In a traditional power system the price of energy is heavily based on the cost of fuel. Some fuels (like gas) may only be economical when energy prices rise to

In a traditional power system the price of energy is heavily based on the cost of fuel. Some fuels (like gas) may only be economical when energy prices rise to a particular level. Nuclear power, solar, and wind are not like that. The fuel is effectively free, and the costs are fixed regardless of demand or energy price. So it makes sense to run the station as much as possible, regardless of how little money the power is sold for. That means that the price would fluctuate depending on the wider market. If the price of gas suddenly drops then nuclear makes less money. Subsidies let you set the price up front at a level that is "fair" to pay for capital and ongoing costs. You can argue that the price is too high, but the presence of subsidies is difficult to avoid. The crazy thing about Hinkley is that the subsidy level is actually linked to wider energy prices. The government have a weird incentive to rig the market in favour of Hinkley C. If electricity becomes cheaper then the scheme will seem like a rip off!