Renewables : a very competitive but intermittent energy

Renewables are developing very rapidly in most areas of the world. Solar and wind energy prices today reach levels lower than fossil fuels prices.

 

Renewables are intermittent and depend directly on the resource: the light intensity or the wind power. The fluctuation of the resource (presence of clouds or wind variation) can generate an irregular power production highly disturbing for grids. Moreover, when the resource disappears (at night or when the wind dies), the production stops completely.  Because of this intermittency, the demand for electricity from the users cannot be met.

 

Once the share of renewables in the energy mix reaches 30%, the grid can face disruption if not serious damage. This prevents the wide development of renewables in remote areas such as Guiana. To increase the share of renewables, technical solutions need to be found at an affordable price to smooth these variations and considerably reduce the effects of intermittency.

 

The solution to alleviate this handicap and keep developing renewables in remote areas lies in the mass storage of this intermittent energy. Mass storage will allow the capture of solar and wind energy and its uniform redistribution to consumers on-demand, day and night. The penetration of renewables in the grid theoretically can reach up to 100%!

 

French Guiana strongly wishes to increase the share of renewables in its energy mix to reach 100% by 2030. This goal can only be achieved by implementing solutions of both massive and long-term renewables storage. Hydrogen technology fits perfectly with this objective.

Storing energy as hydrogen :  ideal for the long haul

 

Different storage technologies are available. Batteries are increasingly used; they provide specific services to store a set amount of energy over a short period. However, they do not fit with long-term energy storage, i.e. over 5 hours. Battery storage also has a substantial impact on the environment.

 

Hydrogen technology is not recent and has been around since the 19th century. This technology is well-known for being flexible and non-polluting.

 

The technology consists in separating the hydrogen and the oxygen from a water molecule (H20) using an electrical current inside an electrolyzer. The hydrogen obtained is pressurized and stored in adapted tanks. Hydrogen is later reunited with oxygen (from the air) inside a fuel cell. This generates electricity and steam only. The production of electricity therefore meets the demand from the consumers. These elements (electrolyzer, storage, fuel cell) put together constitute the hydrogen energy chain.

 

The technology of storage in the form of hydrogen allows the storage of large amount of energy over long periods of time. Today, recent technological developments in the industry enable massive storage of energy at an industrial scale.

CEOG project diagram

With an equivalent of 130 MWh of energy stored, CEOG today is the biggest power plant project worldwide storing intermittent renewable energy using hydrogen.