Arpan Jain,1’3′[17] [18] Terry Walker, A* and Karl Kelly2

Introduction

In the 21st century, renewable sources of energy will be required to fulfill the rapidly growing energy requirements of both developing and developed (Organisation for Economic Co-operation and Development, OECD) nations worldwide. Fossil fuels must be phased out to avoid further increase in global greenhouse gas concentrations that severely threaten biodiversity and a sustainable economic future for the planet (Randers 2012). Biofuels, particularly ethanol and biodiesel for transportation, and biomass-based energy for power provide an attractive alternative to current fuels derived from non-renewable resources. Presently, most of the ethanol produced from biomass in the U. S. is derived from corn via the conversion of corn grain starch into glucose through enzymatic hydrolysis followed by fermentation to ethanol. Unfortunately, the increased demand for corn for use in biofuel production has led to higher prices for all products that utilize

corn, including foods that span from meat and dairy products to processed foods such as high fructose corn syrup (Hill 2009).

Biofuels have received more attention due to their renewable character and the inherent ability to reduce greenhouse gas emissions and geo­political concerns. Significant quantities of lignocellulosic biomass such as sweet sorghum bagasse, corn fiber, corn stover, wheat straw, rice straw, and soybean residues are routinely destroyed as waste primarily through burning, which not only wastes a potential source of biofuel feedstock, but also leads to environmental and health concerns (Claassen et al. 1999). In addition, biomass such as woody biomass can be sustainably produced in many regions of the world, including the United States. At present, lignocellulosic biomass has a worldwide annual production of 10 gigatons (Claassen et al. 1999; Harmsen et al. 2010). Earth’s terrestrial carbon potentially used in photosynthesis amounts to approximately 3,170 gigatons with 2,500 gigatons located in the soils, 560 gigatons in plant matter and 110 gigatons in microbial matter such as marine microalgae species (Jansson et al. 2010). According to Osburn (1993), if 6% of U. S. contiguous land is converted for the cultivation of lignocellulosic biomass and microalgae, all demands of gas and oil may be supplied with no net addition of carbon dioxide to the environment. Woody biomass presents several good possibilities for biofuel production due to its high proportion of convertible polysaccharides.

A gradual shift from biomass sources for biofuel production from crops that are used in food production such as corn requiring excessive inputs to lignocellulosic biomass is currently taking place. By utilizing current technologies, the production costs of ethanol from lignocellulosic biomass are still relatively high due primarily to the cost of cellulose separation, high use of chemicals and energy, hydrolysis and considerable waste production (Sun and Cheng 2002; Harmsen et al. 2010). However, the cost compared to a decade ago has dropped by more than 50% with promising technologies now in the mix.

The greatest challenge will be to better engineer the energy and food systems to reduce cost and to build a resilient society who relishes efficiency and lives within their means. This requires the support of corporate and government leaders, consumers and tax-payers with everyone willing to pay the cost for the switch to renewable energy within the next two decades before uncontrolled climate change effects begin to take hold. The cost for this change has been estimated to be about 5% of the world GDP, a small price to pay for a sustainable planet, but presently the world is unwilling to put even 1% of the GDP towards such an important cause. Once the renewable energy supply chains are in place, the operating cost and abundance of free solar-based (solar, wind, biomass) or geothermal energy without the need for mining of fossil sources clearly holds the long-term advantage for a sustained society. By 2050, conservative estimates show that the world energy supply will increase from about 10% to 40% renewables with about half of that in the form of stored solar or biomass where lignocellulosics play an important role. Renewables will make up a considerable proportion of the energy mix by mid-century, but unfortunately not enough to avoid a 3°C hotter world with up to 50% reduction in biodiversity and sea level rise of 1 to 3 meters by 2100 (Randers 2012). Ironically, the cost to counter the climate effects could easily be on the order of hundreds of trillions of US dollars or close to the world GDP by 2100 just to attempt the rendering of the associated problem that could have easily been avoided with prudent leadership by the current generation rather than placing this burden and cost on the generations to follow.