Energy Return on Energy Invested (ERoEI) is a useful concept if interpreted correctly!

An Essay by S. Tom Bond, Retired Chemistry Professor and Resident Farmer, Lewis County

There are two very important unfamiliar quantities connected with depletion of resources: “energy return on energy invested” and “net energy”.

In simple mathematical form one measures or calculates the amount of output energy of a process, then adds all the input energies and divides output energy by input energy, deriving a ratio. The larger this ratio is, the better the process. If it falls below 1:1, the process takes more input energy than it produces and reduces the energy available. Thus 1:1 is an upper limit on viable input energy. In fact, the useful limit is not a fixed number, but a limit. In practice a useful minimum ERoEI is reached long before 1:1.

To get ERoEI, one must consider all the energy used to produce the energy required for a particular purpose. This is not a trivial exercise. It is full of pitfalls, from setting improper boundaries to the problem to carful attempts to mislead the reader. It is not the purpose of this article to calculate EROEI’s but to help the reader appreciate the difficulty of such calculations, and why such a variety of values appears in the literature.

Let’s consider two cases. First, the energy for fracking gas to make electrical energy used in the home and elsewhere. The energy to find the gas, the surveys, including the energy used by support personnel, their transportation and food, the energy to make the equipment and use it and to get the data into usable form, including the office staff and publication. Next the drilling and fracking, personnel, all the equipment, transportation of fluids and dispose some of it, to process liquids co-produced, (their value must be considered a plus), enrgy for manufacture of chemicals used, steel, including miles of pipe, and the energy to run all that.

Then all the energy to make the pipe to transport the gas to market, to compress it, the energy to support many kinds of workers involved. The energy to store it for later use, and energy to get it to the electrical generating plant. A lot of gas is lost along the way, including the compressors , ect,. so enough must be produced to cover that loss along the way.

Then there is the energy used to run the plant to generate the electricity. Some 60% or more is lost if the gas is used to heat water which turns a turbine. In a “combined cycle” generating plant the gas is used to fire a turbine and the waste heat from the turbine heats water the theoretical loss is as little as 40%, but I read in practice it is nearer to 50%. Then there is the transmission to the customer.

The energy going into the copper and aluminum power lines must be counted. Both are rare elements requiring a lot of energy. When I took my first college chemistry course there was section in the book explaining how they obtained copper from less than 1% ore, 60 years ago. Aluminum must be made by electrolysis at high temperature, in nations where electricity is cheap, from bauxite ore that usually has to be transported to the refining plant. These are hugely expensive in terms of energy. Also, steel towers for the high tension lines and specially grown and treated wooden poles add to the energy costs. Then it can be used in homes, public places and factories.

Compare this with photovoltaic solar. It costs a lot of energy to produce the special glass used in solar panels. Rare elements frequently are called for, and these are expensive to find, mine and manufacture. The panels are expensive, but can be shipped like any other merchandise. They can be placed by local people with little more than usual electrical training. If energy is to be stored for night or cloudy days, some battery must be provided.

A present, this is the weak link, but Tesla is building a “gigafactory” in Nevada, $5 billion dollars worth, to build lithium ion batteries to power its electrical automobiles. It is expected these can be used to store electrical energy from photovoltaic, too. Last week’s Science, journal of the American Association for the Advancement of Science, one of the two most prestigious places for scientists to publish, had a cover article on a lithium-air battery development which overcomes all disadvantages of previous lithium-air batteries. It appears to set the way for 10 times more dense electrical storage. Again, rare elements mined far away are needed.

Wire for conducting the electrical current is minimal if no supply from a remote source is required, as in home and small business installation. How do you think ERoEI compares between these? A caveat applies here. Home and small business photovoltaic must be higher ERoEI than for a city, because there is only one or two stories involved and land is cheap. For cities, remote land must be involved if many stories are involved, and sunlight is a premium. Some can go on roofs, but you cannot block the canyons between buildings, because they are needed for light and air. This, along with conductors for the current, decreases EROEI.

Caution to the reader, you will see all kinds of figures given for each kind of energy production. One to beware of for solar energy, is that people who want to find an unfavorable value for it will want to count the energy input from the sun as a part of energy invested. No, no, no! Energy from the sun is not depleted; it is there day after day, year after year. It doesn’t take away from the future supply from the sun. It is true that energy conversion is in the range of 15 to 20%, but sunlight is not an economic input. It is free.

One to beware of with gas stops the analysis with the energy content of the gas itself, say at the wellhead, i.e. energy content of the gas over energy to get gas out of the ground. Not enough! What you really want is to compare electrical power to the customer when comparing gas production with other processes. You must go all the way to the final consumer. Boundaries of the analysis must be correctly chosen!

Net energy is the difference between the total energy put into a process and the energy recovered from the process, a subtractive operation, rather than a division. It determines how much energy is available for society to use. Generally speaking, a society needs a certain amount of energy to function at the current level. If the ERoEI is high, it is relatively easy to meet the societies’ needs. The lower the ERoEI, the less energy there is to meet needs other than getting more energy.

Unfortunately, it is possible to make money on such schemes with low ERoEI and that will be covered in the next article which is on “rate of return”.

Humanity may exhaust the Earth’s low-cost mineral resources before the end of this century – but better resource management could avoid the worst risks.

From an Article by Nafeez Ahmed, The Guardian UK, June 10, 2014

A new landmark scientific report drawing on the work of the world’s leading mineral experts forecasts that industrial civilisation’s extraction of critical minerals and fossil fuel resources is reaching the limits of economic feasibility, and could lead to a collapse of key infrastructures unless new ways to manage resources are implemented.

The peer-reviewed study – the 33rd Report to the Club of Rome – is authored by Prof Ugo Bardi of the Department of Earth Sciences at the University of Florence, where he teaches physical chemistry. It includes specialist contributions from fifteen senior scientists and experts across the fields of geology, agriculture, energy, physics, economics, geography, transport, ecology, industrial ecology, and biology, among others.

The Club of Rome is a Swiss-based global think tank founded in 1968 consisting of current and former heads of state, UN bureaucrats, government officials, diplomats, scientists, economists and business leaders.

Its latest report, to be released on 12th June, conducts a comprehensive overview of the history and evolution of mining, and argues that the increasing costs of mineral extraction due to pollution, waste, and depletion of low-cost sources will eventually make the present structure of industrial civilisation unsustainable.

Much of the report’s focus is on the concept of Energy Return on Energy Invested (EROEI), which measures the amount of energy needed to extract resources. While making clear that “we are not running out of any mineral,” the report finds that “extraction is becoming more and more difficult as the easy ores are depleted. More energy is needed to maintain past production rates, and even more is needed to increase them.” As a consequence, despite large quantities of remaining mineral reserves:

“The production of many mineral commodities appears to be on the verge of decline… we may be going through a century-long cycle that will lead to the disappearance of mining as we know it.”

The last decade has seen the world shift to more expensive and difficult to extract fossil fuel resources, in the form of unconventional forms of oil and gas, which have much lower levels of EROEI than conventional oil. Even with technological breakthroughs in fracking and associated drilling techniques, this trend is unlikely to reverse significantly.

A former senior executive in Australia’s oil, gas and coal industry, Ian Dunlop, describes in the report how fracking can rise production “rapidly to a peak, but it then declines rapidly, too, often by 80 to 95 percent over the first three years.” This means that often “several thousand wells” are needed for a single shale play to provide “a return on investment.”

The average EROEI to run “industrial society as we know it” is about 8 to 10. Shale oil and gas, tar sands, and coal seam gas are all “at, or below, that level if their full costs are accounted for… Thus fracking, in energy terms, will not provide a source on which to develop sustainable global society.”

The Club of Rome report also applies the EROEI analysis to extraction of coal and uranium. World coal production will peak by 2050 latest, and could peak as early as 2020. US coal production has already peaked, and future production will be determined largely by China. But rising domestic demand from the latter, and from India, could generate higher prices and shortages in the near future: “Therefore, there is definitely no scope for substituting for oil and gas with coal.”

As for global uranium supplies, the report says that current uranium production from mines is already insufficient to fuel existing nuclear reactors, a gap being filled by recovery of uranium military stockpiles and old nuclear warheads. While the production gap could be closed at current levels of demand, a worldwide expansion of nuclear power would be unsustainable due to “gigantic investments” needed.

US Geological Survey data analysed by the report shows that chromium, molybdenum, tungsten, nickel, platinum-palladium, copper, zinc, cadmium, titanium, and tin will face peak production followed by declines within this century. This is because declared reserves are often “more hypothetical than measured”, meaning the “assumption of mineral bonanzas… are far removed from reality.”

In particular, the report highlights the fate of copper, lithium, nickel and zinc. Physicist Prof Rui Namorado Rosa projects an “imminent slowdown of copper availability” in the report. Although production has grown exponentially, the grade of the minerals mined is steadily declining, lifting mining costs. ‘Peak copper’ is likely to hit by 2040, but could even occur within the next decade.

Production of lithium production, presently used for batteries electric cars, would also be strained under a large-scale electrification of transport infrastructure and vehicles. Sustainable lithium production requires 80-100% recycling – currently this stands at less than 1%.

Perhaps the most alarming trend in mineral depletion concerns phosphorous, which is critical to fertilise soil and sustain agriculture. While phosphorous reserves are not running out, physical, energy and economic factors mean only a small percentage of it can be mined. Crop yield on 40 percent of the world’s arable land is already limited by economical phosphorus availability.

In the Club of Rome study, physicist Patrick Dery says that several major regions of rock phosphate production – such as the island of Nauru and the US, which is the world’s second largest producer – are post-peak and now declining, with global phosphorous supplies potentially becoming insufficient to meet agricultural demand within 30-40 years. The problem can potentially be solved as phosphorous can be recycled.

A parallel trend documented in the report by Food and Agricultural Organisation (FAO) agronomist Toufic El Asmar is an accelerating decline in land productivity due to industrial agricultural methods, which are degrading the soil by as much as 50% in some areas.

Prof Rajendra K. Pachauri, chairman of the Intergovernmental Panel on Climate Change (IPCC), said that the report is “an effective piece of work” to assess the planet’s mineral wealth “within the framework of sustainability.” Its findings offer a “valuable basis for discussions on mineral policy.”

But the window for meaningful policy action is closing rapidly. “The main alarm bell is the trend in the prices of mineral commodities,” Prof Bardi told me.

“Prices have gone up by a factor 3-5 and have remained at these level for the past 5-6 years. They are not going to go down again, because they are caused by irreversible increases in production costs. These prices are already causing the decline of the less efficient economies (say, Italy, Greece, Spain, etc.). We are not at the inversion point yet, but close – less than a decade?”

For part 2 of this story see here.

Dr. Nafeez Ahmed is an international security journalist and academic. He is the author of A User’s Guide to the Crisis of Civilization: And How to Save It.