The sanctioned spot price for July 2026 admits five different averages

The sanctioned spot price for July 2026 in Uruguay (UY) admits five different averages of the same month, all arithmetically correct, and the highest exceeds the lowest by a factor of 2,35. The published series holds 744 hourly values and no average of its own. The average is built by whoever reads the table, and the result depends entirely on the volume used to weight each hour.

What the sanctioned spot price measures and who calculates it

The sanctioned spot price is the hourly value that the electricity market administrator sets for energy in the Uruguayan wholesale market and publishes in dollars per megawatt hour. The July 2026 table has 31 day rows and 24 hour columns, that is 744 values, and carries a publication date of 10 August 2026 (primary source: the market operator).

The word that governs the reading is sanctioned. This is neither an estimate nor an average of bids: it is the already calculated and approved value that governs settlement for that hour. That is why the section holding the series orders the files by year and by month rather than by update date: each month closes once.

How the series is assembled and which step sits outside the publication

The publication delivers prices, not quantities. The hourly volumes for the same month live in a separate file from the same operator: the generation-by-source page returns a spreadsheet with the average output of each plant hour by hour, plus an interchange sheet covering the interconnections. Joining the two series is a step neither publication performs on its own.

That file is downloaded from the generation-by-source page by choosing a date range, and it arrives with a warning printed in the first row of every sheet: the values are approximate and come from the SCADA system. The spreadsheet carries separate sheets for wind, solar, thermal, biomass and interchanges, so the weight of each hour can be built by technology and not only by system total.

The numerator does not change; the denominator changes five times

The five averages below use exactly the same 744 prices. The only thing that changes from one row to the next is the weight assigned to each hour: none, system demand, total generation, exported energy or wind generation. The calculation below is original and starts from the two series cited for July 2026.

The distance between the first and the last row is not measurement noise. It is the difference between asking what an average hour of the month was worth and asking what the megawatt hour actually produced by the wind fleet was worth. These are two calculation bases with two different denominators, and each answers a question the other does not. One base must never be subtracted from the other.

The 391 hours at zero and what energy moved in them

Of the 744 hours of July 2026, in 391 the sanctioned price was exactly zero, that is 52,55 % of the month, according to the hourly table for that month. In those hours the system held more available energy than consumption to assign it to, and the market valued it at zero.

Those 391 hours carried 47,41 % of the month’s demand, 66,12 % of all wind generation and 73,56 % of the exported energy. The asymmetry is the point: exports and wind concentrate where the price is zero far more than domestic consumption does, which is why their weighted averages fall to 29,19 and 25,15 U$S/MWh while the demand-weighted one rises to 59,13.

The month recorded exports in 490 hours and in 319 of them — 65,10 % — the sanctioned price was zero. Total exported volume was 224 860,2 MWh, equal to 16,42 % of national generation for the month, against 71 213,0 MWh imported across 153 hours, some 5,86 % of demand.

That hourly figure carries a limit worth fixing before it is over-read: the file delivers hourly averages, so recording exports and imports within the same hour does not prove that both flows coexisted at every instant of that hour. The grain of the data is the hour, and no claim about instantaneous simultaneity survives on it.

The 62 hours at the opposite end

At the other end of the series sit 62 hours with a value of 250 U$S/MWh, 8,33 % of the month and the highest value appearing in the July 2026 table. Their economic weight is disproportionate to their number: they concentrate 10,01 % of monthly demand and only 5,65 % of exports. These are the hours that push the consumption-weighted average upwards.

Reading both ends together leaves the month split into two regimes. A little over half the hours are worth zero and slightly less than one hour in twelve is worth 250; between those edges sits the average of the 353 hours with a positive price, which is 107,98 U$S/MWh. None of those three figures describes the month on its own.

Frequency, lag and status of the data

The monthly sanctioned spot price table appears with a short and fairly regular lag. The seven tables published for 2026 show a cadence of around ten days from the close of the month, with one early release in June. The publication date sits next to each month on the year selection page, and not inside the file itself.

The status of the data is not uniform across the two series combined here. The prices are sanctioned; the volumes in the SCADA file are labelled approximate by the operator itself, in an open data section that declares their origin. A weighted average mixing the two inherits the uncertainty of the weaker one.

That margin can be measured. Adding generation and imports and subtracting exports, the month closes at 1 215 413,9 MWh against a published demand of 1 215 080,4 MWh: a difference of 333,5 MWh, or 0,03 % of the month, attributable to grid losses and to the rounding of hourly averages.

Which question each average answers

The simple hourly average answers one question only: how the price behaved over time, with every hour counting equally. It serves to compare months against each other and to describe the shape of the series. It does not describe what any specific megawatt hour cost or earned, because it ignores the fact that hours are not equal in volume.

The demand-weighted one describes the cost of system consumption as a whole. The generation-weighted one describes the average revenue of the plant fleet taken together. The one weighted by a single technology — wind, in this case — describes what that technology met in the market, which in July 2026 was less than half of what demand paid.

None of the five is a contract quotation. Exports and supply contracts settle through their own mechanisms, which this series does not publish, and for that reason the calculation stops at averages and does not move on to dollar amounts. The opening of these databases rests on article 82 of Law N° 19.355, which in the official base appears as regulated by Decree N° 54/017 of 20 February 2017.

The practical conclusion is that quoting an average of the sanctioned spot price without naming its denominator conveys nothing verifiable. Before using any of these five figures three things are worth fixing: the month, the weight and the status of the data. The sector series that the ministry publishes on its observatory portal constitute a base distinct from the market operator’s, with criteria of their own, and are not interchangeable with these either.

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