Providing real time power measurements and fault diagnostics of solar arrays over the internet. Driven by the trends towards Feed-in Tariff and performance-based incentives, the Power Purchase Agreement segment of photovoltaic(PV) industry has grown at a hectic pace. The result is a dire need for critical monitoring of solar power plants. Current market leaders are not able to fulfill the needs of PV owners, or operators for accurate assessment of system performance, such that there is unknown loss due to under-performance, until the end of billing period. Wattminder has been building an infrastructure to enable prompt detection of under-performance, as well as diagnosing for cause of under-performance, with real-time alerts, or advisories on on-going issues, and instructions to maintain solar power sites at their peak efficiency.