**4.1 Criteria for siting production facilities**

First and critical aspect in establishing successful algae cultivation facility is selection of suitable cultivation site. Site selection is quite a complex task and involves considerable attention on terrain, land costs, sunlight availability, seasonal temperatures, proximity to CO2 and water sources, well-connected transport system, power supply etc. Economical, non-arable flat land with constructible soil is needed for raceway pond installation. Availability of adequate acreage is also an important criterion, as algal cultivation facility should be of scale where production of algae meets economics [64]. Another very important aspect in algal cultivation is availability of enough sunlight. Therefore, it is important to select a geographic location, which is less prone to seasonal variations, receives less rainfall and is climatically suitable to the strain being cultivated. For example, low altitude regions having warm climate and average solar radiation availability for 250 h/ month are considered as good sites climatically [65]. CO2 is regarded as free of cost, but its transportation can add substantial cost to the algae production if the CO2 generation facility is far from the cultivation site [66]. Water availability is another important criterion. Proximity to sea in case of marine microalgae cultivation and assessment of water scarcity footprint in the region in case of fresh water algae cultivation is essential while selecting a site [67]. Various site selection models that consider parameters, such as soil properties, water availability, growth rate, infrastructure proximity etc. have been reported for identification of a suitable site for algae cultivation [68, 69]. These models can serve as useful tools for algae production site selection.
