What is an Ultra High Voltage Grid?
UHV Grid usually refers to DC or AC power grids above 800kV, with large, low loss transmission over higher voltages. Multiple UHV circuits are connected into a network to form an UHV power grid. An ultra-high voltage grid is characterized by the transmission of power at higher voltages. According to physical properties, as the voltage increases, the total amount of transmission in the grid will increase, and the loss over long distances will be reduced. This is very helpful for the power transmission of high-power demand and the establishment of the grid. Under the background that China’s energy production and demand span a long distance, the construction of ultra-high voltage power grid was born.
How does it work?
Two main components are required for the composition of an UHV Grid: long-distance UHV DC or UHV AC transmission lines; High efficiency amorphous metal transformer. The main difference between AC and DC in an UHV network is the transport distance. According to existing research, the loss of DC compared to AC can be reduced by approximately 50% over a route of 1000km or more. This can significantly reduce annual power generation and carbon emissions in areas that require longer transportation distances. In addition, amorphous metal transformers are the core of this transportation network. AMT has a lower loss rate than traditional crystalline iron-silicon transformers when transforming voltage. But because the AMT is more labor-intensive, it is only widely used in China and India, where labor is cheaper. One disadvantage of amorphous metal transformers is that AMTs are much more expensive than conventional transformers because the materials themselves and the processing are more expensive. With the dual low loss of UHV transmission and amorphous metal transformers, the UHV grid can transfer more power with lower loss.
Why are Countries trying to move to a UHV Grid?
China: The reason why China is building an UHV grid is because of geography, a large amount of power resources is far away from the load center. Much of China’s hydropower is in the south-west, while new coal-fired power plants are in the north-west. Most of China’s population lies east of the Tengchong-Mohe line. The distance difference is not easily covered by the ordinary power grid, and the energy consumption loss of the ordinary power grid is also unbearable for the national power grid. The existence of the UHV grid allows cleaner energy to be delivered where it is needed, while decommissioning a single boiler that has historically been used in China. Larger, newer coal-fired power plants could produce electricity more efficiently, which would not only reduce carbon emissions but also reduce pollution in densely populated areas. The UHV grid has helped electrify China and set the foundation for the 2050 carbon neutral goal. At the same time, the problem of low utilization rate due to the establishment of wind power, photoelectricity and other clean energy in distant areas can be reduced as much as possible. The development of electric vehicles in recent years has also been carried out steadily based on adequate electricity supply. It can be said that an ultra-high voltage grid is a necessary condition for the transition to a carbon-neutral society.
Europe: The European goal is to build an integrated super smart grid that combines Europe, North Africa, and the Middle East. The grid would use an ultra-high voltage grid, combined with the advantages of a smart grid, to deliver renewable power over long distances to bring the price of clean energy down to today’s prices. Since Europe is more of an economic market, the aim of establishing an UHV grid is to promote the use of clean energy as well as the logic of a market economy. Clean energy can only be promoted when it can compete with the price of conventional electricity.
India and USA have similar issue with China. Russia is larger and can be better served by a power grid over long distances. Countries such as South America are also starting to build UHV grids to serve the whole country (Brazil, for example).