Backcast Service

Backcasts offer retailers a way to help manage volumetric risks. Utilities and ISO’s bill for actual usage and imbalance up to 70 days after actual usage occurs (which means, for example, that usage and imbalance for May 1st isn’t billed until the 10th business day in July). Unless the retailer is getting full requirements servicefrom the wholesaler, they have some cost exposure for imbalance charges. Without a backcast the retailer should carry sufficient cost on its books to cover potential imbalance from volumetric volatility for over two months.

REBO’s backcast service provides aggregate actual customer usage by interval within 35 days of that usage. This gives the retailer his actual imbalance costs, not including unforeseen energy, up to 35 days before his settlement bill. The result is a defined, and thus lower, imbalance cost on the retailer’s books.

REBO’s backcast provide:

• Screen-scraped settlement profiles by utility or ISO,
• Generated settlement profiles (using actual weather data) if settlement profiles are not provided,
• Generated aggregate backcast data consistent with settlement reporting (based on actual usage data).
• Report backcast versus forecast and schedule
• Report backcast versus settlement

Backcast reports are based on application of actual weather to utility or ISO settlement equations and scaled to actual or forecasted customer usage. Each day after the forecast, actual customer usage arrives for the forecast day. Applying that usage to the non-interval settlement equations, (or, for interval-metered customers, reported interval usage), gradually builds a backcast that by day 35 should match the settlement file received from the ISO (less unforeseen energy). In some cases unforeseen energy is also reported and can be included in the analysis.

Backcasts are used for two reporting functions. First, the daily backcast provides settlement usage prior to the utility or ISO settlement bill, allowing retailers to better anticipate and mange imbalances charges by comparing forecasted and scheduled usage to the backcast. Second, it is also used for comparison with the usage reported by the utility or ISO, and differences are reported.

Backcasts are calculated daily by distributing customer billing data over settlement profiles, adding losses, and summing by interval. The results can be reported in two components: actual usage profile for accounts with billing data, and backcast or settlement profiles with forecasted usage profile for accounts for which billing data has not yet been received, allowing retailers to keep a running assessment of their imbalance position.