Salto Grande delivers energy to two systems as a binational body

Salto Grande is not a plant of the Uruguayan (UY) electricity system: it is a binational body that delivers energy to two systems. The joint technical commission that administers it was created by Argentina and Uruguay, splits generation in equal parts between both dispatch centres, and publishes a data series of its own, on criteria and calendars that belong to no national operator.

What the Salto Grande binational body administers

The joint technical commission of Salto Grande is a binational body created by the Argentine Republic and the Eastern Republic of Uruguay to make use of the rapids of the Uruguay river in the Salto Grande area. Its mission refers back to the 1946 Convention, and it is made up of delegations from both States that form the Plenary.

The complex sits in the area known as Ayuí, upstream of Concordia, in Argentina, and Salto, in Uruguay, 470 km from Buenos Aires and 520 km from Montevideo. The body describes it as the first multipurpose hydraulic development in Latin America, and its institutional profile separates three planes: direction, production and transmission of energy, and execution of the Plenary’s decisions.

What the technical sheet of the complex states

The magnitudes of the complex are published in a single table, without an update date and with the hydrological series dated between 1979 and 2016. Three blocks matter most: the reservoir, which sets how much water can be stored; the equipment, which sets the capacity; and the turbines, which explain how that capacity is divided among units.

The figures close against each other. Fourteen units of 135 MW give exactly the 1 890 MW published, and the average annual capability of 8 546 GWh equals 51,62 % of what that capacity would produce running all 8 760 hours of the year. That percentage describes the relation between two published figures, not the state of the equipment at any given moment.

One item on the technical sheet is worth reading with the unit in view. The market page states that maximum generation capacity is 45 360 megavatios/hora; that number is the product of 1 890 MW by 24 hours, so it behaves as a daily total rather than an hourly value. The distinction matters once the figure is copied into a spreadsheet.

How the energy is split between the two systems

The split is in equal parts and is described without ambiguity: the complex delivers 50 % of its generation to the Argentine system, represented by CAMMESA, and the other half to the Uruguayan system, administered by the electricity market administrator. Applied to the published average annual capability, each system would receive 4 273 GWh.

Energy scheduling is done weekly. The operations management calculates how much energy it can produce over that span from the forecast of river inflows, and that offer is placed at the disposal of the two dispatch centres, which take energy according to each country’s demand. Both may store energy in the reservoir or consume part of it as their needs require.

When inflow exceeds what the two systems absorb, water is held in the lake if conditions allow, and if not it is released through the spillway with 19 bays. Who decides how much may be released without compromising the banks downstream is named on the market page: the body’s own hydrology unit.

The share of the complex in Uruguayan consumption is published in three forms. The market page says it covers on average 53 % of Uruguayan energy demand and, a few lines further down, that it supplies more than 50 % of the energy consumed; the site’s front page gives, in approximate values, 50 % of the energy of the Uruguayan system. These are three different denominators — demand, energy consumed, system energy — and none of the three mentions states the period. One base must never be subtracted from the other.

What the body publishes and how often

The block of its own publications is hydrological before it is energetic, and that matches what the commission administers: a shared river, not a customer portfolio. The data section separates two grains — hourly and daily — and inside it five reports appear under names of their own.

The two speeds matter separately. The hydrological data describe the state of the river today, at the grain of one hour; the annual report describes the management of the body, and at the cut-off date of this note the latest year available is 2024. One series serves to follow the water and the other to follow the institution.

Where its decisions reach a company

The first point of contact is not energy but land. Transmission lines impose a variable easement strip, up to some 77 metres in rural areas, and in the central 69 metres of that strip building dwellings is prohibited; on the rest, single-storey structures are allowed. Any industrial or logistics project near a route meets that restriction before it meets any tariff.

The second point is the metering boundary. The transmission network consists of four substations at 500 kV and 1 300 km of lines, with vertices at the plant site, at Colonia Elía and at San Javier. The ring’s exits towards the national grids, at 500, 150 or 132 kV, are the physical boundaries where energy is recorded for billing through the commercial metering system.

The third is indirect and works on the price of the whole system: the availability of the complex depends on flow, and flow depends on the basin. For a company with material consumption, the daily bulletin of levels is a leading indicator of the regime the dispatch will enter over the following weeks.

What the commission does not do

It does not sell energy to end customers and does not set retail tariffs. It delivers its output to the two national dispatch centres and its commercial relationship ends there: the price an Uruguayan industrial plant pays is formed in a market administered by another body, under rules the binational commission does not write.

Nor does it operate the whole network it built. The lines and substations outside the ring were transferred for operation to the Uruguayan electricity utility and to the Argentine high-voltage transmission company. And it does not publish prices: its open sections carry no tariff, no value of the energy delivered, and no economic condition of the split.

How work with the body is done

Access to information runs through two different doors. The operational one is open and needs no procedure: the hydrological reports are consulted directly. The documentary one carries express conditions, and they are worth knowing before material is carried into a corporate report or a commercial presentation.

The documentation centre establishes that the documents made available are intended for consultation, research and informational use, and that in no case is their use for profit authorised, nor their reproduction, distribution, public communication or transformation without prior express authorisation from the body. That condition covers the materials of the archive, not the consultation of operational data.

The useful conclusion is one of framing. Salto Grande is often quoted as though it were one more national plant, and it is not: its ownership is binational, its split is fixed in halves, its scheduling is weekly and its publications answer to the logic of a shared river. Any figure taken from this body arrives with that condition built in, and whoever uses it in a supply model gains more by naming the denominator than by rounding the percentage.

Analysis, not personalised advice. For transactional decisions, verify the tariff value or the text of the rule directly with the operator or the regulator.