Portfolio loss waterfall
came in against its budget at actual weather . Losses took of expected energy, is unexplained, and sits with no contractual owner.
The largest shortfall against budget is at , against its allowance.Every category is at or better than its budget allowance.
Net budget (P50)
Metered against it
Budget at actual weather
Weather
Metered export
against budget at actual weather
Total losses
Expected energy less metered
Unexplained
Not accounted for by any loss
Data completeness
Weighted by expected energy
From budget to metered exportFrom expected energy to metered export
Each loss bar shows the result against the allowance in the budget. Up is better than budget, down is worse. Click a bar to see what is inside it.Every lost MWh between expected energy and the meter. Click a loss bar to see what is inside it and who owns it.
- Totals
- Weather and design, not controllable
- Better than budget
- Worse than budgetLoss
- Unexplained
- Largest shortfall
Low dataData completeness is here, below . Bars that look better than budget may simply be under-recorded, with the missing losses sitting in unexplained, so read them with care.
The value axis starts above zero so the loss bars stay readable; total bars carry a break mark where they are cut. Source: fictional sample portfolio, January to October 2026.
Inside
Allowed ·Actual ·Against allowance
Items and owners
Unexplained has no items, and the budget allows nothing for it. It is what is left once every counted loss and the metered export are taken away from expected energy, so it grows when meters, inverters or weather stations stop reporting. Compare it with data completeness in the site table.
By site
Bars show the actual loss and ticks show what the budget allowed. Click a site to drill into it. In % view each site is measured against its own expected energy.
Source: fictional sample portfolio, January to October 2026.
Who owns the loss
Each loss item mapped to the party or contract that carries it. Paid curtailment is energy the site was compensated for.
- Owned by a party or contract
- No contractual owner
- Unknown (unexplained)
Source: fictional sample portfolio, January to October 2026.
Losses by month
Every loss category, month by month, with the total the budget allowed marked on each bar. Click a month to set the period, and click it again to go back to the year to date. Click a category in the key to open it.
Source: fictional sample portfolio, January to October 2026.
Sites
Sorted by result against budget at actual weather, worst first. Click a row to drill into the site. A large unexplained share usually travels with poor data completeness.
| Site | Technology | Capacity (MW) | Budget at actual weather (MWh) | Metered (MWh) | Against budget | Losses | Unexplained | Data completeness | Yield (kWh/kW) |
|---|
Source: fictional sample portfolio, January to October 2026.
Method, definitions and sample data
- Net budget (P50)
- The P50 energy budget after the losses it allows for in each category. In this sample it is the gross P50 yield less each category's allowance.
- Weather
- The change in budget caused by the weather actually measured on site. It is not an operational loss, so it is shown in grey.
- Budget at actual weather
- The net budget re-run at measured conditions. This is the fair target for the period, and the starting point for judging operations.
- Allowance and result
- Each category's allowance is the share of expected energy the budget assumed it would lose. The bar is allowance less actual loss, so up means better than budget.
- Expected energy
- The yield model at measured conditions before any losses, used in the absolute losses view. Solar uses plane of array irradiance and module temperature, before the inverter AC limit, in line with IEC 61724-1. Wind uses measured free-stream wind speed through the warranted power curve, corrected for air density.
- Design and weather
- Wake, clipping, inverter thermal derating, row shading, snow, icing and high wind hysteresis. Set by layout, equipment choice and climate rather than by operations, so shown in grey.
- Grid and curtailment
- Network outages and operator instructions, split into paid and unpaid.
- Set point and export limit
- Energy held back by the power plant controller beyond what the grid actually asked for. These losses usually sit with nobody, which is why they persist.
- Balance of plant
- ACB trips, protection relay trips (G99 in the UK), transformer derating and HV faults.
- Equipment availability
- Inverters, trackers, strings and turbines offline.
- Performance
- Losses operations can act on. For solar: soiling, degradation above the warranted rate and module underperformance. For wind: power curve underperformance and yaw misalignment.
- Unexplained
- Expected energy, less every counted loss, less metered export. The budget allows nothing for it. Keeping it small and honest is the real test of the data.
- Counting each MWh once
- Where causes overlap, the lost MWh goes to the first bar that applies, working left to right. The sample data does not model overlaps. A real build has to, using the same exclusion rules as the O&M contract.
- Percentages
- Every percentage is a share of expected energy before losses, so the bars add up.
- Value view
- Each MWh valued at the site's tariff. This is the value of the energy, not lost revenue: paid curtailment was compensated, so it cost the site nothing, and merchant sites earn the price at the time rather than a flat tariff. Paid curtailment stays in so the bridge closes, and the owner chart marks it as paid.
- Largest shortfall
- The single site and category furthest below its budget allowance for the selected view and period, ranked on energy. It carries the spark in the waterfall.
- Data completeness
- The share of intervals with a valid reading from the revenue meter, inverters and weather station, weighted by expected energy.
Sample data. The five sites, their names, tariffs, allowances and every number on this page are fictional, generated to show how the waterfall behaves.