I have done a lot of thinking about this ever since I began my own alternative energy work on ethanol. People have always asked what the next form of energy will be in the United States and the world at large. Typically, in order to answer that, we have examined the various advantages of wind, solar, ethanol, etc. But I have always asked a different question: what made gasoline so great in the first place?
1) A global network of underground pipelines for distribution
2) A worldwide effort for production, which led to regional specialization in different parts of the production and the refining process
3) A relative lack of concern over global warming 20 years ago
4) A high energy content (32 Megajoule/liter for 82 octane)
5) Natural production of the distillation of petroleum (which was in high supply years ago)
6) Liquid form of energy
7) No expensive raw material
8) Common infrastructure -- cars on the market today all run on gasoline today; few run on other forms of energy
Of course there are many more reasons, but those are the few that I could come up with just now.
So now let's examine current alternative energy possibilities like ethanol (yay!). Well, first of all, bullet point number one could not work. These underground pipelines are mixed with high quantities of water, and gasoline's volatility is such that it does not mix with the water (think of oil and water). However, ethanol (alcohol) will mix with the water, and the output will be a very low alcohol percentage solution. Thus, current transport options for ethanol are building a new network of pipelines water-free, creating plants every 20 miles so the energy can be transported via truck, or a quick conversion of ethanol to butanol (not water soluble).
In terms of bullet point two, ethanol is already being produced in Brazil from sugarcane, and accounts for over 80 percent of the country's energy consumption. Some countries, mainly third-world, need all their cellulosic raw materials for food storage. Also, who would fund distribution mechanisms in countries without adequate resources?
Global warming is quite possibly the largest current environmental concern (bullet three). Ethanol is considered a renewable fuel because of its cellulosic raw material, and how corn and other sources absorb oxygen while in the field. Ethanol has been shown to reduce nitrogen emissions, carbon emissions and organic compound byproducts. It is a little better for the atmosphere compared to gasoline, and could help with the global warming problem -- but it is going to depend on the raw material used if production becomes commercialized on the national scale.
The energy content (bullet four) of ethanol highly depends on the raw material used in production. The base level has been estimated by the DOE to be in the low 20s MJ/liter, but corn is said to increase that content by 20 or 30 percent. It is a little lower than that of gasoline, but will the environmental and (hopefully) economical advantages outweigh it?
On to bullet five, the production of ethanol. Oh boy. Ethanol, if there is any chance for it in the future, needs to be produced with a cellulosic base with microorganisms. 5-carbon and 6-carbon sugars (not even to mention 4 carbon, etc…) have about 20 metabolic steps to reach ethanol, requiring different enzyme cocktails. Some microorganisms possess most, if not all, of these metabolic pathways and thus, if used correctly, can take the place of the expensive enzymes. In terms of the form of cellulose, the process should be very similar alternating between forms of cellulose because the basic organic structure differs only slightly between forms of cellulose. However, we need to get away from corn, sugar-cane and wheat within the United States. Over 15 percent of our corn supply is already depleted ever since corn-based ethanol production began. We will never be able to rely on it for the national scale. The U.S. disposes of two billion tons of cellulose waste per year – this needs to be more efficiently utilized.
I cannot argue with number six!
Number seven is sort of highlighted in number five, but to continue: some microorganisms target only certain cellulosic sources with 5 or 6 carbon sugars. These leads to the waste of other cellulosic bases with different numbers of sugars. A microorganism needs to be modified to utilize the whole conglomerate of cellulose.
I think number eight will be the biggest hurdle for all forms of alternative energy. Currently, there are over 145 million cars on the road today (U.S. Department of Transportation) that run on gasoline. In order for a form of energy to be viable, a high majority of infrastructure produced and sold in the United States needs to be compatible with that form of energy. To make a current gasoline vehicle run on ethanol does not require a plethora of work, but to cope with solar power, wind power, hydrogen power, would be require a lot.
I truly believe in leading a nationwide, unified effort for alternative energy, but that is going to require quickly finding what main sources of alternative energy we need to focus on. It is impractical to focus solely on solar energy because we need to consider the parts of the northeastern U.S. that receive at least three months of very little sun in the winter months. At the same time, will hydrogen energy require too much change to infrastructure? Ethanol clearly has its flaws, but so do all forms of alternative energy. What is the tradeoff we are willing to take between environmental friendliness, economic efficiency and the time from research to commercialization?
I have spent a lot of time talking to biotechnology companies over the past few years, and will continue to -- and I have seen the enormous progress that we have made. All we need now is to have a unified effort and to move past the fear of change.