"Geothermal +" : a new card of Green China



Most of the geothermal energy is deeply buried underground, in addition to volcanic eruptions or some places shallow heat can be directly perceived by people, the rich internal heat can only be recognized and utilized by people through drilling and other ways. Since the founding of the People's Republic of China, especially in the past 40 years of reform and opening up, Chinese scientists have not only figured out the distribution of geothermal resources in China and drawn detailed "geothermal maps", but also made outstanding achievements in the development and utilization of geothermal resources, converting geothermal energy into electricity, using geothermal energy for heating and cooling, and closely integrating it with agriculture and other industries. Create a rich and colorful "geothermal +" model, and make it a bright "green business card" of China.

Xizang Yangbajing geothermal power station is well known overseas

On the map of geothermal resources distribution in China, we can see that a large part of the Tibet Autonomous Region is painted "fire red", which is an important part of the internationally famous "Mediterranean - Himalayan geotropics", and is one of the main display zones of the earth's internal thermal activities on the land surface, where the heat storage temperature can reach more than 150 ~ 200℃. China's world-famous Yangbajing geothermal power station in Xizang Province is located on this display belt.

In the 1970s, the Tibet Autonomous Region chose to build the Yangbajing geothermal power Station in Dangxiong County, northwest of Lhasa. At an altitude of 4306 meters, the geothermal field is 200 meters deep, and the geothermal steam temperature reaches 172℃. In October 1977, experimental Unit 1 was built and started trial operation. In 1978, the Yangbajing geothermal power Station met the design requirements. After that, the installed capacity was further expanded, and by 1991, the power station had completed the construction of eight 3,000 kilowatt units with an installed capacity of about 24,000 kilowatts. Under the support of the "medium and low temperature geothermal power generation Project" of the National High-tech Research and Development Program (863 Program), the "screw expansion generator set" of China's independent intellectual property rights was applied to the Yangbajing geothermal power Station twice in 2008 and 2010, which further improved its performance and efficiency.

Yangbajing geothermal Power Station is the highest geothermal power station in the world, creating an international precedent for the use of low-temperature geothermal power generation, and occupies an important position in the development and utilization history of new energy in the world. Since its completion and operation, the Yangbajing Geothermal Power Station has been generating electricity safely and stably. By 2017, the cumulative power generation of the station had exceeded 3 billion KWH, making outstanding contributions to Tibet's economic and social development and environmental protection.

In recent years, China has made new progress in the field of geothermal power generation. On November 25, 2016, the first well of the Dimet geothermal power generation project in Dehong Dai Jingpo Autonomous Prefecture of Yunnan was drilled, and the first unit was successfully connected to the grid in less than eight months. In 2017, Sichuan Kangding small hot water geothermal field was drilled into a high-temperature hot well, and a 200-kilowatt generator set was successfully installed. The 13th Five-Year Plan for the development and utilization of geothermal energy proposes that the newly installed capacity will reach 500,000 kilowatts in 2020. By then, geothermal power generation is expected to make greater contributions to the "greening" of China's energy production and use.

Xiongan New Area leads the construction of geothermal heating and cooling

Many people may still remember the "gas shortage" caused by the lack of natural gas supply in the winter of 2017. Abandoning coal for heating and switching to natural gas can indeed reduce air pollution to a large extent, but the premise of the "coal to gas" clean heating project is a sufficient supply of natural gas. Is there a greener, more economical and convenient way of heating? A lot of people are looking at geothermal energy.

The principle of geothermal heating (cooling) is not complicated, simply put, through the ground source heat pump and deep buried in the pipeline system around the building, winter from the soil or water "extract" heat, sent to the building; Summer "takes away" the heat in the building and releases it into the water or soil to achieve the purpose of cooling the building interior. As far as geothermal refrigeration is concerned, there is also a way called "absorption refrigeration", that is, the thermal energy provided by geothermal steam or geothermal water as a heat source is driven by the absorption refrigeration equipment.

Geothermal heating and cooling have unique advantages. This is partly due to its wide distribution. According to the latest resource evaluation results of the China Geological Survey, the shallow geothermal energy resources of 336 cities at or above the prefecture level can be mined annually equivalent to 700 million tons of standard coal, which is used for building heating, and can achieve 32.3 billion square meters of heating area in winter and 32.6 billion square meters of cooling area in summer. The areas suitable for the development of shallow geothermal energy are mainly distributed in the central and eastern parts of the country, including Beijing, Tianjin and other places. On the other hand, the core technology of geothermal heating and cooling is not difficult, the cost is relatively low, and it is convenient and economical and practical.

In April 2017, the national New area Xiongan New Area was born, its goal is to build "blue and green interwoven, fresh and bright, water city integration, multi-group intensive and compact development of ecological city", mainly geothermal energy, multi-energy complementary heating scheme was first proposed, and "to create a global geothermal utilization model" as one of the goals. Accordingly, more than two months later, the geological survey to support the planning and construction of Xiongan New Area was officially launched. On August 23 of that year, the results of the first stage were announced: the geological conditions of Xiongan New Area are superior, and the conditions for the development and utilization of shallow geothermal energy in the area are suitable, which can meet the heating and cooling needs of about 100 million square meters of building area.

As an important part of Xiongan New Area, the former Xiongxian County in Hebei Province has been at the forefront of the country in the development and utilization of geothermal energy, as early as 2006, the county was named "China's hot spring Town" by the Ministry of Land and Resources and other institutions. In 2009, Xiongxian County signed a strategic agreement with Iceland and Sinopec to vigorously introduce advanced technology and develop geothermal central heating. In the past few years, nearly 80 geothermal Wells have been dug in Xiongxian, and the urban geothermal heating area has reached 2.7 million square meters, accounting for 92% of the total area of central heating, replacing 90,000 tons of standard coal annually, reducing 189,900 tons of carbon dioxide, 0.48 million tons of sulfur dioxide, and 11,900 tons of dust, making positive efforts and contributions to improving urban air quality. Xiongxian has become a "smoke-free city" for heating, and has formed a geothermal energy utilization pattern of "government-led, government-enterprise cooperation, advanced technology, environmentally friendly, and benefiting the people". These accumulated rare experience for Xiongan New area development and utilization of geothermal energy heating and cooling.

According to statistics, by the end of 2015, China's shallow geothermal heating area was nearly 400 million square meters, and the area of hydrothermal geothermal heating was more than 100 million square meters. With the enhancement of winter heating demand in southern China and the further maturity and perfection of shallow and hydrothermal geothermal energy heating technology, the application scope of shallow geothermal energy will be expanded nationwide. According to the "13th Five-Year Plan" for the development and utilization of geothermal energy, during the "13th Five-Year Plan" period, China's new geothermal energy (cooling) includes 700 million square meters of new shallow geothermal energy heating (cooling) area and 400 million square meters of new hydrothermal geothermal heating area.

Beijing Flower Harbor is a model of geothermal horticulture

In Yangzhen, Shunyi District, northeast of Beijing, there is an "International flower port" with a master plan of 4 square kilometers. As a flower production, research and development, display and trading center in Beijing, flower leisure and tourism and cultural exchange center, here was the main project of the 7th China Flower Expo in 2009, every year will hold tulip festival, moon season, Chrysanthemum festival, Spring Festival night flower exhibition. When tourists wander in the sea of flowers, they may have a thought: why can so many flowers that can thrive in different geographical environments bloom brilliantly in the Port of Flowers? The answer is not complicated, that is, the International flower port has adopted the "geothermal + flowers" model.

It is understood that in order to solve the problems of greenhouse and building heating, and highlight the purpose of green, scientific and technological, circular and intensive construction of the park, the International Flower Port has completed the shallow geothermal energy test, water resources demonstration and geothermal geophysical exploration on the basis of site research to the National Northern plant Base, UFyou Software Park, Huaqing Group and other places, after more than 10 expert discussions and demonstration meetings. Finally, the heating form based on geothermal step utilization, supplemented by ground source heat pump and water source heat pump, combined with gas peak regulation is determined. Although the heating method has a large initial investment, compared with the conventional heating method, it has the characteristics of no pollution, zero emission, renewable energy, low system operation cost, and obvious environmental protection and energy saving. It is through the large-scale use of geothermal comprehensive technology, precise adjustment of temperature and humidity and other parameters, to achieve the modern agricultural miracle of "all the world flowers in the port" and "flower Expo will never end".

The Beijing International Flower Port is an example of the application of geothermal energy in horticulture. "Geothermal + agriculture" will bring profound changes to traditional agriculture in many aspects. First, it can expand the planting time and space of varieties. It can not only achieve local planting of non-native varieties, but also help crops to be listed in the anti-season, reduce diseases and pests, reduce production costs, and improve value and safety. The second is to improve the quality and output. So that crops in the virtual more suitable natural environment, the yield increases at the same time, taste, nutrition and other quality is also better. Third, geothermal energy can help raise rare vegetables and flowers, and assist some high-tech agricultural product technology experiments. In terms of aquaculture, the use of geothermal resources can also increase the added value of the industry. For example, hot water farming can greatly shorten the incubation period and growth cycle of many aquatic organisms. It can rely on geothermal resources to develop high-yield fish farming industries.