Algae biofuels have a problem. This alternative fuel source, like many biofuels, helps reduce carbon emissions without taking land away from food production. But it has been abandoned by big companies like Shell and ExxonMobil, which are backing away from investments in this environmentally friendly fuel. Why hasn't such a promising technology come to fruition, and what else can we do to save it?

Algae are photosynthetic organisms that grow in water and produce energy from carbon dioxide and sunlight. Single-celled microalgae are rich in fat and can be converted into biodiesel, a common biofuel. Biofuels are made from a variety of raw materials, including corn and cooked oil. But algae are special because they are produced quickly and are able to produce large amounts of fuel (high productivity).

Over the past decade, the energy industry has invested heavily in the development of algal biofuel production. This makes sense because, a decade ago, there was a need to find alternatives to fossil fuels due to high oil prices and growing awareness of climate change caused by carbon emissions. Algal biofuels were touted as the answer to these problems, leading to a massive investment to follow up.

Unfortunately, we don't have a complete plan for the whole thing. Companies producing algal biofuels struggle to maintain their high productivity on a larger scale, and they find that predators often pollute their farms. They also found that this method of production was not economical. Building ponds to grow algae and provide them with enough sunlight and nutrients to grow is expensive, and to make matters worse, oil prices have plummeted.

It's not just biofuels

Algae can do more than just produce biofuels. In effect, algae is similar to a miniature factory that can produce a variety of useful compounds that can be used to make a range of different kinds of products.

For example, algae can produce large amounts of omega-3 fatty acids, which are an important dietary supplement. This means it could be a sustainable plant-based source of omega-3 fatty acids that we would otherwise only get by eating fish or unappetitive cod liver oil. More generally, algae is a good source of vitamins, minerals, and protein, and people often take things like chlorella, spirulina, etc., because of their health benefits.

Another use is that algae can be made into bioplastics. Ordinary plastic is a product made from fossil fuels and is difficult to degrade and not environmentally friendly. Algae can produce bioplastics with lower carbon emissions and, to some extent, can absorb carbon emissions. The use of algae helps prevent the accumulation of plastics in the environment.

The diversity of products may be the key to later development of algal biofuels. Many of these products are high-value chemicals that sell for much more than biofuels. So by combining algae with biodiesel production, we can subsidize fuel prices and offset the high cost of algae farming.

The concept, dubbed "biorefinery," is a new wave of algae research that hopes to solve problems that have existed over the past decade. We know that refineries produce plastics, fibers and lubricants, as well as fuels. Now we hope to develop algal biorefinery in the same way.

Algae biorefining

To make this approach more cost-effective and sustainable, we need to use waste heat, carbon dioxide and nutrients for algae to grow. These substances are readily available from power plants, factories and water treatment plants, which can reduce some of the costs of algae growth. When algae fuel is produced, it leaves behind a large amount of protein, carbohydrates and other molecules. All of these substances can be converted into the various products mentioned above, or can be used to produce biogas (another fuel source). The biogas can be sold or used to produce the heat needed by the algae in a biorefinery, a closed loop that makes the entire production process much more efficient.

It's easy to see how this process suggests a sustainable and profitable way to produce biofuels from algae. In fact, there are already companies applying this concept to their work. In 2014, Sapphire Energy, one of the world's largest algal biotechnology companies, announced that they were expanding their business to include nutritional supplements as well as biofuels. The shift to biorefinery is becoming more common for many companies looking to diversify their product lines.

Obviously, algal biorefinery cannot solve all the problems that algae commercialization faces today. The industry also faces a number of key issues, such as the loss of efficiency in the large-scale production of algae, as well as pollution during the cultivation of algae. These problems can only be solved through sustained research efforts. Biorefinery may well be the next step in humanity's future away from fossil fuels.