After the March 2011 quake, tsunami and nuclear disasters in Japan, hybrids found a new use, helping deliver electricity during blackouts in disaster zones.
The hybrid has been so successful the only obstacle for Toyota may be that many rivals are in the game now.
"Toyota has led the world on cost-effective fuel-saving hybrid technology for more than a decade, but the competition is really heating up," said David Friedman, senior engineer and deputy director of the clean vehicles program at the Union of Concerned Scientists in Washington, D.C.
The organization thinks that Honda Motor Co., Toyota's Japanese rival, overall offers greener cars, despite Toyota's hybrid success.
"To stay ahead of the pack on hybrids," he said, "they will need to focus their hybrids on boosting fuel economy further and cutting costs, while picking up the pace in innovation in their conventional and electric cars."
The big growth in auto sales is coming these days from emerging markets, where hybrids have yet to catch on because of higher prices compared to gasoline-powered autos.
Uchiyamada acknowledged that costs will have to come down. But he said such nations were also growing concerned about energy efficiency and emissions and they need to offer incentives, or subsidies, for consumers so they can buy hybrids.
"Hybrids have now become a core technology," he said.
Follow Yuri Kageyama on Twitter at www.twitter.com/yurikageyama