Arquivo de etiquetas: economia carbono

The Deep Decarbonization of Energy Systems III

The 3 Pillars of the Deep Decarbonization of Energy Systems

Welcome to chapter three of lecture five. I kept you waiting and I’m really sorry for that, but now is the time to start to looking at the solutions to the challenge of the deep decarbonization of our energy systems. How can we do it, that is the question? And in particular, how can we do it while making sure that we satisfy the conditions for continued economic growth and development and making sure that there is growing prosperity over the globe. This is precisely what we’re going to discuss in this chapter.

But first let me recap what is the scale of the challenge. As we discussed previously, CO2 energy related emissions are of approximately 32 gigaton today, gigaton or billion tons. To have a likely chance which let me remind you, we defined as a probability higher than two-thirds, higher than 66%, to have a likely chance then of staying within the 2-degree limit, the need to get down to approximately 11 gigaton by 2050.531

By comparison, to have a 50% chance only, so only one of out two of keeping below the 2-degree limit, the need to reach approximately 15 gigaton by 2050. So we’re roughly talking of a division by a factor two or even three of CO2 energy emissions in the next 40 years.

When in the meantime the world population is expected to grow and it is expected to grow by approximately one-third by 2050 compared to today.532

And the world GDP is also expected to grow and much faster in fact than the world population. It is expected to be multiplied by something like three by 2050 compared to today. So if we combine these different numbers together it means that we’re talking of dividing emissions per capita by something in between two-thirds and three-fourths by mid-century. And dividing emissions per GDP by a factor of six or nine by 2050, which is huge.

And so how can we achieve this decoupling between population and GDP growth on the one hand and energy consumption and CO2 emissions on the other hand?

If you’ve looked at the number, this is by any standard a major challenge, but this is certainly feasible. And I want to show you how.

The easiest way to understand how that can be done is to decompose the drivers of CO2 emissions. CO2 emissions can be expressed as the product of four inputs. CO2 emissions equal population, that is the first term multiplied by GDP per capita, that is the second term, multiplied by energy use per unit of GDP, that is the third term, multiplied by the CO2 emissions per unit of energy, that is the fourth term. If you multiply these four terms, you get simply the CO2 emissions.

I’m just decomposing CO2 emissions into these four terms to explain you where the emissions come from and in turn, to explain you how the emissions can be reduced, through which mechanisms in particular.533

If we take as a given the population trajectory and if we assume a rising trajectory of GDP per capita, in line with successful economic growth and, and development, then the CO2 emissions are driven mainly by the two last factors out of the four.

The first is the energy divided by GDP. And the second are the CO2 emissions divided by energy.

The first term is what we call the energy intensity, meaning very simply the amount of energy per unit of final output. The amount of energy we consume per unit of GDP we produce. The second term is the carbon intensity of energy, meaning the, the amount of carbon emissions per unit of energy we consume.

So let’s look at the ways in which we can reduce these two different ratios?534

So first, the energy intensity of GDP or as I said very simply, the energy consumption divided by GDP. It can be reduced through what we call energy efficiency and energy conservation measures in all the energy end use sectors. And we’re going to look in detail at each of them. First, passenger transportation and freight transport. Second, residential and commercial buildings. And third, industry.

So what’s the difference in between energy efficiency and energy conservation?

Because I just used both. Well usually we call

  • energy efficiency the technical improvements of products and processes. And we use the term,
  • energy conservation to describe a broader set of measures, including not only technical improvements, but more profoundly structural and behavioral changes that lead to lower levels of energy consumed per unit of GDP.

So let’s simply look at some examples to be very concrete and very precise. Examples of energy efficiency and energy conservation measures in the passenger transport and freight transport, for example to start with.535

  • Well first, improved vehicle technologies. That is more efficient vehicles. Vehicles using less gasoline for example per kilometer traveled.
  • Second, what we can call smart urban design. You can think at least of two things. One, building public transportation systems to reduce the need for the use of private cars, but you can think even more profoundly about building cities in a way that minimizes the distance to travel from where we live to where we work. Again, reducing the need for private transportation cars.
  • Third example. Optimized value change. Again, to minimize the distance, but this time the distance we need to ship the products from where they are produced to where they are consumed.

If we look at the residential and the commercial building sector, we can also think of a number of different options.

  • First, improved end use equipment. So more energy efficient equipment in our buildings.
  • But also what we could call smart architectural design. So building our houses in a way that reduces the need for cooling or heating for example.
  • More generally, improved building practices to improve the energy efficiency of the building envelope and also the use of different, less energy intensive construction materials.

If we look at the industry sector, again, many different options for an energy efficiency such

  • as improved equipment and production processes,
  • material efficiency, but also very importantly because the industry is a huge consumer of heat to produce its products.
  • So reuse of waste heat is an important part of the energy efficiency measures in industry.

536So that’s it for all the different ways in he different sectors in which we can improve the energy efficiency of GDP.

So the ratio of energy consumption divided by GDP. But as I said, it’s not the only driver of possible emission reductions.

We now need to looked at the other term, the improvement in the carbon intensity of energy or the ratio of CO2 emissions per unit of energy consumed. And here too the carbon intensity of energy can be reduced in two different ways.

The first is and very importantly, because it’s really at the core of any successful deep decarbonization strategy, it is the decarbonization of electricity generation. So as I said, your objective is the replacement of the uncontrolled fossil fuels, the phase out of the uncontrolled fossil fuels to produce electricity by a mix of different options, because there are different options to produce electricity with no or very little CO2 emissions.

The first is a mix of all different sorts of renewable energy such as hydropower, wind power, solar power, or geothermal energy. But you can also think of using nuclear power or using the fossil fuels, so the coal and the gas used to produce electricity, but with carbon capture and sequestration. So that’s a first important way in which we can decrease the carbon intensity of energy, by decarbonizing the way we produce electricity.

There is another way which we call fuel switching. It means switching end use energy supplies from highly carbon intensive fossil fuels in transportation or in buildings and in the industry to lower carbon fuels. Electricity is of course one of these possible lower carbon fuels, provided it is decarbonized. But there are other possible forms of lower carbon fuels and in particular, the use of biofuels. So again, this is another way of reducing the carbon intensity of energy which we call fuel switching, switching fuel from high carbon to low carbon sources of energy. So let me summarize.

The deep Decarbonization of energy systems rests on three pillars.

  • The first is energy efficiency and conservation measures.
  • The second is the production of low carbon electricity.
  • And the third is the switching of fuels from high to low carbon energy carriers.

I want to stress here that electricity plays a pivotal role in the deep Decarbonization scenarios because you see electricity in two out of the three pillars.

  • First you see that electricity needs to be almost completely decarbonized and we’re going to come back to that in a moment.
  • But also because electricity overall plays a more important role in energy consumption as fuel consumption switches from high carbon to low carbon options.

It is very important that you remember these three pillars because they really represent the basic framework to think about the deep decarbonization of energy systems in any circumstance. As we’re going to see in the next lectures, the precise options within each of these three pillars, but also their relative importance is going to vary of course from one country to the next. But these three pillars really represent the basic foundation to think about deep decarbonization.


The Basics of Climate Change Science III

The Relentless Rise of CO2

We’ve been talking about the role of particular greenhouse gases what their radiative forcing is what their contribution to total greenhouse climate change is where they come from, and of course we’re going to aim to understand what we can do to control their emission, but we’ve seen that carbon dioxide is really at the center of the story.

It’s about three-quarters of the total anthropogenic greenhouse effect the vast majority about six-sevenths of the carbon dioxide emitted by humanity comes from energy and industrial processes, mainly burning of coal oil, and, gas. About one seventh of the total comes from land use change, mainly deforestation.

Our focus is going to be heavily on the energy sector at the energy sector in a way obviously in a way sad to say is so much at the center of the world economy and fossil fuels are so much at the center of the world’s energy system that finding a way to reduce dramatically the carbon dioxide emissions is not a simple matter It is the central focus of our challenge both in this course and of course in a global agreement.

In this chapter I want to talk about briefly the relentless rise of carbon dioxide emissions. There has just been no stopping it, not even any slowing it.231

This graph shows CO2 emissions from fossil fuel use in the course of the 20th century and up to 2008 in this particular figure, and you can see that this has been the pretty steep ascent, around a 15x increase of CO2 emissions from 1900 till today, from around 2.5 billion tons or it’s showing here as 2500 million tons but I’ll say 2.5 billion tonnes shown in this graph to today around 35 billion tons of carbon dioxide. Now part of that increase has come from the fact that the world population has increased rather dramatically from 1900  until today, from a bit over one and a half billion back in 1900 to today, 7.2 billion people so we’ve had more than a 4x increase the world’s population.

But of course the use of energy per person and the use of fossil fuels as the basis of that energy per person has also skyrocketed. Today and it’s good to keep in mind with 35 million tons of carbon dioxide being emitted with about seven billion people it’s about 5 tons of carbon dioxide per person on the planet. Now that relentless rise of emissions we know, and Charles Keeling whom we’ve already met earlier was the key scientist instrumental in bringing this fact to our attention, has led to the rise in carbon dioxide concentrations in the atmosphere Again we see the seasonality be upward and downward squiggles: CO2 high in the Northern hemisphere springtime just after the fall and winter has returned carbon dioxide into the air and CO2 low each year as carbon dioxide is reabsorbed by vegetation on the planet.

But those those annual cycles are dwarfed by the long-term upward ascent of carbon dioxide. In this graph, we’re just reaching 390 parts per million but I have to tell you sadly as of 2014 in the spring of this year we have reached 400 parts per million month by month for the first time on the planet in about 3 million years and so we have already changed the carbon dioxide concentration over three million years, a longer time period by far than our species Homo Sapiens has existed. We’re carrying the climate in other words to a new configuration unlike anything that humanity has ever experienced and the Keeling curve just reminds us of that fact fact.

Now why has CO2 continued to rise so relentlessly, both in emissions levels and the part that stays in the atmosphere raising the CO2 concentration? It’s because fossil fuels are such a central part of the world economy. In my course the Age of Sustainable Development I really do sing peons of praise to the steam engine as perhaps the single most transformative technological breakthrough in modern history by being able to tap fossil fuel energy via oil, coal, and gas put down in geologic time over tens of millions of years, hundreds of millions of years, and use that what was solar energy and biological form and now is fossil fuel energy we’ve been able to make a modern economy which depends on vast throughputs of energy for our quality of life and yet it is of course that fact, the centrality of fossil fuels, since the steam engine till today, that has made carbon dioxide such a relentless source of increasing greenhouse effect over the past century.232

Now in our time the single most dramatic change in the world economy absolutely second to none is China’s rise to economic pre-eminence as a macro economist I have to love it. Watching an economy go from poverty where the poverty rate was well over half of the entire population to a country, a modern economy where poverty has come down to much less than 10 percent, life expectancy has soared, conveniences of life have increased dramatically, its a wonderful thing from a development experience.

I think can be claimed as the most successful economic development experience in history. It’s in a very short period of time really after 1978 when Deng Xiaoping came to power till now, perhaps a 35 time increase in the size of China’s economy since that time. But it has had very significant side effects and downsides Within China the downsides are massive pollution, massive air and water pollution that has accompanied this very rapid economic development and industrialization. The air is noxious, the waters poisonous, years of life expectancy have been lost to this massive pollution.

The Chinese the leadership and certainly the people know it because they breathe the air every day. But there is a global effect as well, an effect that has global meaning that it also affects China very dramatically and that is that the Chinese have become the largest user of energy in the world, not per person mind you, but given the fact that China is the most populous country in the world with 1.3 billion people, China is the largest user fossil fuels and now by far the largest emitter of greenhouse gases in the world. So dramatic in fact that I think the Chinese government clearly recognizes as does the whole world that China’s leadership in finding a way forward together with the United States, with the European Union, with other parts of the world, on reducing greenhouse gases is now a preeminent aspect of any real solution in this climate challenge. So in the graph that you’re looking at now we see two quite dramatic curves.233

One in China’s total energy use, that’s shown in red. It’s measured in this case in tons of oil equivalent. You take the energy in natural gas, you take the energy in coal and so forth converted to an equivalent number of tons of oil add them up–that’s the totally energy expressed in units of oil and you can see comparing that to the blue curve, the dramatic rise of real gross domestic product measured in the trillions of dollars that China’s economy has boomed and alongside it not unexpectedly has boomed energy use. You can seen that since the blue curve has increased by more than the red curve that energy per dollar of GDP has actually gone down.

The energy intensity of the Chinese economy is falling slightly, but the rise at the Chinese economy is so dramatic that total energy use has increased significantly. And if you look at the next picture you see that China has soared to the top of the world leagues in admissions of carbon dioxide. This is showing total billions of tons of CO2 omitted per year and around 2007 or so China overtook the United States which was long in the lead as the largest emitting economy of the world China became the number one emitting economy. Its a side effect if you will of its stupendous economic rise.

Now why are the emissions so large? For two big reasons: one is of course that the Chinese economy is growing so sharply and the second is that China’s energy is heavily based on fossil fuels and in particular based on the single fossil fue, coal, which emits the most carbon dioxide per unit of energy so coal is the most important driver of China’s emissions and what you can see in this pie chart which looks at total energy consumption of China that China’s overwhelmingly a fossil-fueled driven economy.234

Most are by the way so China is not alone in that but China extraordinarily depends on coal resources for about 70 percent of its total primary energy use, oil another nineteen percent, and natural gas about 4 percent more on top of that. China has major hydro-electric power like get Three Gorges Dam, which is so famous, hat’s about 6 percent of its total primary energy, and about 1 percent is nuclear energy with an intention to have a much larger proportion of energy coming from nuclear power in the future because nuclear power is not carbon emitting.

It’s got many other issues which we’ll discuss but it is a zero-carbon energy emitter and therefore part of China’s trajectory to reduce its CO2 emissions. Now if we look at the global emissions by country in two different interesting ways we see the primacy of China and the United States in this story. On the left hand pie chart we have the world’s emission, they’re 9.6 gigatons or that is billion tons of carbon. Remember to multiply by 3.667 and that would keep you roughly 35 billion tonnes of carbon dioxide, a little bit less back in 2012 but about that. And China as you can see is that that big red wedge, roughly a quarter of the world’s emissions, the United States about 15 percent of the world’s emissions as shown here.

The two combined? Well you’re talking about forty percent of the whole world’s emissions. Look to the chart on the right and you see a little bit different story: the US has been emitting CO2 for so long, it’s been the world’s third-largest economy for so long that it has the lion’s share of the cumulative emissions from the start of the industrial era, roughly the middle of the 18th century. So if we look not at the flow of the emissions but at the accumulation of the emissions in history, there the United States is number one. Well what should we look at?235

Both The flow of emissions tells us how we’re evolving now, the historical emissions tell us how did we get this increased level of CO2 in the atmosphere to begin with since it’s been rising relentlessly over the last 100 years and there the United States plays the biggest role. And not surprisingly the United States looks to China and says you’re such a big emitter you have to cut emissions and China looks to the United States and says well where have you been for the last century thank you, you’re responsible for the accumulation of emissions, you take the lead. What we know and what we’re going to be analyzing with considerable care and detail and what we will be negotiating in the next semester of this course when we’re all global delegates to the global online negotiation is how to take into account historical responsibility, current to flow missions, how to do this in a balanced, fair, and effective manner.236

Now china would also be keen to emphasise this picture. Yes China is the biggest emitting country in the world but after all China’s about one-fifth the world’s population Given that, it’s not surprising that it is a large emitter but per person per person in the United States remains way in the lead and this is a chart which shows for 2012 the emissions per person gain measured as tons per carbon. If you want to change it to carbon dioxide multiply by 3.667 or 44/12 and you can see that the United States is about four-and-a-half tons per person of carbon or about sixteen times up carbon dioxide per person. China’s about two tons per person or roughly speaking a little over 7 tons per capita.237

What about the world as a whole? Well that’s the dotted line, the global mean, and we remember that’s about five tons per person because it’s roughly $35 billion tons of co2 emissions divided by seven billion people on the planet, that’s five tons per capita. So who are the big emitters per person? It’s the richer countries and it’s the heavy energy producing countries: the United States Canada, Australia, Russia, those are the high emissions per capita.238

The big absolute emitters have big populations like China, and China’s now above the global mean, it’s about the global average, because it has been so successful in economic development that it is now using more energy on average and heavily coal-based energy and that is why together with its absolute size it has become the number one emitting country in the world.

What we will look at next time is again putting some of this in context with the most recent debates on climate change out, what’s happening year to year, decade to decade, to the change in Earth’s temperature? That’s the topic for the next chapter.