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Energy the nexus of everything: September 2012 Archives

With the talk in the United States all abuzz about the presidential election this year, President Obama (and advisors) and Mitt Romney (and advisors) have to act as though they know the solution to lowering unemployment and raising economic growth rates. It is hard for anyone running for an election to admit that they might be powerless to affect some energy and economic realities. In this post, I discuss the trend in the figure below: US monthly personal-consumption expenditures (PCE) for food and energy goods and services as a percentage of total household expenditures. I think it is completely possible that the stop in the declining trend of PCE for food and energy that stopped in the early 2000s is indicative of the new reality facing the United States energy and overall economic (and debt) situation.

US PCE Energy and Food.jpg

Figure 1. Personal-consumption expenditures of US households expressed as a percentage of total expenditures. Data are from the US Bureau of Economic Analysis Table 2.8.5.


It doesn't take a PhD in statistics (or engineering, or anything else) to notice the major change in the trends of the time series in the figure. In 1999, the 4-decade trend of decreasing PCE for energy stopped declining and started increasing. In 2007, the (at least) 45-year trend of decade trend of decreasing PCE for food stopped decreasing - just before the beginning of the Great Recession that began in late 2007.  Adding the PCE for "food + energy" shows a minimum PCE percentage of 11.7% in the first two months of 2002. It is a good question of whether or not this will be the minimum percentage PCE for "food + energy" for the US ... for all time.

Several analyses have been done investigating a seeming threshold percentage of US PCE that can be spent on energy goods (and services) before it induces or plays a large role in causing a recession (see James Hamilton's blog entries here (July 14, 20102), here (March 6, 2012), here (September 19, 2012), and there's another one or two or more in there somewhere tracking the same things). But there is much value in considering the role of food in PCE along with energy PCE because food is both the original source of pre-industrial power and it holds high priority in a "hierarchy of needs" sense.

The reason to add the PCE for food and energy is because food is technically an energy source. It is too bad that the statistics needed to plot the data of the figure even further back than 1959 are not readily available, but it is practically certain that the percentage of PCE for food continues higher as one moves back further in time. Before fossil fuels and significant industrialization using wind, wood, and water power in the early 1800s, food was the major energy resource for prime movers. These prime movers were the muscles in humans and animals doing the majority of the physical ('useful') work and providing the most aggregate power. Thus, the quantity of food and fodder produced from the land had the major influence on the amount of power for agriculture and a little industry. The book Heat, Power, and Light: Revolutions in Energy Services, by Roger Fouquet, shows a similar historical graph for the United Kingdom in which he estimates the expenditures for domestic power in the 1500s as at or above 100% of GDP. Thus, in preindustrial times, practically all GDP was to produce power, or useful work!

The data plotted in the figure should be shown in the United States presidential election debates. I'd like to know what our leaders think of this graph and why they think their policies can or cannot affect the trend (or rather new trend since the early 2000s). The likely truth is that demographics and resource constraints have caught up with much of the 'advanced' economies (e.g. EU, US, Japan). There are less young people working to pay for older people to retire. There are fewer older workers retiring because their pensions and retirement funds are not sufficient, thus not making room for new and younger workers. The conventional oil alternatives (oil sands, deepwater, oil shale, biofuels) don't have the same level of pure energetic value of those of the past, and this is the reason that oil prices must remain at current levels in order for new oil supplies to remain viable. I wrote in a 2011 article in Sustainability (see here) how energy return on investment (EROI) and oil price are related. Alberta oil sands are practically the marginal oil supply (in North America at least) and because the oil sands have EROI < 4-5 then the oil price must be near or above 90 $2012/BBL. The economy remains sluggish, unemployment is still below 8%, and the jobs that people are getting are lower paying.

I think that both the 'extreme' left and right are wrong in their approaches. The U.S. can't borrow money and go further into debt to give people high paying jobs while lowering employment, and the U.S. can't borrow money to maintain the same defense budgets of either the Cold War or recent post-Cold War eras. Resource constraints are imposing their real nature upon our real economy. No lowering of interest rates can prevent this impact, and this is why the unprecedented length and level of low US and EU interest rates are not having the 'expected' effects. What we see is that demand for fuels and energy services have decreased (particularly less light duty vehicle miles traveled) since 2008 at a peak near 3 trillion miles (for a nice graph of US vehicle miles traveled see above link to Hamilton blog on Sept. 19, 2012 and search Stanford research on 'peak travel').

Peak travel. A 'bottom' percentage PCE on food and energy. A 'bottom' of interest rates. Coincidence? I think not.

Earlier this year I discussed (The EROI of Algae) some research at The University of Texas on an experimental algae to fuels experiment. A couple of new papers have now been published on the energy return on investment (EROI) of algae-based bioenergy when coupled to a wastewater treatment plant (Energy Return on Investment for Algal Biofuel Production Coupled with Wastewater Treatment: The reason why it is energetically beneficial to couple a wastewater treatment plant to an algal growth facility is because algae, like terrestrial crops such as corn and soybeans, require nutrients as inputs. Wastewater has a high quantity of nutrients that actually must be removed before discharging the water into the some cases to prevent algae blooms! Oh the irony...

In another recently published work, we established that a best case scenario using known technology (not possible future ideas of new strains of algae), the EROI of algae-based fuels was 0.36 when adjusting the relative energy quality of the energy inputs and outputs (for a free accessible copy of the paper see Comprehensive Evaluation of Algal Biofuel Production: Experimental and Target Results  Note that this value of EROI = 0.36 is what we called a 2nd Order EROI that considers only the energy inputs from direct energy consumption (e.g. electricity, fuels) and the energy embodied in materials (mostly nutrients such as nitrogen and phosphorous). If you want to see work that documents the methodology and assumptions of input values, this work is a good place to start to then lead to other literature.

When you add the wastewater to the algae-to-fuels process... could be possible to obtain a 2nd order EROI of 1.4 (as compared to approximately 0.4 without that wastewater). Note that there is energetic value in extracting energy directly from the wastewater, such as via anaerobic digestion, and this can lead to a second-order EROI of 0.4 from a process that otherwise would have EROI = 0 (e.g. generate no useful energy).  This 2nd order EROI = 1.4 sounds promising, indicating that more energy is produced than is needed for production (EROI = energy output / energy input). However, it does not include every investment needed to produce algae and convert it to a fuel. A rough rule of thumb (as if there really is a rule of thumb for producing fuels from algae) is that the capital and labor costs would be near half of the costs of other operating and maintenance costs. By doubling the energy inputs to account for capital and labor, the EROI will be < 1. 

Further, just because a fuel or electricity resource has EROI > 1 even after accounting for all system inputs, that criteria does not relate to societal viability. For example, there is some evidence to support the idea that an EROI > 5 might need to hold for transportation services or liquid fuels (at least in the modern economy). But this is an ongoing area for study.

What does all of this mean? Well, in my opinion, it means we need to treat our liquid fuels (with high-energy density) as very precious resources as we have yet to prove that we can create a renewable liquid fuel even nearly equivalent to gasoline (petrol) or diesel. There is some evidence to show that the United States goes into recession if the EROI of gasoline at the pump drops to near 5 ( Let's keep trying for alternative fuels, but also keep perspective to think about alternative modes of organization and transportation in general. The new targets for US mileage standards to increase to 54.5 miles per gallon are a good step toward focusing people on the constraints on the supply of oil and oil/transportation alternatives.