In recent years, academics and industry have increased their efforts to find solutions to reduce greenhouse gas (GHG) due to its impact on climate change. Two approaches to reducing these emissions are decreasing energy consumption and/or increasing the use of clean energy. Data centers are one of the most expensive energy actors in Information and Communications Technology (ICT). One way to provide clean energy to Data Centers is by using power from renewable sources, such as solar and wind. However, renewable energy introduces several uncertainties due to its intermittence. Dealing with these uncertainties demands different approaches at different levels of management. This work is part of the Datazero2 Project which introduces a clean-by-design data center architecture using only renewable energy. Due to no connection to the grid, the data center manager must handle power envelope constraints. This article investigates some scheduling and power capping online heuristics in an attempt to identify the best algorithms to handle fluctuating power profiles without hindering job execution. Then, it details experiments comparing the results of the heuristics. The results show that our heuristic provides a well-balanced solution considering power and Quality of Service (QoS).