November 30, 2007

#1 Bioenergy Can... Convert Solar Energy into Liquid Fuel

Bioenergy is the ONLY renewable technology that can convert solar energy into LIQUID fuel.

If we expect to substitute renewable energy for fossil fuel energy, we are going to have to tackle the challenge of liquid fuels - how do we replace our dependence on oil, diesel, and gasoline with functionally equivalent biofuels? So much of the positive press about renewables focuses on the urban non-liquid technologies - wind and solar - while negative press focuses on rural liquid technology concerns - the ethanol food vs. fuel dilemma, farm subsidies, water consumption, the net energy balance debate, etc.

My suspicion is that the press is catering to an urban readership that is disconnected from the opportunities, concerns, and sensibilities of rural America. Wind and solar are seen as pristine "clean" and "technological" whereas crops and forests are seen as dirty, wasteful, corporate, manipulative, etc. Anyone coming from a rural orientation could say that wind and solar are "unnatural", inefficient, ugly, irrelevant, and not deployable.

The fact is that we need ALL renewable energy technologies because each region has its own climate, resources, liabilities, and energy opportunities. The waste and subsidies of all of them will reduce as they develop and net energy balance will certainly improve (as they have in Brazil). Renewable energy lobbies on Farm and Energy legislation are necessary to move timetables forward against the obstruction coming from fossil energy lobbies.

Before the invention of solar cells, nature developed its own way of capturing solar energy. Photovoltaic solar arrays are good at converting light to electricity but are incapable of storing the electricity. Here are listed some of their other drawbacks:
• Solar cells are expensive to produce & install.
• Their manufacture requires fossil energy and exotic materials.
• Their production is centralized and requires long distance distribution.
• Arrays conduct and radiate the heat they absorb.
• They do not function efficiently on overcast days or at night.
• They are only efficient in certain climates and regions of the world.

Utilizing photosynthesis, leaves are nature’s own “solar cells.” Plants are nature’s “solar arrays” with big advantages over photovoltaic arrays.

• They store solar energy (as sugars).
• They are self-replicating - requiring no fossil fuels in their manufacture.
• They create shade and absorb heat.
• They function 24 hours a day either respiring oxygen or transpiring water.
• They sequester half their weight in carbon from the carbon dioxide they absorb from the atmosphere.
• They create animal and insect habitats and protect streams.
• They enhance landscapes.
• Their roots prevent erosion.
• They are adaptable to various climates and terrains.

In short, bioenergy using photosynthesis offers a much more natural and flexible solution to energy capture than solar energy using photovoltaics.

We now have four ways to convert this stored energy into biofuels.

Besides transesterification to produce biodiesel and sugar fermentation to produce ethanol, we are now deploying two new commercial-scale platforms for creating biofuels from the solar energy stored in biomass.

Cellulosic biomass (plants, wood, and their wastes) can be separated into its component sugars and lignin using enzymatic or acid hydrolysis biochemistry. The sugars can be fermented into ethanol and the lignin combusted to generate heat, steam, and electricity.

A more robust decomposition of feedstock can be achieved through thermochemical means – pyrolysis and gasification. The range and kind of feedstock is vast. Besides biomass it can include municipal solid waste, sludge, tires, petcoke, autofluff and blends of various feedstock. Industrial BioOils are already being produced from woody biomass through pyrolysis. Distilled alcohols like ethanol and methanol can be produced through fermentation or catalysis of the synthesis gas resulting from gasification. These are clean, low-emission technologies.

If we want to replace fossil fuels, no renewable industry other than bioenergy produces liquid fuels.

This article is the first in a series of five about the unique capabilities of bioenergy.

On November 28th I made a presentation at the Capitol Hill Club to the Biomass Coordinating Council (BCC) of the American Council on Renewable Energy (ACORE) titled "BioEnergy Can Do." My aim was to list what I considered to be the top five unique capabilities of bioenergy that should drive legislative action on Capitol Hill. The five capabilities are:
1. Bioenergy can convert solar energy into liquid fuel.
2. Bioenergy can reduce greenhouse gas emissions.
3. Bioenergy can remediate ecological disasters.
4. Bioenergy can revive depressed economies.
5. Bioenergy can expand energy freedom of choice.


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1 comment:

Unknown said...

You stated that there are four current technologies for the conversion of biomass to liquid fuels. We have pioneered a sonochemical technology that utilizes a heterogeneous catalyst in conjunction with acoustics to to produce alcohols, ester and ketones, etc. for the production of liquid fuels and specialty chemicals. This is all accomplished at low temperatures (60 to 70 degrees C) and low pressures (50 psi). The equipment and catalyst is low cost when compared to other technologies and the end products and well below the production costs as compared to the other technologies. We are able to utilize a wide array of biomass, including MSW, wood waste, ag waste, etc. for the production of products. We have eliminated the fermentation step in the process and reform the molecules into desired products.