Energy: Growth or Static? How EROI determines our future.

Sorry it’s been so long since the last article. life has gotten interesting in the ancient Chinese curse kind of way, but I’m back and hopefully regularly.

I hate economics. It’s a byzantine mess of contradicting methods and rules that gives em a massive headache whenever I try and plumb its depths.

So, instead of getting all dressed up for a full moon to sacrifice a baby goat, which is what I’m assuming is required to gain an understanding of economics, I’m going to stick to something I’m much more comfortable with. Namely physics and energy. Because unlike money, Energy cannot be created or destroyed, which makes it so much simpler to deal with. There is no such thing as energy inflation, or someone deciding to burn a big pile of it. At worst we have to search the nooks and crannies of the universal couch for its loose change that we lost track of, but that’s it.

So what I want to talk about specifically is a topic called the Energy Return on Energy Invested (EROI or ERoEI if you are pedantic. To which I say welcome to my blog, fellow engineer). The quick and dirty explanation is pretty much in the name, how much energy you get out of a generating method compared to how much you used to build it. There are a few articles about it on the internet if you are interested in more of the fine details.

There’s always some… disagreement over EROI values for specific generating sources as everyone wants their preferred choice to be the best. So instead I just want to explore what these numbers mean for how the future will turn out.

We’re just going to ignore anything with an EROI of one or less. That is a completely unsustainable system where you can’t even produce enough energy to sustain your method of energy production, let alone support anything else. We are also going to ignore what is considered the “economic viability threshold.” Partly because as stated earlier I suck at/hate economics, and partly because defining why that specific level of delineation was used involves Way more math and deep dive exploration of energy costs than I really feel like while one glass of wine and one rum hot chocolate into my evening.

Instead I’m going to group things into 3 loose categories: Subsistence, Progressive, and Abundant. All three are valid for survival of the population depending on how much effort you feel is practical to spend on.

First is Subsistence and this is for generation technologies that have EROIs in the low single digits but more than 1. An energy system that has a total EROI in this range would require extremely large investment devoted simply to maintaining itself. For example, if the EROI of the system was 2 that would mean that fully half of the energy of the system would have to be devoted to maintaining and replacing the components of the generating infrastructure. Another way of thinking about it is to picture how much energy it would take to run the society you plan to power, and then overbuild by 1 divided by the EROI.

This is the kind of EROI that humanity existed under for most of it’s history, when the most energy dense sources of power in the world were horses and oxen. Vast majorities of the efforts of society went into maintaining food stocks since people and animals were the dominant sources of energy for civilization. The advent of waterwheels and windmills helped push things away from food as the only energy source to make food. Having the river grind your grain instead of having to feed donkeys to do it saves a surprising amount of food.

But society didn’t really have a way to get past the Subsistence level until the advent of the Industrial Revolution. Being able to use the stored energy in easily accessible fossil fuels gave us huge returns on the energy that allowed more people to actually start using that energy for more than just making enough energy to survive. It was with this excess that things like hygiene, education, and public benefit works started to become more common place. It was also at the beginning of the transition from Subsistence levels to Progressive levels that we started to end the practice of human slavery.

But we now know that fossil fuels and pretty much every other form of power we currently use are not without their draw backs in the form of either environmental externalities or inconsistent energy generation. If we want to continue lifting people out of the energy poverty of subsistence levels of energy we need to find a way to take care of those, hopefully without reducing to much of the EROI of our energy system.

And that’s the current problem that we face. Practically every solution we have available to us to clean up our energy generation imposes a penalty on the EROI. This is true for carbon capture and sequestration, nuclear waste management and disposal, and all kinds of energy storage for firming renewables. Even recycling can be considered a EROI penalty if it is more energy intensive than sourcing new material to construct our energy infrastructure.

But this is not to say that we shouldn’t do these things. We have to decide which of these methods is capable of providing us with the cleanest environment without dropping our EROI back into Subsistence levels. It would be really annoying to have a majority of our population effectively forced to work for the energy industry simply to be able to have enough energy to replace our energy generation infrastructure. Talk about a dystopia. And not even a cool dystopia with roving bands of spiky leather wearing savages.

So what about the last category, Abundance? Well I think my opinion should be really, really obvious, but it doesn’t matter what I think it should be. The important thing is how our entry to this category should be characterized, which is a method of producing energy at any desired level above Subsistence, at any desired time, without any detrimental environmental externalities. Taking into account how dealing with those externalities can impact the availability of energy for use by society, That the purpose of an energy grid is to supply it’s users with energy when they ask for it (so if you have to tell people to change their lifestyles to fit your grid, then your grid isn’t doing it’s job), it makes sense to try to use the option that starts off with the highest EROI doesn’t it? So that we have the most wiggle room to spend on taking care of maintaining our environment while expanding our ability to make energy do our work for us so that we can focus on the things that we find more important or fulfilling, whatever they might be.