Nuclear power is "ridiculously expensive" compared with solar power and cannot compete from a financial standpoint, said the former head of the International Energy Agency.

During a lecture at a symposium in Tokyo on July 23, Nobuo Tanaka, former IEA executive director, said nuclear power is utterly "uncompetitive" with solar power generation in terms of costs for building or expanding nuclear plants.

“I was greatly shocked to hear that the IEA say that ‘solar becomes the cheapest source of electricity generation in many countries’ in its 2017 report,” said Tanaka, a well-known nuclear power advocate.

He has served as an executive board member of the Japan Atomic Industrial Forum Inc., which comprises nuclear plant manufacturers.

Costs for nuclear power plants have been on the rise since the 2011 Great East Japan Earthquake and tsunami that crippled the Fukushima No. 1 nuclear power plant, operated by Tokyo Electric Power Co., and necessitated stricter safety measures.

“Building a new nuclear power plant is ridiculously expensive as it will cost more than 1 trillion yen ($8.98 billion) to install just one nuclear power reactor,” said Tanaka. “It’s utterly uncompetitive.”

Tanaka also pointed out that the resumption of the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture seems to be “difficult” because the deadlock in approval to restart the plant is the result of a “lack of public understanding.”

The former IEA official also mentioned the next-generation reactor, saying Japan should strive for regaining public trust by jointly developing the economically efficient reactor with other countries such as the United States.

One such next-generation type is the high-temperature gas reactor, which is safer and more economically efficient than the light-water reactor currently in use because it uses helium gas as the coolant instead of water, and other types of reactors.