Future Energy Needs and Consequences From a Physical Sciences Perspective Future Energy Needs and Consequences From a Physical Sciences Perspective The sun is the largest exploitable resource: 1 hour of sun to earth = all of mankindâs yearly energy: Basic Science: How to capture and store? We have enough energy in a solar day for meet all the energy consumption of all the people for a year. And it´s easy to say but itâs not so easy to do, we canât go outside with a bucket and take the energy that we need. One of the challenges of solar and other intermittent renewable energy sources (like wind and wave power), is how to store the energy. A second challenge for intermittent renewable energy sources is transporting energy from the place where it is captured to where it is needed. 2 Photosynthesis And the solution maybe can be in the Photosynthesis, where sunlight is used to convert water and carbon dioxide into oxygen and sugars or other materials which can be thought of as fuels. This process happened in plants, algae and certain bacteria. Over the last ten years the drive to develop systems to produce solar fuels on large scales has been an area of increasingly intense global research activity. 3 Artificial photosyntesis The topic is use the Artificial Photosyntesis. This is a term that has emerged to describe processes which use a broad range of systems to mimic natural photosynthesis: sunlight is harvested and the energy is used to chemically convert water and carbon dioxide into fuels. Artificial photosynthesis is the process and solar fuels are the products. This is a great solution, because today a very important environmental issue is how we can get rid of the carbon dioxide that is in the atmosphere, with the artificial photosynthesis we can do this and at the same time get solar fuels for our energy demands. How we saw in the last expositions the most effective way for storage energy is by these fuels. These solar fuels has different uses, for example, some cars use a process where burn hydrogen with oxygen getting as product water and electricity for powered its engines this happened in a hydrogen cell, but in fact these same process a big scale can be used for produced electricity for our homes for example Long-term, solar fuels could provide an alternative to fossil fuels. They would also play an important role in enabling or enhancing other sustainable energy technologies such as hydrogen transport and carbon capture, storage and use. 4 Uses of Solar Fuels These solar fuels has different uses, for example, some cars use a process where burn hydrogen with oxygen getting as product water and electricity for powered its engines this happened in a hydrogen cell, but in fact these same process a big scale can be used for produced electricity for our homes. At the great thing about this is that we can storage the excess of hydrogen and in the night we can still generating electricity. 5 Hydrogen and carbon-based feedstocks are widely used in industry. Fertilizers Pharmaceuticals Plastics Synthetic fuels For all four types of products, if hydrogen or carbon-based feedstocks such as carbon monoxide and methane could be produced from sunlight, water and carbon dioxide, this would provide an alternative to natural gas, oil and coal as raw materials. Solar energy would also replace fossil fuel-derived energy in the production process. 6 Challenges in large-scale production of solar fuels Efficient, so that they harness as much of the sunlight hitting them as possible to produce fuels. Durable, so that they can convert a lot of energy in their lifetime relative to the energy required to install them. Cost effective, so that solar fuels are commercially viable. Scientists and engineers are working together on significant scientific and technological challenges to successfully scale up laboratory prototypes to a commercial scale. The larger the fraction of sunlight that can be converted to chemical energy, the less materials and land would be needed. A target efficiency of about 10%, which is about ten times the efficiency of natural photosynthesis21, would be an initial goal. This is a significant challenge because some materials degrade quickly when exposed to sunlight. There is no doubt of the fuels has a very good market value. 7 All working together Integrating the different processes and materials involved, from capturing and channeling sunlight through to producing a chemical fuel; Identifying inexpensive catalysts to drive different aspects of the process Developing ways to avoid the system degrading quickly because of exposure to sunlight. Artificial photosynthesis requires the expertise of all of these communities working together to address some of the key challenges such as: We need work in only one process that integrate all de different process and materials, for making a very efficient process. This is one of the most important things we need a catalyst that be fast, has robustness and efficient. And of course we need that this catalyst be cheap. All systems for capture and use energy have this problem but the systems that are exposed to the sunlight present specific problems of degradation in its materials. 8 Supercondutivity Temperature Resistivity Kelvin (1902) Matthiessen (1864) Dewar (1904) At this time all of us had hear about superconductors, what is this all about? And why arenât we using it? What is the deal with superconductor? Is the structure, we need to have the correct structure and the correct guy inside this structure and then we need cooling down this compounds for get superconductivity 9 H. Kamerlingh Onnes âMercury has passed into a new state, which on account of its extraordinary electrical properties may be called the superconducting stateâ 1911: Liquid Helium (B.P.: 4.2K) 1911: Observed that electrical resistance R(T) of mercury vanished below Tc=4.2K Tc Superconducting critical temperature 1913: Nobel Prize in Physics Discovery of Superconductivity This is know since long time ago. This men Kamerlingh Onnes was the guy that discover the superconductivity and the first step for that was the liquidfied of helium, that allows to this guy freeze mercury at the same temperature, and when he was checking the properties of mercury at this temperature, he noticed that below 4.2 Kelvin degrees the electrical resistance of mercury was vanish. And this superconductors are great, if the world can be made of these superconductors a lot of problems would be solved. And what are we doing for this? 10 Origin of superconductivity Metal: Periodic arrangement (lattice) of positively charged ions âGasâ of mobile negatively charged changed conduction electrons. Normal State: Scattering of electrons by: Thermal motion of ions Impurities Other electrons Superconducting state: Electrons with opposite momentum P and spin S are paired (P ,-P ) Electron pairs move in concert through lattice e- e- Phonon Cooper pair model One goes up and ones goes down, and one spin one way and one spins the other way. And poof the resistance goes away. 11 Superconducting materials: Maximum Value of Tc versus time The problem with this is that in the past we only had superconducting materials at very low temperatures, but something really good happened since 1980 and was the discover of new materials with high superconducting temperature. It´s good in terms o doing it but bad in terms of living it. 12 A superconductor is a perfect diamagnet. Superconducting material expels magnetic flux from the interior. Superconducting Aplications 14 The grand challenge with superconductors Superconductor state only happens at very low temperature The mechanism for the materials are not well-known yet Non-superconductor Nano-vortices within superconductors (quantum vortex) There is no mechanism for support the superconductors we canât make new materials easily because we don´t know the basic physics of this. This is the actual problem with this things quantum vortex is a topological defect exhibited in super fluids and superconductors. 15 Energy considerations IPhone uses more energy than your refrigerator More E to stream a video than to manufacture and ship a CD 10% of E consumption is on wireless Waste is unavoidable No foreseeable ceiling for use of E for devices 16 The Problem With the Actual Technology The actual technology already has problems with its compounds that do lose energy in its operation. Magnetoresistence Electrical heating Mechanical deformations by heating New technologies Plasma Optical fiber (uses photons/computers uses electrons) Excitons Homemade Sun The Tokamak Reactor Is based in the principle of magnetic confined Inside of it we have temperatures of about 150 million of Celsius degrees Forming a hot plasma Has superconducting coils surrounded the tokamak The issue here is how we can confine it We have with a fusion reactor plasma and we need to confine this plasma and donât let out this plasma or mix this plasma with another particles that can pollute our process This is a very difficult problem to solve itâs not impossible but we need more that only some years for fix this problem. 21 The conclusion We actually have a big amount of technologies that would be a solution for our energy necessities, but actually need more research in this fields. Talking about synthetic photosynthesis we need more research and start to use prototypes than allows improve this technology. About superconductors we need to understand in a better way the physics of these things. The nanomaterial actually are very used maybe we thing another ways for use this materials for avoid our energy wastes.
Comments
Report "Coursera 07 - Future Energy Needs and Consequences From a Physical"