Constraint (observed) · Regional
Matched energy not traded because of central-corridor transmission constraints, selected months 2025-26
Record SAPP-K-0001 · draft, not yet reviewed by a person
Observations
Selected months only: those whose reports were retrieved (Nov 2025; Jan to Jun and Aug 2026). Dec 2025, Jul 2026 and Sep 2026 are not on SAPP's market-reports page as of 10 Oct 2026 (nor as of 16 Oct 2026), and their likely file addresses did not resolve. These are not a range for the year.
all competitive marketsday-ahead market
Coverage. Eight months, the SAPP monthly reports that could be retrieved; December 2025 and July 2026 were not found.
What this does not establish. SAPP's reports attribute the untraded share to central-corridor transmission constraints; the figures do not measure how much trade any one interconnector would add.
Plotted: 9 observations with the measure “traded share of matched energy”. 5 other observations use a different or undefined measure and are in the record's table only.
| Period | Segment | Measure | Value | Denominator | Source |
|---|---|---|---|---|---|
| Nov 2025 | all competitive markets | traded share of matched energy | 44.0% | matched energy, 271.2 GWh | wording checked against the document |
| Nov 2025 | day-ahead market | traded share of matched energy | 27.9% | matched energy, 171.1 GWh | wording checked against the document |
| Jan 2026 | all competitive markets | traded share of matched energy | 58.4% | matched energy, 233.1 GWh (text); Table 6.1 gives 233.4 matched and 136.3 traded | not yet checked by a person |
| Jan 2026 | day-ahead market | headline share not traded ('the remaining 40% could not be traded'; measure not defined by the source) | 40.0% | not defined by the source; equals untraded / matched day-ahead energy (153 GWh matched, 92 traded) by our arithmetic | not yet checked by a person |
| Feb 2026 | all competitive markets | traded share of matched energy | 52.2% | matched energy, 211.8 GWh | not yet checked by a person |
| Feb 2026 | day-ahead market | headline share not traded ('the remaining 50% could not be traded'; measure not defined by the source) | 50.0% | not defined by the source; equals untraded / matched day-ahead energy (145 GWh matched, 73 traded, as the text gives them) by our arithmetic | not yet checked by a person |
| Mar 2026 | all competitive markets | traded share of matched energy | 37.0% | matched energy, 234.9 GWh | not yet checked by a person |
| Mar 2026 | day-ahead market | headline share not traded ('the remaining 66% could not be traded'; measure not defined by the source) | 66.0% | not defined by the source; equals untraded / matched day-ahead energy (155 GWh matched, 52 traded, as the text gives them) by our arithmetic | not yet checked by a person |
| Apr 2026 | all competitive markets | traded share of matched energy | 46.0% | matched energy, 330.7 GWh | wording checked against the document |
| May 2026 | all competitive markets | traded share of matched energy | 58.3% | matched energy, 269.1 GWh | wording checked against the document |
| May 2026 | day-ahead market | untraded share of matched energy | 33.3% | matched energy, 191.0 GWh | wording checked against the document |
| Jun 2026 | all competitive markets | traded share of matched energy | 74.0% | matched energy, 181.6 GWh | wording checked against the document |
| Aug 2026 | day-ahead market | traded share of matched energy | 75.1% | matched energy, 161.06 GWh (traded 120.93, not traded 40.12) | wording checked against the document |
| Aug 2026 | not stated (headline) | share of matched bids not traded (measure not defined) | 33.0% | not defined by the source (refers to matched bids) | wording checked against the document |
How to read these figures
- August 2026: the headline says "transmission bottlenecks along the central corridor resulted in 33% of matched bids not being traded". The report's own day-ahead table gives 40.12 of 161.06 GWh not traded (24.9% of matched energy, or 33.2% of traded energy). The headline refers to matched bids without defining the underlying measure or calculation; its relationship to the day-ahead energy table remains unresolved. Use the headline only as SAPP's stated figure, with this caveat.
- The August report gives an all-market traded total (191.20 GWh) but no all-market matched total.
- January to March 2026: each headline percentage equals day-ahead untraded energy divided by day-ahead matched energy (January: 153 matched, 92 traded, so 61 untraded, 40%). The arithmetic is derived; SAPP does not state the method. On that convention August would read 24.9%. August's 33% instead equals untraded divided by traded energy (40.12 / 120.93). This suggests the August headline used a different denominator, but no SAPP document says so, so it stays an inference.
- January 2026's text (233.1 GWh matched, 136.2 traded) and its Table 6.1 (233.4, 136.3) differ slightly.
- The 46%, 47% and 38% shares in the January to March reports are available volume that was never matched, a different measure from matched energy not traded.
Evidence
- outage effects on the market, April to June 2026"No significant market distortions attributable to outage events were identified during the reporting period." "No significant market distortions attributable to outage events were identified during the reporting period."not yet checked by a personSAPP Quarterly Report, April to June 2026 (Issue Q1-2026/27) · printed p.13 · not yet checked by a person
- outage effects on trades, August 2026"significant transmission and generator outages were recorded in the ZESA and NTCSA control areas which affected SAPP Trades" "significant transmission and generator outages were recorded in the ZESA and NTCSA control areas which affected SAPP Trades"not yet checked by a personSAPP Monthly Report, August 2026 (R08) · printed p.7 · not yet checked by a person
- traded energy, August 2026"A total of 191.2 GWh was traded in August 2026" "A total of 191.2 GWh was traded in August 2026"not yet checked by a personSAPP Monthly Report, August 2026 (R08) · printed p.6 · not yet checked by a person
- Statement"The primary bottleneck was located along the central corridor, specifically at the interconnectors between Botswana and Zimbabwe, as well as between Zimbabwe and Zambia." "The primary bottleneck was located along the central corridor, specifically at the interconnectors between Botswana and Zimbabwe, as well as between Zimbabwe and Zambia."wording checked against the documentSAPP Market Performance Report, November 2025 · p.4 (inferred) · wording checked against the document
- Statement"The primary bottleneck was located along the central corridor", at "the interconnectors between Botswana and Zimbabwe, as well as between Zimbabwe and Zambia." "The primary bottleneck was located along the central corridor", at "the interconnectors between Botswana and Zimbabwe, as well as between Zimbabwe and Zambia."not yet checked by a personSAPP Market Performance Report, January 2026 · p.4 (inferred) · not yet checked by a person
- Statement"The major bottleneck was on the Zimbabwe – Zambia interconnector." "The major bottleneck was on the Zimbabwe – Zambia interconnector."not yet checked by a personSAPP Market Performance Report, March 2026 · PDF p.3 · not yet checked by a person
- Statement"The primary bottleneck was located along the central corridor, specifically at the interconnectors between Zimbabwe and Zambia." "The primary bottleneck was located along the central corridor, specifically at the interconnectors between Zimbabwe and Zambia."wording checked against the documentSAPP Market Performance Report, June 2026 · p.4 (inferred); same sentence in the April and May reports · wording checked against the document
- Statementnames the "central corridor" only; no interconnector names the "central corridor" only; no interconnectorparaphrase, not a quotationSAPP Market Performance Report, August 2026 · printed p.1 / PDF p.2, Outlook · paraphrase, not a quotation
Still unknown
- Which utilities' or countries' bids went untraded; the reports give no per-country or per-interface breakdown (checked in the January to June and August 2026 market reports and the January to March 2026 quarterly report, S-SAPP-Q-2026Q1).
- How SAPP computes the headline share of "matched bids" not traded; no definition was found in its market reports, monthly or quarterly reports.
- How SAPP's April to June 2026 quarterly report (evidence above: no significant distortions from outage events, and a search of it found no mention of congestion or of the Zimbabwe-Zambia interconnectors) fits with its monthly market reports for the same months, which locate the primary bottleneck at those interconnectors. Outages and transmission constraints are different things, so the two need not conflict, but the reports do not reconcile them.
- The August system report's traded total (evidence above) matches the market report's all-market total of 191.20 GWh, not its day-ahead 120.93 GWh, so the two reports' traded figures should not be combined.
- July and September 2026 market performance reports were still not on SAPP's market-reports page on 16 October 2026.
Blockers
- Central-corridor transmission limits leave matched energy untraded · evidence of the constraint
Connections
- Joint action or dependency with New wholesale market (SAWEM), Open access to the networks, NamPower outages, ZiZaBoNa interconnector
Institutions named
A role is shown only where a quoted source says what the institution does on this reform.
Reach: 1 cross-border links, 1 blockers, 1 institutions in 1 country. Counted from the records.