From Chisato Horiuchi in Tokyo, Japan
Ammonia co-firing demonstration project has started in Japan (provided by JERA, a thermal power plant in Aichi Prefecture)
Environmental pollution caused by nitrogen has emerged as a new issue for the international community. The problem is that nitrogen compounds, which are sprayed in large quantities as fertilizer in agriculture and discharged from factories and cars, pollute the air, water, and soil. Emissions in Japan are declining, but there are issues with recovery and reuse. As the government focuses on "ammonia power generation" for decarbonization, new measures will be needed.
■ Japan "Twice the world average"
The amount of nitrogen discarded in the environment in Japan between 2000 and 2015 is 41 to 48 kilograms per person per year, which is about twice the world average. In August 2009, teams such as the National Agriculture and Food Research Organization (National Agriculture and Food Research Organization) and the National Institute for Environmental Studies published such a report. Since 2000, we have comprehensively investigated the amount of nitrogen emitted by agriculture, forestry and fisheries, manufacturing, waste treatment, etc., and clarified the detailed income and expenditure.
Environmental pollution by nitrogen is an "old and new problem." At the beginning of the 20th century, the "Haber-Bosch method", which synthesizes ammonia from atmospheric nitrogen, was put into practical use, and nitrogen fertilizer dramatically increased agricultural productivity. On the other hand, ammonia and the like are called "reactive nitrogen" and pollute the environment. It flows out into rivers and the sea, leading to "eutrophication", and the decrease in agricultural land productivity due to excessive fertilizer application is becoming a problem.
■ Global warming effect that exceeds CO2
Developed countries have tightened emission regulations for nitrogen oxides (NOx) in the exhaust gas of factories and automobiles, but countermeasures have been delayed in emerging and developing countries. Nitrous oxide is one of the warming gases and is known to have a stronger warming effect than carbon dioxide.
According to a survey by the National Agriculture and Food Research Organization, the emission of reactive nitrogen from human activities in Japan decreased by nearly 20% from 2.29 million tons in 2000 to 1.86 million tons in 2015. Many experts say, "It can be said that it is an honor student in emission control measures."
However, overall nitrogen waste has been flat for the last 16 years, and per capita emissions are still higher than the world average. If it is quiet, the wind from the international community may increase.
■ The international community is paying close attention
In fact, the international community is accelerating the development of measures against nitrogen pollution. The United Nations Environment Program (UNEP) reported in a 2014 annual report that "nitrogen pollution is a large-scale, complex, little-progressed reduction, and a global problem." It has been pointed out that the nitrogen produced and discarded by human activities has already exceeded the total amount of naturally occurring nitrogen and has exceeded the "planetary boundaries". UNEP took up this issue in 2019 and called for a shift to "circular use" in which nitrogen in the environment is recovered and reused.
The "International Nitrogen Initiative" (INI), an organization of scientists, has established the "International Nitrogen Management System" (INMS) to grasp the balance of nitrogen and utilize it for policy making, and will publish the "International Nitrogen Assessment" in 2010. In combating global warming, the scientist organization "Intergovernmental Panel on Climate Change (IPCC)" led political negotiations and led to international rules. A composition similar to this starts to work even with the nitrogen problem.
There are also movements at the regional and national levels. The European Union (EU) has published the "European Nitrogen Assessment", which examines the effects of nitrogen on water, air pollution and global warming in the region. In particular, he considered food production and the food system as a problem, and pointed out that 80% of the nitrogen input was not in the human mouth and was released into the environment. China has also announced an action plan to curb the use of fertilizers in the agricultural sector. India has also set goals to reduce the release of urea fertilizer into the environment and to halve the fertilizer.
■ "Japan has a weak sense of crisis"
In Japan as well, research on nitrogen recovery and reuse technology has started in the government's large-scale project "Moonshot-type research and development," but the creation of a system for recycling-type utilization is yet to come. At the symposium held by the National Institute of Advanced Industrial Science and Technology in November 2009, there were a series of concerns from experts, such as "In Japan, there is little sense of crisis and it may become a boiled frog" and "policy measures are required."
Particularly controversial was the government and power companies planning to use ammonia to achieve decarbonization. The government has stated in the Basic Energy Plan that "hydrogen and ammonia will be the main supply and regulation power of electricity by 50 years", and as a "mixed fuel power generation" that mixes and burns ammonia at coal-fired power plants and as a means of transporting hydrogen. It shows a policy to utilize ammonia.
Ammonia, when burned under ideal conditions, becomes nitrogen and water and does not emit CO2. However, depending on the combustion conditions, a large amount of NOx is generated, which has been one of the reasons why ammonia power generation has not received much attention. The Ministry of Economy, Trade and Industry states that "NOx suppression technology is completed with 20% co-firing", but there is no technical support as to whether it can be suppressed even if the co-firing rate is raised.
■ Adjustment of interests, many parties
Furthermore, measures against leakage will become an issue in the process of production and transportation. Currently, the world production of ammonia is about 200 million tons per year, and most of it is locally produced and consumed as fertilizer. Coal combustion of ammonia with coal-fired power requires 20 million tons per year for Japanese power plants alone, which is comparable to the world trade volume. Even if we increase production and supply capacity in cooperation with overseas, environmental measures cannot be avoided.
The reason why the response to nitrogen pollution has been delayed is that the sources are wide-ranging, such as agriculture and industry and sewage treatment, and many parties are involved. For example, organic farming that does not use chemical fertilizers is a key to controlling nitrogen, but it is inevitable to change consumer awareness and adjust interests with producers and fertilizer manufacturers. The issue is who will bear the cost of waste disposal.
Internationally, there has been a movement of "inter-convention coordination" to seek countermeasures in related treaties such as the Framework Convention on Climate Change and the Convention on Biological Diversity. In Japan as well, related ministries and agencies such as the Ministry of Agriculture, Forestry and Fisheries, the Ministry of the Environment, and the Ministry of Economy, Trade and Industry will set up a forum for discussions, deepen the understanding of related industries and consumers, and urgently consider the mechanism of collection and reuse and the pros and cons of regulation. There is a need.
