Forbes has an interesting article looking at the health effects of different energy sources, more specifically, the number of (human) deaths per unit of energy produced. For all the publicity nuclear energy accidents get, it’s worth noting that the mortality rate from nuclear energy is about 90 deaths per tkWhr (trillion kilowatt hour of energy produced), while coal is 170,000 deaths per tkWhr! To be fair, that coal rate is the global average and the US is much better than that (mainly because of existing pollution controls)…but even then, it’s a whopping 15,000 deaths per tkWhr. The complete list:
Energy Source Mortality Rate (deaths/trillionkWhr)
Coal – global average 170,000 (50% global electricity)
Coal – China 280,000 (75% China’s electricity)
Coal – U.S. 15,000 (44% U.S. electricity)
Oil 36,000 (36% of energy, 8% of electricity)
Natural Gas 4,000 (20% global electricity)
Biofuel/Biomass 24,000 (21% global energy)
Solar (rooftop) 440 (< 1% global electricity)
Wind 150 (~ 1% global electricity)
Hydro – global average 1,400 (15% global electricity)
Nuclear – global average 90 (17% global electricity w/Chern&Fukush)
You can read more over at Forbes.com.
I have mixed feelings about this one. PlanetSolar is less than one day from completing a circumnavigation using a boat powered only by the sun; it’s taken them about 600 days to do this. I’m not quite sure what they’re trying to prove here. If you want to go ‘green’ on your trip around the world, solar just can’t compete with wind. Sailboats are a proven ‘green’ technology that are faster and can go more places in the world’s oceans (PlanetSolar is limited more to the equatorial regions where the sun’s more direct rays result in more powered gathered by the solar panels). Likewise, storms pose little challenge for sailboats but the cloud cover hurts the performance of PlanetSolar. Yes, solar is useful even on sailboats for powering shipboard electronics, but when it comes to propulsion, the abundant wind on the oceans is a fantastic, proven resource.
A solar boat? I don’t get it. Hoist the mainsail, matey.
Solar energy technology is advancing fast enough that I’ve decide to lump together several updates into single posts now and then.
To start with, the Frauenhofer Institute has showed off some highly flexible solar panels, placing them on a ski helmet. This may not sound like a big deal, flexible panels have been around for a while, right? Well, not really. Typically, when you see a flexible panel, it can only bend in one direction – around a cylinder, for example. This new technology allows the panel to conform to compound surfaces, like a sphere or, in this case, a ski helmet. For now, testing this on ski helmets is a good, extreme use environment (the solar cells become more efficient with cold, but batteries become less efficient). Just about ever helmet design could benefit the user with this – motorcyclists, construction workers, bicyclists, you name it. The first product, a ski helmet, is targeted for sale at the end of 2012.
Solar cell comparisons invariably come down to one key metric, the efficiency. Going along with this is measuring reflectance, or how much solar energy is reflected and thus unable to be converted into electric energy. Scientists at Natcore Technology have set a new record for this, producing wafers that absorb an incredible 99.7%! This promises to increase solar panel efficiency, which in turn will lower cost and increase adoption of solar energy worldwide.
There are two main types of solar energy devices on the market today – photovoltaic panels that covert visible wavelengths into electric power, and solar thermal that takes the abundant infrared radiation emitted by the sun and uses that heat energy to do the same (via turbines or other methods, or just using the heat directly to heat a house or water heater). Now, Naked Energy has designed a hybrid solar energy system which has solar panels to make electricity, but also pumps water through the tubes to make that heat available for other energy uses (heating a house being the most feasible). It’s not a utility-scale sort of system, but great for home or business users.
Engineers at the University of Delaware have developed a prototype hydrogen generator that has the potential to revolutionize solar energy production. Solar thermal energy is used to vaporize zinc oxide powder. This gas is then reacted with water to produce hydrogen gas and zinc powder (which can then be fed back into the system). The shortcoming of any solar energy system is energy storage, and a system that produces hydrogen gas solves that as the gas can be stored for later conversion to electrical power in a fuel cell.
The system requires further testing but it’s off to a promising start! Read more at Physorg.
While there are many methods of converting heat energy into electrical energy, they’re typically inefficient (thermoelectric) or need to be done at a larger scale (steam turbines). Researchers at the Hong Kong Polytechnic University are showing promising results with a different approach. You see, the atoms in a liquid are in constant motion. They found that when copper ions collided with a strip of graphene immersed in a solution, the collision dislocated an electron out of the graphene, and it then traveled through the graphene strip, essentially replicating the function of a battery and illuminating an LED as a result.
As with any science, further tests are needed to verify the reaction and rule out secondary effects being responsible (such as chemical reactions). If validated, though, this has enormous potential, for it would enable the generation of electrical energy from any heat source (something planet has no shortage of). It’ll be interesting to see if this pans out.
Read more here.