Rating agency Moody’s has warned it may downgrade ten European energy utilities, mostly because of their exposure to falling commodity and power prices.

Among those on review for downgrade are ratings related to Centrica, Dong Energy, EDF, E.On, Engie, RWE and Vattenfall.

At EDF, Moody’s noted the company exposure to power prices in France, which have fallen by 23% over the last three months.Moody’s reiterated that EDF’s ratings could be downgraded if the Hinkley Point C nuclear project or the acquisition of nuclear plant manufacturer Areva NP were to go ahead “without their risks being adequately mitigated”.

Dong Energy may be downgraded because of its exposure to falling oil and gas prices.

Engie also has exposure to oil and gas, and that will put pressure on cash flows while power prices are falling, especially in Belgium. The company will be under pressure despite the restart of its Belgian nuclear plant, Moody’s said.

Regarding RWE, Moody’s has concerns about falling power prices in Germany, especially as the utility has a large proportion of fixed-cost nuclear and coal plant.

The rating agency generally maintained the rating level of groups that had only moderate exposure to commodity-linked earnings, and had enough financial flexibility to absorb the negative impact of low power prices. These included ScottishPower parent Iberdrola and Irish energy company Viridian.

Moody’s has already downgraded Melton Renewable Energy UK, which operates five UK biomass-fuelled power plants totalling 174MW, along with landfill gas projects. The biomass plants include two – Thetford and Eye – fuelled with chicken litter. Moody’s highlighted the loss of Levy Exemption Certificates and a reset of biomass electricity prices expected on 1 October, as well as the company’s exposure to electricity wholesale price shifts. Melton Renewable Energy was known as MEIF Renewable Energy until it was acquired by funds managed by Octopus Investments in October last year.