A forecast-versus-actual file becomes a balancing-cost report in one pass

Latvia settles renewable output against a forecast at 15-minute resolution: any shortfall or surplus is bought or sold back at the market's imbalance price. A producer usually has that price in one place and its own forecast-versus-actual numbers in another, with no easy way to see what a bad forecasting day actually cost.

Drop in an Excel or CSV export with a timestamp, forecast and fact column; the app finds the right columns by header name, or by a fixed layout when headers are missing, and detects the covered period automatically. A file up to 50 MB parses entirely in the browser, nothing is uploaded anywhere. The period auto-fills from the file, capped at six months, and the app fetches Latvia's Final imbalance price for that window from the Baltic Transparency Dashboard.

React, TypeScript and Vite on the front end, Recharts for the chart, the xlsx library for parsing. Imbalance volume is forecast minus fact; balancing cost is imbalance volume times the imbalance price; cost per MWh is total cost divided by total produced volume. An interval with no matching price is excluded from the totals rather than interpolated. The Baltic Transparency Dashboard blocks direct browser requests, so a Vercel Edge Function proxies the price call in production.