UPDATE 1-Engie and sonnen team up for French solar power package

* The companies start selling home photovoltaic kits

* Engie sees taget market of three million houses

* French retail market opens up to more competition (Adds Frankfurt dateline, quotes from sonnen CEO, detail, context)

PARIS/FRANKFURT, April 26 (Reuters) - French utility Engie and German solar battery maker sonnen have teamed up to offer a package of solar panels and home power storage to French households, they said on Thursday.

Sonnen, a venture capital-backed start-up, said the package, called “My Power”, would be available immediately.

Herve-Matthieu Ricour, head of Engie’s French retail unit, said in Paris the utility estimated there were about three million power customers in France with detached houses that are suitable for the solar and storage package.

In the south of France, users could cover nearly 100 percent of their power needs between May and September with the package, he said, while in the north customers would be able to generate about two thirds of their electricity needs.

Sonnen’s Chief Executive Christoph Ostermann told Reuters in Germany that the company hoped to replicate inroads in the German and Italian markets, helped by France’s goal to reduce its reliance on nuclear energy and the dominant position of former monopoly EDF.

“Engie has tested the systems and is now going into this market,” Ostermann said.

“Together, we would like to become a dominant player in French home solar batteries within two to three years.”

Ostermann said sonnen could appeal to customers wanting to become more autonomous in a power market still more than 90-percent supplied by EDF.

Nuclear production used to guarantee French consumers cheap power but retail prices have increased by around 20 percent over the past five years as reactors age, power needs grow and the build-up of renewable energy takes time.

Worldwide, sonnen has sold 30,000 batteries for storing solar power to small generators with a combined 210 megawatts of capacity, mostly to rooftop solar panel owners in Germany, Italy, the United States and Australia.

The French storage market is in its infancy, whereas in sonnen’s home market, there are vast opportunities to sell batteries for 1.6 million solar rooftop systems, sonnen said.

But France has an edge in legislation to support the take-up of smart meters that will enable data apps to share energy flows and to market related services, and with an investment subsidy for the purchase of photovoltaic systems.

Germany is deliberately lagging behind in the adoption of smart meters, due to doubts over cost-benefit and data privacy considerations. (Reporting by Geert De Clercq and Vera Eckert; Editing by Sudip Kar-Gupta and Mark Potter)