The Bee vs. the Bear
In a recent exchange that I had in the comment section on one of the many energy websites I peruse a fellow commenter brought up the notion that biofuels are not worth pursuing because of photosynthesis’s inefficiency in converting raw sunlight into plant cells and ultimately a biomass fuel. According to the commenter, biofuels are ‘nonsense’ because when compared to alternatives, biofuel is extremely inefficient. And this is true; photosynthesis is extremely inefficient relative to other forms of modern energy conversions. Of the total amount of energy (in the form of sunlight) that hits a corn plant, between 0.5 and 0.25% of the sun’s energy is converted into starch in the corn kernel. Sugarcane is more efficient at converting sunlight into energy, at around 8% efficiency. The commenter cited Nobel Laureate Hartmut Michel, whose work in the 80s provided a general understanding of photosynthesis and more recently has come out as an ardent critic of biofuels. Michel’s work on photosynthesis is laudable and provides a foundation for plant science to flourish. His critique of biofuels (or at least how today’s media interprets it) fails to acknowledge the distinct difference between how biofuels and fossil fuels are derived.
Biofuels and fossil fuels are rarely, if ever, compared on even terms. Critics of biofuels place fossil fuels and biofuels side-by-side and rate efficiencies, often citing Michel’s elucidation of photosynthesis’s poor efficiency while neglecting to equate the formation process of fossil fuels. However, if we translate this biofuel-to-fossil fuel comparison into a simple analogy, we can easily see the error in the equation. Let’s imagine that a biofuel producer is a colony of bees and a fossil fuel producer is a bear. Bees travel away from their hive and collect a non-dense energy source, pollen, and bring it back to the hive where they convert it into a dense energy source, honey. Bears, on the other hand, simply find a hive and consume the already converted and densified energy source. How can you equally compare the process that bees and bears go through to produce (or simply find) and honey? Biofuels and fossil fuels are no different. Bioenergy producers accumulate biomass within a radius from their plant and covert the relatively less-energy dense feedstock into an energy product that is comparable to the constituency and energy density of fossil fuel products. Fossil energy producers sink a straw into the ground and extract what was once biomass and minimally process it into the fossil energy products that we all know and depend on. Acting as a bear, the ease of extracting energy dense fossil fuels has enabled our economy to flourish along with negatively influencing climate change, geopolitical relations, and the number of hives we have left to tap. Conversely, bioenergy producers collect resources through actions that ensure the biomass resource will regrow so that they can return a following season to collect their feedstock.
Yes, photosynthesis is inefficient just as bees are inefficient in regards to producing honey. Despite their inefficiency flowers return each spring (in great part thanks to bees) and hives continue to produce honey. I have no argument that the inefficiency of photosynthesis and land-use change is an important consideration when planning the future of biofuels. General energy efficiency measures in our homes, businesses, and transportation sector must be a top priority for any energy policy measure to succeed in the long run. However, despite the low efficiency of photosynthesis, plant life flourishes and is a burden in many regions of the world. And, if we synergistically pair bioenergy production with farming, forestry, and general waste management models in areas where excess biomass is present, bioenergy production will bring about greater resiliency to the original systems and our energy infrastructure.
Getting back to the analogy, life for bears with access to considerable amounts of honey is, no doubt, pretty great. All they have to do is go from hive to hive and enjoy their seemingly endless supply of honey. However, unlike a bear, modern society does not have millions of years to wait for fossil fuel to replenish its reserves, climate change to fix itself, or geopolitical rivals to learn to share. We must adapt our energy production systems to the reality of lower energy densities among renewable energy sources and live more like bees rather than bears.