In this session, we are going to discuss renewable energy sources. Renewable energy sources are numerous, diverse, and so it will be necessary to look at each of them even if briefly and see what advantages they offer and what disadvantages also they offer. We have renewable energies that are mostly local and micro in nature. This is a common feature of most of them, and therefore, they don't really enter in international affairs. They are not a subject of discussion in between countries, although there is now an International Renewable Energy Agency that has the job of promoting renewable energies. But normally, renewable energies are implemented at the local level, at the micro level. There are exceptions to that in notably large hydroelectric dams, large hydroelectric projects, which may affect the situation of rivers that cross many countries and, therefore, may create some tensions. We'll speak about that when we come to hydro. Renewable energy sources can be divided into broad important categories. One is those renewable energy sources that we control. In other words, that we decide when to use or not to use. This is the case for hydro. It's a case of biomass. This is renewable energy sources that we control in full. Then there are other renewable energy sources that we don't completely control or we don't control at all, we can forecast maybe, but don't control and that is solar or wind. We may know when the sun is available or is not available or we don't control, and we cannot have the sun on order when we need the electricity, and similarly, we don't control the wind. So sometimes the wind blow, sometimes the wind doesn't blow, and that's not necessarily when we need the electricity from wind. Another distinction that is sometimes proposed for renewable energy sources is in between those energy sources that are utilized for electricity, for production of electricity, and those energy sources that are utilized for the production of heat. Of course, if you produce heat at a sufficiently high level, which is say around 400 degrees centigrade, then with that heat, you can produce steam and operate a turbine. The steam causes the turbine to turn and that creates a rotary movement, which causes a generator to rotate, and then that way you produce electricity. So heat sometimes can be transformed into electricity but not always. If you have low-grade heat, which means heat at low temperature less than 100 degrees or just barely above 100 degrees, that's not sufficient for producing electricity. But it is sufficient for heating your home or heating sanitary water, the kind of water that you will use when you take a shower or even cooking food. So heat can come in different qualities. Then there is transportation in the transportation field. The only kind of renewable energy sources that are available is biofuels. That is, fuels produced from biomass. This is something that is possible and we'll learn how to do as we shall explain. We expect several benefits out of renewable energy sources, notably elimination of emissions that are negative for the environment and improvement in energy security because most of the renewable energy sources are available domestically. If they are not available domestically, they are not traded internationally not easily. Finally, we expect the creation of jobs. Although much emphasis has been put on green jobs in the past, but experience has told us that these green jobs are not necessarily captured by the country that is implementing renewable energies. This graph comes from a publication of the International Renewable Energy Agency, and it shows the situation of renewable energies in 2010 and what they consider possible for 2030. The International Renewable Energy Agency looks forward to the possibility of doubling the utilization of renewable energies between 2010 and 2030. It is an ambitious objective, but they believe that it is feasible. So what are the renewable energy sources that we use today? If you look at the left-hand side of the graph, and you will see that 51 percent of renewable energy sources in use today consists of traditional biomass. This is wood collected in the fields by the people that live in countryside in Africa or in India and that have no other source of energy. They have no access to commercial energy and rely on wood or dung to cook and heat their poor dwellings. Okay. So today renewable energy sources are majority constituted by such traditional biomass. Then there uses of more modern biomass and as a total heat production accounts for 71 percent of the total use of renewable energy sources. So it is by far the most important utilization of renewable energy sources. Then there is a small component which is the utilization of biofuels in transportation, and then there is power generation. Power generation accounts for approximately 20 percent of total use of renewable energy sources. Within that 20 percent, by far, the most important component is hydroelectricity. So today we can say that the use of renewable energy sources is primarily for heat and for power out of hydroelectricity. Other components such as wind or solar are really not very important at a global level. How is this situation expected to change or how could it change if there is an effort to double the use of renewable energy sources? As you can see on the right side of the graph, heat production remains the predominant target of utilizing renewable energy sources. It still accounts for more than half of the total. Traditional biomass is substituted for by something called modern biomass, and then there are other forms of more advanced use of biomass. A lot of that is still utilized in producing heat. We have a more important component that comes from the sun, solar thermal heat, and then we have utilization in transport, which increases very significantly, and that again is from biomass. It's biofuels. Then we have the power sector electricity generation, and there hydropower remains the most important. But we have a very significant increase in the use of wind and solar. We will talk about the different solutions of solar. PV stands for photovoltaic. CSP stands for concentrated solar power. We will explain what this is. In this table, you have some figures from the International Energy Agency, that tell you what they expect in terms of use of renewable energy sources. Here you will note that they expect a decline in the use of traditional biomass, both in absolute terms and in percentage of total biomass uses. In the second part of the table, you have electricity generation. There you see that hydro today accounts for three-fourths of total electricity generation out of renewable sources, and the share of hydro is expected to decline in all scenarios. But remains the single most important source of electricity from renewable energy sources. Although, in some scenarios wind comes very close or closer, about two-thirds of the contribution that comes from hydro. Finally, in the last portion of the table, you see that the expected or possible development of biofuels. Here you see that even in the last scenario, which is represented in the last column on the right 2035, you see that the role of biofuels is expected to reach a maximum of 14 percent of total, which means that the remaining 86 percent of fuels will still need to come from fossil sources.
