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Biomass and Bio Fuels

The Basics of Biomass (and MOST other renewable energy sources)

As a source of energy, biomass offers a host of positive qualities; It is fairly plentiful, relatively inexpensive to use, and helps reduce agricultural waste problems. Most importantly, however, biomass is a renewable, energy source, thanks to the carbon cycle and solar energy.

Photosynthesis

Photosynthesis is the process by which plants absorb the sunlight, store it, and convert it into energy to grow and survive. It is represented by the following equation: where the plant takes in Carbon Dioxide and Water, stores and uses the glucose to grow and live, and releases Oxygen back into the environment.

6 CO2 + 6 H2O energy C6H12O6 + 6 O2

The energy is supplied by solar energy (sun light). The glucose (C6H12O6) is used by the plant as a storage medium for the energy. As the plant grows it will use the glucose to supply the plant with energy.

Decay

When plants die, this process simply works in reverse.

C6H12O6 + 6 O2 decay 6 CO2 + 6 H2O

Source: JPM Photosynthesis and decay in the same picture! Splendid!

Walking through almost any forest is the best way to witness the decaying process in action. The ground is generally strewn with dead and decaying leaves, limbs, branches, and sometimes entire trees. If they did not decay, we would be faced with a serious dead-tree population problem in our forests. Then imagine the scope of this problem times millions of years. This helps illustrate, the nature and the value of the carbon cycle. However, in Pennsylvania about 320 million years ago (and even today) the forests did not decay. Instead, the trees fell into swamps (bogs) and were protected from the decay process. Eventually these trees formed coal, and in the oceans, plankton and algae went through similar processes. There, the stored solar energy eventually formed oil (protection from oxygen at the bottom of the ocean, with sediment burial). Now as we use the fossil fuels (combustion) we release CO2 back into the atmosphere.

 

Source: EJS This is a man excited by the prospects of Biomass..

So, instead of allowing the biomass to rot naturally as explained above, we can harvest it and combust the biomass for home heating, industrial use, or electricity generation. Let Dr. Mathews tell you the full story. QuickTime (3.6 mb) Real Media (1.1 mb) Windows Vid. (.8 mb) Text Version

Biomass does not contribute as much to electricity as it does to industrial heat generation where industries that produce a combustible biomass waste product and require heat use the waste. Paper mills are a good example of this. The whole tree does not go into the paper manufacturing; bark, leaves, and small branches are combusted to generate the heat to drive off the water from the water/cellulose slurry.

When we discussed lighting, sperm whale oil was the fuel of choice for some of our ancestors. Candles would have also been produced from animal fat (pig fat worked well), and if the need arose, we could combust fats (currently pig fat is too valuable to burn, it is used in frying potato chips.)

Advantages of Biomass

• It is renewable;
• There is no net carbon dioxide released into the atmosphere (greenhouse gas)
• Its use could stimulate American jobs in agricultural areas
• Its use could improve international trade balances, and consequently, could help improve national security (more on this later)

Disadvantages of Biomass

• Biomass requires large plots of land, increased fertilizer, and more insecticide use (perhaps)
• In a world where many people starve to death, using food as fuel (such as corn) is perhaps an abuse
• Biomass is heavy (high water content), so transportation costs can be high, influencing the economic feasability of biomass use
• Energy demand is constant, but only a percentage of biomass crops can yield harvests year round, requiring the need for storage. Harvests will also be weather and disease dependant.

The bottom line: Expect to see biomass being integrated into existing utilities that burn other fuels, rather than the creation of large biomass-only utilities.