Lesson 3: Energy Supply and Demand
Lesson 3: Energy Supply and DemandThe links below provide an outline of the material for this lesson. Be sure to carefully read through the entire lesson before returning to Canvas to submit your assignments.
3.1 Lesson 3 Introduction
3.1 Lesson 3 IntroductionWelcome to Lesson 3!
Welcome to this exploration of world energy consumption. In 2024, humanity used approximately 186,000 terawatt-hours of energy that's enough to power every home, factory, vehicle, and data center on Earth. But where does this energy come from? How has our relationship with energy evolved since the days of wood fires? And what choices will determine whether we meet growing demand while protecting our climate?
In this lesson, we will be learning about the changes in energy supply and demand throughout history. We will be looking at both U.S. energy use and world energy use to understand patterns at multiple scales. While there are lots of numbers in this unit, it is important for us to remember trends and estimates, and not worry about the exact values. Energy data is complex and constantly updated—for example, the most recent energy data is available from the EIA U.S. Energy Facts Explained.
To illustrate this approach: In the latest U.S. data, we see that about 9% of U.S. energy comes from renewable sources. But what's most important to remember isn't the precise percentage—it's the bigger picture: petroleum and natural gas are the primary sources of U.S. energy use, and together those two sources account for nearly 75% of total U.S. energy consumption. That trend—fossil fuel dominance with renewables gradually growing—is the key takeaway.
Lesson 3: Learning Objectives
Upon completing this lesson, you should be able to:
- Analyze historical trends to understand how the Industrial Revolution transformed global energy use
- Compare energy consumption patterns across countries and connect them to GDP, geography, and lifestyle
- Investigate interactive data visualizations to see how fossil fuels still dominate—and how renewables are rising
- Evaluate three potential energy futures from the International Energy Agency and consider what "Net Zero" really means
- Calculate real-world applications like energy doubling time to grasp the scale of future demand
By the end, you'll not only understand the numbers behind global energy you'll be equipped to think critically about the policies, technologies, and personal choices that will power our shared future. Let's begin.
3.2 Global Energy Consumption
3.2 Global Energy ConsumptionIn 2024, the world wide energy consumption was about 186,000 TWhs (or 635 Quadrillion BTUs). The energy mix used by the whole world is shown below in the figure from Our World in Data. This figure is interactive, so you can slide the bar across and see how that information changes over time. The largest energy source for the whole world is Oil, followed by Natural Gas and Coal. This means most of the world's energy comes from fossil fuels. If you slide the bar around, you can see how renewable has begun to steadily increase in the past decade or more.
Energy consumption numbers are always reported a few years behind, so we are always looking into the past before we plan for the future. As of 2024, the world's total primary energy consumption was about 186,000 TWhs (635 Quadrillion Btus).
What is interesting to see in this chart, which goes all the way back to 1800, is that for the first 100 years, the main energy source was only biomass and relatively consistent. In that time, nearly all energy was from biomass in the form of wood. Do you know what happened in the late 1800’s to start the exponential growth of energy use?
The Industrial Revolution played a key role in human development and energy use. Some inventions in that time period include:
- Steam Engine- allowed for travel and transportation of goods
- Discovery of Oil- Titusville PA 1859
- Textile Machinery
- Internal Combustion Engine
- Electric Generator
- Electric Lighting
After the industrial revolution, we start to see an increase in coal use, followed by oil and finally natural gas. Recall from lesson 1, those three energy sources are called our Fossil Fuels. Those three energy sources also account for the majority (over 80%) of the world’s energy use.
Please use the interactive features of this figure (using the arrow next to the year 1800) to adjust the time frame and investigate this chart further.
Data table for the Global Primary Energy Consumption by Source chart.
Use the following link to downlaod the data (csv file) for the Global Primary Energy Consumption by Source graphic.
The figure below shows how energy use is used per person (or per capita). You can see which countries have the highest energy use per person, in the dark red. The US is one of the highest consumers (but not the highest). Which country do you think is the highest user of energy per capita?
You can also explore this data, to see how it has changed over time. One major change over time is with China, which starts the time-laspe as about 1,000 kWh/ per person and ends the time-lapse at over 30,000kWh/per person.
- Do you expect this number to steadily increase?
- What do you expect to happen to India in the next 10 years?
- Do you think US energy use has increased, decreased or stayed the same over time?
Please click on the "Explore the data" for more analysis of each country over time.
Data table for the Primary Energy Consumption Per Capita chart.
Use the following link to downlaod the data (csv file) for the Primary Energy Consumption Per Capita graphic.
3.3 World Energy Outlook
3.3 World Energy OutlookAccording to the International Energy Agency, the world energy outlook for 2025. This report is modeling three different potential energy futures, Current Policies Scenario, State Policies Scenario and Net Zero Emissions Scenario. Those three scenarios are shown below.
Three Scenarios, Three Futures
Please take a look at the World Energy Outlook 2025 Executive Summary of this latest report.
Key takeaways include:
- Energy demand is expected to grow through 2050, but that rate depends on the speed of which India and Southeast Asia grow.
- While coal will continue to decline, natural gas and petroleum and still expected to grow throughout the mid-century. Coal use is expected to peak somewhere around 2030.
- Global temperatures will continue to increase, expected to reach 3°C by 2100 if current policies remain. Under the Net Zero Emissions Scenario we can still expect an increase in global temperature of 1.65°C
- Electrification plays a growing role worldwide. Data Centers and AI account for 10% of world wide electricity consumption, however the US sees a larger share of these centers.
Nearly 9% of the world population still live without electricity, and nearly 2 billion people rely on polluting cooking methods such as open fires and charcoal.
Podcast: World Energy Outlook 2025 (32:17)
Transcript: World Energy Outlook 2025 podcast (32:17)
[Dan Hewitt] Welcome back to the IEA's podcast, Everything Energy. I'm Dan Hewitt.
This week, we're looking at the 2025 edition of the IEA's World Energy Outlook. It's widely viewed as the most authoritative source of energy analysis and projections. It uses the latest energy data, technology and market trends and government policies to explore a range of possible energy futures. And here to talk through some of the report's key findings are lead authors, Lara Kotze and Tim Gould.
Lara is the IEA's Director of Sustainability, Technology and Outlooks, and Tim is the IEA's Chief Energy Economist.
OK, Lara Kotze and Tim Gould, thank you so much for joining us. Now, to start with, I want to just remind people about the purpose or the aim of the World Energy Outlook. So, could you just boil it down into a couple of sentences, the key aims of it?
[Lara Kotze] Yeah, thank you very much, Dan. So, every year for the past several years now, we produce and release the World Energy Outlook. And basically, as we know, there is no single storyline about the future of energy. We do present always multiple scenarios, none of which is a forecast. and we explore implications of policy, technology and market trends through 2050, actually. And the reason why we do this is that we intend to give all the possible data and consequences for policymakers, energy stakeholders at large, to take the best decision for the energy future.
[Dan] OK, now there is another full commentary about some of the scenarios that you mentioned, but I think the best way to talk about the WEO is to look at the big themes. So, we're going to start with energy security. And the report said that energy is at the heart of today's geopolitical tension. So, Tim, I wonder if you can tell me a bit more about what's been driving that.
[Tim Gould] Yeah, thanks, Tim. I think the thing that strikes us when we look at the energy landscape today is not just any individual aspect of energy security, but the fact that we have such a range of issues that cover pretty much all of the fuels and technologies that are out there. So, when you look at oil, there's an issue of sanctions. When you look at gas, there's obviously been the extreme tensions around Russian supplies to Europe or the cut to Russian supplies to Europe and what that's meant for global markets. But also, when you think of electricity, there's been a lot of strains on electricity systems in recent years that have become clear through blackouts and other operational incidents that also brought that into very much the political domain. But when you look also at new technologies coming into the system and particularly the supply chains for critical minerals, you've had very much in the news, the export controls on rare earth elements and battery-related technologies. So, the sense that that market concentration, the extreme level of market concentration that you have for some of those technologies and some of those critical minerals, that's also very much a feature of the energy security discussion. So, across all of those different elements, there are things that make a very complex landscape from our perspective and demand responses also from the energy policymakers who we're trying to communicate with also as part of this report.
[Dan] And just staying with critical minerals for a second could you explain to us some of the vulnerabilities there specifically about China in terms of about the refining they do about the problems that happen if you have so much concentrated in one country.
[Tim] So I think first of all we need to be clear that we're talking about a different category of threat when we when we when we refer to critical minerals and because these are not things that are used directly in the energy sector as fuels. So, it's not the same as a shortfall for oil, where everyone who uses oil feels the effect of a spike in prices. But these are extremely important inputs, these critical minerals, to a range of really important bits of the energy infrastructure. So, copper for wiring, for transmission lines, all of the battery metals like cobalt and nickel and lithium going into the batteries that then provide really important services in the energy sector. And rare earth elements that go into electric motors and other aspects of energy related technology. So, when you have a shortfall in those areas, they really affect your ability to bring those technologies into the system at scale. So that's a little bit the context. And when we look at the degree of concentration, so China has a very high share of the market for refined output of a lot of those products. It's also a huge user of those outputs. That's one of the reasons why it has this very strong position. But it does mean that one of the golden rules of energy security is diversification. So, whenever you see a high degree of market concentration in any part of the energy sector, that's a cause for looking carefully at what risks might emerge as a result. And that's very much the situation that we see at the moment for critical minerals.
[Dan] Okay, staying with vulnerabilities, the report also mentions threats from weather and cyber-attacks. So, Laura, I wonder if you could just tell us a bit more about that. And how can you build in resilience to those threats?
[Lara] Yeah, thank you very much, Dan. I think as Tim mentioned earlier, the key thread here is multiple threads throughout multiple fuels and technologies and what you have been seeing particularly for the electricity sector is that the risks that are concerning electricity and their security are multiplying and we have been trying to track data about what's happening and the two areas have particularly struck our attention one has been how quick cyber-attacks are increasing. And we find that over the past four years, the number of cyberattacks directed to energy utilities have tripled. This is clearly showing for us an increasing vulnerability towards electricity supplies. An interesting feature here is that AI is actually helping the cyber-attacks to happen on one hand, but on the other hand, we are also seeing that those utilities that that have AI embedded in their systems are the ones that are able to come out of the attack more quickly. So, at the same time, AI being a threat can help to security here. The other is really extreme weather, and now those are influencing the functioning of electricity systems. You can have very high temperature, therefore bringing up electricity demand, but at the same time, what would happen is that conventional generation such as hydro may be very low, you wouldn't probably have wind, so you have a supply that is constrained, demand that is very high, and in some cases very violent events that could be storms or others. So, we were simply trying to track and understand how serious is this problem, and for last year we have actually found that 200 million households were affected by blackouts that that were directly linked to extreme weather events. So, something that is large and that we should increasingly take into account when making sure that electricity is up at all times.
[Dan] Okay, now another big theme is the world's thirst for energy and the shifting center of gravity of where that demand might come from. So, could you put into context the scale of that energy demand and the developing countries that could be driving it?
[Lara] Yeah. So, I think that one area that we have been trying to highlight is the commonalities across all of the scenarios that we are portraying in the World Energy Outlook. And we need, first of all, to understand why do we need energy and who will need it. So, we are seeing important drivers that point to very clear directions. The first is, where is the economy growing? And the economy is growing most in the service sector, meaning digital, meaning financial services, meaning health care. And the service sector tends to be very electricity intensive. So, it's already an indication that we're moving towards an economy that is more dependent on electricity than before. The other big driver is, of course, where is population? And we are seeing some important shifts there happening. As we speak, actually, China is experiencing a big population, and in the next 10 years, we'll actually be seeing less people in China, 50 million less people living in China than today. We all know that China has been driving demand of energy, basically writing the history of energy for the past 10 years or so. And this is changing. This is changing as more people are living in other emerging countries and developing economies, in particular, India. Southeast Asia, but also Latin America and Africa. So, population there are becoming richer. They are requiring more energy for cooling needs, owning more refrigerators, owning more cars. And therefore, we are very clearly seeing across all of the scenarios that the increase in energy demand is coming mostly from this group of countries that are altogether, not in a single way, taking the baton from China that has driven and written the energy history for the past decades over to the next decade. Okay and let's move on to renewables because another big theme in the report is the rising role that renewables are going to play. So, could you put into context how fast they are growing compared with other fuels in other sectors? Yeah, I think the renewables growth has to be really put in the context of the electrification of the economy We only understand it through that, actually. Electricity is the fastest growing fuel, if we may say so. And we need to understand which fuel and technologies are going to provide all this additional electricity that the world will need. And we find that all low emission technologies are growing very, very fast, led by solar. And the reason why solar is leading this growth is a combination of three factors. First is a cost. Solar is becoming more and more cost competitive. Many countries around the world are still having policies in place that support the deployment of solar. A third, importantly, 80% of the increase in electricity demand is actually happening in places where the solar resources are excellent. This was not the case in the past, where most of the growth would be in the northern hemisphere, where you don't necessarily have the best solar resources. So, all these three things happening at the same time put Southern in a very good position. Nuclear is also growing very, very fast. We have been saying for the past several years that nuclear were experiencing a renaissance. And the data are very clear. 2025 is already seeing a record in terms of electricity generation for nuclear, growing another over 30% to 2035. and we're seeing the largest amount of new construction happening for the past 30 years. So, a very strong growth of all low emission fuels.
[Dan] Okay, now staying with the energy mix, let's look at fossil fuels. So, what does the report say could happen to the consumption of oil and gas if we stay on our current path? So, one of the scenarios mentioned in the report.
[Tim] So we do have, we've brought back this current policy scenario after a few years. It's back in the WEO 2025. And one of the findings from this year's World Energy Outlook is that if you just look at the policies that are in place, so enacted formally, and you also take a relatively cautious view on how quickly new technologies can be brought into the system, then that extends a horizon out for oil and natural gas growth beyond 2030 and towards mid-century. And so that's created a lot of interest and because when you look at another set of scenarios that we produce, the stated policy scenario, we have a different picture. We have oil flattening out around the end of this decade. And last time we did the stated policy scenario, gas also had a similar kind of trajectory. But this year, primarily because of policy changes in the United States and lower prices, because lots of new LNG coming to market, that period of gas growth extends out into the 2030s. So that's the broad picture for oil and gas demand in those two kind of more exploratory scenarios.
[Dan] Okay, let's dig a little bit more into oil. What could change the different scenarios for the way the world uses oil, oil demand?
[Tim] The thing that makes the biggest difference is EVs and electric mobility. There is a number of different ways in which you can approach the differences between that CPS trajectory that continues to grow and the flattening that we get in the stated policy scenario. Efficiency policies make a difference. The way that we collect and recycle plastics makes a difference and, but the single biggest factor is electric mobility because it's all about road transport and road transport is nearly half of oil demand. And in the the scenario that keeps rising. You know you have electric mobility continue to expand in in established markets notably in China, and but also in Europe where you have strong policies in place. But elsewhere doesn't really follow suit because you haven't followed through with putting the infrastructure in place and getting the incentives in place for consumers to buy electric. And that is one of the things that differentiates that outlook from a flattening outlook for oil demand, where you have outside of Europe, outside of China, particularly in emerging developing economies where car ownership rates are increasing quite strongly. You know, those choices switch also across much more so to electric in that stated policy scenario. And that's the key reason why you have that flattening.
[Dan] Okay, well, let's talk about liquefied natural gas, LNG. It talks about a wave of it. So, who is going to be producing it and exporting it? And where is it going to go?
[Tim] The growth is coming overwhelmingly from the United States, followed by Qatar. So, there's been this wave of new final investment decisions taken for LNG export capacity. And that wave has only grown stronger over the last 12 months since we last produced the World Energy Outlook because there's been a lot of new project approvals overwhelmingly in the United States that just make that wave even bigger than it already was in the last WEO. So that then extends out and some of it will come to Europe. Europe, domestic production is down, you know, and it's also moving away from pipeline gas from Russia, of course. So, it does need more LNG. China, in our view, will take some more LNG. But there's some new markets as well. And as prices come down for natural gas, there's potential then for countries like India or countries in Southeast Asia to also take in some of that LNG. And that's exactly what we see in our scenarios. It goes into industry. Some of it goes into power. Some of it goes into transport. You know, these are countries that by and large need cooling rather than heating. They have a very good solar resource. So, it's not going to be the same picture for gas use as you get in a place like Europe, where you have a large winter heating requirement. So, you need to be very conscious of those regional, you know, those regional factors and exactly where gas might come into the system.
[Dan] And before we leave fossil fuels, I've got a question about coal. Coal demand is growing 50% faster than the next fossil fuel. I'm interested to know what's driving that.
[Tim] So over the last few years, a lot of that has had to do with China. As Laura was mentioning that, you know, we've had a lot of electricity demand growth in different parts of the world, but China's been particularly strong. And where you also have peak demand increasing, you're bringing some of that backup capacity into the system, and a lot of that in many parts of the world has been coal. So that's one of the reasons why coal demand has been rising in recent years. But the future doesn't necessarily look like the recent past. And the speed at which countries like China are building out not just renewables, but also nuclear. In our view, it reduces the call on coal. How quickly that happens, you can see interesting variations across the different scenarios. But even with all of that extra electricity demand, at a certain point, if you continue the momentum behind solar, if you continue the momentum behind wind and nuclear and other technologies, that starts to have implications for coal too. And that's why we do see coal use going into decline before the end of this decade.
[Dan] Okay, now, so we were talking about the energy mix there. So, I think it makes sense to talk about global emissions. Now, the report says there is less momentum than before behind national and international efforts to reduce emissions. And I just wonder if you could tell us a bit more about what's caused that momentum change, and really what it means for global emissions
[Lara] Yeah, so, as we, as we mentioned at the very start then we, we are taking here a scenario approach and what we are doing is understanding and give really the consequences of each of the choices in front of all of energy professionals. So, in the current policy scenario that the team mentioned earlier that we reintroduced this year, we're actually seeing emissions remaining pretty high and rather flat to the 2050. In the stated policy scenario, we see a peak and a modest decline in emissions. And we have also, as we have been doing since 2021 now, also the net zero by 2050 scenario, which by design brings emissions down to zero in 2050. And what are the implications of each of those emission trajectory? The first, the current policy scenario would lead us to, by the end of the century, around 3 degrees warming, the stated policy scenario around 2.5 degrees warming, and the net zero by 2050 scenario, 1.5 degree warming. Something important to note that has happened for the first time this year is that across all of the scenarios, temperature, the 1 .5 degree temperature will be surpassed by 2030 in all of the scenarios and in all of the scenarios of course by different degrees we will stay above this threshold for several decades. This for us is another clear sign that the resilience measure within the energy sector will become ever more important.
[Dan] And Lara I want to pick up on what you were saying earlier about electricity. Now the IEA has spoken in the past about the age of electricity coming soon, but now we're talking about its arrival. So, what are we pointing to? How has it moved from something expected to something we're living in today?
[Lara] I think, first of all, we start from the data over the past few years. It has been very clear that electricity demand has grown much faster than energy demand, and this has happened sequentially over several years now. And for the reasons we have explained at the beginning, we are moving towards a society that is increasingly service based. Large parts of the population that are living in areas requiring cooling are becoming rich enough to actually buy air conditioners. And of course, the very big push of AI data centers and digital technologies are really pushing electricity demand very strongly up. So, there are a couple of pointers here. So, the fact that electricity demand is growing and growing stronger than energy demand is true across all of the scenarios that we have explored. And to give a sense of scale, the minimum amount that we're seeing being required from now to 2035 being additional is 10,000 terawatt hours, which is the entire amount of electricity that advanced economies are consuming today. This is huge. So, we often say that electricity accounts for around 20% of final energy uses but the reality is that sectors accounting for over 40% of the global economy use electricity as a primary input. So electricity has a disproportionate importance in the economy as we live in today and is only going to grow in the next 10 years That's why we're really saying we are here, it's the age of electricity, and it's becoming even stronger.
[Dan] And just a question on potential roadblocks about electrification. Are we concerned that the grids are ready to meet that rising electricity demand? Not sure, Tim, if you want to answer that.
[Tim] So we are concerned, yes. We've had a situation over the last 10 years that investments in generation have risen very substantially, up to around $1 trillion worth of investment each year. But if you look at the investment in grids, they've risen at less than half that pace, and there are around $400 billion each year. And what that means over the last 10 years is that 10 years ago we were spending, for every dollar going into generation, we were spending about 60 cents on infrastructure. Now that ratio has gone down to $1 for generation to 40 cents on infrastructure. And that is not where we need to be, because especially with the sorts of developments that Laura's been talking about, where you have new technologies coming into the system. You've got a lot of new demand. You need to be connecting up new loads. You need to be managing variability. You need your infrastructure to be working extremely well. And that's not the case in many countries. And so, there is this sense that investments in grid need to pick up very substantially in order to ensure the reliability, but also to make sure that we're using these new resources cost effectively. Because if you see lots of curtailment, that can be a way at the margin to manage some of these new resources, but too much of it, and you're just wasting a valuable asset. So, you need to make sure that the kit, the grid, is really fit for purpose, make sure that it's smart and that it's connecting new uses, connecting people who don't have access to electricity at the moment. So, I think it's a really important component of the future.
[Lara] If I may come in here, I think Tim has brought in a very, very important point. We are seeing changes in the way electricity demand is coming in particular peak demand is growing very, very strongly and this growth in in peak demand that we're expecting over the next decade is larger than the increase we have had in what we call dispatchable sources over the past decade so we are going to be seeing increase in all dispatchable sources over, over the next decade being hydro, natural gas, coal but importantly, we're seeing very much a new star rising and this is batteries. Batteries is the fastest growing capacity of a dispatchable source out there. We're expecting to see a tenfold increase for a number of reasons because it can help being there at all times. It can help with the flexibility required by the amount of solar and cooling that are coming into the system. So, we have seen spectacular growth over the past couple of years, spectacular cost declines and we are seeing we are expecting to see a very, very big deployment of this technology.
[Tim] Just coming back in, if i might, uh because there's I mean we've gone through this uh this conversation without mentioning the word uh efficiency and it's probably uh you know we would we would look back and regret if we didn't mention it because it's super important also in this on in this area. Um, you know there's a lot of new air conditioning units being bought around the world and the efficiency of those units is a really important factor in determining peak demand and in determining some of the strains that we might see in electricity systems. And one of the aspects of the new analysis that we put in this year's World Energy Outlook is to say, well, if the technical efficiency of those air conditioners was up at the level that we see in some of the leading countries of the world, I mean, Japan, for example. That would reduce overall consumption substantially for cooling. I mean, you could bring it down by roughly a quarter, but it would have particularly important implications for peak demand and some of those strains that you get on the systems. You know, at moments when you need to have as much flexibility as you can. So, there's a really important part of this debate is around improving those minimum energy performance standards and the ways that you can ensure that the efficiency of the appliances that we're buying is as good as it can be. And this is not a question of making stuff more expensive for consumers, because by and large, you can find more efficient appliances on the shelves in different countries around the world at really at minimal or no cost differential to the average that's being bought today.
[Dan] Okay, another source of energy demand that's in the news a lot is data centers. And I just wonder if we can reflect on what the report says about the scale of investment in data centers and how much energy demand, they could potentially use.
[Lara] So what's happening at data centers today is remarkable. We have been seeing over the past decade a doubling of data center servers and we are expecting these to actually double again by 2035. Investments that are going into data centers today are basically on par of what we're seeing in the oil sector. So, when we say data is the new oil, there is also some very clear economic figures that back that up. Data centers are very energy intensive. In fact, they're very electricity intensive. And currently they are concentrated in three areas of the world. They are in the US, China and the European Union. 85% of data centers are in these three locations. So, in certain regions of the world, in particular the US, they are going to mean a very significant change in electricity demand trends. We are coming out of a decade of electricity demand being flat in advanced economies. Data centers are changing actually this shape. So, electricity demand is returning to growth because of data centers. In the US, they will account for 50%. So, half of the electricity demand growth in the U.S. is going to be driven by data centers. So, this is very, very significant. But when you look at the step back in the global level, data centers today are around 1.5 percent of global electricity use. And in terms of growth, they will account for around 10 percent. So, a very significant part. But we mentioned earlier, demand for cooling, demand for appliances, demand for other types of uses is also growing very fast. So, at the global level, significant, but not huge. At local scale, it can have very, very big implications.
[Dan] Now, bringing together some of these ideas that we've spoken about, and I'd love to hear both of your thoughts on this. And it says, to meet some of these challenges, policymakers need to show the spirit of 1973. And I'd just be interested to know what you think that means. What do we mean by that?
[Tim] Well, I'll have a first go. Around the time, that's obviously around the time that the IEA was created, first oil shock, and the initiative that then led to countries coming together to resolve some of these pressing energy security issues that arose because of that spike in oil prices. So the first thing, the first association that we're looking for there is when we think about some of these new emerging energy security challenges, whether that's in the electricity sector, but particularly now in some of the supply chains for critical minerals and elsewhere, can we think about rallying around to find solutions there, to find mechanisms for cooperation that will allow us to address them in the same way that we did back then, 50 years ago, on oil security. And obviously that led to the creation of the IEA back in the day.
[Lara] Yeah, I think that what we were putting together over the past year, the World Energy Outlook, we found through data, very much confirmation of a lot of the discussions that were held in London and the Future of Energy Security Summit. So multiple risks, risks multiplying across different fuels, across different technologies, across critical minerals. And we felt, and in particular the executive director mentioned that in an op-ed on critical minerals, it's a bit of 1973 moment, certainly for critical minerals, but for energy security at large. So, I think we are trying to ring an alarm bell to policymakers that those risks are there in a systemic way as never before. So, we would go back to the principles of energy security, try to work all together on diversification, predictability and cooperation. So, this is a bit the sense of the 1970 dream moment.
[Tim] And this one sort of remark that also the executive director made with the launch of the World Energy Hourly, that it's very important to respond to these energy security threats, these risks that we've talked about. But you can't forget other policy goals. So, you need to think about, as he put it, the synergies and the trade-offs that might arise also with really important goals on affordability, on access, on competitiveness, but also on climate change.
[Dan] Okay, well, Laura Kotze and Tim Gould, thanks so much for talking to me.
[Lara] Thank you, Dan.
[Tim] Thanks a lot, Dan.
3.4 Current and Future Energy Sources of the World
3.4 Current and Future Energy Sources of the WorldThe figure below shows the per capita energy consumption for each country. The energy sources are also split out by source, so you can see where each country gets their energy. The US consumes the most energy per person. Interact with the graph and answer the following questions.
- What country is #2 energy consumer per capita?
- What is the average energy consumption per capita for the average citizen of the world?
- What source of energy is the highest for a citizen of China?
- In 1965, which country was the second largest energy consumer in the world?
Data table for the Per Capita Primary Energy Consumption by Source, 2024 chart.
Use the following link to downlaod the data (csv file) for the Per Capita Primary Energy Consumption by Source, 2024 graphic.
The figure below shows the Global Primary energy consumption by source. This shows how the world wide energy sources have changed over time. As you explore the data, answer the following questions.
- What was the primary world-wide energy source prior to 1860s?
- What is the primary world-wide energy source today?
- In what year do you see Nuclear become an energy source?
- What renewable energy source is the largest percentage of world-wide energy?
Data table for the Global Primary Energy Consumption by Source chart.
Use the following link to downlaod the data (csv file) for the Global Primary Energy Consumption by Source graphic.
Energy Consumption and Electricity Projections
According to the International Energy Outlook (2023), global electricity generation will increase through 2025, however most of generation will be produced from renewable (zero-carbon) technologies. It is important to note that Net-Zero Carbon technologies are renewables, however, it can include nuclear power. Nuclear power plants do not emit any carbon emissions, so the figures below include nuclear as well as renewables. There has been increased discussion about nuclear power in recent years, including Small Modular Reactors (SMR), so it is possible to see a resurgence of nuclear power in the next 10-20 years.
In the IEA 2023 report, the combined share of fossil fuels (coal, petroleum and natural gas) is expected to decrease. They also predict that electric vehicles are expected to account for 29%-54% of all new vehicles sales by 2050. China and Western Europe are leading the switch to Electric Vehicles.
You can see in the figures below that the EIA predicts that world-wide electricity generation is expected to increase anywhere between 30-76% through 2050. The gray shaded area on the charts represents the level of uncertainty in development depending on a number of policy and economic factors. Renewables and nuclear are expected to produce most of the world’s electricity needs through 2050.

Note: Shaded regions represent maximum and minimum values for each projection year across the IEO2023 Reference case and side cases. Ref=Reference case.
Text description of the World Electricity Generation by Fuel Type image.
The image displays six line graphs representing global electricity generation projections by fuel type, measured in billion kilowatthours, from 2020 to 2050. The graphs include total electricity generation, coal, solar, natural gas, wind, and nuclear. Each graph features a black line depicting the reference scenario and a shaded area indicating projection uncertainty. The total electricity generation graph shows a steady increase. Coal remains relatively stable, while solar shows substantial growth. Natural gas and nuclear exhibit slight increases, and wind shows moderate growth. The top right corner features the EIA logo.
The figure below shows the expected electricity generation through 2050 from different areas of the world. China is expected to grow in all electricity generation, including fossil fuels, however their zero-carbon technologies are expected to account for most of their electricity generation through 2050. They are projected to have rapid growth in renewables through 2030 and start to level off as we get closer to 2050. Western Europe is expected to see nearly all of their increase in electricity generation to come from zero-carbon sources, while fossil fuel generation is decreasing. India shows a dramatic increase in electricity production from net zero-carbon sources, while fossil fuels remain plateaued through 2050. Africa shows an increase in electricity generation from all sources through 2050.

Note: Each line represents IEO2023 Reference case projections. Shaded regions represent maximum and minimum values for each projection year across the IEO2023 Reference case and side cases.
Text description of the electricity-generating capacity image.
The image is a multi-panel chart depicting projected electricity-generating capacity for zero-carbon and fossil fuel-based technologies across four different regions: China, Western Europe, India, and Africa, from 2020 to 2050. Each panel contains line graphs representing both types of technologies with area shading to show range variations.
- China - The graph shows a significant increase in zero-carbon technologies, represented by a blue line and shaded area expanding upwards from 2020 to 2050. The fossil fuel-based technologies, shown in black, remain relatively stable.
- Western Europe - The graph shows a moderate rise in zero-carbon technologies, with fossil fuel-based ones remaining relatively constant, similar to China's panel.
- India - The blue line for zero-carbon technologies shows strong growth, indicating a rising trend. Fossil fuel-based technologies shown in black remain mostly flat.
- Africa - Both zero-carbon technologies and fossil fuel-based technologies are projected to rise, but zero-carbon technologies are expected to increase at a faster rate.
Future energy use:
While no one has a crystal ball to predict where our future energy use may come from, estimates from both the EIA and IEA expect energy use to grow in the future. Most of this new electricity/energy production is expected to come from renewable or net-carbon zero sources.
3.5 Growth in Energy Demand
3.5 Growth in Energy DemandFor a long time, growth in the world and the U. S. energy consumption as a function of time, follow what is known as exponential function. Now it looks like we have switched to linear growth, but time will tell if this is a permanent change. The exponential increase is characterized as follows. The amount of change (increase in energy consumption) per unit time is proportional to the quantity (or consumption) at that time.
We can determine how long it takes for N0 to become 2N0 (twice its original number or double). That time period is called doubling time. After some mathematical steps it can be written as:
3.6 Energy Reserves and Resources
3.6 Energy Reserves and ResourcesFossil Fuels account for a large portion of the world's energy sources. These fossil fuels are non-renewable fuels with a finite lifetime. So, the question is: Will we have enough supply for future energy requirements?
The answer to this question depends on the quantity of fossil fuels we have in the ground. Energy sources that have been discovered but not produced cannot be easily measured. Trapped several feet below the surface, they cannot be measured with precision. There are several terms used to report the estimates of the energy resources. The most commonly used terms are “reserves” and “resources.”
- "Reserves" represent that portion of demonstrated resources that can be recovered economically with the application of extraction technology available currently or in the foreseeable future. Reserves include only recoverable energy.
- “Resources” represent that portion of the energy that is known to exist or even suspected to exist, irrespective of technical or economic viability. So reserves are a subset of resources.
| Source of Energy | U.S. Reserves | U.S. Annual Consumption | World Reserves | World Annual Consumption |
|---|---|---|---|---|
| Petroleum (billions of barrels) | 46.4 | 7.39 | 1650 | 35 |
| Natural gas (Wet) (Trillion Cu. Ft.) | 691 | 32.1 | 6922 | 132 |
| Coal (billions of short tons) | 469 | 0.51 | 1139 | 8.56 |
Coal
While much of the world has decreased their use of coal over the past two decades, both China and India have been increasing their use of coal. Push the play button below to show how coal usage has changed since 1900. The US was the #1 producer of coal until the 1980s, when China became #1. Since then, China's coal production has continued to increase with the exception of a small dip during COVID.
Data table for the Coal Production by Country graphic.
Use the following link to downlaod the data (csv file) for the Coal Production by Country graphic.
As of 2025, total world proved recoverable reserves of coal were estimated at 1139 billion short tons. In many countries, such as the US, coal consumption has been decreasing. However, in China and India, coal use has increased significantly in the past decade.
Five countries have nearly 73% of the world's coal reserves:
- United States—28%
- Russia—18%
- China—13%
- Australia—9%
- India—7%
Petroluem
Based on data from OPEC (Oil Producing and Exporting Countries), the highest proved oil reserves including non-conventional oil deposits are shown in the graphic below. This shows which regions of the world have the highes amounts of oil reserves. You can interact with this figure to show the historical change of proven reserves or create different types of charts to separate by country.
Data table for the Oil Proved Reserves chart.
Use the following link to downlaod the data (csv file) for the Oil Proved Reserves graphic.
The top countries for oil resereves are Venezuela, Saudia Arabia, Canada Iran and Iraq. The US does have considerable about of oil resources and lands in the top 10 of oil producing countries.
Based on data from BP (British Petroleum), proved gas reserves were dominated by three countries: Russia, Iran and Qatar, which together held nearly half the world's proven reserves. According to the US CIA The World Factbook, the US has the 4th largest reserves of natural gas. Due to constant updates about the shale gas estimates, these are difficult to say with certainty.
How Long Will the Reserves Last?
How long these reserves do last depends on the rate at which we consume these reserves. For example, let’s assume that we have $100,000 in the bank (reserves) and if we draw 10,000 dollars every year (consumption) the reserve will last for 10 years (\$100,000/\$10,000 per year). However, in this case, we are assuming that we do not add any money to our deposit, and we do not increase our withdrawal.
This is generally not true in the case of life of an energy reserve. We may find new reserves, and our energy consumption or production can also increase. In the case of energy reserve, although we know that we might find new resources, we do not know how much we could find. But the consumption can be predicted with some accuracy based on the past rates.
Lifetime of current reserves at constant consumption
We can calculate the life of current petroleum reserves by dividing the current reserves by current consumption.
- At the current rate of consumption, the approximate lifetime of the world’s petroleum, natural gas, and coal reserves is 47.1 years, 52.4 years, and 133 years, respectively.
- At the current rate of consumption, the current U. S. petroleum, natural gas, and coal reserves will last approximately for 6.3 years, 21.5 years, and 919 years, respectively.
It is important to note that the entire U.S. petroleum consumption is not coming from the U.S. reserves because we import more than one half of the consumption. Because we import more than one half of the consumption, the petroleum reserves at the current rate will last about 11 years. If the consumption increases in the future, the life will be less. However, there is also a chance of adding more reserves with more exploration and discoveries. The increase in consumption can change depending on the price of petroleum and other alternative fuels. Likewise, us moving to electric cars and harnessing unconventional oil reserves can extend the lifetime of these reserves.
Therefore, these lifetimes are not carved in stone. It can be debated whether the U.S. reserves will last for 6 years or 10 years or even 20 years, or we may never run out! But there is increasing consensus that we must change our lifestyle. Even if we won't run out, the environmental consequences of continued use are pushing us to change anyway, but more on that later...
The R/P ratio can change from year to year, similar to our bank balance. We can add more if we make more or consume more. That changes the time we can draw on the balance.
Therefore, we must conserve, innovate (get more with less), or learn to live without these resources.
3.7 Current and Future Energy Sources of the USA
3.7 Current and Future Energy Sources of the USAThe current energy use in the US can be easily found by accessing the EIA US energy Facts Explained. Below there is some discussion about energy use in the US. While the values may change slightly from year to year, it is important to remember the trends and rough estimates for the values. For example, the latest chart from EIA might have renewables at 8.24 Quads and Petroleum at 38%. You will not be expected to remember the actual number, but roughly the amount. In the latest values from EIA, petroleum and natural gas account for 74% of the US’s total energy use. If we include coal, the fossil fuels account for over 80% of US energy use.
The chart below is a Sankey Diagram. This allows us to see where all of our energy use in the US is going. If we follow the blue box for Natural Gas, we can see we start with 33.4 Quads of Natural Gas. From that, 13.3 Quads of Natural Gas is used for Electricity Generation. Small amounts of Natural Gas go to Residential (home heating), Commercial and Industrial uses. Even a small amount of natural gas goes to transportation, which we will discuss more in lesson 12.
But lets go back to the Electricity Generation Block in orange. We can see a total of 32 Quads of energy goes into Electricity Generation. This comes from a variety of sources, actually a little bit from every sources on the left hand side. Of that 32 Quads coming into the Electricity generation, only 13.3 Quads leaves as electricity. Where does the rest of that energy go? Follow the Gray line to the right hand side.
Are you surprised? Of all the energy used in the US, approximate 65% of this is Rejected Energy! Only about 35% of our energy consumption in the US goes to useful energy use. We will discuss why in Lesson 4 on energy efficiency.

Image description: Estimated U.S. Energy Consumption in 2023
The image is a Sankey diagram illustrating the estimated U.S. energy consumption in 2023, totaling 93.6 quadrillion BTUs (Quads). It shows the flow of energy from various sources to different sectors and highlights the amount of energy that is ultimately rejected or used. Energy sources are color-coded and include solar (yellow, 0.89 Quads), nuclear (red, 8.1 Quads), hydro (blue, 0.82 Quads), wind (purple, 1.5 Quads), geothermal (brown, 0.12 Quads), natural gas (light blue, 33.4 Quads), coal (gray, 8.17 Quads), biomass (light green, 5 Quads), and petroleum (dark green, 35.4 Quads). The energy flows into categories such as electricity generation (orange, 32 Quads), residential (pink, 11.3 Quads), commercial (pink, 9.3 Quads), industrial (pink, 26.1 Quads), and transportation (dark green, 28 Quads). Finally, the diagram shows rejected energy (gray, 61.5 Quads) and energy services (gray, 32.1 Quads). The logo of Lawrence Livermore National Laboratory is in the top right corner.
[Transcribed text]
Source: LLNL October, 2024. Data is based on DOE/EIA SEDS (2024). If this information or a reproduction of it is used, credit must be given to the Lawrence Livermore National Laboratory and the Department of Energy, under whose auspices the work was performed. Distributed electricity represents only retail electricity sales and does not include self-generation. EIA reports consumption of renewable resources (i.e., hydro, wind, geothermal and solar) for electricity in BTU-equivalent values by assuming a typical fossil fuel plant heat rate. The efficiency of electricity production is calculated as the total retail electricity delivered divided by the primary energy input into electricity generation. End use efficiency is estimated as 65% for the residential sector, 65% for the commercial sector, 49% for the industrial sector, and 21% for the transportation sector. Totals may not equal sum of components due to independent rounding. LLNL-MI-410527
Fossil Fuels
Fossil Fuels still remain a major component of energy use in the US. As shown in the figure above, over 80% of US energy use is produced from fossil fuels. The three fossil fuels are coal, oil and natural gas.
As a result of innovations in oil and gas extraction, U.S. imports have dropped considerably. While the US still consumes a lot of oil for transportation, a lot more oil has been discovered and produced domestically.

Image description: U.S. energy net imports by major source, 1950-2023
The image is a line graph titled "U.S. energy net imports by major source, 1950-2023," measured in quadrillion British thermal units. The horizontal axis represents the years from 1950 to 2023, while the vertical axis measures energy quantities ranging from -10 to 25 quadrillion British thermal units. There are four colored lines, each representing a different energy source. The brown line shows crude oil imports, peaking around 2005 at over 15 units before declining to approximately 2 units by 2023. The maroon line indicates petroleum products, with fluctuations around 5 to 10 units until it declines to negative values in recent years. The blue line for natural gas remains relatively stable from the 1970s, eventually dipping below zero after 2000. The black line represents coal and coal coke, consistently near zero, slightly fluctuating around the mid-20th century. Each energy source is identified with corresponding colors in the legend below the graph. At the bottom left, the "eia" logo is visible, along with a text box citing the data source.
Looking at the U.S. Energy Profile, It can be seen from the imports profile that the US Crude oil imports have significantly reduced between 2005 and 2019 from a peak of 25 Quadrillion BTUs. Another significant change that can be noted is that the US is now exporting natural gas (below zero on the y axis) instead of importing it. Although crude oil is imported, US exports finished petroleum products resulting in less net imports. As a matter of fact, US total energy exports exceeded the imports in 2019 since 1950.
The top five countries (sources) of US total petroleum in 2019 were Canada (49%), Mexico (7%), Saudi Arabia (6%), Russia (6%) and Columbia (4%).
The U.S. also ranks:
- first in worldwide reserves of coal;
- sixth in worldwide reserves of natural gas;
- eleventh in worldwide reserves of oil.
US Energy Consumption by Source and the chart of the US Energy consumption by source and user sector shows each energy source and the amount of energy it supplies in British thermal units (BTU). Petroleum is the leading source of energy in the US in 2019 with 36.72 quadrillion BTUs. Next is natural gas with 32.10 quadrillion BTUs. Coal supplies 11.31 quadrillion BTUs of energy. Renewable energy and nuclear power are responsible for 11.46 and 8.46 quadrillion BTUs respectively. Of the total petroleum consumption, 72% is used for transportation and another 23% is used by the industrial sector. Similarly, 35% of the natural gas (largest fraction) is used for power generation. On the other hand, 76% of the residential and commercial energy needs are met by natural gas. The actual percentages are not required to be memorized but answers to the questions such as: Which fuel is most used by power plants for power generation? Which sector uses petroleum the most? Approximately what fraction of the electricity is generated by renewable energy? (10, 25, 50 or 90) What is the primary purpose of coal use? etc. need to be answered.
US Energy Consumption by Source and Sector
The graph shows how dependent the U.S. is on our petroleum supply, as it accounts for almost 37% of our energy. Our next two highest sources of energy, like petroleum, are non-renewable and include natural gas and coal. Only about 11% of our energy comes from renewable energy sources such as wood and water (hydroelectricity). According to Energy Information Administration, US renewable energy consumption surpassed coal for the first time in over 130 years in 2019. Of the 4.12 trillion kWh of electricity generated in the US, 38% was from natural gas, coal accounted for about 23% and nuclear adding another 20%. Renewable sources contributed to 17% of the total electricity generated.

Image description: U.S. Energy Consumption by Source and Sector, 2024
The flow diagram illustrates the U.S. energy consumption by source and sector for the year 2024, measured in quadrillion British thermal units (Btu). On the left, the energy sources are listed with corresponding percentages: petroleum (35.3, 38%), natural gas (34.2, 36%), renewable energy (8.6, 9%), nuclear (8.2, 9%), and coal (7.9, 8%), totaling 94.2 quadrillion Btu. The lines connect these sources to various end-use sectors on the right: transportation (28.1, 38%), industrial (26.1, 35%), residential (11.2, 15%), and commercial (9.5, 13%) with a total of 74.9 quadrillion Btu. In the center, a section is dedicated to the electric power sector, splitting into electricity sales (13.5, 41%) and energy losses (19.3, 59%), with a total of 32.8 quadrillion Btu. Different colored lines represent energy flow from each source to sectors, indicating the percentage allocation.
In 2023, fossil fuels made up 84% of total U.S. energy consumption, the lowest fossil fuel share. The greatest growth in renewables over the past decade has been in solar and wind electricity generation. Liquid biofuels have also increased in recent years, contributing to the growing renewable share of total energy consumption. 2020 was the first year that renewables surpassed coal consumption in the U.S.
US Energy Consumption Over Time

Image description: U.S. Primary Energy Consumption
The image is a line graph displaying energy consumption trends in the United States from 1950 to 2024, measured in quadrillion British thermal units (Btu). The horizontal axis represents years from 1950 to 2024, while the vertical axis represents energy consumption in quadrillion Btu, ranging from 0 to 50. Five colored lines represent different energy sources. The green line indicates petroleum consumption peaking around 40 quadrillion Btu in the early 2000s. The brown line, representing natural gas consumption, steadily rises, nearly intersecting petroleum consumption in 2020 and again in 2024. The blue line shows coal consumption, peaking around 1990 but sharply declining thereafter. The red line, depicting total renewable energy consumption, shows a gradual increase. The yellow line, representing nuclear electric power, rises sharply around 1970 and stabilizes. A legend at the bottom specifies the color coding for each energy type.
The most significant decline in recent years has been coal: US energy consumption from coal was at a high of 37% in 1950 to only 9% in 2023. Biomass, which includes wood as well as liquid biofuels like ethanol and biodiesel, remain relatively flat, as wood use declines and biofuel use increases slightly. In contrast, wind and solar are among the fastest-growing energy sources in the projection, ultimately surpassing biomass and nuclear.
US Energy Consumption History
The plot of US energy consumption shows the relative amounts of each type of energy that was consumed for each year. The history of the energy consumption profile of the United States indicates that petroleum makes the largest part of the energy demand over the past seven decades. Natural gas has taken the second over the past decade with the production of gas from shale. Coal has been replaced by renewable energy and natural gas for electricity generation. Among the renewable energy sources, biomass has the larger share followed by wind energy. Wind energy and solar energy are the fastest growing energy sources.
Answers to the following questions need to be looked for in the material presented above.
- Of all the renewable energy sources, which renewable source is used most?
- Which of the renewable sources is used most for transportation?
- Approximately what fraction of the electricity is generated by nuclear energy? (10, 20, 50 or 90)
Electricity
Electricity demand is expected to grow in the future. Visit the webpage US electricity explained - Sources and profiles
Examine for:
- Sources of U.S. electricity generation
- What are the notable changes in the major sources for electricity generation between 1950 and today?
- Role of renewable energy in the electricity generation.
Growth in electricity use for in the residential and commercial sectors is partially offset by improved efficiency. However, increases in demand from electric cars and data centers are causing a expected increase in electric demand. In 2023, Fossil Fuels accounted for 60% of US electricity generation, with natural gas accounting for most of that.
Most capacity additions over the next 10 years are expected to be renewables.
Did You Know?
Demand-side management programs address efficiency. By being more efficient, we can do more with less, and then reduce the demand for energy. This can include changing the time when higher use items are used, like dishwashers and EV charging to times when the demand on the grid is less.
3.8 Conclusion: Energy Supply and Demand
3.8 Conclusion: Energy Supply and DemandLesson 3 Review
Throughout this lesson, we've traced humanity's energy journey: from biomass-dependent societies before 1800, through the fossil-fueled explosion of the Industrial Revolution, to today's complex global system where over 80% of energy still comes from oil, coal, and natural gas. We've seen how energy use per person varies dramatically by country—and how factors like efficiency, climate, economic structure, and policy shape those differences far more than income alone.
Most importantly, we've looked ahead. The International Energy Agency presents us with three distinct pathways:
- Current Policies: ~3°C warming by 2100
- Stated Policies: ~2.5°C warming if promises are kept
- Net Zero by 2050: Limiting warming to ~1.65°C through rapid clean energy transition
The data is clear: global energy demand will continue to rise, especially in developing economies. But how we meet that demand is the defining question of our century. Renewable energy and electrification are accelerating. Nuclear power is being reconsidered. Efficiency gains offer immediate impact. And every nation—and every individual—has a role to play.
Your takeaway: Understanding energy isn't just about memorizing statistics. It's about recognizing connections—between history and innovation, between policy and personal choice, between today's consumption and tomorrow's climate. As you move forward, keep asking: What kind of energy future do we want to create—and what will it take to get there?