2021-06-15
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The proportion of renewable energy continues to increase, and energy storage equipment has become an important support for energy transformation. For this, Taipower has restarted the evaluation of several large-scale pumped storage hydropower plants, and the "Dajiaxi Guangming Pumped Storage Hydropower Project" will take the lead this year (2021) Start the EIA.
The plan plans to open a 10.7-kilometer tunnel between Deji Reservoir and Guguan Reservoir, and build a pumped-storage hydroelectric power generation unit with a maximum capacity of 368MW, making the two reservoirs the third large-scale energy storage facility in Taiwan. It will be put into use in 2019, adding new force to the "Best Backup Pitcher" who will use peak electricity in the future.
In May of this year, the Kaohsiung Xingda Power Plant had two accidental failures, which caused Taiwan-wide power outages on 513 and 517. Even President Tsai Ing-wen bluntly said it was "unacceptable." The reason behind this is that apart from the unit tripping and electricity consumption exceeding expectations, the severe drought this year has led to poor water conditions, which has also prevented the "reserve pitcher" hydraulic unit from fully generating power and providing immediate support. The Deji Reservoir in Taichung has been in operation since February. Stop generating electricity.
Deji Reservoir is located in the upper reaches of Dajia River, with an altitude of 1,400 meters. It is the highest reservoir in the country with an effective storage capacity of about 180 million cubic meters. It is the largest reservoir in central China and the fourth largest in Taiwan, second only to Zengwen Reservoir and Feicui Reservoir and Shimen Reservoir.
The water of Dajia River originates from Nanhu Dashan, and starts from the most upstream Deji Reservoir. After six times of hydropower utilization, it finally converges to Shigangba to supply water resources in Taichung area. From Deji Reservoir to Shigangba, about With a length of more than 50 kilometers, there is an altitude difference of 1,200 meters.
The river bed of Dajiaxi is steep and the potential energy is sufficient, which is an excellent condition for hydroelectric power generation. During the Japanese occupation period, it was planned to build a sky-cooled power plant (now Tianlun Branch of Dajiaxi Power Plant). At present, there are Deji along the Dajiaxi River. , Qingshan, Guguan, Tianlun, Ma'an, etc., a total of 19 conventional hydropower generating units, with a total installation capacity of 1137MW, accounting for about 2/3 of the capacity of Taiwan's conventional hydraulic installations, and an annual power generation of about 2.6 billion kWh, nearly half of which in Taiwan Most of the conventional hydroelectric power comes from Dajia River.
Hydropower generation is divided into two types: "conventional" and "pumped storage". The tail water after conventional hydropower generation will be released to the downstream of the river, and the pumped storage unit will flow the water into the lower pond for repeated use. Pumping and storing hydraulic power is equivalent to energy storage facilities. During off-peak hours, electricity is used to pump water from the lower pool to the upper pool, and then from the upper pool to the lower pool to generate electricity during peak hours.
At present, Sun Moon Lake in Taiwan has two pumped -storage hydroelectric energy storage power plants , Daguan No. 2 Plant and Mingtan Power Plant . Compared with conventional hydraulic power, pumped-storage hydropower units are less affected by drought. Even if the water conditions are not good in 2020, conventional hydropower generation will be reduced by nearly half , but pumped-storage hydropower will only decrease by 1%. In the first quarter of 2021, pumped-storage hydroelectric power generation will be about 200 million kWh higher than conventional hydropower.
Although hydroelectric power generation only accounts for about 2% of Taiwan's total electricity consumption, it has the excellent advantage of rapid support. It takes about 15 minutes for a conventional hydraulic unit to start up to full load, and it only takes 3 to 5 minutes for a pumped-storage hydraulic unit, which is much faster than 2 hours for gas-fired units and 6 hours for coal-fired units. The fast take-off and landing pumped-storage hydraulic unit is suitable for energy storage equipment for future intermittent renewable energy.
In response to Taiwan's energy transformation policy, the proportion of renewable energy continues to increase. In order to stabilize the quality of power supply and the safety of the power system, Taipower began to evaluate the use of existing reservoirs to build pumped storage hydropower generating units in 2016, including Feicui Reservoir, Shimen Reservoir, Deji Reservoir Reservoirs, Mudan reservoirs, etc. are all options.
Among them, the Deji Reservoir managed by Taipower, the "Dajiaxi Guangming Pumped Storage Hydropower Project" (hereinafter referred to as Guangming Project) took the lead in completing the feasibility assessment this year and entered the environmental assessment process in April.
Guangming plans to use the Deji Reservoir as the upper pool, and the Guguan Reservoir (with a storage capacity of about 5 million cubic meters) as the lower pool, with a new head water tunnel about 10.7 kilometers long, and two vertical axis reversible frequency conversion Francis units, The maximum total device capacity is 368MW. There is a height difference of about 450 meters between the two reservoirs, which is larger than the difference between Mingtan Power Plant and Daguan Power Plant. The head water tunnel is also longer than the Sun Moon Lake pumped storage unit, which is more than five times that of the diversion tunnel of Daguan No. 2 Plant. The construction has its own advantages. difficulty.
According to the "Environmental Assessment Law" , the cross-border water diversion project will directly enter the second stage of environmental impact assessment. The total cost of the Bright Project is about 26.4 billion. The goal is to pass the environmental assessment in 2024 and to be commercialized in June 2034.
In the future, Taipower plans to use the photovoltaic power generation peak during the day to pump water for about 5.5 hours, and release water to generate electricity during the second peak time at night. The annual power generation is estimated to be 450 million kWh, and the pumping power needs about 590 million kWh. In line with this plan, it is also necessary to expand existing transmission lines and update towers.
In fact, the Bright Project had , when Taipower considered the cost-effectiveness of power generation and gave up. Taipower explained that it takes about 1.25 kilowatt-hours of electricity to pump and store water to generate 1 kilowatt-hour of electricity. This is to convert off-peak power into peak use, and it needs to be effectively matched with time-based electricity prices to achieve economic benefits.
In response to the increase in the proportion of renewable energy in the future, the energy storage system will help alleviate the impact of intermittent energy grid connection on the power system. Taipower is also looking for a ready-made reservoir that can build 500MW of pumped and stored water.
In addition, Taipower revealed that the Shimen Reservoir’s pumped-storage hydropower project is estimated to complete the feasibility assessment at the annual meeting in 2022. The preliminary plan is to set up a small-scale 40MW reservoir with the Shimen Reservoir as the upper pond and the Houchi weir as the lower pond. Although the pumped-storage hydraulic unit started relatively late, the project is relatively easy, and it may be completed before 2025 at the earliest.
If the Shimen Reservoir’s pumped-storage hydropower generation project goes smoothly, Taiwan will have a new pumped-storage hydropower storage facility 30 years after the Mingtan Power Plant’s pumped-storage unit was completed in 1995.
