EdF plans to start construction in late 2021 or early 2022, it said. Construction would take 10-12 years.
The planning inspectorate will decide within 28 days if the application is complete. A full public examination is expected in autumn.
UK installed nuclear capacity currently stands at 9GW, although around 2GW of that has been off line since 2018 because of continuing issues with the graphite core at Hunterston B and at steam pipes at Dungeness B.
Sizewell C is "a near replica of Hinkley Point C", which means it "will benefit from significantly reduced construction costs and lower risk", Edf said.
Hinkley C has been subject to delays and is over budget. EdF said last year that there was increased risk of a 15-month delay to the project, and revised up its budget by £2bn-3bn. And earlier this month it said Covid-19 could delay construction, although the first 1.6GW unit is still scheduled to come on line in 2025.
EdF reiterated its support for the regulated asset base model to finance new nuclear projects, where some of the construction risks are shifted to the taxpayer.
Hinkley C has a 35-year contract for difference with a strike price of £92.50/MWh.
The government announced its intent to support nuclear power following its victory in the general election in December 2019.
Installed capacity will fall sharply from 2023 as plants come to the end of their operational life.
The 1.2GW Sizewell B will be the only existing plant that remains on line by the end of 2030 — its operational life ends in 2035.
Currently one unit at Sizewell B is being paid to stay off line to help the grid manage weak demand caused by the coronavirus pandemic. The grid needs to keep some flexible thermal generation such as biomass and CCGT on hand to maintain inertia and help balance out variable wind energy.
The need for flexibility on the grid will be likely to grow as a huge rollout of offshore wind is underway. Capacity is expected to double to 20GW by 2025, while the government has said it intends to raise the target for 2030 to 40GW.
