In October 1994, HIDISA was granted a thirty-year concession for the generation, sale and commercialization of electricity from the Diamante hydroelectric system (the “Diamante System”). Located on the Diamante river, in the Province of Mendoza, the Diamante System has an installed capacity of 388.4 MW, which represents 1.4% of the installed capacity in Argentina, and is composed of three dams and three hydroelectric power generation plants (Agua del Toro, Los Reyunos and El Tigre). The Diamante System covers a total distance of approximately 55 km with a height differential between 873 m and 1,338 m. From 1990 to 2009, its annual average generation was 615 GWh, with the highest level of generation (943 GWh) reached in 2006 and the lowest level (375 GWh) recorded in 1997.

HIDISA’s revenues are composed of energy and capacity sales. Total revenues for the twelve-month year ended December 31, 2009 were Ps.149 million, corresponding to a net generation of 600 GWh, 2.8% lower than in 2008, with a hydraulic contribution of 991 Hm3, 11% lower than in 2008.

HIDISA made 59% of its sales in the spot market. Availability of the power plants reached 87.8%.

The following chart shows certain relevant statistical data on Hidroeléctrica Diamante:

		2005	2006	2007	2008	2009
	Net Generation (GWh)	666	943	700	617	600
	Energy Purchases (GWh)	309	345	356	351	327
	Total Energy Sales (GWh)	975	1.288	1.056	968	927
	Average Price (Ps. / MWh)	70,5	83,9	118,0	142,4	160,6
	Average Gross Profit (Ps. / MWh)	31,2	40,8	50,8	56,7	65,4
Note: Gross Margin before amortization and depreciation charges.