Mar
13
Getting a Handle on Biomass for Fuel
March 13, 2008 | Leave a Comment
Renewables are all the rage and biomass sources are leaders in using solar energy to catch atmospheric CO2 into hard forms such as plant materials to use for feedstocks for fuel production. Bit how viable is biomass? There is already a backlash to the U.S. corn to ethanol effort with food production diverted to fuel, excessive land use, poor stewardship of the land, tax incentives and advantages that give corn based ethanol an unfair advantage and other arguments.
So viability has to be considered in the wide sense that a given area can be used in a variety of ways. From pristine wilderness to high tech manufacturing or luxury office space land has a value and each person sees different potentials in every parcel. Yet humanity and other creatures on the planet are exploiting land and what is growing on it. This makes it incumbent on people to be the arbiters of what grows where. We choose even when we don’t.
Some 2/3s of the earth’s people do not have electricity at home. They use biomass for heating, lighting and cooking now. It is wildly inefficient, worse than a high tech societies choice of internal combustion engines for personal transport. The tradition of the burning hearth isn’t well done either leaving most of those 2/3s of humanity gasping for survival. Their energy choice is burning, usually at optimistic efficiencies of 5% to maybe 15%. Fuels are gathered from plant growth, animal waste and refuse from nearby higher developed areas. The health hazards are considerable. Exposures range from particulates on to carbon monoxide, nitrous oxides, formaldehyde and other noxious organic compounds.
High birth rates equal survival in those people’s minds, too. The rapid growth of population and the advance of medical services and education drive the surviving child rates to even higher populations. The result is that gathering of fuel materials can lead to deforestation, denuding of areas, encroachment of wildlife habitat, desertification and other difficult problems of land use. All for perhaps a 7.5% efficiency. In my humble opinion, that makes burning fossil fuels with multiples of efficiency improvements look great.
Here are some numbers to consider (Hat tip to Al Fin and his source, inforce.dk).
Humanity is going through 400 exajoules (1 exajoule = 10 to the 18th J, EJ/y) of energy a year. This is against the land biomass storing 3000 EJ/y. While these numbers are subject to interpretation, the multiple of biomass stored to humanities use of energy is still 7.5 to 1. This is in the face of a completely unorganized effort to maximize the land use for recycling CO2 for fuel production. Take out electrical generation from coal, nuclear, and natural gas, and consider that oil and gas products fuel most everything moving and the ratio soars. By no means has humanity made good use of the biosphere.
Thus it is clear that biomass has an immense unorganized role yet to be utilized. When one looks at the rush to corn ethanol that makes about 4.2 tons per U.S. acre and compares it to miscanthus that can make 20 or more tons an acre the prospects seem even easier.
Plants make mostly human inedible products. Starches, sugars and proteins are way behind the production of lignin, cellulose and hemicellulose. To adequately feed the whole of humanity now isn’t a huge production problem. It’s a political and economic problem. The usable land not needed for food production is far more than necessary to produce feedstocks for recycled CO2 based fuels. Corn, rice, wheat, soy and other food crops are better at compiling useful starches, sugars and proteins, yet do not constitute our major share of land use. Vegetables and fruits are also not large land use items. Humanity can still feed itself well when politic and economics permit it to be so.
That leaves plenty of land and biomass to recycle into fuels. With technology bringing growth to solar photovoltaic, solar thermal, geothermal, atomic fission, and perhaps soon fusion, electric potential can invade the transportation fuel market and shift use and improve efficiency even further.
Biomass already powers 2/3s of the planet’s people at very poor efficiencies. Some 14% of world energy is supplied by biomass to 4.5 billion people. A little imagination that suggests a pyrolysis unit making just syngas or upgrading to methane would revolutionize much of the world’s standard of living.
However, everyone who reads this post will be on the Internet, using a computer. Very high tech. We all depend on these tools to learn and grow. The challenge is to ratchet up the knowledge for ourselves to adapt to the opportunities for biomass to displace fossil fuels. Then we should be passing on what we learn and are able to provide in sustainable technologies to the other 2/3s of us.
Is biomass viable? Yes, and much more – beyond one’s first impulse. Armed with a little information about the current state of available biosphere recycling of CO2 and some insight into the possibilities, the opportunities are astonishing.