Natural gas fired replacement power will contribute nearly 1000X more CO2 emissions every day
Last night, the first reactor of the Kuosheng Nuclear Power Plant shut down permanently, six months prior to its scheduled retirement date of December 27 due to lack of spent fuel storage capacity, preventing spent fuel from being removed and replaced with fresh fuel. The reactor closure is a significant step towards Taiwan’s nuclear free goal and its energy transition, which aims to eliminate all nuclear power generation on the island, and replacing it with renewables and natural gas.
Through its energy transition, Taiwan aims to be a leader in green energy in the Asia-Pacific region, while also eliminating what is sees as a significant threat to health and safety in nuclear power and reducing greenhouse gas emissions. President Tsai recently pledged Taiwan’s goal of net zero emissions by 2050 and the country is looking to take the rare step of putting this goal into law by amending its Greenhouse Gas Reduction and Management Act.
Already, Taiwan has made huge strides in policy implementation of offshore wind and can claim the leadership role in APAC. Solar PV installations have increased by nearly 400% since Tsai took office, and the Chinshan Nuclear Power Plant (NPP1) is being decommissioned. With the shutdown of Kuosheng-1, Taiwan is halfway to achieving its nuclear-free ambitions.
Taipower expressed confidence to me that energy supply will be sufficient this summer because it has already commissioned Kuosheng-1’s replacement power: the 500MW combined cycle gas turbine (CCGT) Chiahuei 2 Independent Power Provider (IPP), as well as 500MW of solar PV. Taipower is also bringing back several units CCGT units that have been sidelined for repairs.
Already, at 2:20pm peak when demand breached 37,000 megawatt hours (MWh), nuclear’s share of power generation feel to 7.6%, down from the usual 9~10%, while solar reached 8.7% — the first time that solar has exceeded nuclear in power generation. Reserves fell from yesterday’s 16% to 11.84%, but still comfortably in the green.
However, as the day wanes, this won’t last, and Taiwan will again fall back on natural gas fired power to maintain supplies to compensate for Kuosheng-1’s sizable output.
Prior to its coast down in which Taipower operated the reactor at lower output to preserve fuel, the 985 megawatt (MW) Kuosheng-1 had been operating at or near (or even over) 100% capacity. Taipower statistics reveal that the 985MW Kuosheng-1 reactor operated at 101.94% capacity in March, generating 710,131 megawatt hours (MWh), or 22,907MWh daily.
Solar PV, by contrast, operates at 15% capacity factors in Taiwan (annualized – this is somewhat higher during the summer), generating about 75MW per hour, or 1,800MWh daily.
The Chiahuei 2 IPP unit is operating at capacities as high as 98%, generating roughly 11,760MWh daily. Together, these generate 13,560MWh daily, far off the generation of Kuosheng-1. Further, while natural gas-fired power emits less CO2 than coal-fired power, it is still substantial. The US EPA estimates that combined cycle natural gas power plants emit 407 kilograms of greenhouse gases per MWh, suggesting that the Chiahuei 2 adds 4,786 metric tons of CO2-equivalent into the atmosphere every day. Further, the 1000 combined MW of Chiahuei and solar PV will not fully replace Kuosheng-1, and the two additional CCGT units needed to make up the difference will add another 3,804 tons of GHG emissions into the atmosphere every day, for a total of 8,590 tons per day.
Nuclear power also has a carbon footprint, primarily in the construction phase but also in the mining and refining of uranium. Through the life of the plant, this is estimated to 400 grams per MWh – resulting in Kuosheng-1 emitting 9 tons of GHG daily.
Taiwan’s EPA representative suggests that these are just hiccups on the path towards a greener future, and perhaps they are correct. Yet this CO2 being emitted today will spend centuries in the atmosphere.