The environmental pollution caused by the excess of human energy consumption and the foreseeable depletion of fossil fuels underline the need for new eco-friendly, sustainable and cost effective energy sources. Recent research works on microalgae have identified this new bio-material as a promising technology for bioenergy production, wastewater treatment, the development of high value added products and CO2 capture. Microalgae can be used to produce biodiesel, bioethanol, methane or hydrogen. However, one of the newest applications of this bio-material is its use in microbial fuel cells (MFCs). The resulting microalgae-MFC systems can produce electricity using the electrons released to the anode during microalgae degradation. Furthermore, microalgae can be grown in the cathode chamber, capturing the CO2 therein and using light as power source. This critical review presents an overview of new applications of microalgae for bioenergy production. It includes as a novelty the use of microalgae for electricity generation in microalgae-MFCs and capturing the CO2 emissions of these systems, their advantages, limitations and future prospects. (C) 2016 Elsevier B.V. All rights reserved.