对藻类作为潜在的生物燃料原料的兴趣源于自然菌株中观察到的两个特征。首先，许多藻类在光合作用方面非常有效，将高达6％的入射太阳能转化为生物量。光合作用的理论极限约为事件阳光的11％[1]，而大多数农作物的成绩少于1％，甚至甘蔗仅达到2％左右。藻类的生产力是如此之高，以至于大多数情况下，挑战是阻止它们的生长 - 正如最近在中国奥林匹克划船湖以及世界各地露天游泳池中藻类生长的经验所证明的那样。

其次，对于少数这些藻类，这些捕获的能量中的大部分都以植物油的形式储存，可以将其提取并加工成生物柴油，就像今天的大豆或棕榈油一样。与大豆和棕榈不同，藻类不需要肥沃的农田生长，因此从相对较小的其他非生产力土地或水中提供大量生物燃料的可能性，以及许多公司PetrosunandBioFieldsare considering large scale algae farms in desert regions.

但是，这些优点目前被两个相关的缺点否定。

第一个是封闭式alg的资本成本很高ae production systems, or ‘bioreactors’. The highest rates of photosynthesis are only possible if other growth constraints are absent. This means that algae must be cultivated in a soup of nutrients (as might be provided by a sewage plant), and in the presence of elevated levels of carbon dioxide (as might be provided by a power station). Enclosing algae production in a bioreactor located close to a good source of both nutrients and CO2 is technically feasible and has been demonstrated in飞行员秤植物，但是生物反应器的管道，泵等的资本成本为这条路线的经济可行性带来了非常重要的障碍。此外，电站和污水处理工程之间只有太多土地，而且通常比农田贵。一些估计将这条路线的生物燃料生产成本定为每桶石油同等成本。

另一种方法是在类似稻田的开放池塘中广泛种植藻类。这种方法的支持者认为，产生足够的藻类以满足世界的大部分运输燃料需要农业解决方案，与甘蔗类似的规模类似在美国的巴西或玉米。这消除了二氧化碳浓度升高的藻类的可能性，但是尽管增长率较低，但与生物反应器相比，池塘的成本降低的可能性应弥补这一罚款。但是，第二个缺点在这里显而易见。天然发生的藻类很快就会到达开放的池塘，并开始争夺营养，阳光和空间。由于将生物燃料藻类用于创造油而不是原始繁殖能力的能力，因此他们很容易被超越材料，并且油产量急剧下降。

这两个问题有许多可能的解决方案。一种有趣的方法正在开发夏威夷的外壳is a hybrid route. Large quantities of biofuel algae are grown in closed systems, and then released into open seawater ponds to multiply up. The hope is that by introducing cultivated biofuel algae at a sufficiently high rate, naturally occurring invasive algae will not have time to overtake their less prolific relatives before the resulting biomass is harvested for oil.

The widespread adoption of algae as a biofuel feedstock will ultimately depend upon its economic performance compared to other low-carbon alternatives – for example, the continuing expansion of sugar and starch-based ethanol, thermochemical and other ‘second generation’ routes using abundant cellulosic feedstocks, and the increasing use of electrical power for transport.

Growing biofuel feedstock in the desert sounds like a perfect answer to the debate about food prices and agricultural land use, but electricity generated by concentrated solar power stations may ultimately prove a more economic ‘well to wheel’ use of desert areas in North America and North Africa purely on logistical grounds – power cables are considerably cheaper than pipelines, and mirrors don’t need constant feeding.