July 10 (Bloomberg) — Developers will spend more than $134 billion annually by 2020 on solar-energy systems, up 51 percent from this year, as falling panel prices make electricity produced from sunlight cost-competitive with power from other sources, according to a report from Navigant Consulting Inc.

Growing demand for photovoltaic systems in emerging markets including Chile, South Africa and Saudi Arabia will be bolstered in other regions by increased use of both large, utility-scale power plants and smaller, distributed generation systems, the Chicago-based company said in an e-mailed statement today.

“By the end of 2020, solar PV is expected to be cost-competitive with retail electricity prices, without subsidies, in a significant portion of the world,” Dexter Gauntlett, a Navigant analyst, said in the statement.

The company expects a total of 438 gigawatts of solar capacity to be installed from this year through 2020.

By 2017, the year after some U.S. tax incentives are cut, solar power will achieve grid parity “in most major markets,” according to the report.

To contact the reporter on this story: Justin Doom in New York at jdoom1@bloomberg.net

To contact the editor responsible for this story: Reed Landberg at landberg@bloomberg.net