Lecture 2 Review

                                                
The first topic of Lecture 2 was Fossil Fuels, which we currently use for 85% of our energy needs. There are three types of fossil fuels - Oil, Coal and Gas. Oil is the world's primary fuel as it is energy dense and easy to transport. Natural Gas is the cleanest in terms of pollutants formed after combustion, and Coal is the hardest to extract. To give an idea of the price of Oil, in terms of volume, it costs less than 25% compared to bottled water.

                                     
We then moved on to look at Nuclear Energy. We currently only produce energy through fission, as fusion requires initial temperatures that are nearly impossible to achieve on earth. However it would be preferable to use fusion as it produces no radioactive waster and the raw materials are easier to obtain. On a global scale Nuclear Power produces 16% of the world's electricity, though this varies largely from country to country, mainly due to public perception. The Chernobyl disaster is responsible for a lot of bad publicity for Nuclear Power, and it is only recently that the general public have restored their faith in it.

Next we moved to renewable energies, in Solar Thermal. Looking at solar resources globally, it can be seen there are many suitable sites. The best area of the US, in terms of average solar energy received is the South West. However there are different technologies suited to different temperature regions. High temperature areas can generate electricity through thermodynamic cycles and generators. This isn't viable in lower temperature areas, however they can still use Solar Thermal to cook and distill water etc.
 

Thermodynamic cycles were discussed, and a demonstration of a Stirling Engine was shown (video clip available here).  We then looked at the different High Temperature technologies on offer. Parabolic Dishes, Power Towers and Parabolic Troughs are technologies that use the heat they absorb to generate electricity, on the order of tens of megaWatts.. The Drake Landing Solar Community in North America was given as an example of a community planned to use energy only generated through solar power. Also, various technologies were explained, such as Linear Fresnel, Solar Distillers and Cookers, Solar Water Heaters and Solar Cookers.