The core of the load processing is called the “Load Aggregator.” The load aggregator is a Fortran program that runs on the web application server. Input data for the load aggregator are stored in a run-specific temporary directory on the web application server. The aggregator processing steps are shown in Figure 13. Two versions of the load aggregator are used – one for TOU tariffs and another for standard (one-period) block-rate tariffs. An auxiliary program provides the ability to dynamically generate TOU mask files, if a cached version does not exist on the web application server. These mask files are generated from a summary description of the tariff TOU periods, retrieved in real-time from the TAP server using the SOAP protocol. SOAP (Simple Objects Access Protocol) is a process that provides a way for applications running on different operating systems, with different technologies and programming languages to communicate over the internet.