The economy of our country is developing at a high speed, accompanied by a strong increase in energy demand. This is a problem posing many great challenges, when primary energy sources such as coal, oil and gas… are exhausted, not enough for domestic demand, hydropower potential has been exploited to the limit. Only about 2.7 GW of large hydroelectricity over 30 MW is expected to put into operation in the period of 2021 – 2025, and about 2.8 GW of small hydroelectricity will continue to be built. Thus, the development of renewable energy (RE) is an inevitable trend and an important supplementary source for the power system, especially for the supply of electricity to the Southern regions. RE has been playing an increasingly important role recently.
The role of energy storage system in the operation of Vietnam’s electricity system
In 2019 and 2020, our country has witnessed the strong development of RE, namely solar power and wind power. By the end of 2020, 16,700 MW of solar power capacity (including rooftop solar power) has been connected to the national power system (accounting for 24% of the total capacity of the system). And if the total capacity of hydropower plants in operation (20.7 GW) is also included, the proportion of capacity from RE has accounted for 55.17% of the total capacity of our country’s electricity system.
The context of non-hydro RE development in 2019 and 2020:
In 2019, the total installed capacity of electricity sources nationwide reached 55,231 MW, increasing 6,701 MW; total electricity production was 240.1 billion kWh; commercial electricity demand reached nearly 209.8 billion kWh, increasing 9.05% compared to 2018 (in which the South increased by 8.3%) [1]. The demand for electricity increased sharply, especially in hot periods from June to August. Drought occurred in many areas, causing the water volume to be very low in hydropower reservoirs, and hydropower output decreased by 16.3. billion kWh compared to 2018, by the end of 2019 the total amount of water stored in hydroelectric reservoirs was short of 11 billion m3 to a full reservoir. There was almost no backup for power system. The total commercial electricity of Central Power Corporation (EVNCPC) in 2019 reached 72,671 billion kWh, increasing more than 9% compared to 2018 [2] (accounting for 34.6% of the total national electricity demand), while there is only an expanded Vinh Tan 4 coal-fired power source (600 MW) put into operation and the expanded Duyen Hai 3 coal-fired power plant (688 MW) initially grid-connected at the end of the year. The system had to mobilize oil-fired power sources with an output of about 1.8 billion kWh to supply electricity to the South.
On the other hand, 2019 also witnessed the rapid development of RE, especially solar power. From only 86 MW in 2018, solar power has increased more than 54 times to 4,696 MW in 2019, while the electricity output reached 4.932 billion kWh (in 2018 the output was just 22 million kWh). Together with wind power (723 million kWh), biomass electricity (410 million kWh), non-hydro RE sources have contributed 6.065 billion kWh to the system.
According to EVN’s summary, in the 2016-2018 period, the trends of power transmission from the North to the Center, and from the Center to the South are still the main trends of inter-regional transmission. However, by 2019 when the South was supplemented with a large amount of new power sources, especially RE sources, the transmission power on the inter-regional 500 kV transmission line decreased significantly, especially in the summer months of 2019 when Northern and Central regions, the load increased due to extreme hot weather and the high mobilization of solar power plants put into operation. So, there was a time when the transmission trend was from the South to the Center and the North.
RE is focused to develop in the South with a total solar capacity of 3,491 MW and wind power of 288 MW in 2019, helping to compensate for electricity shortage due to delayed power sources here. However, power grids in some areas could not keep up with the rapid development of solar power, causing transmission congestion at times, and such difficulties in system operation that the system has to reduce generating power, only ensuring the release of 4,200/4,880 MW of RE put into operation.
At the end of 2020, the total installed power capacity of the whole system will reach 69,300 MW, increasing by 14,000 MW compared to 2019, of which RE has risen by 11,780 MW. The electricity output of the whole system reached 247.1 billion kWh, increasing only 2.9% compared to 2019. National commercial electricity reached 216.95 billion kWh, rising by 3.42% compared to 2019. Causes of the growth rate of electricity demand has slowed down due to the impact of the Covid-19. In 2020, non-hydroelectric RE sources contributed 12,203 billion kWh, accounting for 4.9% of the electricity produced in the whole system, of which solar PV produces 10,877 billion kWh, accounting for 4.4%. For the South, the total commercial electricity in 21 provinces of EVNCPC in 2020 reached 75.438 billion kWh, only increasing by 3.8% compared to 2019 [2].
It can be seen that the additional power capacity in 2020 is mainly from RE sources, of which the solar power in 2020 reached 16,700 MW, accounting for 24% of the system’s total power capacity. With rooftop solar power, the whole country has only 272 MW in 2019, but by the end of 2020, rooftop solar power source rose above 7,780 MW, accounting for nearly half of the total capacity of solar power sources. In which, the total capacity of rooftop solar power in the regions of Southern Power Corporation (EVNSPC) is 5,658 MWp, ranking highest in the country, while the areas belonging to Ho Chi Minh City Power Corporation has a total capacity of this source of nearly 365 MWp.
At the end of August 2020, there are 52 solar power plants located in the Southern region that have been energized and put into operation, with a total installed capacity of 2,584 MWp and over 2.26 billion kWh contributed by Southern solar power plants (in the first eight months of 2020), accounting for 4.43% of the total electricity output of the entire Southern power system.
Different from 2019 as mentioned above, the load’s growth rate hit the bottom in 2020, mainly due to Covid-19. At the same time, great numbers of businesses and individuals developed solar energy sources to keep up with the time limit benefiting from the incentive mechanisms for solar power (according to Decision 13/2020/QD-TTg of the Prime Minister). However, the amount of new capacity in 2020 was concentrated in the last months of the year, so the impact would mainly occur in 2021. It was a year of slow increase in electricity demand. But for the South, because the added amounts of traditional power sources are not significant, the amounts of RE played an efficient role of supplementary power supply, especially at the noon peak time of the load.
The development of solar and wind power in the South by 2021:
Currently, the installed capacity of non-hydro RE nationwide has been over 18,000 MW and may reach 23,000 MW by the end of 2021.
Regarding wind power, to EVN, by July 2021, businesses have signed power purchase agreements (PPA) with EVN including 144 wind farm projects with a total capacity of more than 8,144 MW. According to the progress reported by the investors until the beginning of August 2021, there are 21 wind power plants with a total capacity of 819 MW put into commercial operation. It is expected that 106 wind power plants with a total capacity of 5,655.5 MW will be put into commercial operation before October 31, 2021 [3].
Regarding rooftop solar power, as of July 24, 2021, there are 104,282 installed projects with a total capacity of 9,580 MWp, generating 3,074 billion kWh to the grid, and according to the calculation, the CO2 emission reduced by 3,263,122 tons. Rooftop solar PV is popularly installed in the South, where there are great amounts of solar radiation and high numbers of sunny hours.
1/ Rooftop solar power:
The total number of customers installing rooftop solar connected with the grids of EVNSPC by the end of June 2021 is 54,062, with a total installed capacity of photovoltaic panels of 5,523 MWp (equivalent to 4,417.6 MW). The cumulative output of grid-connected rooftop solar power of the customers in the first 6 months of 2021, purchased by EVNSPC, is 3,189 billion kWh.
Ho Chi Minh City is also one of the areas strongly developing rooftop solar power. The cumulative output purchased by EVNHCMC in the first 6 months of 2021 is 135 million kWh.
2/ Solar farms:
By the end of June 2021, there are 66 energized solar farms, with a total installed capacity of 3,281.35 MWp in 9 provinces: Binh Thuan, Tay Ninh, Long An, An Giang, Ba Ria – Vung Train, Ninh Thuan, Binh Phuoc, Hau Giang, Vinh Long.
Electricity output received from solar power plants in June 2021 was 396.03 million kWh, decreasing by 3.36% compared to May 2021, but rising by 61.73% regarding the same period (244.87 million kWh) and accounting for 5.92% of the electricity output of the whole system (excluding self-use and rooftop solar power of customers). The total electricity output of solar power plants cumulative in the first 6 months of the year is 2,452 billion kWh, accounting for 6.01% of the electricity output of the entire Southern system.
3/ Wind power plants:
By the end of June 2021, there have been 15 energized wind power plants, with a total installed capacity of 754.13 MWp in 4 provinces: Binh Thuan, Ninh Thuan, Bac Lieu, and Ben Tre.
Power output of wind power plants in June 2021 was 69.73 million kWh, and accounted for 1.04% of the power output of the whole system. Accumulated in the first 6 months of 2021, the electricity output received from wind power plants is 588.53 million kWh, accounting for 1.54% of the total electricity output received by the whole system (excluding self-used electricity from customers).
Cumulative in the first 6 months of 2021, according to EVNSPC, the South’s electricity consumption reached 39,666 billion kWh, rising by 8.98% over the same period in 2020 (power consumed in the first 6 months of 2020 reached 36.40 billion kWh). Particularly, electricity generated from RE reached more than 6,229 billion kWh (from wind farms, rooftop solar power and solar farms were 588.53 million kWh, 3.189 billion kWh, 2.452 billion kWh respectively).
Thus, solar and wind power account for 15.7% of the total power consumption in the first 6 months of 2021 of EVNSPC. Obviously, RE has contributed a significant amount of electricity to the Southern power supply.
According to EVN, accumulated in the first 6 months of 2021, the electricity output produced and imported in the whole system reached 128.51 billion kWh, rising by 7.4% over the same period in 2020. In which, the proportion of mobilized output of some main types of power sources on the total electricity output of the whole system as follows:
– Hydroelectricity reached 30.46 billion kWh, accounting for 23.7%.
– Coal thermal power reached 66.67 billion kWh, accounting for 51.9%.
– Gas turbines reached 15.66 billion kWh, accounting for 12.2%.
– Non-hydroelectric RE (wind power, solar power, biomass power) mobilized reached 14.69 billion kWh, accounting for 11.4%. In which, the southern region alone contributed 6.364 billion kWh [*].
– Imported electricity reached 624 million kWh, accounting for 0.5%.
– Mobilized oil thermal power is insignificant, reaching 2 million kWh.
When a series of wind farms are put into operation by the end of this year, the total capacity of RE will rise up to 23,000 MW. This trend will continue until the hot season when reservoirs of hydropower plants are at the lowest water level (preparing for the period of water storage), not generating enough capacity.
The contribution of RE to the electricity supply for the Southern region is an increasingly important factor. As of the first 6 months of 2021, electricity output from wind and solar power sources in the South is 6.364 billion kWh, accounting for 43.3% of electricity generated from RE (non-hydroelectricity) of the whole country. It is expected that by October 30, 2021, when 119 wind farms are put into operation with a total capacity of 5,655.5 MW to receive the discounted prices (according to Decision No. 39/QD-TTg dated September 10, 2018 of the Prime Minister on the mechanisms supporting the development of wind power projects in Vietnam) [4], it can be seen that the proportion of electricity produced from RE in the South will keep growing remarkably./.
Source: nangluongvietnam.vn
