The offshore wind sector has been hit by rising costs in the past few years, and the Conservatives argue the contracts awarded in today's auction risk locking in high prices for decades.
One of the biggest successful projects is the first phase of Berwick Bank in the North Sea, which could end up as the largest offshore wind farm worldwide.
Other projects to be awarded contracts include the Dogger Bank South wind farm off the coast of Yorkshire and the Norfolk Vanguard project off the coast of East Anglia - while Awel Y Mor was the first successful Welsh project in more than a decade, the government says.
Chris Stark, who is overseeing the government's clean power push, described the results as "a great outcome for the country" and said that the mix of English, Scottish and Welsh projects would help to get electricity to people's homes more easily.
The government wants at least 95% of Great Britain's electricity to come from "clean" sources by 2030, partly to help tackle climate change by reducing carbon emissions from burning fossil fuels. These clean sources include renewables – such as solar and wind – and nuclear energy.
Offshore wind is widely seen as the backbone of Great Britain's future clean electricity system, with plentiful wind resources off the country's coastlines.
The government wants at least 43 gigawatts (GW) of offshore wind by 2030 to help meet its clean power target.
That is a big step-up from its current offshore wind capacity, which stands at 16.6GW, with a further 11.7GW under construction, according to the government.
Building offshore wind and connecting it to the grid takes time – and many analysts have viewed this auction as crucial to get enough wind to meet its target.
The 8.4GW secured at this latest auction just about keeps the offshore wind target in reach, several analysts have told the BBC. But all those projects will still need connecting to the grid to generate electricity.
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