Ziheng Zhu and Hanjie Mao were up late in their Beijing lab when the numbers finally aligned—15.7 terawatts of solar and wind power, precisely calibrated to meet every hour of global electricity demand in 2050. Their team at Tsinghua University had just proven what many called impossible: the world can run entirely on renewable electricity within three decades. Published in Nature Energy, their high-resolution model maps a viable path to net-zero emissions by mid-century, offering not just hope but a technical blueprint for a planet on the brink.
The urgency is undeniable. With global temperatures already 1.2°C above pre-industrial levels, scientists agree that net-zero emissions by 2050 are essential to avoid the worst impacts of climate change. Yet until now, doubts persisted about whether renewable energy could reliably power everything from Nairobi’s hospitals to New York’s subway systems. The Tsinghua model dispels that uncertainty with unprecedented precision—simulating electricity demand across 0.25-degree grid cells worldwide, hour by hour, for an entire year.
The study reveals that 15 to 20 terawatts of variable renewable energy (VRE)—primarily wind and solar—would be enough to power the planet without fossil fuels. Crucially, over 80% of this renewable capacity would be located within 200 kilometers of where electricity is needed, minimizing transmission losses and infrastructure costs. The model also highlights a powerful equity dividend: low-income regions like sub-Saharan Africa could access electricity at lower costs than today, thanks to abundant local solar and wind resources. In a striking finding, the team estimates that solar panels alone would require more than 9 million hectares of land globally—roughly the size of Portugal—but stresses that much of this could be placed on non-arable or degraded land.
“This is not a fantasy,” says Zhu. “We’re showing that with coordinated investment and smart grid planning, every person on Earth can have reliable, clean power by 2050.” The model evaluates 15 different scenarios, factoring in everything from population growth to technological advances, and consistently finds that ultra-high-voltage transmission lines and distributed solar play pivotal roles in balancing supply and demand.
The impact extends beyond emissions. By prioritizing energy access and cost equity, the study redefines climate action as a tool for global justice. As nations gather for the next round of climate talks, the Tsinghua model offers more than data—it offers direction. The path to 100% renewable energy is no longer hidden. It’s mapped, measured, and within reach.