The price of going solar is dropping dramatically, with rooftop solar systems costing around 80 percent less today than in 2008. Panels are getting cheaper and easier to mass-produce, and the technology is becoming more efficient at turning sunbeams into clean electricity. In some parts of the United States, solar power is actually cheaper than conventional fossil fuel energy.Solar energy is having a moment.

Plunging costs are allowing more Americans to put photovoltaic panels on their rooftops. Nearly 200,000 homes and businesses added on-site solar projects last year, bringing the country’s total count to more than 600,000, according to a recent industry report. Across all solar sectors, companies installed a record 6,200 megawatts of PV capacity in 2014 — a 30 percent jump over the previous year. By 2020, developers worldwide are expected to spend more than $134 billion annually on solar energy systems, up by more than 50 percent compared to 2013, according to Navigant Consulting Inc.

Perhaps no project better captures the industry’s achievements than the Solar Impulse 2, the panel-powered aircraft currently circumnavigating the globe and set to land on U.S. soil this spring. Solar experts say the Impulse mission shows the public just how far PV technology has advanced.

With the solar plane, “We’re able to do something we weren’t able to even 10 years ago,” said Neil Abrams, a professor and solar energy researcher at the State University of New York’s College of Environmental Science and Forestry in Syracuse.

This revolutionary single-seater aircraft made of carbon fiber has a 72 meter wingspan (larger than that of the Boeing 747-8I) for a weight of just 2,300 Kg, equivalent to that of a car.The 17,000 solar cells built into the wing supply four electric motors (17.5 CV each) with renewable energy.During the day, the solar cells recharge lithium batteries weighing 633 Kg (2077 lbs.) which allow the aircraft to fly at night and therefore to have virtually unlimited autonomy.

Gregory Wilson, who directs the U.S. Department of Energy’s National Center for Photovoltaics in Golden, Colorado, said the aircraft showcases the best of existing solar technology. Solar cells on the plane are about twice as efficient at turning sun rays into electricity as a typical household model. The cells themselves are flexible and wrap around the plane’s wings, unlike the stiff, flat rectangles used in most rooftop systems. The aircraft’s battery storage system makes it self-sufficient, whereas most buildings with solar panels still rely on the utility grid to keep the lights on around the clock. “It shows that those technologies are just right out there beyond our fingertips, but could start becoming real [for consumers] within a couple of years,” Wilson said.

Two Swiss pilots, Bertrand Piccard and André Borschberg, are leading the airborne mission, which launched March 9 from Abu Dhabi in the United Arab Emirates. Now the world’s only solar-powered aircraft ‘Solar Impulse-2′ is all set to fly to Varanasi on Wednesday 18th March after a week’s stopover in Ahmedabad as part of its round-the-world trip.

“Only ten hours left before Solar Impulse-2 take off from Ahmedabad with Andre Borschberg at the controls in Flight three on round-the-world trip with zero fuel,” the ‘Solar Impulse-2′ (SI-2) team tweeted on Tuesday.

German test pilot Markus Scherdel (C) poses with Solar Impulse co-founders Andre Borschberg (R) and Bertrand Piccard after taking the solar-powered Solar Impulse 2 aircraft on its maiden flight at its base in Payerne June 2, 2014. Photo: Reuters

Earlier, the SI-2 team had postponed departure from its scheduled date on March 15 due to bad weather conditions. Later, it was scheduled for departure on March 17, which was extended by one more day until March 18.

The globe-trotting SI-2 landed at the SardarVallabhai Patel International Airport in Ahmedabad on March 10, around 15 hours after it took off from Muscat. Andre Borschberg, the project’s co-founder and pilot, besides its co-pilot as well as president Bertrand Piccard have spent more than a week in the city.

The aircraft began its journey on March 9 from Abu Dhabi. Swiss pilot Bertrand Piccard had flown the plane from Muscat to Ahmedabad, while his co-pilot Borschbergh will fly the solar-powered aircraft to Varanasi. From Varanasi, the SI-2 is scheduled to fly to Mandalay in Myanmar, Chongqing and Nanjing in China and thereafter to the USA.

The massive adoption of solar power and other renewable energy resources is critical for fighting climate change. Scientists say the world must reduce emissions of greenhouse gases to 80 percent below 1990 levels within the next four decades in order to keep the planet from warming by 2 degrees Celsius (3.6 degrees Fahrenheit). To achieve those reductions, most of the world’s remaining oil, coal and natural gas will have to stay in the ground, global climate experts agree.

Yet only about 21 percent of the world’s electricity generation comes from renewable energy and hydropower at this point, according to U.S. energy statistics. Solar PV systems account for only a sliver of that amount.

If countries boosted solar output to 20 percent of total energy production by 2025, global emissions would drop by around 19 percent, Wilson said. “Solar is almost certainly going to be the most significant technology in the next 20 years for taking carbon out of our electricity system,” he said. The Solar Impulse, he added, “at least is going to get the public asking the right questions about energy supplies.”