For starters, what are biofuels? Biofuels are known as any fuel made from organic matter, with the most well known fuels coming from corn, soybeans, palm, algae and many other plants. So now what are algae? This is a trickier question than you think, but most of us know algae as the green colored “scum” found on ponds and unfortunately sometimes on pools. Scientifically speaking, algae are photosynthetic organisms of the kingdom Protista, and they range in size from being microscopic to being hundreds of feet long in the form of huge kelp or seaweed.1 Most importantly, algae are abundant on Earth. Thus, while you may have heard of corn based ethanol starting in the early 2000s, and more recently alternative fuels .
While only a small percentage of the total algal species have been cultivated and tested, algae has already shown the capability to produce 60% dry weight mass in oil content.2 To shed some light on that number, algae are projected to have 60 times higher oil yield than soybeans and 5 times greater yield than palm oil per acre of land on an annual basis.3 Moreover, did you know that algae have produced food, feed stock, and pharmaceutical products for over 20 years?! So why not use it now to make fuel?
How Do You Make Algal Biofuel?
There are three major steps to making algae into biodiesel fuel:
- Growing or cultivating the algae
- Harvesting and extracting the oil
- Transesterification (turning oil into diesel)
1. The two most popular of growth or cultivation methods are in outdoor ponds or photobioreactors, respectively. In the pond scenario, algae are grown in large swimming pool-like ponds using just sunlight and carbon dioxide from the atmosphere. While ponds generally have lower operation costs, they suffer from problems of water quality, light uniformity, gas mixing, and space issues. Photobioreactors solve these pond problems and additionally optimize the algae’s growth temperature and pH levels.4 Furthermore, using photobioreactors allows the algae to be cultivated into fuel vertically, as high as they can be built, which is great for land use optimization, and could be the solution to the global food vs. fuel debate.
Large “swimming pools” such as these are an example of outdoor ponds that use light, water, and CO2 from the atmosphere to grow.5
This algal piping is actually a photobioreactor that moved the algae through the tube to ensure that optimum light and water quality are both available.6
2. Harvesting and then extracting oil from algae is the hardest part of the process. Harvesting algae requires separation and isolation of the algae from everything else. Once the algae have been harvested the oil can be extracted. This is done essentially by popping open the algae to release the oils so they can be separated from the algae cell walls and plant matter.
3. Transesterification, or turning oils into diesel, has been put into practice since the 1860s when the diesel engine first came into existence. Over the past century, car owners, and more recently grease recycling companies have turned vegetable oil into diesel for the car. While many different recipes are used to make diesel, they all have the same starting and ending products: triacylglyerols (TAG) and alcohol, which is usually in the form of ethanol, to produce fatty acid methyl esters—better known as diesel—and glycerol,7 as pictured below:
A catalyst is normally used in conjunction with heat to start the reaction. Once made, the mixture is filtered to separate the products and obtain the diesel.
Algae’s Future in Energy
The U.S. government has already invested heavily in biofuels. Legislative pieces such as the Energy Independence and Security Act of 2007, Renewable Fuel Standard, and numerous other bills have provided funding and support for biofuels over the past decade.9;10 Last year the Department of Energy (DOE) released a National Algal Biofuel Technology Roadmap outlining what needs to be done for the success of the algal biofuel industry. In addition, the DOE provided $24 million in grants to three companies to begin more extensive algal biofuel research and development efforts.11
Moreover, big oil companies such as Exxon, BP, Valero, and Chevron have staked their claim in the algae-based energy industry, partnering with promising start ups such as Solazyme and Martek. Similar to this, many biotech companies such as LS9 and Amyris have entered the market with their own unique production methods. Additionally, many companies have found enough VC funding to start from the ground up and begin scaling their product.12
Historically, energy producers and energy companies have focused on isolating the energy source and maximizing output. However, with the renewable energy movement and more broadly the growth of green, companies are renovating the way they produce energy. Solazyme for example is one start up that is taking this idea of material utilization to the extreme. Using the byproducts of algal biodiesel production, they are creating nutritional, chemical, and health related product lines.13 While this is an economically obvious choice, it represents more importantly a step in an uncharted territory, environmentally conscious energy production. Solazyme and many other algal biofuel companies have recognized that while scalability is an end game of any renewable technology, energy efficiency and cost competitiveness are also integral to the success of the technology. These companies are establishing a stronghold in the biofuel space and represent some of the few companies that are beginning to stand strong without dependence on government subsidies to be profitable.
New to the scene 10 years ago, algae have been a hot topic of discussion in the renewable industry over the past decade. With promising numbers and endless potential, many people believed algae would be primary energy source in the near future. However, the last few years have seen a rapid cooling of enthusiasm for algal biofuel. Many skeptics are calling algae a laboratory feedstock after its failure to produce on the large scale as of yet. As recently as January of this year, Shell oil and many other companies have cut funding and reallocated resources into other projects as a reflection of their diminishing excitement for algal biofuels. Nonetheless, cleantech market intelligence firms have projected that the algal biofuel market will reach $1.3 billion by 2020.14
While it remains unclear as to what the future holds for algal biofuels, it appears that there is strong support and investment in a future from both the private and public sector. Let’s keep the hope alive for algae!
