Photovoltaic Curtailment and Compensation in Mauritius and the Indian Ocean

In Mauritius and across the Indian Ocean islands, solar can be curtailed by the utility when midday PV exceeds what a small, isolated grid can absorb — and in most cases compensation depends entirely on what your PPA or connection agreement says, not on a statutory rule. This page explains who curtails, why it happens on island grids, whether you get paid, and what to check in your own contract.

There is no general statutory compensation scheme in Mauritius comparable to Europe's redispatch rules. Whether curtailed energy is paid depends on the individual agreement with the Central Electricity Board (CEB), which is the single buyer and grid operator: utility-scale IPPs typically negotiate curtailment and deemed-energy clauses in the PPA, while small-scale schemes (residential and SME net-billing style arrangements) are usually paid only for energy actually exported. If your contract contains no deemed-generation or minimum-offtake clause, curtailed kWh are simply lost revenue. Read the curtailment, force-majeure and dispatch-instruction articles of your own agreement before assuming any entitlement — that is where the answer lives, and it varies contract by contract.

Mauritius, Réunion, Rodrigues, Seychelles, Madagascar and the Maldives all run small isolated systems with no interconnector to export a surplus. Two physical limits bite: instantaneous PV share versus the system's ability to hold frequency (inertia and spinning reserve from thermal and bagasse units), and local network constraints such as feeder or transformer limits. Around midday, solar floods the grid; by evening it vanishes and conventional units must ramp back up. When the operator cannot safely reduce must-run thermal plant any further, or when reserve margins are too thin to absorb a cloud-induced ramp, the cheapest lever is to cap or disconnect PV. This is why curtailment on islands is a structural feature of high solar penetration, not an occasional fault.

Distinguish three cases, because they carry different commercial consequences. (1) Contractual export caps: your connection agreement fixes a maximum injection in kW or kVA — this is not curtailment, it is a permanent design limit, and losses recur every clear day. (2) Dispatch-instructed curtailment: the utility sends a set-point or a switching instruction during a system event — this is the case where PPA compensation clauses, if any, apply. (3) Inverter-side technical limitation: over-voltage derating, frequency-dependent power reduction, or an internal power limit set at commissioning — often mistaken for utility curtailment. Only measurement separates them: log inverter set-point, grid voltage and frequency at the point of connection alongside irradiance, and the cause becomes visible in the data.

Compensation claims and investment decisions both need a defensible loss figure. Build it from a should-produce baseline: modelled output from measured plane-of-array irradiance and module temperature, compared minute by minute against metered AC output, with the difference attributed only where a curtailment signal or a voltage or frequency excursion is present. Sum the resulting kWh per event and value them at your applicable tariff. This is the same principle behind Stromfee's PV Watcher, which continuously measures what each plant should produce against what it delivers, so a plant that quietly under-produces is caught rather than absorbed as noise. Without such a baseline, a curtailment discussion with any utility is an argument about opinions rather than about energy.

If your contract does not pay for curtailed energy, storing the surplus is usually the only way to recover it. A battery charges through the midday hours when PV would otherwise be capped and discharges into the evening peak, when island systems are most expensive to serve. In hotel and commercial profiles typical of Mauritius — where air conditioning dominates the load — this shifts self-consumption into the hours that actually cost money, and it also lets a site stay inside a contractual export cap without spilling energy. The size follows from the curtailed energy profile, not from a rule of thumb: measure the daily capped kWh and the evening load first, then dimension the system to that measured shape.

First, obtain and read the curtailment, dispatch and metering clauses of your PPA or connection agreement, and note whether deemed energy is mentioned at all. Second, install measurement at the point of connection covering irradiance, voltage, frequency and inverter set-point, so every future event is documented from the day it happens. Third, reconstruct the last twelve months from inverter and meter data to size the problem in kWh and rupees. Fourth, take the quantified case to the CEB or your offtaker — a documented energy loss with a matching grid event is negotiable, an unmeasured complaint is not. Only then decide between contract renegotiation, storage, or load shifting; the data determines which one pays.

The Stromfee BESS system — connected

Charge DirectorAutomixerBESS EngineerPV Watcher