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Comment Re:Capitalism, ho! (Score 4, Informative) 107

I don't have the FCC's spectrum allocation chart handy, but here's the one for Australia: http://www.acma.gov.au/webwr/radcomm/frequency_planning/spectrum_plan/arsp-wc.pdf

The only unallocated spectrum is below 9kHz and above 275GHz. Obviously a lot of overlap can occur at VHF and above (if you allow for the odd tropospheric ducting event to cause interference) but TV is the last of the big chunks of spectrum, everything on the chart that isn't broadcasting (orange/red colour) is hacked up into small pieces.

Comment Re:Great (Score 3, Informative) 227

Re: Energetics of solar panels. Modern panels "pay" for themselves about 10-15 times over.

See Permanently dispelling a myth of photovoltaics via the adoption of a new net energy indicator

In the case of a building which requires windows I would suggest only counting the solar cell manufacturing cost as the glass and installation cost happen regardless. Unless said building didn't require the windows to be replaced, in which case it's valid to count it.

Comment Re:Numbers please... (Score 1) 182

To be fair it would be best to compare energy densities while compensating for the increased efficiency of electric motors over an ICE.

Perhaps we need a new unit: km/kg. So if you have a vehicle which can travel 100km on 10kg of petrol the target would be a 10kg battery which can get the vehicle the same distance.

Personally I don't see the need for equal petrol/electric vehicle ranges as the inconvenience of traveling to a designated refueling station is removed because there is electricity in my garage. (Obviously this doesn't work for everyone but it has massive potential for a significant portion of the population).

Comment Re:Modify this (Score 1) 270

Yeah, I guess it all depends on the proportion of generating capacity. My logic was along the lines that electricity is only cheap at night because the demand is very low. If the demand at night became on par with daytime (ie: if sufficient storage was implemented such that demand was near constant) then the day/night price difference could potentially be much smaller, making stand along storage much less economically viable.

Comment Re:Heat retention for how long ? (Score 2) 270

I'm not familiar with the context of your quote, but I suspect the logic is something like this: gas "amount" is typically measured is joules, as in "the number of joules of heat energy you'll get from burning x "amount" of gas. So, burning 1J of gas results in roughly 1J of heat being deposited in a room. However, if you use a heat pump powered by electricity 1J of electricity produces ~2-3J of heat in the room, as a heat pump cools down outside in order to heat inside.

The same logic is applied when comparing traditional electric heating (bar radiators, for example) to modern reverse cycle air conditioners.

Comment Re:Heat retention for how long ? (Score 5, Interesting) 270

I've been doing some research into renewable energy in an Australian context at the University of Newcastle. The most commonly thrown around figure is 1C/day of loss at operating temperatures.

In doing some simple simulations (using real world demand, wind farm output and direct solar irradiance data) I've found that 50GW of wind farms (peak, scaled by 50x from Australia's current ~1GW peak wind capacity) and ~42GW of concentrated solar thermal (roughly 53x53km square area, spread across Australia on 12 sites) with 24hrs of storage is able to supply all of Australia's current electricity demand. The thermal storage dropped to ~10% capacity at it's lowest point.

The simulation tried to closely model the Beyond Zero Emissions Zero Carbon Australia 2020 plan. Their modeling uses a different demand profile, one scaled to a proposed 2020 level after compensating for growth, electrification of cars etc.

Comment Re:Where is the fun? (Score 1) 854

I feel that Quake Live and Starcraft 2 (ladder) do a very good job of this. They're both games which aren't afraid to be difficult to master and as such accept that a small difference in skill makes for a massive difference in score. Contrast this to, say, Bad Company 2: Everyone plays on the same servers because it's a very "normalised" game. A wide range of skill levels tend to result in similar scores.

Comment Re:Question (Score 3, Interesting) 117

Here's a quick and dirty stab at some calculations:

Wikipedia claims that reverse osmosis requires 6kWh to produce 1000L of water, or 21.6 kJ/L.

To evaporate water already at 100C requires ~41kJ/mol, or 2.3kJ/L. To heat 1L of water from 20C to 100C requires 33.6kJ. So, by this very simplistic model it would require ~34kJ/L to desalinate water by boiling.

Now the efficiency of PV vs thermal in a solar powered system depends on the efficiencies of the collectors. PV is ~25%, at best, solar insolation -> electricity. Heating water to evaporate it is a much more difficult calculation. Basically water doesn't have to be at 100C to evaporate and the losses in a thermal system would increase as the temperature differential (system->ambient) increased but in the end I'm not really educated enough to comment accurately. Hopefully the numbers above will give you some feel for the problem though.

Comment Re:3-D (Score 2, Insightful) 261

Just like with every other technology, starting from human history and the discovery of fire and a wheel.

"Computers are useless. They can only give you answers." - Picasso

I guess that's what you get when people have no foresight. But I agree that 3D is overused right now, just like stereo was when it was young. Have you listened to Voodoo Child lately? That song flys left and right like a dunk sailor.

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