Colombia's firm energy market just bet on solar doing hydro's job
In April 2024, Colombia's reservoirs closed the month at 32.91% of capacity, roughly two percentage points above the 27% level XM has identified as the threshold for formal rationing measures, per XM's own public reporting during that period. Eighteen months later, at the country's most recent reliability charge auction, 4,441 of the 4,489 MW awarded, 99% of the new firm capacity, went to solar, clearing at USD 18.2 per MWh. A system that nearly rationed power on hydro just built its next decade of contracted backup around a resource nobody has forced through the same test.
The reliability charge, Colombia's capacity market, exists precisely because a hydro-heavy grid needs paid, contracted backup for dry years. Historically that backup skewed thermal, mostly gas, plants that can sit idle and answer a dispatch instruction at 9pm in the dry season regardless of what the sky is doing. This auction did not add backup of that kind. It added solar, at a clearing price that looks nothing like what firm capacity has cost in the past.
What a firm energy obligation actually promises
An Obligación de Energía Firme is not a promise to deliver full nameplate output on demand. For a thermal or hydro plant it is close to that, fuel and water permitting. For a solar plant it is a statistically derated fraction of capacity, computed from historical generation performance under defined conditions. The plant gets paid the reliability charge either way. What changes is what happens if a Declaratoria de Escasez is triggered and the grid actually needs the energy the obligation promised.
That distinction rarely mattered while solar was a minority share of the reliability charge. It matters more with every auction where solar is effectively the entire marginal addition, because the aggregate firm energy commitment the system is relying on is increasingly a statistical estimate rather than a physical guarantee backed by stored fuel or stored water.
A firm energy obligation without storage behind it is a statistical promise wearing a capacity market's price tag.
The near miss the auction came after
The 2024 episode was not a freak afternoon. Reservoirs sat close to 30% through March and April of that year as El Niño intensified, prompting XM to publicly urge water and power conservation and Colombia to briefly suspend energy exports to Ecuador. By 2025, XM was again flagging reservoir levels as the lowest for August and September in twenty years. Two dry-year scares inside eighteen months is a pattern, not a tail event, and a capacity market built to price around exactly that pattern just leaned harder into a resource whose firmness is a formula rather than a fuel tank.
To be fair to the auction result, ENFICC methodology exists precisely to haircut solar's nameplate down to something defensible, and CREG did not hand out full capacity credit for 4,441 MW of panels. The derating is the point. The open question is whether that derating was calibrated against a hydrology regime as stressed as the one Colombia just lived through, or against a longer, gentler average that understates what a real Declaratoria de Escasez asks of the resources backing it.
What we think follows
Lenders sizing debt against reliability charge revenue from a standalone solar OEF, no storage, no firm fuel behind it, should treat that cash flow with meaningfully less certainty than an equivalent GWh/day from thermal or hydro, even though the auction clears them at the same mechanism and, this round, a strikingly low price. A DSCR that books $18.2/MWh of OEF income as contracted-grade the way it would book a gas plant's reliability charge is pricing a statistical estimate as if it were a physical asset. The lenders already haircutting solar OEF revenue are doing the right thing. The ones treating the auction clearing price as evidence of low risk are reading a price signal that reflects abundant solar bids, not a tested capacity guarantee.
Our own pipeline sits in Peru rather than Colombia, so we are not underwriting this specific market. But the design logic travels. Of ZFC Energy Group's four projects, only Olmos Wind, approximately 135 MW in Lambayeque, carries integrated battery storage rather than a bare generation interconnection, targeting Ready-to-Build in the first quarter of 2028. That is the difference between a resource that can answer a capacity call on demand and one that can only report a probability.
The open question
Does CREG revisit the ENFICC methodology, or attach storage or hourly-delivery requirements to future firm energy obligations, before the next hydrology test forces the question in real time? Or does the reliability charge keep clearing paper firm energy that has not yet been asked to prove itself against a Declaratoria de Escasez, leaving that proof for whichever dry year comes next.
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