Lower carbon emission electricity is power generated from sources that release little or no greenhouse gas over their full lifecycle, from construction to operation to decommissioning. The main sources include solar, wind, nuclear, hydroelectric, and geothermal energy, along with fossil fuel plants equipped with carbon capture technology. Together, these low-emission sources supplied about 39% of global electricity in 2022, a share projected to reach 71% by 2030.
What Counts as Low-Carbon Electricity
Every electricity source produces some carbon emissions, even if only during manufacturing or construction. The key distinction is how much. Coal and natural gas plants release large amounts of carbon dioxide every hour they run, because they burn fuel continuously. Low-carbon sources either use no fuel at all (solar, wind, hydro) or use fuel that produces minimal emissions during operation (nuclear).
The International Energy Agency groups low-emission electricity into four categories: solar and wind, other renewables (hydro, geothermal, biomass), nuclear power, and fossil fuel plants fitted with carbon capture and storage systems. What unites them is a lifecycle carbon footprint that is dramatically smaller than conventional coal or gas generation.
How Emissions Compare Across Sources
The most useful way to compare electricity sources is by lifecycle emissions: the total greenhouse gases released per kilowatt-hour, covering everything from mining raw materials to building the plant to generating power over its entire lifespan. These numbers vary depending on location, technology, and study methodology, but the overall picture is consistent.
Nuclear energy produces roughly 6 to 12 grams of CO2 per kilowatt-hour across its full lifecycle, according to analysis by the International Atomic Energy Agency. Solar PV has dropped rapidly as manufacturing has improved; recent studies place it between 20 and 80 grams per kilowatt-hour, with newer panels trending toward the lower end. Wind power falls in a similar low range. The IPCC notes that these recent values for solar and wind are an order of magnitude lower than coal and natural gas, meaning fossil fuels emit roughly 10 times more carbon per unit of electricity.
For context, a typical coal plant produces around 800 to 1,000 grams of CO2 per kilowatt-hour. A modern natural gas plant emits roughly 400 to 500 grams. The gap between these and any low-carbon source is enormous.
Solar and Wind: The Fastest-Growing Sources
Solar PV and wind power are driving the global shift toward lower-carbon electricity. Renewables provided 30% of global electricity in 2023, and that share is forecast to reach 46% by 2030, with solar and wind together accounting for 30% of all generation at that point.
The cost picture has shifted dramatically. For new power plants entering service in 2030, solar PV is projected to cost about $37.58 per megawatt-hour, and onshore wind about $48.78. Compare that to a new natural gas combined-cycle plant at $64.55. Solar PV is now cheaper than natural gas in most regions, even without tax credits. Pairing solar with battery storage (a PV-battery hybrid) brings the cost down further to roughly $29.58 per megawatt-hour, making it the cheapest new electricity source available.
Offshore wind, at about $53.44 per megawatt-hour, costs slightly more but is still competitive with gas. Geothermal comes in at $58.54 and hydroelectric at $31.86.
Nuclear Power’s Role
Nuclear energy is one of the lowest-carbon electricity sources in existence. Its lifecycle emissions of 6 to 12 grams of CO2 per kilowatt-hour are comparable to wind and lower than most solar PV estimates. Unlike solar and wind, nuclear plants generate power around the clock regardless of weather, which makes them useful for providing steady baseline electricity.
The trade-off is cost. New advanced nuclear plants are projected at $133.88 per megawatt-hour, making them the most expensive low-carbon option by a wide margin. Construction timelines often stretch to a decade or more. Existing nuclear plants, however, are already paid for and continue producing cheap, nearly carbon-free electricity, which is why many energy plans count on keeping current plants running alongside new renewable capacity.
Carbon Capture on Fossil Fuel Plants
Fossil fuel plants can be retrofitted or built with carbon capture and storage (CCS) systems that trap CO2 from exhaust gases before it reaches the atmosphere. Most CCS technologies target 90% capture efficiency, and some operating facilities have exceeded 95%. In theory, capture rates of 98 to 99% are possible.
A natural gas combined-cycle plant with CCS is projected to cost about $81.45 per megawatt-hour, roughly 26% more than the same plant without carbon capture. The technology remains limited in scale. Only about two dozen CCS projects exist worldwide, and only two have ever operated on coal power plants (one of which shut down in 2020). CCS is considered a bridge option, useful in specific situations but unlikely to compete with the falling costs of solar, wind, and batteries for most new electricity generation.
The Biomass Question
Biomass power, which burns organic material like wood pellets or agricultural waste, occupies a gray area. The argument for calling it low-carbon is that the plants absorbed CO2 while growing, so burning them simply returns that carbon to the atmosphere rather than adding new carbon from underground fossil reserves. In practice, it is more complicated.
Whether biomass electricity actually delivers low net emissions depends on the type of material burned, how it was harvested, the efficiency of the power plant, and critically, the time frame you examine. A forest cut for fuel may take decades to regrow and reabsorb the released carbon. During that gap, the emissions are real. Scientists have urged that any classification of biomass as low-carbon should be tied to what is actually happening on the landscape, not assumptions about eventual regrowth. Biomass generation is projected to cost about $126.20 per megawatt-hour, placing it among the more expensive options.
The Carbon Cost of Building Clean Energy
Shifting to low-carbon electricity is not entirely emission-free. Mining the materials, manufacturing solar panels and wind turbines, transporting components, and constructing new facilities all consume energy, some of which still comes from fossil fuels. Researchers at Columbia University calculated the cumulative emissions from building out this infrastructure under different scenarios.
On the current slow pace of renewable buildout (a trajectory leading to 2.7°C of warming), the construction process itself would produce an estimated 185 billion tons of CO2 by 2100. Building faster changes the math significantly. An aggressive buildout limiting warming to 1.5°C would generate only about 20 billion tons of construction-related emissions by 2100, equivalent to roughly six months of current global emissions. The logic is straightforward: the faster renewable infrastructure comes online, the sooner it powers its own expansion, reducing the need for fossil fuels in the manufacturing supply chain.
Storing Low-Carbon Electricity
One challenge with solar and wind is intermittency. The sun sets, the wind stops, and demand does not always match supply. Storage technologies are essential for making low-carbon electricity reliable around the clock.
Lithium-ion batteries are the dominant solution today, especially when paired directly with solar farms. Green hydrogen, produced by splitting water using renewable electricity, is another option for longer-duration storage. However, the round-trip efficiency of green hydrogen (converting electricity to hydrogen and back to electricity) is only 28 to 52%, meaning roughly half the original energy is lost in the process. This makes hydrogen better suited for seasonal storage or industrial uses where batteries are impractical, rather than everyday grid balancing.
What the Global Shift Looks Like
The trajectory is clear. Low-emission electricity sources are projected to supply 100% of global power generation by 2050 under international climate targets. The economics are accelerating this shift: solar PV is already the cheapest source of new electricity in most of the world, and battery costs continue to fall. The remaining challenges are building transmission lines fast enough, scaling up storage, and managing the retirement of existing fossil fuel plants that still have years of operational life left. The energy transition is not a single technology replacing another. It is a portfolio, with solar and wind doing the heavy lifting, nuclear providing steady output, hydropower and geothermal filling regional niches, and storage tying it all together.