Tuesday is the weekly QGECE seminar day. Today's speaker is Mostafa Odabaee. Mostafa is doing his Masters with the Centre. Today he will talk about the progress in his research on metal foam heat exchangers. This is a project we started earlier this year and I was not sure where it was going to lead. We started from the basic premise that, in a natural dry cooling tower, the heat exchangers account for about two-thirds of the total tower cost. The present heat exchanger technology is finned tube bundles. We asked ourselves the question if we could do better by using a newer technology, i.e. metal foams. Mostafa's results so far show that metal foams offer significant advantages over finned tubes. For example, a 50-MWe geothermal plant needs to dump about 300 MW of waste heat depending on its efficiency. According to Mostafa's results, 52 bays of metal foam heat exchangers would be able to dump this to air whereas 200+ bays of finned-tube bundles would be required to do the same job. This has significant implications, metal foam heat exchangers would probably cost about one-quarter of the finned tube counterparts and, as importantly, they would offer a much more compact altetrnative. The latter point is important because it would make it possible to fit the heat exchanger bundles inside the tower, which is an important advantages in areas where dust storms are a frequent event.  The sketch shows the two alternative heat exchanger placement options for natural draft dry cooling towers.  In the vertical arrangement, the heat exchanger bundles are placed around the skirt of the tower and therefore are exposed to dust and other elements.  In the horizontal arrangement, they are placed on an elevated plane inside the tower and the structure of the tower protects them from possible dust storms.

Maybe not in Australia yet but around the globe, the stars are aligned favourably for the renewable energy companies. One of these stars is the strong renewable energy push coming from the Obama administration. But according to the US investment analyst, Jeff Siegel, it is not the only one. In an article published yesterday, he argues that the basic fundamentals of supply and demand no longer favor oil over the long term. Climate-change legislation (and to a lesser extent, coal reserves, which are not enough for 250 years but rather about 100 years, according to a 2007 National Research Council report) will certainly impede coal-fired power-plant development. And unless upfront capital, decommissioning, and waste-storage costs come down for nuclear, he doesn't believe it’ll be the solution to our energy woes despite its carbon advantage. So the bottom line according to Jeff Siegel is that we can no longer safely rely on only nonrenewable resources to supply all our power generation. And any investor who counts out renewable energy at this point is going to miss out on a lot of money. Some of his favourite renewable energy stocks include First Solar, US Geothermal, Ormat technologies, Yingli Green Energy, EnerNOC Inc, SunPower, SolarFun, Vestas (Copenhagen:VWS).