SL has a couple full time employees building it. Also, they publish a lot of info about their build process. Centos doesn't. Sometime their releases are slower.
You're right that you can do probably that if you only ever keep the layers separate. The moment you e.g. provide export functions that combine the layers, you're currently in a grey area. With the new license, it's no longer a grey area, but you explicitly need to release your source data to be in compliance.
about 54 TB. But only about 2% of tiles have ever been seen. Each zoom level has 4 times as many tiles as the previous level and zoom level 18 (the highest) doesnt have a lot of data.
Quote: "OSM does NOT pre-render every tile. Pre-rendering all tiles would use around 54000GB of storage. As the following table shows, the majority of tiles are never viewed. In fact just 1.79% are viewed."
Those figures are about a year old, though it does give a newer figure for space used which is about 1200TB or 2.7% of the total size estimated.
20%? Over 60% of our electricity is consumed when the sun shines. Currently we get less then 1% of our power from solar. Storage will not matter for a very long time.
In Tampa FL with optimal tilt and no shade a panel rated at 1 peak watt would generate 5.3 watts a day X 30.4 days a month * 4500w panels = 725 Kw per month
Thanks. For optimal tilt that implies a sun tracking system, correct? Do most installations track? Do the sun trackers use much energy to rotate all the panels? Are they reliable, or do they add maintenance costs. The system costs we are talking about here do not include trackers or installation of trackers, correct? How much would that add.
Florida gets a lot of sun. I agree with you that a tracking array of new panels in Florida gives those numbers.
For people in other parts of the country and without trackers I find this site that has monthly solar radiation numbers to be useful for estimating output.
No tracking system. Here are some average numbers of hours of peak energy a day for a fixed system
Portland Or 4.0, Chicago 4.4, Tampa 5.3, San Francisco 5.4
Total hardware costs are currently about $1.75 watt for panels, inverter and hardware. Fed Tax rebate is 30%.
Thanks. Ok, your peak equivalent hours number for Portland OR using a fixed position is 4, implying an average of 365 * 4 * 4.5k = 6570kWh/year, correct?
The federal DOE site calculator for the same 4.5kWh fixed tilt plant gives 4580 kWh/yr for Portland (http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/US/...), ranging from 142 kWh/mo in December to 578kWh/mo in July. What accounts for the discrepancy between the two calculations?
A good bit of the discrepancy is that the calculator assumes that the DC to AC conversion is only 77% efficient (see "DC to AC Derate Factor" in the calculator), while the naive calculation assumes 100% efficiency of conversion, right?
Do these installations just pick the best single angle and stick to it all year? It seems like you must be able to get a reasonable benefit by adjusting your panels say, once a month.
Yield from that isn't very big, and far outweighed by the cost of making the whole installation moveable. If you're going to put everything on a moveable frame anyway, it's better to have it servo-controlled so that it's at least adjusted continually.
It took me some thinking to decode it as well. He has ratings numbers per watt-peak of the rating. Watt peak is a normalized output rating for a panel under some conditions and doesn't actually mean it's producing that in a given condition. He has numbers that a brand new 1 watt-peak panel gives 5.3 watts a day of power in a certain location with a certain configuration. He has a 4500Watt peak installation. So he multiplies the 4500 watt peak by the watts per day per watt-peak. The watt-peaks cancel out, giving watts per day. Multiplying further by days per month gives the average watts per month (average per year) for the 4500Wp installation in the given location. Basically, it's correct, but one has to understand that the W, typically called Watts, in the panel rating is not Watts, but a normalized Watt-peak rating of the panel. It is worth noting that solar salesmen will often intentionally confuse the two, leading homeowners to believe that their new installation has much higher capacity than it actually does.
It's not a matter of decoding-- it's wrong. Watts are a rate of energy usage. It's like saying that my car can drive 60 MPH per day. Doesn't make any sense.
(I do think you're right about the confusion and exploitation of the difference between peak power and average power.)
That reads like an industry press release designed to confidently befuddle.
For example, addressing the concern that ethanol production crowds out food production, it simply states that a different kind of corn is used... ignoring that the same land and other inputs could be used for food crops.
Addressing the concern about greenhouse gases, it mainly talks a bunch about 'vehicular gaseous hazardous air pollutants' and carbon monoxide – not the same as 'greenhouse gases'. The only reference to "life cycle analysis" is a sentence-fragment quote from an unnamed study with unclear context.
And 'myths' #4 and #5, that ethanol takes more water to produce and results in lower gas mileage? Well, this 'debunking' actually concedes both those 'myths'.
That said, the guy is a mechanical engineer at ANL, so I wouldn't take it as a sanctioned response from ANL. Claiming that the other corn isn't used in food production is disingenuous by the guy, since it is being used, but just via animals.
If you look at the lab biofuels splash page (http://biofuels.es.anl.gov/), you'll see they're working on things like water, nutrients and algal biofuels to improve the process.
There's a lot of work going into making 2nd generation biofuels actually viable, using cellulosic biomass and crops that can grow on marginal land. People are even working on producing fuel molecules that aren't ethanol (e.g. butanol).
We have a saying at work: Ethanol is for drinking, not for driving.
