Solar and wind energy are the two renewable sources best positioned to replace fossil fuels, and they’re already doing it at scale. In the first half of 2025, solar and wind together added 403 terawatt-hours of new generation globally, more than covering the entire increase in worldwide electricity demand. Renewables as a whole now supply 34.3% of global electricity, edging past coal’s 33.1% share for the first time.
Why Solar and Wind, Specifically
Other renewables matter. Hydropower still generates more electricity than either solar or wind individually, and geothermal and biomass serve important roles in certain regions. But hydro is largely built out in developed countries, geothermal is limited to specific geology, and biomass raises its own emissions concerns. Solar and wind are the two technologies with the combination of falling costs, rapid scalability, and near-universal geographic availability needed to displace coal and natural gas at the pace climate targets demand.
The economics have shifted decisively. New solar plants entering service in 2030 will produce electricity at roughly $38 per megawatt-hour, according to the U.S. Energy Information Administration. Onshore wind is even cheaper at about $32 per megawatt-hour. Compare that to $53 for a new natural gas plant. Solar and wind aren’t just competitive with fossil fuels anymore. They’re significantly cheaper.
Solar Energy’s Rapid Rise
Solar grew by a record 306 terawatt-hours in the first half of 2025 alone, a 31% jump that pushed its share of global electricity from 6.9% to 8.8%. That single increase covered 83% of all new electricity demand worldwide. The growth is driven by mass manufacturing of photovoltaic panels, particularly in China, which has collapsed prices and made solar accessible to countries at every income level.
Commercial solar panels today typically convert 20% to 22% of sunlight into electricity, a figure that has steadily climbed over the past decade. Research cells in the lab have reached efficiencies as high as 47.6%, which signals meaningful room for improvement in the panels you’d install on a roof or in a solar farm. Solar does require more land than wind: roughly 10 times more acreage per megawatt of capacity. But panels can be placed on rooftops, over parking lots, on degraded land, and increasingly integrated into building materials, which reduces the footprint issue considerably.
Wind Energy’s Strengths
Wind generated 11% of U.S. electricity in 2024, and U.S. wind capacity has grown from 45 gigawatts in 2010 to 156 gigawatts in 2024, averaging 11% annual growth. The newest onshore wind farms achieve capacity factors around 38%, meaning they produce electricity at 38% of their theoretical maximum. That’s a notable improvement from the 31% average for projects installed between 2004 and 2012.
Offshore wind is a newer frontier with even more potential. Ocean winds blow harder and more consistently than winds over land, yielding capacity factors that could reach 60% for new projects by mid-century. The U.S. is early in this space, with just 174 megawatts of offshore capacity so far, but Europe and Asia have built far more. Wind farms also have a smaller land footprint than solar arrays, and the turbines can coexist with farming and ranching on the same acreage.
The Intermittency Problem and How It Gets Solved
The most common objection to solar and wind is obvious: the sun doesn’t always shine and the wind doesn’t always blow. This is a real engineering challenge, not a dealbreaker. Three solutions are already being deployed at scale.
First, battery storage. The International Energy Agency projects that grid-scale battery capacity needs to expand 35-fold between 2022 and 2030, reaching nearly 970 gigawatts. About 170 gigawatts of new storage capacity will be added in 2030 alone, up from 11 gigawatts in 2022. Lithium-ion batteries can absorb excess solar generation during the afternoon and release it during evening demand peaks, smoothing out the daily cycle.
Second, long-distance transmission. High-voltage direct current (HVDC) lines can move electricity efficiently across hundreds or thousands of miles, connecting regions where the wind is blowing to regions where it isn’t. The U.S. Department of Energy has identified this as critical infrastructure: when it’s cloudy in one state, it’s often sunny in another, and HVDC lines let the grid take advantage of that geographic diversity. These lines also help integrate offshore wind and give system operators precise control over power flows to maintain grid stability.
Third, solar and wind naturally complement each other. Solar peaks during summer afternoons while wind often peaks on winter nights and during storms. Running both together reduces the total amount of storage needed.
Beyond Electricity: Replacing Fossil Fuels in Industry
Electricity accounts for only part of global energy use. Thermal energy, the heat used in manufacturing, chemical production, and heavy transport, represents nearly 50% of total energy consumption and is much harder to decarbonize with solar panels and wind turbines alone. You can’t easily run a steel furnace or a container ship on direct electricity.
This is where green hydrogen enters the picture. Produced by splitting water using renewable electricity, green hydrogen acts as an energy carrier that stores solar and wind power in chemical form. It can fuel high-temperature industrial processes, power fuel cells in ships and trucks, and serve as a feedstock for fertilizer and chemical manufacturing. Green hydrogen doesn’t replace solar and wind; it extends their reach into sectors that can’t simply plug into the grid.
Supply Chain Vulnerabilities
Scaling solar and wind to fully replace fossil fuels requires enormous quantities of specific minerals. Solar panels depend on materials like gallium, indium, and tellurium for certain cell types. Wind turbines rely on rare-earth elements for their powerful permanent magnets and aluminum for their nacelles and structural components. The U.S. was 100% reliant on foreign sources for gallium and indium as of the most recent assessment, and more than 75% dependent on imports for tellurium.
These supply chain concentrations represent a genuine vulnerability. Diversifying mineral sources, investing in recycling infrastructure for retired panels and turbines, and developing alternative cell and magnet designs that use more abundant materials are all active areas of work. The constraints are manageable but not trivial, particularly if deployment continues accelerating at its current pace.
What the Targets Require
To stay on track for net-zero emissions by 2050, the IEA’s roadmap calls for renewables to reach over 60% of total electricity generation by 2030. Renewables hit 34.3% in the first half of 2025, meaning the world needs to nearly double that share in five years. Solar’s explosive growth trajectory makes this ambitious but not impossible, especially as costs continue falling and battery storage scales up.
The transition isn’t a future hypothetical. In the first half of 2025, the combined growth in solar and wind generation nearly matched the growth in total global electricity demand, while coal generation actually declined. The replacement is already underway. The question now is speed.