|September 25, 2007|
Biomass - Growing Renewable Energy
|Vancouver, Canada (GLOBE-Net) - As the world expands its reliance on renewable energy sources to cut greenhouse gas emissions and to shore up available sources of energy supply, various forms of renewable energy are being examined. This article is the first of a two-part series on renewable energy -- focusing on biomass, its advantages and disadvantages. A future GLOBE-Net article will examine wind energy from a similar perspective. |
Biomass is generally defined as biological material derived from living, or recently living organisms, both plant and animal. In the context of biomass for energy this generally means plant based material such as the residue from food crops, grassy and woody plants, residues from agriculture or forestry activities, so-called "energy crops" such as surplus corn and soybeans and the organic component of municipal and industrial wastes.
Just as there is wide diversity in the characteristics and properties of different classes of material that can be used for biomass-based energy generation, so too is there a wide range of conversion technologies to make use of them. These include both thermal and chemical conversion technologies.
Canada has a number of companies that are developing leading edge technologies in this area.
For example, Vancouver-based Nexterra Energy is a leading developer and supplier of advanced gasification systems that use waste fuels "inside-the fence" at institutional and industrial facilities. Another Canadian company, Ontario-based Iogen Corporation, is a pioneer in enzymatic, cellulosic ethanol technology that converts agricultural materials such as straw, corn stalks, and switchgrass to ethanol, which can be used to replace or complement gasoline as a transportation fuel.
Biomass is touted as a renewable, low carbon energy source that is widely used and generally economically available throughout the world. Its use is also championed for additional environmental and social benefits such as lower net carbon emissions compared to fossil fuels.
But as noted in an earlier article The debate over Biofuels, a growing chorus of naysayers is challenging both the climate change benefits and the use of biomass itself for energy production. Some critics maintain that bio-fuels actually produce more greenhouse gases than conventional fossil fuels, and that using biomass to make energy in wealthy, industrialized nations like Canada threatens the food security of the world's poorer nations.
Even the venerable Organization for Economic Development and Cooperation (OECD) has waded into the debate, stating that biofuels may actually be doing more harm than good. An OECD-FAO Agricultural Outlook report for 2007-2016 says that biofuels may "offer a cure that is worse than the disease they seek to heal." The report also states that even in the 'best-case scenario', biofuels will only be able to achieve a 3% reduction in energy-related CO2 emissions by 2050, thus failing to reduce petroleum fuel consumption.
For Canada, bio-fuels are seen as an essential part of our economic and energy future and bio-fuels production as a way to improve the viability of Canada's farms and forest industries without significantly affecting food exports.
Competing claims and counterclaims make it very difficult to fathom where the truth lies with respect to the production of renewable energy, particularly from biomass. An examination of the world's renewable energy endowments (that is the amount of energy available from renewable sources each year) shows clearly that there more than ample solar, geothermal, wind and ocean energy and biomass to supply all the world's energy needs indefinitely.
What is overlooked in all this is that, with the possible exception of solar, renewables are highly location dependant. One major consequence of this is a trend away from an homogenous global energy supply system based on oil, natural gas and grid electricity towards a patchwork of regional energy economies each powered by its own unique portfolio of renewable and non-renewable energy supplies.
Additionally, most renewables are harnessed through conversion to electricity or, in the case of solar and geothermal, to electricity and heat. The exception to this is biomass which is a highly flexible energy source capable of producing liquid and gaseous fuels or being burned to produce heat and electricity directly.
Food Crops for Biomass
It is argued that if it is managed on a sustainable basis, biomass can be harvested as part of a constantly replenished supply source, as part of either woodland or arboricultural activities or as part of dedicated programs for the planting and harvesting of new crops destined for energy production. The economic realities are that high value materials for which there is an alternative market (i.e. good quality, large timber, high value food crops, etc.), are very unlikely to become available for energy applications. However there are huge resources of residue biomass and co-product wastes that exist in both the developed and developing world which can become significant in terms of their economic return if used for energy production.
Currently large scale production of ethanol from biomass is mainly located in Brazil and North America, produced from sugar cane and corn respectively. All gasoline sold in Brazil has a blending of 22 % - 26 % ethanol. The amount of ethanol produced in Brazil has risen considerably since the start of the Brazilian PRO-ALCOOL programme in 1975. In the United States the main biomass feedstocks for power are paper mill residues, lumber mill scraps, and municipal waste. For biomass fuels, the main current feedstocks are corn (for ethanol) and soybeans (for bio-diesel), both considered surplus crops.
The issue of crops being used for energy biomass turns in large part on the issue of what is surplus and what is not. A recent analysis by Lester Brown of the Earth Policy Institute of current and planned ethanol production facilities indicates that fuel-related demand will draw down half of U.S. corn supplies by 2008, causing higher grain prices and disruptions in the global food economy.
See article Fuel vs. Food: surge in grain prices projected
So where does this leave us? For one thing the various studies that show the negative impacts of biomass for energy supply provide a useful set of bounds or specifications for the use of biomass feedstocks. These studies show that the use of food crops, even surplus crops, for energy supply is likely to be unsustainable because of the impact on food prices.
But what of non-food crops like switchgrass and fast growing "weed trees" such as poplar? Here the case for energy crops is far more robust, particularly since this type of feedstock can grow in marginal areas and not affect food supply. Additionally, there are huge volumes of forest wastes potentially available for energy production.
Forest Waste as Biomass
With respect to the use of forest industry waste as a feedstock, the main barrier here is that pulp mills and sawmills currently operate in an integrated fashion where pulp mills receive saw mill residues for the cost of transportation. Any significant use of the waste stream for energy purposes would add cost to pulp mill operations.
Nevertheless, there are potential solutions to this such as the use of two tier pricing and guaranteed supply. Forest "slash" (the waste left behind at the sites of logging operations) may also be a significant source of feedstock -- bearing in mind, of course, that a certain amount of "slash" must be left in-situ to maintain the fecundity of the soil.
This issue has particular relevance in British Columbia. Eighty companies have expressed interest province wide in using forest waste to produce bio-energy and are seeking guarantees of a stable biomass supply for 20 years. However, BC Forests Minister Rich Coleman said the Province will not be rushed into announcing policy changes until his ministry has developed a new forest tenure program for waste wood. At the same time, he said BC Hydro has to set a rate for energy from biomass that makes economic sense,
At issue is the allocation of the waste wood. The pulp and paper sector --- which has plants in beetle- hit communities such as Prince George, Kamloops and Quesnel --- has expressed concerns that a subsidized rate for bio-energy could tip the scales in favour of independent power producers who would be bidding against the pulp sector for chips.
Lastly, there are huge and growing volumes of urban waste biomass -- everything from sewage and landfill to restaurant grease.
In the final analysis, it is clear that the biomass energy sector will continue it's near exponential growth and the overall determining factors that will guide further investment in this area will be the price and availability of suitable feedstock, and the comparative price of fossil fuel energy. The challenge will be to create a system for the use of non-food energy crops, and for forest, agricultural and municipal waste, that is truly sustainable.