HDF Energy is planning what it claims will be the world's largest solar-plus-storage project, in French Guiana

French hydrogen specialist HDF Energy has launched the Centrale électrique de l’Ouest guyanais (CEOG) project, which promises to be one of the world’s largest solar-plus-storage power plants.

HDF says the project will be built in three stages: the development phase this year, in which it will work with local consultancies to conduct topographic and other studies as well as an environmental impact assessment; construction, in 2019 and 2020, in which the plant will be deployed over 12 months; and operation, spanning 2020 to 2040.

The company says electricity will be provided through the combination of a utility-scale PV plant, mass and long-term energy storage in the form of hydrogen, and short-term storage, using batteries.

The $90 million plant, expected to generate around 50 GWh per year, will be near Saint-Laurent-du-Maroni in northwestern French Guiana, and will cover the energy needs of local households as well as of those of the nearby municipality of Mana. The facility will be able to produce a fixed electrical daily output of 10 MW until evening and of 3 MW during the night.

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With an equivalent 140 MWh of energy stored, CEOG is the biggest power plant project worldwide storing intermittent renewable energy using hydrogen, according to HDF. The world’s largest storage project, under development by Tesla and Neoen in Australia, has a marginally lower capacity of 129 MWh.

HDF says its technology enables the storage of large amounts of energy over long periods, compared to lithium-ion batteries. The company claims its technology consists of an electrolyzer, storage tanks and a fuel cell. After separating hydrogen and oxygen from a water molecule through the electrolyzer, the resultant hydrogen is pressurized and stored in tanks. This hydrogen is then combined with oxygen in the fuel cell, enabling the production of electricity and steam.

According to Berlin-based renewable energy consultant, Stephan Franz, who wrote recently about hydrogen-based storage, the cost of water electrolysis – at approximately €0.10/kWh ($0.12/kWh) without electricity costs – means hydrogen in the electricity and heat sector will not be an economic option for some time. Mr Franz says, however, hydrogen does have the potential to be the “missing link” of energy transition, especially if used for energy storage in winter months.