Spanish solar manufacturer Isofotón and ENDESA (NYSE: ELE), the leading Spanish electrical utility, have signed an agreement to work together on a handful of future solar installations... and are even planning to build a silicon plant together.

Isofotón has agreed to supply panels for a number of specific projects the companies have selected, but are not publicly identifying at this point, Álvaro Pérez de Lema, head of North America investor relations, told Cleantech.com.

According to officials, one of the motivations for the deal was to ensure that ENDESA has access to the equipment the company expects it will need for solar installations between now and 2011.

The agreement also provides for collaboration on several projects involving concentrating photovoltaic technology, which the two companies may commercialize together.

In addition, ENDESA, Isofotón and the regional government of the Andalusian region in Spain plan to collaborate to develop and construct a polysilicon plant in Los Barrios to guarantee both companies’ supply needs.

Development on the project, named Silicio Energía, should commence in the coming months, with the facility becoming operational in 2009. The plant is expected to cost €250 million and yield 2,500 tonnes of polysilicon per year, equivalent to 250 MW of PV modules. ENDESA will supply the power required to operate the plant.

The two companies have been working for a number of months on their relationship, according to officials.

ENDESA has installed or has ownership stakes in photovoltaic installations throughout Spain, and is currently installing of 850 kW of photovoltaics at fossil fuel power stations located around the country.

Isofotón is the largest photovoltaic and thermal solar energy company in Spain, and one of the largest in the world. It has a commercial presence in over 60 countries and has subsidiaries in China, Ecuador, Italy, Morocco and the Dominican Republic, as well as a project office in Senegal.

It has a limited presence in North America, and according to company officials, has no plan for further North American expansion at this time.