Tag Archives: 19th

When crude oil reserves were first tapped on a commercial scale in the 19 th and 20 th Centuries, the oil was relatively close to the surface and needed less energy to pump and refine than is currently demanded to carry out the same practice. As oil has become scarcer, deeper wells and more energy intense retrieval practices are needed to produce the energy products our economies hinge on. In spite of efficiency gains in recovery and refinement processes, the ever increasing effort required to produce usable energy from it continually decreases the ultimate return on the energy invested for oil. The energy returned on energy invested (EROI) of any energy product fundamentally affect its economics and sustainability as a viable energy source. This week’s DataPoints blog will briefly look at the predicament of fossil energy’s finite nature and the upside of renewables. Coal, as an energy feedstock, has an excellent EROI of around 80:1 delivered to a power plant. After losses are accounted for in the production of electricity, coal remains one of the soundest energy sources with an estimated EROI between 24:1 and 12:1 . Additionally, the energy density and hydrophobic nature of coal further affirm reasons behind its historic dominance as the economically wisest option among energy sources. Considerable hype has pushed shale gas to the forefront of energy speculations. Power producers are converting and building plants to operate on natural gas as prices have declined and remained low over the last five years. With increasing environmental concerns surrounding fracking and potential price volatility of natural gas , regulation is likely to fetter its current hype. With environmental regulations and its finite nature, natural gas EROI will ineviatably decrease. Bioenergy critics will cite the low EROI of some bioenergy products, such as corn ethanol at around 2:1 . The infancy of the bioenergy industry and its production systems provides opportunities for significant efficiency gains that will strongly affect their ultimate EROI in the production of biofuel, electricity, and heat. Fossil energy sources are precluded from much of the EROI gains from improvements to efficiency because of penalties to their EROI from their finite existence.  Corn ethanol was built on the foundations of agriculture, which put a greater impetus on food calories than purely energetic calories. Currently available technologies and potential advanced in cellulosic ethanol contribute to varying EROI estimates that reach upwards of 40:1. The potential to improve the EROI of cellulosic ethanol is far greater than the potential with oil. Continue reading →