Siemens Energy has expanded its stake in solar thermal company Archimede Solar Energy to boost its Italian solar operations.

Siemens will raise its stake from 28 to 45% to help speed up the setup of solar receiver production in Massa Martana, Umbria, Italy.

Archimede is expected to increase its annual production capacity to about 75,000 solar receivers by 2011 and to 140,000 per year.

The solar firm is a joint venture between Angelantoni Industries Spa and Siemens.

The Priolo Gargallo project in Sicily, Italy, will use 1,500 Archimede Solar receivers with molten salt as a heat transfer medium and is expected to be operational in this summer.

Siemens said it will now be able to add molten-salt receiver technology from Archimede Solar to its portfolio of solar thermal power products.