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 CO2 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.