Utilities around the world are supersizing their solar farms. Nowhere is that more apparent than in southern Egypt, where what will be the world's largest solar farm - a vast collection of more than 5 million photovoltaic panels - is now taking shape. When it's completed next year, the $4 billion Benban solar park near Aswan will cover an area 10 times bigger than New York's Central Park and generate up to 1.8 gigawatts of electricity. But Benban probably won't hold on to its title for long. China is planning to build a two-gigawatt solar farm in the northwestern province of Ningxia, and the state of Gujarat in western India recently gave the go-ahead for a five-gigawatt facility. Japan is even talking about putting a large-scale solar farm in space. There are huge savings for larger projects," says Benjamin Attia, a solar analyst. A 2017 report from the U.S. National Renewable Energy Laboratory found that the cost of photovoltaic systems shrank by a factor of five from 2010 to 2017. Even the punitive tariffs on Chinese solar panels enacted earlier this year by the Trump administration are unlikely to slow the spread of large-scale solar, which in the U.S. is already cheaper and much cleaner than coal. "Governments have wised up," says Attia. "They just want the cheapest, fastest way to add new electricity supplies. For nuclear, procurement can take a decade. For gas, it's up to four years. If you're talking solar and things go smoothly, you can build a reasonably large project in 18 months."