Renewable Resource: Biomass and Biofuels

What is biomass? Any organic matter that can be used for fuel. – Wood = #1 biomass fuel used globally. – Crops, seaweed, compost, animal waste Biomass get energy from sun through the process of photosynthesis.

US biomass

Biofuels: Biomass that is altered into the form of combustible liquids (ethanol or biodiesel) Reasons behind push for biofuels: – Abundance of biomass These plants can be grown throughout the world. Would help us get away from foreign oil imports – Reduce overall impact on climate change. Since plants are part of the fast carbon cycle they would have no net increase in CO 2 in atmosphere – Little impact on current infrastructure

But biofuels aren’t all they are cracked up to be… If biofuel production is done on a large scale then a decrease in biodiversity may occur. – Clearing of natural land to create biofuel crops – Soil erosion through large scale clearing – Increase in food prices – Nutrient leaching of soils. Increased water use in arid regions Alternate forms besides corn can be expensive

THE FOLLOWING SLIDES ARE THE PROS AND CONS OF VARIOUS BIOFUELS

Biodiesel PROS Decreased the waste stream from various restaurants because used the waste oil from cooking. Easy to convert gas cars to biodiesel cars, and diesel cars would need no alteration. Cons Requires government subsidies to be done on a large scale If plants are grown solely for this purpose than large land areas are needed for crops Increase fertilizer and pesticide runoff Energy needed in the conversion to usable energy Produced from vegetable oil from soybeans, rapeseeds, sunflowers, oil palms, jatropha shrubs.

Corn ethanol PROS Currently being produced on commercial scale in the US. – E10 = 90% gasoline and 10% ethanol – E15 = 85% gasoline and 15% ethanol CONS Large government subsidies to make commercial scale ethanol competitive ENERGY INTENSE process to distill ethanol Costly If all corn were used to create ethanol we would still only create about 18% of required energy. Conversion of plant starches into simple sugars that can be made into ethanol.

Cellulose PROS Uses the “waste” of the plants and not edible parts Could utilize 80% of the waste Create 30% US transportation fuel CONS Cellulose is a complex sugar that is extremely tough to break down. Only one commercial enzyme available to break down and it is expensive. Environmental impact removes nutrients from soil since they aren’t left to decompose. Uses the waste material of plants (husk, stems, non edible parts)

Algae PROS More efficient at photosynthesis than plants. Can be grown in almost any area Can utilize waste water CONS If grown in open surface water may impact other organisms. Require a great deal of nitrogen and phosphorus, which can pollute other water supplies. Very energy intense to break the cell walls

SYNTHETIC ORGANISMS PROS DNA technology has come a long way and we can alter genes to work in our favor CONS Costly We don’t know the long term impact and if other genes can react.

Overall Biofuels are not an ideal solution to supplying our transportation energy needs. – Costly and would not be able to compete without great government subsidies – Energy intense process so become a negative energy gain. – Quantity and production, there is no way to create an equivalent amount of energy required for fueling our cars.