How Efficient Can We Get?

The U.S. Department of Energy’s Energy Information Administration projects that our energy consumption will increase by 10% between now and 2040. Because it also projects robust growth in population, GDP, miles driven, home starts, size of new homes, etc., a 10% growth over 25 years seems low.

The justification for such a low increase is their projection that the efficiency of energy consumption will increase dramatically. Sadly, they have overestimated improvements in energy efficiency in 93% of their forecasts

For example, they expect miles per gallon for passenger cars to increase from the 2014 figure of 30.7 to 46.8 mpg by 2040. I don’t say that’s impossible–there are cars capable of getting that mileage today. But that level of improvement has never been achieved in our history.

Similarly, they expect a total increase of 56 billion square feet of commercial floorspace between now and 2040. But they expect total energy consumption to drop from 213 thousand BTUs per square feet to 191.8 thousand BTUs per square feet, so total energy consumption in the commercial sector only rises from 17.78 quads to 20.88 quads by 2040.

The same is true for every category they examine. At the end of the day, they expect energy intensity, as measured by thousand BTU per 2005 dollar in GDP to drop from 6.79 to 3.99 between now and 2040.

That’s an improvement of 2% per year. Is that possible?

Well, we’re certainly off to a good start. The EIA’s chart starts in 2011, when energy intensity was rated at 7.30–that’s well above 2% a year.

But if you look back a ways, it gets a bit dicier. About half the time, rates of decarbonization are below 2%, and half are above. But the half that are above 2% include the most recent economic unpleasantness, which the EIA specifically does not forecast for the next 25 years. They also include dramatic fuel switching to lower intensity natural gas.


The real problem for decarbonization as a strategy is that the easy stuff gets done first. Decarbonizing becomes progressively more difficult.

Globally, there is scope for dramatic improvements. Every time a villager in India quits burning dung and starts using even as dirty a fuel as coal, he contributes to decarbonization.

In fact, I would hazard the guess that historical improvements in decarbonization have been driven primarily by fuel substitution.

Making a dollar of U.S. GDP in 2009 took 60% less oil, 50% less energy, 63% less directly burned natural gas, and 20% less electricity than it did in 1975. But in an advanced economy such as the American one, we’ve already taken the easy steps. Much recent improvement is down to switching from coal to natural gas, which has proven to be a blessing–but unless coal is completely retired, has little in the way of further improvement to offer. As the DOE projects coal usage in the U.S. to increase (very slightly) between now and 2040, they don’t seem to think we’ll move much further down that road.

As with last year’s report, I also think they don’t pursue their own assumptions very rigorously. If climate change is going to make the U.S. Southwest significantly warmer, and if more Americans are going to move there (for a variety of reasons), then why don’t they show air conditioning rising by more than they do? If vehicle miles traveled are going to rise so dramatically, by almost one trillion miles, why is so little thought given to congestion and the waste energy it causes? They show no sign of projecting major construction of roads and freeways.

Do I think decarbonization at a 2% annual rate can be achieved between now and 2040? Yes. Do I think we are on the road to doing so? No.

I think we will make good progress in some areas–but not all. And I think we will define good progress as coming in short of the EIA projections.

Which is why  my projection for U.S. energy consumption in 2040 is 120 quads.

6 responses to “How Efficient Can We Get?

  1. Thanks for the link to the DOE’s batting average. EE can be a tough sell.

  2. MPG increase has been passed as a regulation, to a much higher level than 46. It is not a matter of improving energy efficiency, but of reducing the size of the cars.

  3. Two points: EVs will probably make a big impact on mileage figures by 2040 and southwest aircon needs are ideal for solar panels.

    How does EIA calculate these figures? Do they include self-generation by solar into these consumption figures?

  4. Who in their right mind would want to ‘decarbonize’??

    More CO2 is completely harmless, and it is clearly beneficial to the biosphere. The planet is measurably greening due to the rise in CO2.

  5. Smokey ….. what ARE you smoking?

  6. I think focusing on energy efficiency improvements, or reducing total energy used, is not the right way to look at the problem. The problem is burning carbon to make energy, not how much energy is used.

    Strategies which focus on energy conservation by regulation, or by negative inducements like penalties or carbon taxes are misguided, to some degree, for two reasons. First, they derive, and properly so, from a fossil fuel sensibility, but make very little sense in a post carbon world. More importantly, they are designed to preserve a free market solution to the AGW problem. I would submit to you that this is very dangerous thinking.

    If the past thirty years or so has not been instructive on just how badly a free market model addresses the development of alternative energy, then someone has not been paying attention. AGW is a crisis which should be not solved locally, or regionally, or by laissez-faire economics. It is rightfully the bailiwick of Federal energy policy, and should be addressed by fiat. Just like, say, our Interstate highway system, which was built by fiat. Imagine if our Interstate system was left to the laissez-faire economics of renewable energy: homeowners would by hiring driveway pavers to lay down their own personal 1/10 of a mile of road. Out of their own pocket..

    Progress on renewable energy has been excruciating slow the past three decades because it is almost impossible to make it renewables work in a corporate for- profit model. It has driven too many good men and women to despair. But renewable energy as a publicly-owned non-profit utility makes perfect and simple sense.

    If a homeowner can get free electricity from the sun after his infrastructure investment in rooftop PV has been recouped, so can a nation. We sit bathed in a 10,000-fold excess of free energy from sun, wind, and tide just begging for the plucking. According to the best available information, a mere four to seven years of current U.S. spending on fossil fuels would buy us all a brand spanking new 100% renewable energy-only utility system, complete with smart grid.

    And, if we had that, we would not need to restrict energy use by making it expensive because despite how much more energy we used, not a single molecule of CO2 would be going to the atmosphere. The best way to stop people from burning fossil fuels is to make fossil fuels ridiculously expensive by comparison to super low cost renewable electricity. The best way to control fossil fuel use is to make it irrelevant.

    I am hoping that China will be true to its word in the next few years. They are about to demonstrate to the world that the construction of large-scale solar and wind farms, by government edict, is the only way to accomplish our very ambitious goals in time to actually avoid disaster.

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