Energy Transition: The Future Ahead

The industrial sector’s focus on shifting from fossil-fuel dependency to renewable sources, has led many to question how the transition will effect industrial applications. Will hoses that convey high profile materials require new standards? Will this affect applications like valves and heat exchangers? Also, when will this post-oil world require these changes be implemented? To address these questions, we looked into two recent books: Energy Transitions by Vaclav Smil and The New Map by Daniel Yergin. What follows is a condensed version of these books. The conclusion? The changes for the next energy transition are not yet known. Read on to learn why.

By KCI Editorial

What Are Energy Transitions? Why Do They happen?

Since its dawn, humanity has been using natural resources for survival and comfort. For a long time, plants and animals were the only ‘fuel’ and the human body the only ‘prime mover’; a prime mover is “any device which transforms thermal, kinetic, or chemical energy into useful work”.[1] It is therefore possible to conclude that the history of energy transitions is the history of change in fuels and prime movers throughout our brief stay in this planet.

In terms of fuel, individuals moved from biomass – the mass of living biological organisms in a given area or ecosystem at a given time[2] – to coal to oil to gas. In terms of prime movers, there was a transition from muscle to wind and water (such as windmills, sails, and water wheels), to steam engines and turbines, and then to internal combustion engines and gas turbines.

Figure 1. Concise history of lawn mowers.[11,12,13]
What was the drive for these earlier shifts? Figure 1 provides a comprehensive example of the cause of this transition. Moving from a manual lawn mower (a) to a gas-powered one (b) required the latter to be invented; that is, technology availability. It also required however, that both the machine and fuel, be conveniently available at a reasonable cost. In a nutshell, energy transitions happened in the past when better, more efficient, and convenient technology and fuels became available. Or, if a fuel source became depleted or restricted, as in the case of whale oil for illumination or moving from wood to coal due to diminishing forests.

The move from (b) to (c) is a bit more complicated. Now, for the first time in history, the drive for change includes environmental considerations along with technology, cost, and convenience. For many people, the alternative (c) offers lower emissions with convenience, and that is enough to justify the update. Of course, an even better environmental choice would be to go back to the manual lawn mower, as generating electricity might also be a source of emissions, as in the case of thermal power plants burning coal.

One can therefore conclude that the next energy transition is predicated on using renewable energy sources to reduce emissions and move away from finite fossil fuels. According to the EIA (U.S. Energy Information Administration), “Renewable energy is energy from sources that are naturally replenishing but flow-limited; renewable resources are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time.”[3] Solar and wind offer the best examples of this intermittency, as the amount of power that can be generated each day varies through seasons and can be predicted only up to a point.

Types of Energy

Smil[4] lists nine major kinds of renewable energies: solar radiation; its six transformations as running water (hydro energy); wind; wind-generated ocean waves; ocean currents; thermal differences between the ocean’s surface and deep waters; photosynthesis (primary production); geothermal energy; and tidal energy. Being renewable does not mean lack of emissions. Burning wood (generated by photosynthesis) is a source of emissions after all. Also, being a low-emissions source of energy does not mean it is renewable, as in the case of nuclear power stations; they use uranium as fuel, which has limited recoverable resources in the same way as oil.

Why are emissions a problem? Yergin[5] offers a concise explanation. “Using average annual data from the years 2009–2018 (see Figure 2): Some 210 gigatons of carbon were annually, on average, naturally released by such processes as the decay of plants and breathing by people and animals. But 9.5 gigatons came from fossil fuels and 1.5 from land use. This added up to a total of 221 gigatons released. Only 215.7 were captured in the natural annual cycle—that is, absorbed by vegetation and the ocean—leaving a residual 4.9 gigatons in the atmosphere uncaptured, (there is also a budget imbalance factor). That uncaptured 4.9 gigatons is only 2.2% of the naturally captured CO2. That may seem a very small amount in any given year. But, over the years, it accumulates and builds up in the band of gases known as earth’s atmosphere. Water vapor is the most prevalent greenhouse gas. Others include nitrous oxide and methane. Some of these gases dissipate after a year or ten years; others last much longer. Some are more potent than CO2. These greenhouse gases become a shield of sorts, a global ‘greenhouse’ around the planet, retaining more of the sun’s heat, which otherwise would flow back into space. The result is greater warming for the earth—thus known as the ‘greenhouse effect’.”

Figure 2. The carbon cycle: average annual 2009-2018 estimated.

There is plenty of evidence that the planet is warming and that humans are contributing to it. However, the relationships of cause and effect between this warming and climate are yet not well understood. A recent book, reference #6 for example, argues that many extreme weather events, such as tornados and droughts, have not seen any increase in frequency for the last 100 years, and so are not linked to global warming as many sources often try to report.

Even if the effects of climate change are disputed, some facts still stand. Emissions of hazard pollutants caused – and still cause – health problems in many places, including the United States.[7] It is worth noticing that concerns over air pollution can be directed linked to the enactment of many pieces of American legislation – chiefly among them the Clean Air Act – and the creation of the Environmental Protection Agency (EPA), that is today responsible for setting emission’s limits and enforcing these limits.

Timeframe and Challenges for the Next Energy Transition

Energy transitions are nothing new, and one thing that history has taught us is that they take a long time to happen. Smil[8] studied major transitions for five Countries (U.S., China, Japan, Russia, U.K., France) for a period of 150 years. Tracking consumption from wood to coal and onward, he measured how long it takes for an energy source to go from a 5% to a 25% share of total energy supply. “The repeated answer is that it takes decades of gradual penetration. After crude oil claimed 5% of the total American energy supply in 1905, it took 28 years to reach 25%, and the rise was even slower for natural gas, 33 years from 1924 to 1957. Today, despite the attention lavished on solar cells and wind, those up-and-coming renewables have yet to reach even the 5 percent mark.”[8] Figure 3 illustrate this point with data collected by the EIA (U.S. Energy Information Administration).

Although the shift to renewables is desirable, and eventually inevitable, ‘neither its pace nor its compositional and operational details are yet clear.’[4] Despite the modern understanding of science, advanced manufacturing technology, abundance of materials, and environmental concerns, there is no indication that the forthcoming shift will be any different from the previous ones from a time perspective.

Figure 3. Shares of total U.S. energy consumption by major sources in selected years (1776-2019). Note: Wood includes wood and wood waste; Other Renewables includes biofuels, geothermal, solar, and wind.[9]
Transformation Hindrances

There are several challenges that hinder the pace of transformation. Two of the most notable are: density and infrastructure.

Renewables have both lower energy density and lower power density. Energy density refers to the quantity of energy contained per unit of mass or volume. The more concentrated the energy is – that is, the denser – the less fuel required for a given application. A direct consequence of this is, for example, the extreme difficulty in finding an alternative fuel for jet engines in planes; any alternative for aviation kerosene needs higher or similar energy density. Some biofuels have been tested, but concerns over the impact on land requirements and food production are often cited as an impediment to large scale supply.

Another important density measure is power density, which is the rate of flow of energy per unit of land area. It is interesting to note how much land it takes to produce (or consume) a certain amount of energy. Today, a relatively small amount of land is used to produce the majority of the energy the world consumes. Smil calculated that land requirements for fossil fuels extraction, processing, and transportation, along with land for generation and transmission of thermal electricity, take no more than 30,000 km2. This is a land surface area equivalent to Belgium’s. On the other hand, using phytomass (plant biomass) would require ‘12,500,000 km2, roughly an equivalent of the entire territories of the United States and India, an area more than 400 times larger than the space taken up by all of modern energy’s infrastructures.[4]

Figure 4. Power density versus area for different energy sources and end users.[10]
Figure 4 helps understand this concept. The higher power densities mean less land requirements. However, there is also a matter of infrastructure. Today’s energy-hungry end users are being served by a vast array of ‘Coal and uranium mines, oil and gas fields, coal trains, pipelines, coal carrying vessels, oil and LNG tankers, coal treatment plants, refineries, LNG terminals, uranium processing (and reprocessing) facilities, thermal and hydro electricity-generating plants, HV transmission lines and distribution lines, and gasoline and diesel filling stations constitute the world’s most extensive, and the most costly, web of infrastructures that now spans the globe.[4]

A similar infrastructure needs to be built to renewables, whatever they are. The best sites in terms of incidence and availability for wind and solar, for example, probably will be distant from the end users. High-density cities, for example, will not probably have large areas of available land in their vicinity. In order to connect them, new infrastructure for storage and transmission is needed. In other words, we are talking about a shift in distributing energy from a relatively small number of high power density sites to a world with a great number of energy-generating sites, using different, low power densities technologies, each contributing to a small amount of the total energy supply.


Despite ambitious goals proclaimed by politicians, the world in 2030 (or even 2050) tends to be similar to what we are experiencing now. Lower carbon? For sure, with more efficient prime movers and a larger share of renewable sources. With hope, also some decrease in the per capita use of energy.

Back to the questions that initiated this conversation, how will the shift from fossil-fuel to renewable sources effect applications in the industrial sector? Given the challenges in technology and infrastructure we explored in this article, it is safe to say that renewables are still not requiring major changes in application design, and this scenario will likely persist for the foreseeable future.


  4. Smil, Vaclav. Energy Transitions: History, Requirements, Prospects; Praeger, 2010.
  5. Yergin, Daniel. The New Map : Energy, Climate, and the Clash of Nations; Penguin Press, 2020.
  6. Koonin, Steven E. Unsettled: What Climate Science Tells Us, What It Doesn’t, and Why It Matters, BenBella Books, 2021.
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