News Navigator: Why does 'zero-emission thermal power' come in for so much criticism?

The Mainichi Shimbun answers some common questions readers may have about the "zero-emission thermal power," and criticism of it.

Question: How is coal-fired power a problem in the fight against global warming?

Answer: Coal-fired power generation emits more carbon dioxide than other types of thermal power generation, such as burning natural gas. Although there is a worldwide movement to stop using coal for electricity, there are also efforts to reduce CO2 emissions while continuing to use the same plants.

Q: How can emissions be cut?

A: The Japanese government is aiming to reduce emissions to practically zero by using hydrogen and ammonia, which produce no carbon dioxide when burned, as fuels. This kind of thermal power generation is called "zero-emission thermal power." Here, "zero-emission" means "no CO2 emissions."

Q: Can we really get to zero?

A: Hydrogen and ammonia fuels need to be produced artificially. For example, there is only a small amount of hydrogen in the atmosphere, and most artificial hydrogen is currently made from natural gas or coal. Using fossil fuel to create hydrogen generates carbon dioxide. As a result, according to an estimate by the environmental non-governmental organization Kiko Network, burning ammonia alone to generate electricity would only reduce CO2 emissions by 21% compared to using only coal.

Q: Is there anything else that we can do besides changing the fuel?

A: There is a technology in development to capture and store carbon dioxide underground after it's released into the air. But this is still in the testing stage in Japan, and has several issues that need solving before it can go into use. The Japanese government has sought to lead Asia in zero-emission thermal power generation, including pledges made this month to Indonesia and Thailand to support the implementation of ammonia mixing and combustion technology. However, there is deep-rooted criticism from environmental groups that Japan is simply attempting to keep its own coal-fired plants running for a long time.

(Japanese original by Mayumi Nobuta, Science & Environment News Department)