With climate change and green energy narratives becoming the central themes of the 21st century energy industry, the following article makes a quantitative argument of the aspects overlooked and why ethanol blending and battery electric vehicles would fail to meet green energy objectives.
Does Ethanol Help Reduce CO2 Emissions?
While shrouded in political fumes, the price of ethanol blended fuels depend on both prices of crude oil and sugar rich crops, such as sugar cane, sugar beet and corn. While the former is independent of seasonal changes, the later depends on annual weather patterns and the water table. A chief parameter that has a direct effect on fuel consumption is calorific value., i.e., how much energy is contained in a unit of fuel and how much can be extracted with technology.
Performing a mass balance between ethanol and gasoline with the assumption of complete combustion, the stoichiometry is as follows,
Analysis
From the analysis made, it is clear that,
- There is no significant improvement in reducing CO2 emissions between combusting ethanol and gasoline. Increasing the ethanol content in fuel blends would only cause motorists to purchase more fuel for the same mileage.
- Ethanol is an agricultural product and any seasonal variations due to weather or famines and droughts, is bound to create price fluctuations to consumers.
- Subsidies tend to encourage more sugar rich crops which can offset production of other types of crops resulting in inflationary pressures.
- When climate change is a cause of concern, it would be imprudent to depend on the uncertainty of climate for energy security.
Battery Operated Vehicles for Heavy Transportation
Taking a Lithium-ion battery at 100 kWh with an energy density of 0.16 kWh/kg, and an expected mileage of 30 kWh/100 miles,
And gasoline with a calorific value of 44,300 kJ/kg [44,300/3600 = 12.30 kWh/kg] with average density of 0.75 kg/lit [2.84 kg/USG]
Therefore, to conclude,
- To deliver 100 kWh of energy, ~8.13 kg of gasoline [with a calorific value of 44.3 kJ/kg] is required, whereas with a battery pack at 0.16 kWh/kg, the weight added to the vehicle would be 625 kgs, i.e., nearly 77 times increase in weight.
- Considering the case of heavy transportation, with chassis weight, body components, poorly maintained roads, road traffic, weather issues such as rain & snow causing temperature variations in battery performance, an erratic power supply sources to charge and weight of passengers with goods, then both the size and weight of the vehicular battery pack weight would also increase drastically.
- This would cause the battery pack to be unable to deliver the required power since most of the power would be wasted to overcome the weight of the goods/inventory and the vehicle itself.
From the basic mass and energy balance performed, the author would like to convey, that the shortcomings that plagues the world’s energy transition effort is in the “Energy Density” of the fuel sought after. What is required is a source of fuel which is highly energy rich for a given mass of fuel.
Nuclear, LNG, diesel, gasoline, jet fuel and natural gas offer high energy densities while renewable sources such as solar, wind are very diluted sources of energy requiring more efforts to concentrate them. Towards this, significant efforts need to be made to enhance the energy density by many folds.
