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.
The electric generators in coal power stations in Australia (ie: ones that I'm aware of) use synchronous generators which don't use rare earth magnets. They have a DC power source which energises an excitation winding to create the internal magnetic field.
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.
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).
$14 for the exam? Wow, I'm going for an Australian standard licence on Jan 29th and it's $210 for the exams ($70 each for theory, regulations and practical). Even the foundation licence is $70, or $35 if you're under 18. Next you'll probably tell me that a Yaesu FT-857D costs $1000...
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.
Sounds like a good idea, but would widespread use cause cheap power at night to no longer be cheap? It would help to even out electricity prices, but I don't see it being a viable long term business under the current electricity trading system.
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.
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.
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.
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.
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.
They do. They're called "how to vote cards". As you walk into the polling booth you're handed bits of paper from people representing many of the major parties. They contain facsimiles of the ballot papers which have been filled in to their liking, allowing you to copy the vote your favourite party wants without thinking.
For reference, here's another analogy I thought up: "Climate is saying that one in every six rolls of a die will be a five. Weather is trying to say that the next roll is definetly a five". It's not perfect as the outcome of any roll of the die is independent of previous results while weather is somewhat predictable, but that's a subtlety that someone who misunderstands the difference between weather and climate isn't likely to pick up on.
That method works to some degree. The problem is that it requires a good memory of what's open and where it is. This feature seems to give you a graphical snapshot of everything which, for some people, would make finding an open tab faster given that a) they don't have to remember where is is and b) it allows their brain to process graphical rather than textual information.
Nobody has said this yet, but why don't nerds want this information? I would love to know how much power a phone emits, because it would help me choose a phone which will work as far away from the tower as possible by going for the highest power model.
With the numbers in the article I calculated 167W/m^2, or about 6% given the nominal 1000W/m^2 of incident solar radiation. I'm not sure if that's 24 hour output though, depending on how much night time output those numbers include the efficiency could be almost double. This is an overall system efficiency too, so I'm going to put this project into the "pretty reasonable" catagory. This form of low carbon electricity generation has the big advantage of producing much more consistant output, which is great for allowing controlled smoothing out of wind output.
At least the minister's response quoted in the article is positive. The summary butchered it:
"This is a good question but not a question to destroy our project," Oettinger said. "This question must be answered by a good answer and so we need ways to ensure that our import of electricity is from renewables."
Telstra's universal service obligation is what makes them horribly expensive for the bulk of the population. They seem to have a policy of a nation wide pricing structure, so city customers essentially subsidise country customers. Maybe, just maybe, this will result in slightly lower prices from them and therefore more competition. Right now the only city Telstra customers are the mums, dads and grandparents who don't want to research telecommunications services (because, frankly, it's boring at bat shit) and go with Telstra because it's a name they've always been with.
Also don't forget that the size of the writes can make a big difference. If it writes in 512-byte sectors then writing one byte causes the same wear as writing 512. I've got no idea how to predict a shortened lifespan given this fact, it's highly dependent on the user's usage habits. All I can say for sure is that the only time a drive will get close to it's expected lifespan is if it's used in something like a video editing environment where all writes are large, contiguous files. God help you if you ran squid on one though, or accidentally let Windows use it for virtual memory.
Slashdot Mirror
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.
The electric generators in coal power stations in Australia (ie: ones that I'm aware of) use synchronous generators which don't use rare earth magnets. They have a DC power source which energises an excitation winding to create the internal magnetic field.
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.
Because it it did, the Sun would be the most evil entity in the Solar System.
Well, to be fair skin cancer is very common in Australia:
Cumulative risks to age 70 years of having at least one NMSC were 70% for men and 58% for women
Source
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).
$14 for the exam? Wow, I'm going for an Australian standard licence on Jan 29th and it's $210 for the exams ($70 each for theory, regulations and practical). Even the foundation licence is $70, or $35 if you're under 18. Next you'll probably tell me that a Yaesu FT-857D costs $1000...
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.
Sounds like a good idea, but would widespread use cause cheap power at night to no longer be cheap? It would help to even out electricity prices, but I don't see it being a viable long term business under the current electricity trading system.
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.
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.
I'm no expert, but since the atmospheric pressure on Mars is so low propellers/balloons etc probably won't work very well.
Which is why Starcraft 2 has avatars for "1000 1v1 wins" for each race.
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.
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.
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.
They do. They're called "how to vote cards". As you walk into the polling booth you're handed bits of paper from people representing many of the major parties. They contain facsimiles of the ballot papers which have been filled in to their liking, allowing you to copy the vote your favourite party wants without thinking.
Woops, screwed that up a bit eh? Meh, it gets the idea across.
For reference, here's another analogy I thought up: "Climate is saying that one in every six rolls of a die will be a five. Weather is trying to say that the next roll is definetly a five". It's not perfect as the outcome of any roll of the die is independent of previous results while weather is somewhat predictable, but that's a subtlety that someone who misunderstands the difference between weather and climate isn't likely to pick up on.
That method works to some degree. The problem is that it requires a good memory of what's open and where it is. This feature seems to give you a graphical snapshot of everything which, for some people, would make finding an open tab faster given that a) they don't have to remember where is is and b) it allows their brain to process graphical rather than textual information.
Nobody has said this yet, but why don't nerds want this information? I would love to know how much power a phone emits, because it would help me choose a phone which will work as far away from the tower as possible by going for the highest power model.
With the numbers in the article I calculated 167W/m^2, or about 6% given the nominal 1000W/m^2 of incident solar radiation. I'm not sure if that's 24 hour output though, depending on how much night time output those numbers include the efficiency could be almost double. This is an overall system efficiency too, so I'm going to put this project into the "pretty reasonable" catagory. This form of low carbon electricity generation has the big advantage of producing much more consistant output, which is great for allowing controlled smoothing out of wind output.
Corporation, n. An ingenious device for obtaining individual profit without individual responsibility. - Ambrose Bierce
At least the minister's response quoted in the article is positive. The summary butchered it:
"This is a good question but not a question to destroy our project," Oettinger said. "This question must be answered by a good answer and so we need ways to ensure that our import of electricity is from renewables."
Telstra's universal service obligation is what makes them horribly expensive for the bulk of the population. They seem to have a policy of a nation wide pricing structure, so city customers essentially subsidise country customers. Maybe, just maybe, this will result in slightly lower prices from them and therefore more competition. Right now the only city Telstra customers are the mums, dads and grandparents who don't want to research telecommunications services (because, frankly, it's boring at bat shit) and go with Telstra because it's a name they've always been with.
Also don't forget that the size of the writes can make a big difference. If it writes in 512-byte sectors then writing one byte causes the same wear as writing 512. I've got no idea how to predict a shortened lifespan given this fact, it's highly dependent on the user's usage habits. All I can say for sure is that the only time a drive will get close to it's expected lifespan is if it's used in something like a video editing environment where all writes are large, contiguous files. God help you if you ran squid on one though, or accidentally let Windows use it for virtual memory.