Amid the controversy, China's UHV project pressed the fast-forward button.
Do you know how many UHV lines are under construction and under construction in China today? Here is a copy of the latest published data from grid companies:
"By the end of 2020, China has completed a total of 35 UHV projects under construction, with a total of 35 UHV projects under construction, with a total length of 48,000 km of UHV lines under construction. In addition, during the '14th Five-Year Plan' period, the State Grid will plan to build the UHV project '24 to 14 straight', and continue to increase uhV. (Reply to "UHV" for details of all UHV projects built and under construction)
Map of UHV lines put into operation and under construction in China
From the perspective of investment amount, in 2022, the State Grid plans to invest 501.2 billion yuan. Driven by the continuous increase in power demand, the power supply side investment and construction institutions are expected to reach an average annual investment of 650 billion yuan at the power grid end by 2025, and the cumulative investment during the "14th Five-Year Plan" period will reach 3 trillion yuan. What is this concept? It should be known that China's GDP in 2021 is 114 trillion yuan, and the average annual investment in UHV at the power grid end is expected to account for 0.57% of it.
At this time, it has been 18 years since the UHV transmission technology was first formally proposed by the State Grid in 2004. No one has started from scratch like an ancient person, and the power grid enterprises cannot be said to be hard-working. However, the controversy over UHV has been endless, and it is not without reason.
#成本: a throw of "ten billion"
When we tried to figure out the problem of "the cost per kilometer of UHV lines and the average cost of a single UHV line", we found that power grid companies have not published reports on their overall economy. However, the relevant financial information of UHV engineering suppliers has been revealed: the construction cost of UHV AC single line is about 18-25 billion yuan, and the construction cost of UHVDC single line is about 20-30 billion yuan. It is not just a throw of money, it is simply a throw of "ten billion"!
The reason for the huge cost, in addition to the particularity of equipment and wire, but also because compared with conventional high-voltage lines, there are great particularities in UHV projects in terms of project bidding, construction management and settlement, and adversely affect the cost and cost of the project. For example, the construction of ordinary high-voltage lines usually adopts mature construction methods such as concrete on-site mechanical mixing and conventional models of pole grinding group towers, while UHV needs to improve the centralized mixing and tower construction lifting system in the foundation engineering, and its overhead process also requires new equipment, so it increases the cost of a lot of tools development and purchase and new construction processes.
Those who claim to "build UHV at all costs" on the grounds of ensuring energy security listen to it, uhvon projects of course must pay attention to the return on investment, not to mention to solve the problem of mismatch between new energy demand and supply between the east and west of the mainland, and not only the road of "UHV"...
#占地: The width of the line corridor is about 100 meters
How big is the UHV line footprint? The following set of data may subvert your imagination.
According to the "National Standard Urban Power Planning Specification of the People's Republic of China GB/T 50293-2014" on urban power lines, the width of UHV line corridors is 90 to 110m, which is about 3 times the width of the 220kV high-voltage line corridor common in cities.
In addition, in order to ensure the safety protection distance and avoid electromagnetic interference, dangerous influences and accidents, the minimum vertical distance between UHV overhead power lines and buildings, ground and street street trees is also strictly regulated, which is also equivalent to squeezing the area of surrounding residential areas, industrial areas and farming areas.
It is not difficult to see that the UHV line engineering line is wide and involves a wide range, so its basic and temporary floor area are large. Not to mention the shortage of land resources in the city, it is difficult to open up vacant land for UHV projects, even in the relatively vast mountains and plateaus, such a large area is bound to double the cost. The cost here is mainly reflected in the land allocation fee, the compensation fee for the relocation of old facilities, the off-site temporary facility fee, the stretching site fee, the soil and water conservation fee, the forest vegetation restoration fee and other fee rules.
To add that, based on the characteristics of UHV power point-to-point transmission, other cities through which the line passes not only sacrifice national land resources, but also can hardly enjoy the benefits of UHV, so how to balance the stakes is also a science.
#时间: In years
The huge workload invisibly prolongs the project cycle. According to statistics, not to mention the additional preparation time such as land acquisition, the UHV construction cycle is generally 2-3 years, or even longer. As the saying goes, there are many dreams in the night, and there are many uncertainties brought about by the long construction span. For example, the risk of rising prices, labor costs, machinery costs and project management fees...
Some people here may refute that in the name of the modern "highway" and the ancient "Beijing-Hangzhou Grand Canal", it is worth it to claim that these waits are worth it, that "the merit is in the present, and the benefit is in the thousands of autumns". Well, let's talk about the efficiency of UHV power transmission.
#效率: Send goose feathers for thousands of miles
The line will lose a part of the power in the transmission process anyway, because the loss is inversely proportional to the voltage square, in theory, the UHV at the same distance is an effective means to reduce the loss of long-distance transmission. So from the results, how much is the actual rated power, and how much can the UHV loss be reduced? We found a set of key data.
UHV lines already built and under construction in China in 2020
According to the above table, whether it is AC or DC, the rated power of UHV lines is concentrated in the range of 5GW to 12GW. According to the calculation of the UHV loss recognized by the power grid by 5% to 10%, the output power of each line is basically not more than 10GW, considering the proportion of UHV transmission lines, it is only equivalent to transporting a medium and large-scale power station (at the same time, the new thermal power technology, Yangxi Power Plant has a total planned installed capacity of 7.48GW). And such a laborious UHV transmission is wind power, photovoltaic and other unstable discontinuous new energy, it is impossible to be fully loaded, transmission capacity also has a great space for unusable, perhaps also in the sending end to establish a supporting thermal power plant to stabilize the power generation...
Finally, the above mentioned "UHV power point-to-point transmission characteristics", which also means that UHV projects can not benefit surrounding cities like ordinary power stations, but can only "point-to-point city directional support", from the perspective of efficiency, I am afraid that there is really a suspicion of "sending goose feathers thousands of miles".
#碳中和路上,
UHV is to the left and the energy autonomous domain is to the right
Having said so much about UHV controversy, but we are by no means stark opponents, we are well aware of the importance of the "electric highway" for long-distance power transmission. In "How Far Away Are Partition Walls From Us?" ", we mentioned:
"Centralized traditional energy power generation + UHV line to the left, to solve the problem of ultra-long-distance power transmission;
Distributed new energy generation + energy storage + microgrid to the right, to solve the problem of local consumption of new energy;
It is as if we need both large and intertwined rivers and small ponds that can be self-sufficient, and there are no advantages or disadvantages between the two, but to go hand in hand and complement each other. ”
We are just worried that the development of UHV has no security boundary, and will show a "barbaric growth" posture in the future, not to calculate the economic account, and to build an UHV as soon as there is demand, resulting in a lower return on investment, which is both laborious and financially harmful.
Under the common goal of carbon neutrality, how to more efficiently integrate "UHV transmission over long distances" with "self-sufficient energy autonomous domains" so that they can perform their respective duties, take their place, do their part, and get what they want, should be a new problem that policymakers urgently need to think about.