Biodiesel: Waste Oil and Microalgae as Alternatives for Ecological Security

1. Introduction

It appears after considering a variety of options that waste oil (yellow grease) and/or microalgae, as opposed to the myriad other plant oils currently used or contemplated, there may be two productive and more ecology-friendly methods of creating enough biodiesel fuel to make a contribution to reducing the world’s reliance on fossil fuels. While biodiesel has been around for almost one hundred years, until the past two decades, biodiesel has not demanded the attention it does now as a viable major alternative, both as a money-making opportunity and as an environmental silver bullet. The trouble is that as in most environmental questions, there are two (or more) sides, and they are a little like nitro and glycerin.  Where they coincide, they explode. Thus, while some crops are capable of producing tomorrow’s industrial fuels, there is the potential cost, in starvation and the planet’s survival. While some developing countries with vast geography may see biodiesel as a future export industry and domestic solution to oil dependence, it often comes at the expense of using those same fields or food forests to grow food, or at the cost of clear-cutting trees which are essential to the earth’s supply of oxygen. Sorting out the multitude of competing claims is never easy. Microalgae do not require setting aside fields used to grow food crops to produce fuel and yellow grease involves recycling already used cooking oil available in sufficient quantities around the world to at least make a difference.

2. Brief Historical Development of Biodiesel

The diesel engine was developed by Rudolph Diesel over 125 years ago as an alternative to the bulky steam engines of the day and as a means of bringing the smaller more efficient engine to smaller companies. (Radich 1)  Diesel’s engine differed from the engine created by Nicklaus Otto in that Diesel’s system did not require a spark. Ignition was based on compression of the fuel until it ignited.  Higher compression resulted in higher power. Diesel foresaw being able to use vegetable oil to run his engines, making it easier to produce fuel wherever his engines were available. Rudolph Diesel used peanut oil to run his prototype engine at the outset and later experiments improved the performance of these oils by transesterifying them with alcohols to produce what we call “biodiesel”. However, because distillate from petroleum was cheaper to use and plentiful, it was not until the 1970s when oil supply problems arose that the idea of using biodiesel arose again. But it was another 25 years before marketable production was undertaken, though at levels far below what would be considered significant. (Radich 2) 

Now, a complex set of competing interests have arisen to create the demand for alternative and eco-friendly fuels, and biodiesel has been one of the important considerations in the mix of solutions. But it seems that no matter in which direction a step is taken, there is peril and some objections from some interested group. Since biodiesel can be made from, among other things, food crops, there are those who believe producing them does not meet ecological, environmental and human needs. In the following sections, some of these complex competing interests are discussed.

3. Basic Advantages and Disadvantages of Biodiesel Fuel

Although particular biodiesel produced from a variety of sources may have different properties and pros and cons, the following are some of the general advantages and disadvantages of biodiesel fuels. 

Since biodiesel fuel autoignites, the speed with which it ignites is measured by the fuel’s cetane number. Diesel fuel made with petroleum distillate has cetane ranges from 40 to 52, while soybean biodiesel could range from 45.8 to 56.9. Higher cetane ratings mean faster ignition. (Radich 2). According to the U.S. Energy Information Administration, the lubricating properties of biodiesel (lubricity) are more reliable than petroleum based diesel. (Radich 2; Alternative Fuels Data Center). Biodiesel is also a cleaner burning fuel than petroleum based diesel, reducing tailpipe emissions. (Alternative Fuels Data Center; U.S. Energy Information Administration). When blended with petroleum, up to a 20% blend (B20), biodiesel is energy balanced, having approximately 3.2 times the energy expended to produce it. (Alternative Fuels Data Center). Biodiesel may also be carbon neutral as some sources such as soybeans or palm oil absorb CO2 while growing, although, as discussed in more detail below, this issue is complicated by the competing negative effects of clear-cutting swaths of land to make room for these crops.  Biodiesel is also safer to handle, given its somewhat higher flashpoint (150°C compared to 52°C for petroleum diesel).

On the other hand, biodiesel does have some low temperature performance issues, having to do with the formation of wax crystals, resulting in clogging, and this is generally worse for yellow grease biodiesel than soybean biodiesel. (Radich 3). Traditionally, in colder climates, this could pose performance challenges. However, there are additives and strategies (such as heaters, parking vehicles inside in Winter, using engine block or fuel filter heaters) that can be utilized to reduce the effects of cold weather. (Natural Resources Canada). There are also limitations on some of the sources of biodiesel feedstocks, as for instance with yellow grease, which in the United States is insufficient to meet transport fuel requirements. (Radich 7). On the other hand, China produces enough yellow grease annually (44 billion gallons, over twenty times as much as the United States) to satisfy a larger portion of its lower biodiesel requirements. (“Chinese Consume”). Another downside, as described in Liu, et al, and Table 3 therein, is that for plant oils, enormous tracts are land would be needed, monopolizing too much of a country’s arable land for non-food production, and resulting in cutting down far too many trees. (Liu et al, 142-143; Doornosch, and Steenblik, 3-4 ).

4. Competing Interests in Biodiesel Production and Use

4.1. Introduction

An ear of corn can go to the market to feed people or can be used to feed starving people, or it can be used to produce fuel. On a field that is already part of a farm used to grow food, using it to produce corn is probably acceptable to most interests. However, using the field to produce corn to turn a higher profit by selling the corn to make biofuels could leave more people starving. The slogan “Fill ‘er up, starve a child” would not be acceptable to almost anyone. Of course, businesses do not always behave like good citizens, and therefore using that field to make more money may be logical, from a corporate profits standpoint. 

Also, if an undeveloped or developing country is trying to establish exports, or import less fuel, it might decide that it is also preferable to use that field to grow corn to make biofuels. These are just a few of the complications regarding an already existing field on an already existing farm. What if the field were instead a stand of trees, and they were cut down to make room for soybean farms or palm plants to produce biodiesel? What if they were instead millions of stands of trees?  What if the stands of trees were in the Amazon Rain Forest? What if instead of clearing land to grow food so that starving people can be fed, land is cleared to grow feedstocks to make biofuels? What if no remaining lands are cleared to grow food because the real money is in selling crops to make fuel? What if the farms are not owned by Farmer Jones, but rather some enormous agribusinesses with stockholders and profits to make, and every single tree for as far as the eye can see is cut and the land burned to make way for palms or soybeans? Maybe it sounds a little like Avatar on Earth. As Doornosch and Steenblik point out:

...expansion...could not be achieved...without significant impacts on the wider global economy...It is more likely that land-use constraints will limit the amount of new land that can be brought into production leading to a “food-versus-fuel” debate. Moreover, land use will be driven by the net private benefit owners can derive from their land. Any diversion of land from food or feed production to production of energy biomass will influence food prices... The effects on farm commodity prices can already be seen... The growth of the biofuels industry is also likely to place pressure on the environment and biodiversity... [I]n tropical regions, where suitable and available land is mostly concentrated ... as long as environmental values are not adequately priced ... there will be powerful incentives to replace natural ecosystems such as forests, wetlands and pasture land with dedicated bio-energy crops.... (4)

The foregoing hypotheticals are, in some cases, not hypothetical, as in the case of Malaysia and Indonesia, where millions of trees have been cleared to plant palm plants for biodiesel, or in the case of Brazil and the Amazon, where trees have been cleared to make room for crops such as soybeans to make biofuels or sugars to make ethanol.  In each of these countries, there are many, many tens of millions of hungry mouths to feed, and there are people on many sides arguing over these complexities. (Doornosch and Steenblik 3-4). Which interest is best served? To produce cleaner fuel to save the planet? To grow food for the starving? To grow the economy of a developing country by exporting billions of barrels of biodiesel? There are no easy answers, but part of the solution may lie in using waste oil and microalgae, two more sustainable methods that do not involve some of these choices.

4.2 Yellow Grease (Waste Oil)

Doornosch and Patil et al. identified waste oil as one of two sustainable methods for producing biodiesel. Because it involves essentially recycling cooking oil which has already been used, it does not involve any charge on the environment as with plant oils (Doornosch and Steenblik 4-5; Patil et al. 107). As Patil et al. point out, in fact using waste oil to produce biodiesel would serve the interests of removing the waste oil from the environment, something that is often mandated by law because when discarded in sewer systems, waste oil can create environmental problems. (Patil et al. 107). Moreover, using waste oil also reduces the cost of the biodiesel as waste oil is generally cheaper than edible oils, and after transesterification, yellow grease actually had a higher cetane rating than diesel, indicating more efficient ignition. (Patil et al. 107)    Patil et al. also reported that viscosity of the waste oil biodiesel was similar to regular diesel, which means no modifications of equipment are necessary. (111)

As for issues regarding diminished performance under cold conditions, Patil et al. noted that many advancements had been made in developing mixtures and additives to combat this problem, in particular where biodiesel is mixed with regular diesel (“This problem could be overcome by the addition of suitable pour point depressants or by blending with diesel oil.”) (Patil et al. 111). Finally, the extent of production could limit the effectiveness of yellow grease as an alternative to fossil fuels, unless yellow grease is viewed as an additive with Diesel (e.g. B20, which means 20% biodiesel, 80% diesel). Patil et al, notes that 100 million gallons of waste oil are generated each day in the United States, while around 800 million gallons of oil are consumed. It would appear then that waste oil is not a total solution by itself but indeed can account for a significant percentage of the solution. (Patil et al. 107).

4.3 Algae as Feedstock for Biodiesel

Another option that may be added to the basket of biodiesel feedstocks is microalgae, the production of which, like waste oil, does not involve the same environmental concerns in the supply chain as plant oils, such as soybeans and palm oil. In addition to the tens of thousands of potential strains of microalgae available to choose from, there are other advantages to using algae as feedstocks for biodiesel. First, microalgae reproduce using CO2 and photosynthesis, finishing an entire growth cycle within, in some cases, as little as 8 hours, but typically doubling in size in 26 hours. (Liu et al. 136). They are also capable of adapting to a wide range of conditions (Liu et al. 136), which means they could be used to grow in places where nothing else grows, making use of lands not in competition with growing food, one of the major issues in the production of biodiesel debate currently. In Liu, et al., Table 3 appears to show that while there is not enough arable land in the United States to produce sufficient biodiesel feedstocks from any other material. (Liu et al. 142). With microalgae’s higher yield (compared to soybeans, microalgae yields are 100 times higher per hectare of land, and 10 times that of palm oil, jumping to 300 and 30 times, respectively for high yield microalgae (Liu et al. 143), less land area is needed to meet “all transport fuel needs of the United States” (Liu et al. 143). According to Liu, et al., microalgae is the only biodiesel feedstock that could meet these needs (at only 2.4% of existing cropping area) without exceeding the entire existing cropping area of the United States. By way of example, Liu, et al., suggests that Soybeans would require five times the entire existing cropping area of the United States. (143).

The current major disadvantage in producing microalgae biodiesel feedstocks is that the development of this technology is in its infancy (Liu et al. 133-135) and current production costs remain high. Research remains to be done to find higher-yielding strains, and develop techniques for extracting the oil. (Liu et al. 152).

5. Conclusion

The debate of feed vs. fuel will continue so long as biodiesel feedstocks rely on land and crops with dual uses, such as palm oil and soybeans. Some of the commentators have observed that commercial interests are focused on profits, and where decisions regarding land use are concerned, owners generally choose whichever produces more profit. Hunger in the world, in particular in developing countries, is not abating, and with the continued expansion of the economies in developing countries, such as China and Brazil, transportation needs are expanding geometrically. There are more people to feed, and more transport vehicles to fuel. Finding balance is one of the most challenging issues today. Recycled waste oil (yellow grease) could be one part of the solution, and developing microalgae biodiesel feedstocks and production technology could be another. These provide promise, whereas some other methodologies provide dilemmas.

Works Cited

Alternative Fuels Data Center: Biodiesel Benefits & Considerations. U.S. Department of Energy 2012, http://www.afdc.energy.gov/ fuels/biodiesel.html.  Accessed July 30, 2012.

“Chinese Consume 3 Million Tons of Toxic Recycled Waste Oil Each Year”. The Epoch Times, 2010, http://www.theepochtimes.com/n2/china-news/waste-oil-recycled-oil-regenerated-oil-carcinogen-china-food-poisoning-31712.html. Accessed July 30, 2012.

Doornosch, Richard and Steenblik, Ronald. “Biofuels: Is the Cure Worse Than the Disease?”. Organization for Economic Co-operation and Development: Roundtable on Sustainable Development, 2007, http://www.ft.com/intl/cms/fb8b5078-5fdb-11dc-b0fe-0000779fd2ac.pdf. Accessed July 30, 2012.

Liu, Jin, Junchao Huang, and Feng Chen. “Microalgae as Feedstocks for Biodiesel Production, Biodiesel” 133-160 in Feedstocks and Processing Technologies, Dr. Margarita Stoytcheva (Ed.), Shanghai: InTech, 2011, http://www.intechopen.com/books/ biodiesel-feedstocks-and-processing technologies/microalgae-as-feedstocks-for-biodiesel-production. Accessed July 30, 2012.

Natural Resources Canada, Office of Energy Efficiency (OEE):  Biodiesel Safety and Performance 2010, http://oee.nrcan.gc.ca/transportation/alternative-fuels/fuel-facts/biodiesel/7031. Accessed July 30, 2012.

Patil, P.,  V. Gude,  H. Reddy, T. Muppaneni and S. Deng, "Biodiesel Production from Waste Cooking Oil Using Sulfuric Acid and Microwave Irradiation Processes," Journal of Environmental Protection, Vol. 3 No. 1, 2012, pp. 107-113, http://www.scirp.org/ journal/PaperInformation.aspx?paperID=16861. Accessed July 30, 2012.

Radich, Anthony. “Biodiesel Performance, Costs, and Use”, 2004, http://www.eia.gov/oiaf/ analysispaper/biodiesel/. Accessed July 30, 2012.

U.S. Energy Information Administration, “Biodiesel and the Environment”, 2012,  http://www.eia.gov/energyexplained/index.cfm?page=biofuel_biodiesel_environment. Accessed July 30, 2012.