- Could you please tell us which countries were the pioneers of UHV technology? Where was this technology first tested? And what were the goals pursued by its enthusiasts?
In the 1970s, the Soviet Union began research on 1000 kV UHV AC transmission and transformation technology. In August 1985, the Ekibastuz-Kokchetav line (497km) and two 1150 kV substations were completed and passed through 6 years commercial operation with the system rated voltage of 1150 kV. Totally 2000 km 1150 kV UHV AC transmission line was built, including five substations. 1200 km line was built in Kazakh Republic, of which Ekibasstuz – Kochetaf – Kustanai section was about 900 km and ran at 1150 kV rated voltage, and the other sections mainly at 500 kV rated voltage.
Japan’s 1000kV power system is concentrated in Tokyo Electric Power Company. In 1988, the construction of 1000kV power transmission project began. In 1999, two 1000kV transmission lines with a total length of 430km and a 1000kV substation were built. The first is the 1000kV transmission line from the atomic power plant along the coast of the Sea of Japan in the north to the Tokyo area in the south, the second is to connect power plants along the Pacific coast.
In the 1970s, Italy and France were commissioned by the Western European International Power Generation and Supply Federation to demonstrate the use of AC 800 kV and 1050 kV transmission schemes in the European continent. Afterwards, Italy completed the 1050 kV test project in October 1995. By December 1997, it had operated at the system rated voltage (1050 kV) for more than 2 years.
In 2009, China completed the 1000 kV AC transmission and transformation project: the southeast Shanxi-Nanyang-Jingmen UHV AC project. This is China’s first UHV AC transmission line. In Dec. 28th, 2008, the world’s first ±800 kV UHV DC transmission line from Yunnan to Guanzhou was put into operation, the Changji-Guquan ±1100 kV UHVDC project was put into operation in 2018.
The main goal of the UHV project is to improve economic efficiency, increase transmission capacity and transmission distance, save transmission corridors, and improve grid stability.
- Please tell us about the benefits of UHV technology. What new opportunities does it provide to electricity suppliers and consumers? Maybe you could list current cases (not from history) confirming that it can be applied successfully?
Compared with the original voltage level power transmission technology, UHV power transmission technology has advantages in many aspects. UHV power transmission technology can increase transmission capacity, increase transmission distance, reduce line corridors, reduce line losses, and improve grid structure. UHVDC can be used in the connection between island and mainland, island and island through long-distance submarine cables.
UHV power transmission technology can solve some of the problems that have plagued the energy industry for a long time. It can be used in areas where energy and load are unbalanced to achieve large-scale long-distance power transmission. At the same time, it can solve the problem of large-scale new energy consumption, promote the development of new energy, and provide opportunities for the reduction of global environmental pollution and carbon emissions.
±1100 kV Changji-Guquan UHVDC project. The Changji-Guquan ±1100 kV UHVDC project was in completed in 2018. The transmission capacity reaches 12000 MW, and the transmission distance is 3324 km. The Changji-Guquan UHVDC project can transmit 100 million kW·h of electricity every 8 hours and 20 minutes, solving the problem of imbalance between energy and load in the east and west of China. Compared with the ±800 kV project, the line loss per thousand kilometers of this project is reduced from 2.8% to 1.5%, and it has the capacity of 60 to 80 billion kW·h of annual power transmission. The Changji-Guquan ±1100 kV UHVDC transmission project is the world’s highest voltage level, largest transmission capacity, longest transmission distance, and the most advanced technology level UHV transmission project. It can reduce the annual coal consumption in East China by 30 million tons and reduce 24,000 tons of soot, 149,000 tons of sulfur dioxide, and 157,000 tons of nitrogen oxides every year.
- You have listed several benefits of using this technology. Why, then, is it still not so widespread? What is holding back its commercial distribution?
When various countries developed UHV technology in the last century, the key technologies were immature, and countries could not solve the problems of radio interference, audible noise, power frequency electric field and magnetic field in UHV. At the same time, under the economic conditions at that time, there was not such a large transmission capacity demand as it is now, and the maximum economic benefits of UHV technology could not be realized. Therefore, many power transmission projects operated at lower voltage levels.
At present, with the development of key technologies, UHV technology has been improved in terms of reliability and stability. In China, UHV technology has developed rapidly and has achieved significant economic benefits. In the future, with the advancement of the global grid interconnection goal and the promotion of new energy, the demand for UHV transmission will increase.
- Could energy transition catalyze the spread of UHV technology? Or can the technology itself be able to facilitate the transition to renewable energy sources, especially in those countries and regions where their use is not yet commercially viable?
The energy transition and UHV technology are coordinated with each other. The transformation of energy and the development of renewable energy put forward the demand for large-scale power transmission. In order to connect solar energy and wind energy to the grid on a large scale, people are more inclined to UHV technologies with high economy and large capacity.
With the increasingly severe environmental problems such as global warming, the development of new energy has become an irreversible trend. Without UHV, the centralized development of new energy sources cannot be deployed over long distances and can only be consumed locally. People should speed up the construction of UHV power transmission channels, so that wind power, solar power and other power output will be included in this channel as soon as possible, increase the proportion of clean energy access, and effectively improve the energy structure. UHV power transmission has significant advantages such as large capacity, high efficiency, low loss, low footprint, and good safety. All major clean energy bases and power-consuming regions in the world can be placed within the coverage of UHV power grids. Therefore, the development of UHV technology will greatly promote the development of renewable energy.
For countries and regions that have not yet used renewable energy commercially, UHV technology can connect the local area with the rest of the world. For countries and regions rich in new energy, UHV technology can promote the development of local renewable energy, increase the proportion of local new energy, and increase new energy exports. For countries and regions with relatively few renewable energy sources, UHV can be used to connect energy sources from other countries to promote the consumption of new energy. Therefore, UHV power transmission can balance energy distribution around the world and improve economic benefits.
- Could you please estimate what the future holds for UHV technology? Does it have a horizon for reaching mass use? And if so, how long will this horizon be – 20, 30 or even 40 years?
UHV power transmission can promote the use of renewable energy, greatly reduce environmental pollution and the greenhouse effect, and the value it brings is immeasurable. In the next 25 years, the global population is expected to increase by 2 billion people, and electricity demand will increase by 90%. Developing countries have a particularly strong demand for energy, and most of the demand growth in the next 30 years will come from these countries. Electricity consumption per capita in the Asia-Pacific region is expected to double. Environmental pollution caused by energy emissions and global warming are issues that we must face together. UHV technology allows us to introduce renewable energy in a sustainable and efficient manner.
From a global perspective, the global clean energy distribution is uneven. Wind energy is mainly distributed in the Arctic, central and northern Asia, northern Europe, central North America, eastern Africa and coastal areas of all continents; solar energy is mainly distributed in North Africa, East Africa, the Middle East, Oceania, Central and South America and other areas near the equator. Most of these clean energy resource-rich areas are far away from load centers. UHV technology can safely, efficiently, and cleanly transmit energy from country to country, region to region, continent to continent over long distances, thereby coordinating the development, allocation and utilization of energy resources on a global scale.
Now, UHV power transmission has developed rapidly in China and other countries. At present, UHV power transmission technology is advanced and mature, and the economy of clean energy continues to improve. With climate issues becoming a common problem faced by mankind, UHV technology will develop rapidly in the next 10 to 20 years. At the China-EU Technical Equipment Seminar on the Global Energy Internet held in Berlin, experts said that by 2050, the Global Energy Internet will be basically completed. By then, the global clean energy will account for 80% of primary energy. Global energy carbon dioxide emissions can be controlled at about 11.5 billion tons, only half of the emission level in the early 1990s. The goal of controlling global temperature rise within 2℃ will be achieved.