Chixoy Reservoir Level and Power Limit: Daily Grid-Operator Data

How low is the Chixoy reservoir, and how much power is it costing the grid? This page answers with the grid operator’s own daily records. The Administrador del Mercado Mayorista (AMM), which runs Guatemala’s national grid, publishes a post-dispatch report every day. In it, the five Chixoy units appear with the megawatts each one may deliver. The note on the record for 25 September 2026 reads “Según la curva de abatimiento de la potencia en función del nivel de embalse” (according to the curve that lowers power as the reservoir level falls). We read that report daily.

Chixoy today

How to read it: when AMM’s note ties the limit to the reservoir, the limit follows AMM’s derating curve, and the notes that give both numbers pair a lower limit with a lower elevation. On 26 and 28 March 2025 a note read “Con cota de 794 msnm tiene una potencia disponible de 276.2 MW con cinco unidades” (at an elevation of 794 m, 276.2 MW available with five units). On 13 August 2025 another read “se llego a la cota 780 msnm, la planta con 5 unidades puede aportar potencia 259.6 MW” (the reservoir reached 780 m; the plant can deliver 259.6 MW with five units). A low limit on its own does not prove a low reservoir: in May and June 2025 the notes set it by the criteria for a given week instead (see the month table). We do not convert megawatts into metres ourselves: AMM’s curve is not in any of the reports we read (checked 26 September 2026).

The last two weeks

A day appears only when AMM’s reports carry a limit for it. When we read it, the latest day’s record can still be open; the next day’s report closes it, so the table fills in as the reports arrive.

Reservoir elevations written in AMM’s notes

AMM does not print the elevation every day. When a note does, we keep it, with the note as AMM wrote it. The elevation written on 27 August 2026 (776.60 m) was 25.78 metres lower than the one written on 13 January 2026 (802.38 m). Notes that state a threshold (for example “cota menor o igual a”) or a band edge of the curve are not counted as readings.

Month by month

The limit is the figure AMM applies whatever the reason written in the note. Of the 164 derating records we read for unit CHX-H1 from 1 January to 25 September 2026, 149 name the reservoir (its level, its elevation or the word embalse); 11 cite the derating curve without naming the reservoir, 2 an energy-and-capacity calculation and 2 carry no note. Some 2025 notes cite other reasons: in late May 2025, for example, they refer to the criteria for a given week. A month with no row means AMM’s reports we read carry no Chixoy limit for it; that is not the same as full capacity, so the table leaves it out rather than filling it in.

Units out for other reasons

What this page does not show

• A daily reservoir level. Only the elevations AMM’s notes happen to state. The weekly monitoring reports of the Ministry of Energy and Mines (MEM) were not readable by our script on 25 and 26 September 2026 (the site returned an access error).
• The reservoir’s operating range (its full and minimum levels): not in these reports.
• Other reservoirs. In the reports we read, only Chixoy’s records carry notes that tie a unit’s limit to the reservoir level, so this page covers Chixoy alone.
• Generation. The limit is the power each unit is available to deliver, not the energy Chixoy actually produced.

For what the drought means for your electricity supply, see power outages in Guatemala; for rivers, Guatemala river levels; for the rainfall background, El Niño in Guatemala.

How this page works

• Source: AMM’s daily post-dispatch report (a zip with one spreadsheet, sheet Indisponibilidades, rows CHX-H1 to CHX-H5) and its monthly archive, which back-fills the history from January 2025. AMM describes itself as “una entidad privada, sin fines de lucro” (a private, non-profit entity) created by article 44 of the General Electricity Law, Decreto 93-96.
• Per-unit limit per day: the record that covers that day. A record still open when we read it counts only for its first day until the next report closes it.
• Five units together: shown only when all five units carry a limit that day.
• If AMM’s report cannot be read, the last good data stays on the page and the date line above the box turns red after 50 hours.