What is Carbon Neutrality? Simple Definitions for Basic Environmental Terms by Kawasaki

As declared by the Japanese government, carbon neutrality means reducing greenhouse gas (GHG) emissions to net zero.^*1

Note that the goal is not eliminating emissions to zero but achieving “net” zero. Each industrial sector has already taken actions to decrease CO₂ emissions, including the introduction of renewable energy technologies, such as solar power generation, and the thorough implementation of energy-saving measures. However, reducing emissions down to zero is technically impossible. For this reason, many companies strive to absorb unavoidably generated CO₂ to make it even, or to achieve net zero.

One solution to absorb CO₂ is the carbon dioxide capture and storage (CCS) technology, which separates and collects CO₂ in the exhaust gas from facilities, such as thermal power plants, and buries it underground. In fact, this process is already in practical use overseas and is being developed in Japan as well. Furthermore, the method to remove CO₂ directly from the atmosphere, or direct air capture (DAC), has recently gained attention, and Kawasaki is advancing its use.^*1 Another possible measure is planting trees to let the greenery absorb CO₂ through photosynthesis.

As seen above, while actions to reduce CO₂ emissions from the source are being put into place, the CO₂ inevitably produced is absorbed by CCS technology, DAC technologies, and tree planting to suppress emissions to zero overall.

The term GHG is the collective name for gases that have a greenhouse effect, including methane, nitrous oxide, and CFCs, in addition to CO₂, which accounts for more than 90% of overall emissions.

According to the Special Report on Global Warming of 1.5°C (SR15) released by the Intergovernmental Panel on Climate Change (IPCC) in 2018, the global average temperature in 2017 was approximately 1°C above preindustrial levels in 1750. If global warming increases at the same rate, the global environment will suffer significant damage due to extreme changes in climate.

Therefore, the Paris Agreement was adopted in 2015, and developed countries, including Japan, formulated GHG emission reduction targets for 2030. The SR15 states that carbon neutrality must be achieved worldwide in order to prevent a temperature rise exceeding 1.5°C by 2100.

In 2007, Japan had already set the goal of cutting GHG emissions by half by 2050. In response to the Paris Agreement, there was once an unofficial goal to reduce emissions by 80% in 2050 as compared to 2013, but the 2050 Carbon Neutrality Declaration was additionally released in 2020.

The world’s leading countries have also started to address carbon neutrality. Europe is developing regulation to determine the tax rate according to the CO₂ emitted during the production process. China, the world’s largest emitter, announced their goal to reach net zero by 2060. The Biden administration of the United States established the objective to accomplish net-zero GHG emissions by 2050, and an Executive Order explicitly stated they would put the climate crisis at the center of their foreign policy and national security decision-making. The policy related to carbon neutrality thus moves the economies of many countries and creates a new market that involves infrastructure development and employment.

However, steps toward carbon neutrality are not easy. The Synthesis Report of the IPCC Sixth Assessment Report (AR6) “Climate Change 2023”, as published on March 20, 2023, states that the net global GHG emissions need to fall by 60% (the number for CO₂ is 65%) below 2019 levels by 2035 in order to limit warming to 1.5°C. Since environmental change is happening faster than expected, the Secretary-General of the United Nations António Guterres commented that “the climate time bomb is ticking,” and called on developed countries to commit to reaching net-zero GHG emissions by 2040, which is 10 years earlier than originally planned.*² It goes without saying that the situation is dire.

You may have heard of many environmental terms similar to ones mentioned already, including carbon zero, net zero, carbon free, carbon offset, carbon negative, and zero emissions. This section will differentiate these terms.

The 2050 Carbon Neutrality Declaration by the government of Japan mentions the use of hydrogen as a key strategy. Hydrogen is a carbon-free energy that can be used in a broad range of industries by combining renewable energy with water electrolysis and CO₂ storage and reuse technologies. 

Moreover, the Japanese government expressed its intent within the Basic Hydrogen Strategy to take the lead in setting global standards for clean hydrogen, as well as to clarify the transition to clean hydrogen. In response, Kawasaki now places greater emphasis on hydrogen applications than ever before. Kawasaki is advancing the development of hydrogen energy technologies for each process in the entire supply chain that consists of “production”, “transportation”, “storage”, and “utilization”, and is working to expand the use of hydrogen by developing a hydrogen supply network and hydrogen power generation system that does not generate CO₂.

As an initiative for the future, Kawasaki is also working on the development of DAC technologies that directly extracts CO₂ from the atmosphere. Kawasaki’s DAC features its original solid absorber that does not require high temperature heat for CO₂ separation. To achieve this goal, what is essential is not only the techniques of the machine manufacturer, but also the collaboration between industry and academia, as well as the expertise of chemical companies.

The CO₂ removal from exhaust gas called Kawasaki CO₂ capture (KCC) uses solid absorbers specially developed for the purpose of allowing the separation and capture of CO₂ with less energy. Kawasaki aims to realize carbon dioxide capture, utilization, and storage (CCUS) technologies, including trapping and reusing recovered CO₂. A test facility has already been installed in a coal-fired power plant, and trials to separate and capture CO₂ from actual flue gas have already started. In addition, a project in cooperation with a municipality has been launched for demonstration tests of CO₂ separation and capture.