Why do hydropower stations affect the ecology?

Human beings have used dams to retain water and construct water conservancy projects for thousands of years. From China's Dujiangyan water diversion for irrigation to the urban water supply system of ancient Rome, the successful control of floods and utilization of water resources through building canals and dams has become an important part of the history of human civilization for thousands of years. After industrialization, especially after the invention of electricity, the use of hydroelectric power to benefit mankind once became a symbol of the progress of human civilization. By the beginning of the 20th century, the construction of large dams had become synonymous with economic development and social progress. It is not difficult to see that many important dams and hydropower stations built in the United States in the 1930s and 1940s were named after the president. The international community has admiration for large dams and pride in being able to build hydropower stations. Since dam construction was seen as a symbol of modernization and humankind's ability to control and utilize natural resources, dam construction surged. By the time it reached its peak in the 1970s, two or three new dams were being put into use almost every day around the world. According to statistics from relevant organizations, by the end of the 20th century, 90% of the electricity in 24 countries in the world came from hydropower, and in one-third of the countries, hydropower accounted for more than half. 75 countries mainly rely on dams to control floods, and nearly 40% of the world's farmland relies on dams to provide irrigation. There is no doubt that dam construction and hydropower generation have become an important part of today's human social civilization. In particular, the contradiction of water resources in modern society is very prominent, and dam construction is an important way to solve water resources problems.

1. Water resources significance of dam (hydropower) construction

The role of dam construction is not single. In addition to flood control, irrigation, shipping, tourism, aquaculture, etc., the most important Mainly water supply and power generation. One of the important functions of modern dams is to control floods and convert them into usable water resources by building dams to store water. Taking our country as an example, due to the monsoon climate, heavy rains are concentrated. Although floods occur from time to time, overall, fresh water resources are very scarce. With the development of the economy and the growth of social water demand, one of the measures to solve my country's water shortage is to build a number of large-scale water storage reservoirs to increase the flood storage capacity of each river basin during the flood season, thereby increasing the availability of water resources. Throughout history, any developed country in the world, if there is no guarantee of sufficient natural water resources due to special circumstances, almost without exception must rely on dam storage to solve its water supply problems.

In contrast, China's dam construction lags far behind. Theoretically, there are more than 80,000 dams in our country, but in fact most of them are irregular small earth dams. In fact, there are not many dams that can truly fully exert their dam functions. According to statistics from the China Large Dam Commission, by the end of 2003 there were only 4,694 dams with a height of over 30m (including 132 dams with a height of over 30m under construction), and the installed capacity of dams over 30m under construction was 56,300MW. The total storage capacity of my country's reservoirs is only 584.3 billion m3 (of which 140.5 billion m3 is under construction). In 2004, the national hydropower generation capacity was approximately 330 billion kWh. If compared in terms of per capita reservoir water storage, the gap between China and the United States in their controllable water supply capabilities through human engineering is more than 100 times. Therefore, our country's society and ecological environment have been greatly impacted by natural disasters. On the one hand, there are frequent floods, on the other hand, there are severe droughts, severe water resource shortages, and serious water pollution. The fundamental solution to these problems cannot be separated from the construction of a certain number of dams to increase the ability to regulate natural water resources.

For developing countries, the contradictions between flood prevention and disaster reduction and water shortage are very prominent. Due to limitations in national power, less developed countries are far from adequate in the development and utilization of rivers, and their capabilities in flood control, irrigation, water supply, and water diversion are often unable to meet the needs of social development. For example, more than 400 of my country's more than 600 cities have insufficient water supply, and more than 100 of them are seriously short of water; my country's 300 million rural population still does not have access to water that meets sanitary standards. In fact, water shortages in many areas of our country will have a more fatal impact on the future development of our national economy than floods. With the development of modernization and the improvement of people's quality of life, the demand for water resources will increase greatly. To solve the shortage of water resources, one of the most powerful measures is to build a number of large-scale water storage reservoirs to increase the flood storage capacity of each river basin during the flood season, thereby increasing the total amount of available water resources. In this sense, the construction of dams and hydropower is not only the development of energy resources, but also flood prevention and disaster reduction and the development of water resources.

2. Hydropower resources and development and utilization

According to statistics from the International Hydropower Association in 2003, the theoretical reserves of hydropower in the world are approximately 40 trillion kilowatt hours (kWh). , the technological development potential is about 15 trillion degrees, and the economic development potential is about 8.8 trillion degrees. The theoretical installed capacity of some hydropower in mainland my country is 694.4 billion kilowatts (based on 8760 operating hours), and the annual power generation is 6.0829 trillion kilowatt hours, of which the technically developable capacity is 541.6 million kilowatts, and the annual power generation is 2.474 trillion kilowatt hours. "Economically feasible "Development volume" (capacity of 448 million kilowatts, power of 1.753 trillion degrees), ranking first in the world. One thing that needs to be noted here is that the concept of installed capacity is rarely used internationally to express the hydropower resources of various countries. Because installed capacity is a value that is difficult to objectively determine. For example, pumped-storage hydropower stations play an extremely important role in the current development of the electric power industry. However, many pumped-storage power stations actually only have installed capacity but no power generation (or even power consumption) and cannot be used as developed hydropower resources. Secondly, depending on the characteristics of hydropower resources in various countries, the installed capacity of various hydropower stations may vary greatly. 〖3〗

This problem of unclear expression of the degree of hydropower development has not attracted enough attention from some hydropower workers. Many people often compare the degree of development of my country's installed capacity with the annual power generation development of foreign countries. Compare the degree. Therefore, comparison results often one-sidedly exaggerate the extent of hydropower development in my country. Now, we should gradually promote the expression of the degree of hydropower development using annual power generation, because this number can not only objectively reflect the degree of hydropower development, but also can be used to compare the degree of hydropower development with foreign hydropower development. In addition to this, there is a level of development of hydropower resources called "economically exploitable". Some experts believe that because the scope of its economic development depends on many conditions, it will inevitably change with the development of the situation, the advancement of science and technology, and the rising prices of oil, gas, and coal. Therefore, many countries suggest that it should not be used in this way. as a measure.

3. Sustainable development of the world calls for hydropower development

3.1 Resource situation

Throughout the twentieth century, humans have consumed 142 billion tons of oil and 265 billion tons of oil. coal. At present, the world's proven remaining recoverable reserves of oil are only more than 140 billion tons, and based on current production, the static guarantee life is only 40 years; the remaining recoverable reserves of natural gas are 15 billion cubic meters, and the static guarantee life is only 60 years. Although the world's coal reserves are larger, if the current consumption rate is maintained, they will be exhausted in more than a hundred years. Therefore, in order to achieve sustainable development of human society, the world's energy structure must be transformed as soon as possible to be dominated by renewable energy. Renewable energy is essentially different from mineral resources. It is a variable of time. The longer it is used, the greater the amount of resources. On the contrary, it cannot be saved, and it will disappear over time regardless of whether you use it or not. Therefore, prioritizing the development and use of renewable energy is the greatest energy saving and development resource. Although wind energy and solar power generation technologies have broader development prospects, according to the current technical level, other renewable energy power generation technologies such as wind power and solar energy cannot meet large-scale social needs. Currently, about 20% of the world's electricity comes from hydropower, while other renewable energy sources account for only a small proportion. Hydropower is currently the only renewable energy source that is technically mature and can be developed on a large scale.

3.2 The role of renewable energy in hydropower cannot be replaced

Renewable energy mainly includes wind energy, solar energy, water energy and biomass energy. In addition, there are also some such as tidal energy, geothermal energy, etc., but The proportion is smaller. Biomass energy has broad application prospects, but my country currently mainly uses simple direct combustion. Although there are relatively advanced biomass energy application technologies abroad, the raw materials for biomass energy must also be produced through planting, making them renewable. Sex is still subject to great limitations. Solar and wind energy resources are very abundant and have broad application prospects. However, I am afraid that only after large-scale energy storage technology is solved, can they be applied on the same scale as water energy. Compared with current solar energy, wind energy and water energy, the main difference is that they are random, dispersed and not very efficient. Solar energy is eternal, but it also changes with time and weather. It cannot generate electricity in the dark or rainy night; wind power is unpredictable and cannot be controlled by humans.

In terms of power generation efficiency, some wind turbines in Europe and the United States are rapidly increasing in size. Some wind turbines are 10 times more efficient than old units, but their output is still not comparable to that of a medium-sized hydropower station. Some developed countries have envisioned forming a wind power grid, but there are many problems and it has not been realized so far. Its role is far from being comparable to that of thermal power, hydropower, and nuclear power. According to experimental research by an internationally renowned Israeli solar energy research institution, currently relatively mature large-scale solar power generation applications only rely on solar energy to preheat circulating water in thermal power plants to reduce fuel consumption. Due to this shortcoming of wind energy and solar energy, generally speaking, solar energy and wind energy currently play an auxiliary role in agricultural electricity consumption, or use batteries to form small independent power sources to provide domestic electricity in remote areas. The United Nations has been helping third world countries to promote wind power technology, but currently most of them are stuck in solving the problem of domestic power supply in remote and dispersed areas, and it is still difficult to form a strong power grid. 〖4〗

3.3 Environmental Pressure

In terms of the environment, with the acceleration of global industrialization, the scale of energy production and consumption has increased dramatically, causing serious environmental pollution. At present, harmful gases such as sulfur dioxide and dust that cause acid rain due to coal burning can be controlled through technology. However, due to the large amounts of greenhouse gases (GHG) such as carbon dioxide, methane, and nitrous oxide produced after the combustion of fossil fuels and petroleum-derived energy, there is no effective solution. These gases absorb solar radiation and prevent it from radiating from the atmosphere to outer space. The long-term accumulation of energy causes the global climate to continue to heat up. Research shows that when the equivalent carbon dioxide concentration reaches a certain value, climate change will lead to an intensification of the global water cycle, have a major impact on regional water resources, and will also have serious consequences for local agricultural and forestry production, triggering frequent natural disasters, directly Threaten the human living environment. Since the first World Climate Conference held in Geneva in 1979, the World Meteorological Organization and the United Nations Environment Program have strengthened scientific research on the effects of GHGs. At the United Nations Conference on Environment and Development held in Brazil in June 1992, 166 countries, including China, signed the Framework Convention on Climate Change. At the Kyoto Conference of the Parties held on December 1, 1997, the legally binding Kyoto Protocol was formed. It stipulates that developed countries must limit emissions of six greenhouse gases and reduce emissions by at least 5% from 1990 levels between 2008 and 2012. In this situation, the use of clean hydropower cannot but be a wise choice to reduce greenhouse gas emissions. There are about 8.8 trillion kilowatt hours of water resources in the world that can be economically exploited per year. If it can be fully developed and utilized to replace burning raw coal, more than 4 billion tons per year, which is equivalent to reducing carbon dioxide emissions by nearly 10 billion tons per year.

4. Environmental problems plague dam construction and hydropower development

Since the 1960s, the construction of the Aswan Dam in Egypt triggered a dispute over dams between the United States and the Soviet Union. debate. Out of the need for political struggle, in order to criticize the Aswan Dam built with the help of the Soviet Union, a trend of slandering the Aswan Dam and infinitely exaggerating the side effects of the dam was set off in the world. For a time, many scholars tried their best to find the side effects of dams as a fashionable idea. Under the distortion of political opposition, the image of dams was artificially demonized. Some opportunistic anti-dam organizations have taken advantage of this to create hype. Before the 1990s, there was the so-called World Anti-Dam Alliance internationally. In 1991, when the 17th International Conference on Dams was held at the United Nations International Conference Center in Vienna, Austria, there were tents and demonstration slogans camped by anti-dam alliance demonstrators outside the venue. Protests and demonstrations against dam construction have almost always accompanied the International Conference on Dams. At that time, the demonstrators just mechanically shouted slogans such as opposing the construction of dams and letting rivers flow freely, which did not have much appeal and were not enough to attract people's attention.

As countries around the world pay attention to development and environmental issues, people will inevitably make necessary reflections on the role of dams. As a result, dam construction in some areas will inevitably face ecological and environmental protection issues. questions and challenges.

It is undeniable that dam construction, like other human civilization activities, will inevitably have side effects. Dam construction and storage do have side effects: resettlement, sedimentation, impacts on fish and biodiversity, submergence of land cultural relics, generation of greenhouse gases, Changes in downstream hydrology and physical phenomena, regional integration issues, etc. These issues require serious consideration and careful handling by engineering decision-makers and technicians. In fact, these environmental issues during the dam construction process have always been one of the focuses of attention of the dam industry. Many dams built in the early 20th century around the world already had fish passages on them. The sediment problem in my country's Sanmenxia was once questioned by water conservancy workers in most countries in the world before the construction of Sanmenxia. Because of this, it can be said that the ecological and environmental effects of the vast majority of dams built at home and abroad so far have more advantages than disadvantages, including the Sanmenxia Reservoir after reconstruction, otherwise there would be no need for them to exist. Of course, because there is nothing in the world without side effects, the construction of dams at any time will inevitably face a choice of balancing pros and cons.

Under the influence of anti-dam and deep reflection on dams, in April 1997, 39 people from different countries and social classes and members of Greenpeace discussed the "World Bank" in Grande, Switzerland. "After a report on dam construction issues, it was proposed to establish the "World Commission on Dams", referred to as WCD. In May 1998, after obtaining the consent of organizations and departments in relevant countries, WCD began to conduct a survey of 125 dams in different countries around the world and established a database of dams. In November 2000, the report "Dams and Development—A New Decision-making Framework" was formally presented. They plan to submit the report to the World Bank and the United Nations Committee on Environment and Development after soliciting opinions from relevant international organizations, hoping to form an international standard for decision-making on future dam construction. However, the report had a huge repercussions in discussions among relevant international organizations, and was strongly opposed by representatives of developing countries in particular. According to statistics during the discussions of the International Commission on Dams, only three countries agreed to accept the decision-making framework proposed by the WCD. In February 2001, the heads of three international organizations on water conservancy, hydropower and dams (International Commission on Dams, International Commission on Irrigation and Drainage, and International Hydropower Association) jointly wrote to the President of the World Bank emphasizing: Although the WCD The report can be used as useful information to trigger discussions on dam construction issues, but it is extremely insufficient as a criterion for decision-making on dam construction. At the same time, he said he could not accept the unfair conclusion in the report on the role of existing dams.

5. Debates and results about dams and hydropower

5.1 Differences in understanding of dams and hydropower

Although hydropower is currently the only one that can Large-scale application of renewable energy power generation methods. However, with people's attention to nature and ecosystems and the rapid growth of global environmental awareness, dams and hydropower projects are experiencing unprecedented tests. This situation has caused dams and hydropower projects that have been built or are being planned to become increasingly sensitive topics. Some projects that have a greater negative impact on the environment and society have encountered strong resistance from the public and were eventually forced to stop. . The debate surrounding the pros and cons of dams reached a climax in the 1990s with the establishment of the World Commission on Dams and the presentation of the "Dams and Development" report. The report of the World Commission on Dams is the product of people's deep reflection on dam construction. It is the first time that the World Bank and other international organizations have made full use of the enthusiasm of anti-dam organizations and commissioned the World Commission on Dams to systematically summarize and summarize from the perspective of environment and society. Various problems that dams can create. The report systematically summarizes the various negative impacts that dams may have through a detailed investigation of some existing dams. 〖5〗

5.2 Conclusions of the World Summit on Sustainable Development

With the deepening of people’s understanding of sustainable development issues, the demand for water energy resources in the evolving world has become It's getting sharper every day. In many developing countries, hydropower resources are the main way to provide sustainable energy. On the African continent, fossil fuels are scarce and water is abundant. However, the construction of hydropower projects and social progress have been hampered by controversy over the environmental issues arising from dam construction. In order to solve these problems, the 1996 World Summit on Sustainable Development first established the status of small hydropower as clean renewable energy that does not require the construction of dams, and encouraged the development of small hydropower in various countries.

Since then, through further debates about dams and hydropower issues from all walks of life, especially on the basis of the "Dams and Development" survey report of the World Commission on Dams, some misconceptions such as "the greenhouse gas emissions of hydropower are equivalent to thermal power" have been clarified. after. At the World Sustainable Development Summit held in Johannesburg, South Africa, in 2002, the 192 countries present unanimously recognized that compared with burning mineral resources to obtain electric energy, developing hydropower has disadvantages both in terms of resources and the environment. conducive to sustainable development. After discussion, the meeting concluded that as countries around the world are encouraging the development of various renewable energy sources to slow down global warming, it is necessary for large-scale hydropower to be recognized as a renewable and clean energy source. The World Summit on Sustainable Development finally made a resolution to adopt the Johannesburg Plan of Implementation, calling for the diversification of global energy supply and an increase in the share of renewable energy, including large-scale hydropower. The summit also committed to increasing intergovernmental promotion of renewable energy, including hydropower. International cooperation activities in the field of renewable energy. It is also recommended that a hydropower and sustainable development forum be held in China in 2004 to discuss a series of topics through a high-level forum in the global hydropower field to further complete the tasks of the Johannesburg Sustainable Development Summit and promote the sustainable development of the world.

5.3 Beijing United Nations Forum on Hydropower and Sustainable Development and the Beijing Declaration

In accordance with the program requirements of the World Summit on Sustainable Development and entrusted by the United Nations Commission on Sustainable Development, the United Nations Economic Together with the Ministry of Social Affairs and the National Reform and Development Commission of China, a forum seminar on hydropower and sustainable development was held in Beijing on October 27, 2004. More than 500 government officials, experts, scholars and non-governmental organization representatives from more than 40 countries and regions gathered together to discuss hydropower and sustainable development, environmentally friendly hydropower development technology, management of established hydropower stations, and hydropower development. Topics of concern to hydropower projects such as scientific decision-making and the role and impact of hydropower development on economic and social development were discussed and a broad understanding was reached.

The introduction and speeches of the Beijing United Nations Forum on Hydropower and Sustainable Development and the final adoption of the Beijing Declaration on Hydropower and Sustainable Development to promote hydropower development can be accessed here.

5.4 The gap in public opinion propaganda in our country

It is understood that for this meeting convened by the United Nations, our country’s news media did not make many positive reports, and some reported different opinions. The media is not alone in distorting reports. In addition, many anti-dam NGOs in China have a negative attitude towards this conference. In fact, the conference was not organized by the Hydropower System, as some news media distorted reports, but by the United Nations. The principles and spirit of the meeting, including attendance and specific speech arrangements, are all determined by relevant United Nations agencies. The meeting was held in accordance with the plan of the United Nations 2002 Summit on Sustainable Development and is part of the United Nations New Millennium Plan. Some anti-dam organizations and some anti-dam public opinion not only oppose this conference to promote hydropower development, they even have a negative attitude towards the conclusions of the 2002 World Summit on Sustainable Development. In fact, nearly a hundred members of Chinese anti-dam NGOs (most of whom were journalists) had attended the 2002 World Summit on Sustainable Development in Johnresburg, South Africa, and they knew about the summit at that time. Decision made to support the development of hydropower. However, almost no domestic media reported positively on this at that time. On the contrary, since 2003, there has been one wave of anti-dam upsurges in my country. A lot of anti-dam propaganda that one-sidedly emphasizes that hydropower damages the ecological environment is still very popular in our country.

In fact, any human activity will have an impact on the ecological environment, and the ecological impact of dams also has pros and cons. For example, the social and ecological benefits of my country's Fengman, Xin'anjiang, Ertan and other large hydropower stations are very significant, and the positive ecological and environmental benefits far outweigh the negative impacts. It should be said that many of the arguments used in anti-dam propaganda that are popular in China are untenable. Many of the issues we are currently debating have been debated internationally for a long time. At the World Summit on Sustainable Development, these issues have been fiercely debated on many occasions. It was not until the 2002 summit that 192 heads of state reached a consensus to establish the status of large-scale hydropower as a clean and renewable energy source, and decided to encourage and promote hydropower development worldwide.

I believe that politicians from all over the world will not understand the actual situation as well as some of our tabloid reporters, fake experts and extreme environmentalists, nor will they not pay attention to the world's ecological balance and sustainable development issues. They will eventually be able to come up with support The conclusion about the development of hydropower must still be reasonable. The key to the problem is that some people in our country have not yet been able to realize this, or are unwilling to admit it.

6. Conclusion

It should be admitted that until now, many public opinion propaganda in China still have some incorrect views on hydropower. It should be said that this is the understanding gap between our country and the mainstream consciousness of the world. At present, many public propaganda media in our country lack scientific knowledge and are influenced by anti-dam ideological trends. The so-called "nobility" and "romanticism" they promote are often based on extreme respect for nature based on sacrifice and preventing the development of people in underdeveloped areas. To this day, some media still frequently promote some unscientific anti-dam views that are contrary to the requirements of the World Summit on Sustainable Development. However, although the task of publicizing hydropower science is still very arduous, we believe that with in-depth discussions on hydropower understanding, truth will surely defeat fallacies. Faced with the problems of meeting people's development needs and pressure on the environment and resources, our people, like most people around the world, will have an increasingly comprehensive understanding of hydropower. In order to truly realize the sustainable development of the country and the world, we must promote the scientific spirit of seeking truth from facts and expose all pseudo-scientific and pseudo-environmental propaganda in the name of respecting nature and protecting the original ecology. In accordance with the requirements of the World Summit on Sustainable Development, Vigorously develop clean and renewable hydropower resources. Use the scientific concept of development to guide our country's construction, build a harmonious society, and achieve our country's goal of being well-off and the sustainable development of society.