Hinkley Point C nuclear power station in the context of "Somerset"

A steam turbine or steam turbine engine is a machine or heat engine that extracts thermal energy from pressurized steam and uses it to do mechanical work utilising a rotating output shaft. Its modern manifestation was invented by Sir Charles Parsons in 1884. It revolutionized marine propulsion and navigation to a significant extent. Fabrication of a modern steam turbine involves advanced metalwork to form high-grade steel alloys into precision parts using technologies that first became available in the 20th century; continued advances in durability and efficiency of steam turbines remains central to the energy economics of the 21st century. The largest steam turbine ever built is the 1,770 MW Arabelle steam turbine built by Arabelle Solutions (previously GE Steam Power), two units of which will be installed at Hinkley Point C Nuclear Power Station, England.

The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible expansion process. Because the turbine generates rotary motion, it can be coupled to a generator to harness its motion into electricity. Such turbogenerators are the core of thermal power stations which can be fueled by fossil fuels, nuclear fuels, geothermal, or solar energy. About 42% of all electricity generation in the United States in 2022 was by the use of steam turbines. Technical challenges include rotor imbalance, vibration, bearing wear, and uneven expansion (various forms of thermal shock).

The EPR is a Generation III+ pressurised water reactor design. It has been designed and developed mainly by Framatome (part of Areva between 2001 and 2017) and Électricité de France (EDF) in France, and by Siemens in Germany. In Europe, this reactor design was called European Pressurised Reactor, and the internationalised name was Evolutionary Power Reactor, but it has been simplified to EPR.

The first operational EPR unit was China's Taishan 1, which started commercial operation in December 2018. Taishan 2 started commercial operation in September 2019. European units have been so far plagued with prolonged construction delays and substantial cost overruns. The first EPR unit to start construction, at Olkiluoto in Finland, originally intended to be commissioned in 2009, started commercial operation in 2023, a delay of fourteen years. The second EPR unit to start construction, at Flamanville in France, also suffered a more than decade-long delay in its commissioning (from 2012 to 2024). Two units at Hinkley Point in the United Kingdom received final approval in September 2016; the first unit was expected to begin operating in 2027, but was subsequently delayed to around 2030.