Low harvesting efficiency is another challenge for economoical biodiesel production. The existing harvesting techniques are expensive or they cause biomass contamination. In future, the concept of bio-flocculation can receive more attention. Exploration of efficient bio-flocculants can considerably lower the cost of harvesting process. The idea to integrate microalgae cultivation with harvesting by the aid of bacteria should be researched further. Low oil extraction efficiency also increases the cost of biodiesel. Extracting oil from wet microalgae biomass, called milking, can be an attracting choice; however, this idea is rarely studied. Keeping in view, the current developments and issues in microalgae technology; low-cost biodiesel production cannot be deemed, unless it is integrated with other technologies. The use of microalgae for bio-refinery, waste water treatment, animal feeding, and fertilizers should be promoted. Most recently, interest is growing to use microalgae for CO2 fixation and electricity generation in microbial fuel cells. In future, investment in microalgae technology, research and developments may propose new approaches to lower the cost of microalgae biodiesel.