Just days after the U.S. Energy Department’s National Renewable Energy Laboratory (NREL) released new analysis that nearly doubled previous estimates on how building rooftops could generate national electricity sales, there was interest expressed worldwide. 

Scientists from NREL - along with their counterparts from solar energy research institutes in Germany and Japan- met in Freiburg, Germany earlier this week as the Global Alliance of Solar Energy Research Institutes (GA-SERI) convened a worldwide gathering of experts to discuss the future of PV. 

"PV is on a pathway to low cost," Greg Wilson, director of NREL's Materials Applications and Performance Center and co-director of the National Center for Photovoltaics told them.  "When you add PV to inexpensive storage or another means of introducing flexibility into the grid, PV can be attractive as a primary energy source." 

Analysts at NREL have used detailed light detection and ranging (LiDAR) data for 128 cities across the United States, along with improved data analysis methods and simulation tools, to update the estimate of total U.S. technical potential for rooftop PV systems. 

The analysis reveals a technical potential of 1,118 gigawatts (GW) of capacity and 1,432 terawatt-hours (TWh) of annual energy generation, equivalent to 39 percent of U.S. electricity sales. 

This current estimate is significantly greater than that of a previous NREL analysis, which estimated 664 GW of installed capacity and 800 TWh of annual energy generation. Analysts attribute the new findings to increases in module power density, improved estimation of building suitability, higher estimates of the total number of buildings, and improvements in PV performance simulation tools.

The analysis appears in "Rooftop Solar Photovoltaic Technical Potential in the United States: A Detailed Assessment." The report quantifies the technical potential for rooftop PV in the United States, which is an estimate of how much energy could be generated if PV systems were installed on all suitable roof areas. 

At the Mar. 30 workshop in Germany, participants expressed confidence that a substantial expansion of manufacturing capacity will be spurred on by demand for PV catching up to supply. “This renaissance of growth will carry PV to a new level of energy impact - to the terawatt (TW) scale, where 1 TW equals 1,000 gigawatts (GW),” said NREL. It added that annual global PV installations reached 60 GW in 2015, which is approaching global production capacity. 

“In view of drastically reduced PV costs, cumulative global installations in excess of 3 TW are anticipated by 2030, provided current research and development (R&D) and investment paths are continued. PV cost projections make this technology increasingly attractive for low-cost domestic electricity supply,” said NREL. 

In order to provide a major contribution to global climate goals, total installations on the order of 20 TW will be needed by 2040. This will require stable PV R&D support worldwide and systemic investments targeted at reducing production costs, increasing efficiency, and improving reliability, it added.

Globally, PV is, of course, not the only answer in ways of using the sun for energy. In Morocco, which has set itself ambitious renewable targets, they are finding different ways to harness the sun while cutting carbon emissions. Unlike PV, Concentrated Solar Power (CSP) uses the sun to heat fluid that then powers turbines to supply electricity at night.

The solar power plant at Ouarzazate in southern Morocco is the world’s biggest concentrated solar power plant, according to the Financial Times. “Called Noor 1 after the Arabic word for light, the concentrated solar power (CSP) plant is designed to deliver 160 megawatts of electricity at peak output. It is the first of three stages in a project expected to provide 510MW of generating capacity by 2018,” according to the FT.

Dina Medland is an independent writer, editor and commentator with a strong focus on issues around corporate governance, ethics, the workings of the boardroom and sustainable business. She is on the team of contributors to @ForbesEurope and is an ex-Financial Times staff member who has been a regular contributor in recent years. Further details about her background and a portfolio of work – including her commercially sponsored blog ‘Board Talk’ are available on her website http://www.dinamedland.com.