than any other major power source, contributing disproportionately to the sector's climate impact.
Coal's molecular structure explains its massive carbon footprint. The U.S. Environmental Protection Agency reports coal combustion releases approximately 900-1,050 gCO2/kWh at the power plant, depending on coal quality and plant efficiency. When lifecycle impacts, including mining, transport, and plant construction, are included, total emissions typically reach 820-980 gCO2e/kWh, though some assessments show ranges up to 1,000+ gCO2e/kWh for older, less efficient facilities.
The combustion process releases more than just carbon dioxide. Sulfur dioxide, nitrogen oxides, and particulate matter accompany the greenhouse gas output. Mercury and other heavy metals also escape during coal burning.
Coal plants typically convert only 33-38% of coal's energy potential into electricity. The rest escapes as waste heat. In 2019, coal-fired generation required 10,551 British thermal units per kilowatt-hour, reflecting this poor efficiency. Older facilities in developing countries perform even worse, with some operating at less than 30% efficiency.
Natural Gas Generation Ranks Second in Emissions
Burning gas is cleaner than burning coal. Research from NOAA atmospheric scientists the current combined cycle gas power plant emits lower CO2 per kWh of electricity than the coal-fired power plant. However, the average emission rate over its entire life cycle is typically in the range of 450-500g CO2e per kWh.
While natural gas combustion produces roughly 50% less CO2 than coal, methane leakage throughout the supply chain significantly reduces this advantage. Scientists estimate that 2-3% of produced natural gas leaks before reaching consumers, though some production basins show higher rates.
Analysis from the Clean Air Task Force notes that accounting for these leaks using 20-year global warming potential can substantially narrow the gap between gas and coal. The difference stems from methane's potent heat-trapping properties over shorter timeframes. Pipeline infrastructure, compression stations, storage facilities, and distribution networks all provide opportunities for methane escape.
Combined-cycle natural gas plants achieve roughly 50% efficiency compared to coal's 33-38%. These plants capture waste heat from gas turbines to generate additional electricity, reducing emissions per kilowatt-hour by 30-40% compared to simple-cycle designs.
Renewable Energy Sources Offer Near-Zero Emissions
Using renewable sources of power significantly reduces carbon emissions. This is because solar, wind, and hydro sources of power do not consume fuel. Therefore, there is no carbon emitted during their operation.
Solar Power's Low Carbon Profile
Multiple lifecycle assessments show that rooftop solar panels emit between 40-50 gCO2e per kWh of electricity produced over their lifecycle. Of these emissions, manufacturing is estimated to account for about two-thirds of the total emissions due to the high energy consumption involved in the production of solar panels.
Solar panels pay off the emissions generated during their production in 1 to 3 years. After that, solar panels produce electricity with almost zero emissions for the next 25 to 30 years, thus making solar energy 20 times cleaner than coal.
Wind Power Achieves the Lowest Emissions
The U.S. Department of Energy reports that the emissions factor for wind energy is 11gCO2e per kWh over the entire lifecycle. A 2014 peer-reviewed study of 153 or so lifecycle assessments concluded that wind emissions were between 10gCO2e/kWh and 40gCO2e/kWh, with a median value of 11-12gCO2e/kWh. The values diverge depending on the locations of manufacturing, origins of materials, type of wind turbine, and fuel type for manufacturing.
The major emissions associated with wind energy are related to its installation, including towers made of steel, foundations made of concrete, and rotor blades made of fiberglass. Wind turbines, after installation, generate electricity for 20 to 25 years without consuming any fuel or generating emissions.
Hydroelectric Power's Variable Profile
There’s greater complexity in hydroelectric power plants. Turbines do not emit gases while in operation, but reservoirs emit gases while decomposing organic matter. The International Hydropower Association studied 500 reservoirs and determined the median emission of 23 gCO2e per kWh of electricity.
There can be big differences between individual plants. Some can remove carbon from the atmosphere, and others in tropical regions with shallow water and abundant vegetation may release a lot of methane. The amount of emissions from a reservoir peaks in the first 10-20 years after flooding and then decreases as the organic material runs out.
On a household scale, energy storage and backup systems such as EcoFlow Delta Pro Ultra X can be combined with solar energy and use energy more efficiently by storing low-carbon electricity generated during the day for use at night or during power outages.
Comparing All Major Generation Sources
Comprehensive lifecycle assessments from national laboratories provide standardized comparisons across technologies. These evaluations account for emissions from raw material extraction through construction, operation, and decommissioning.
| Power Source | Typical Lifecycle Range (gCO2e/kWh) | Primary Emission Source |
| Coal | 820-980 | Combustion |
| Natural Gas | 450-500 | Combustion + methane leaks |
| Solar PV | 40-50 | Manufacturing |
| Hydroelectric | 20-35 (median ~23)* | Reservoir decomposition |
| Nuclear | 5-20 (median ~12)** | Construction/fuel processing |
| Wind | 10-40 (median ~11-12) | Manufacturing |
*Hydroelectric range wider due to reservoir variability; tropical reservoirs can exceed 100 gCO2e/kWh
**Nuclear range varies with uranium ore grade, enrichment method, and system boundaries. Nuclear facilities achieve some of the lowest lifecycle emissions, with median values around 12 gCO2e/kWh, comparable to wind. All nuclear emissions come from uranium mining, fuel processing, and plant construction. The fission reaction itself produces no greenhouse gases. Long operational lifespans of 60+ years spread construction emissions across an enormous amount of electricity generation.
Real-World Example: Canada's Electricity Grid
A good example of how a diversity of generation sources impacts carbon intensity is Canada's electricity sector. The Canada Energy Regulator reports that Canada's carbon intensity is 100 gCO2e per kWh of electricity, which is much lower than other grids that operate predominantly using fossil fuels. This is because Canada has 60% of its electricity generation sources as hydro and a significant amount of nuclear power.
However, there are large regional variations. The provinces of Alberta and Saskatchewan are largely dependent on fossil fuels and are responsible for most of Canada’s greenhouse gas emissions in the power sector. The provinces of Quebec and British Columbia are rich in hydropower and use it to generate electricity that produces little greenhouse gas emissions. Since 2005, Canada’s power sector has reduced its greenhouse gas emissions by more than 50 percent, largely by phasing out coal. During 2015-2022, the province of Alberta reduced its greenhouse gas emissions in the power sector from 41.3 to 19.4 megatonnes.
Move Toward Cleaner Energy Sources
Power production is a major contributor to the production of CO2 emissions in the energy sector; hence, it is an area of importance in the fight against global warming. The production of CO2 emissions from coal is 60 to 100 times higher than that from wind energy. Gas production produces 40 to 50 times more emissions than wind energy, taking into consideration the methane leaks.
Power sector emissions in the United States dropped 32% between 2005 and 2019. About 65% of this decline can be attributed to a shift from coal to natural gas, and about 30% can be attributed to an increase in renewables. To continue improving, we must accelerate a transition to low-carbon sources of electricity such as wind, solar, nuclear, and hydro.
Frequently Asked Questions
Q1: What Are Greenhouse Gases and Why Do They Matter for Power Generation?
Greenhouse gases cause the heating effect in the atmosphere, thus increasing the Earth’s temperature. Carbon dioxide emissions, produced by the burning of fossil fuels, account for the largest amount of emissions in power plants. Methane emissions, coming from natural gas infrastructure, also account for high emissions, especially in the short term. Coal-fired power plant emissions amount to 900 to 1,050 grams per kWh, while those in wind farms amount to only 11 grams.
Q2: Which Type of Power Generation Produces the Most Greenhouse Gases?
Coal-fired power plants generate the highest emissions of any major source. Lifecycle assessments show coal produces 820-980 gCO2e/kWh depending on plant efficiency and mining methods. Oil-based generation ranks second at 650-750 gCO2e/kWh, followed by natural gas at 450-500 gCO2e/kWh. All fossil sources produce dramatically more emissions than renewable alternatives, which typically range from 10-50 gCO2e/kWh.
Q3: How Do Natural Gas Power Plants Compare to Coal in Terms of Emissions?
Natural gas produces roughly 50% less CO2 than coal during combustion. Modern combined-cycle plants emit approximately 450-500 gCO2e/kWh compared to coal's 820-980 gCO2e/kWh. However, methane leakage during extraction and distribution reduces this advantage. Scientists estimate 2-3% of gas leaks before reaching consumers. When measured over 20-year timeframes where methane's warming impact is strongest, the gap between gas and coal narrows substantially.
Q4: What Are the Lifecycle Emissions of Renewable Energy Sources?
Renewable sources produce dramatically lower emissions than fossil fuels. Wind power measures 10-40 gCO2e/kWh with a median around 11-12, solar PV 40-50 gCO2e/kWh, and hydroelectric 20-35 gCO2e/kWh on average. These figures include manufacturing, construction, operation, and decommissioning. Manufacturing creates most renewable emissions, typically offset within 1-3 years. Facilities then generate electricity with virtually zero emissions for 20-30+ years, making renewables 20-80 times cleaner than fossil fuels over their lifetimes.
Q5: What Can People Do to Reduce Their Power-Related Greenhouse Gas Emissions?
Install solar panels to generate clean electricity in your home. The CO2 savings from reduced manufacturing emissions are repaid in 1-3 years. Take part in your electricity provider's green energy plans to purchase electricity from wind, solar, or hydroelectric stations. Use more efficient insulation materials, LED lights, and energy-efficient appliances. Advocate to close fossil fuel-powered stations sooner and increase clean electricity generation. Every kilowatt-hour of electricity from renewables reduces CO2 emissions by 0.5-1.0 kg more than fossil fuel electricity.
References :
Energy Information Administration (EIA), “Natural gas-fired electricity generation produces fewer emissions than coal”, https://www.eia.gov/todayinenergy/detail.php?id=48296
NOAA Chemical Sciences Laboratory, “Methane leakage from natural gas systems”, https://csl.noaa.gov/news/2014/148_0109.html
Clean Air Task Force, “Lifecycle greenhouse gas emissions of natural gas and coal”, https://www.catf.us/resource/analysis-lifecycle-greenhouse-gas-emissions-natural-gas-coal/
Canada Energy Regulator, “Provincial and territorial energy profiles of Canada”, https://www.cer-rec.gc.ca/en/data-analysis/energy-markets/provincial-territorial-energy-profiles/provincial-territorial-energy-profiles-canada.html
U.S. Department of Energy, “How Wind Energy Can Help Us Breathe Easier”, https://www.energy.gov/eere/wind/articles/how-wind-can-help-us-breathe-easier