A solar farm cannot export its nameplate capacity
A commissioning team expects a 100 MW solar farm to earn revenue from all available sunshine. A temporary export ceiling changes both delivered energy and the value of removing the constraint.
Permanent case linkYour task
Quantify constrained energy and its price-dependent value. Decide whether the proposed early upgrade merits further engineering and commercial review.
Your role
Connection analyst reviewing a staged energisation plan
Practice data & worked solution
Available output is not delivered energy
Original synthetic four-hour scenario. Each row lasts one hour. Output equals the lesser of available MW and export limit MW; no voluntary economic curtailment. Prices remain fixed. Ignore losses, certificates, PPAs, taxes and operating costs. Upgrade removes only the stated ceiling and costs A$2,000 for this test period; this is not an actual network quote.
| Hour | Available MW | Export limit MW | Price AUD per MWh |
|---|---|---|---|
| 1 | 40 | 70 | 50 |
| 2 | 90 | 70 | -20 |
| 3 | 100 | 70 | 40 |
| 4 | 60 | 70 | 100 |
Your analysis
- Calculate export, constrained energy and spot receipts in each hour. Separate the physical quantity lost from its commercial value.
- Remove the export ceiling with all else fixed. Calculate incremental receipts and compare them with the A$2,000 cost.
- Replace the hour-two price with A$80/MWh. Recalculate the decision and identify which permissions and engineering evidence are still missing.
Worked solution
Energy and receipts
Available energy totals 290 MWh. Export is 40, 70, 70 and 60 MWh, totalling 240 MWh. Constrained energy is 0, 20, 30 and 0 MWh: 50 MWh. Receipts are A$2,000, −A$1,400, A$2,800 and A$6,000, totalling A$9,400. A negative price makes additional unhedged export a payment, not a benefit.
Upgrade break-even
Unconstrained receipts total A$10,200, only A$800 more: 20 × (−20) + 30 × 40. Net benefit after the A$2,000 cost is −A$1,200. The quantity gain alone is not an investment case. A real plant may alter dispatch or have different contract incentives; that behaviour is excluded here.
Transfer and decision gate
At A$80/MWh in hour two, constrained receipts become A$16,400 and unconstrained receipts A$19,200. Incremental receipts are A$2,800 and net benefit A$800. This supports further review, not authorisation to exceed the agreed limit. Check connection rights, plant models, commissioning tests and actual curtailment instructions.
Review your response
- Energy: MW is converted using the one-hour duration, and export never exceeds the limit.
- Value: the negative-price hour has the correct sign; constrained MWh are not valued at an unweighted mean.
- Sensitivity: both base and revised incremental receipts reconcile.
- Decision: technical permission and commercial value are separate gates.
This checklist supports self-review. No tutor marking or independent credential is included.
Related topics 5
Sources & evidence
All figures are original teaching inputs, not observations or published forecasts. The official source supplies industry context, not this dataset. Source link checked 17 October 2026. Obtain the connection agreement, dispatch instructions, loss factors and commissioning hold-point approvals before using the result operationally.
AEMO network connections