Kevin_Lowe said:
You claimed earlier that it was "magical" to think that renewables could replace non-renewables. Suppose we decided that instead of spending money on new non-renewable power stations we would spend the same money on putting the best value-for-money solar installations on the roofs of buildings. I'm thinking about sufficient solar hot water systems for places that use hot water, and photovoltaics on the rest of the space. How far would that get us in terms of replacing non-renewable energy sources? How much money would we have to spend, to get x% of our energy needs just from solar this way, and what would x be for a reasonable investment? How much net carbon dioxide would this save (or cost)?
Hey, Dr. Buzz0, can you help me out here? I did some of the math myself, based on some quoted figures, but as such I had to make some simplistic assumptions. Correct me if I'm wrong, please.
Okay, first of all, Dr. Buzzo says that, on average, we receive 200 watts per square meter with current solar technology. So I make the assumption that we cover every single roof in all of New York with these solar panels, and they have the same efficiency (they may have less, considering the weather in New York City). Then, I took the square kilometers of the Urban areas of New York City (not the overall Metropolis area, as there's less rooftops to factor in there, I believe).
So...
According to an article I found with google:
New York passed the 2005 record for peak energy usage at least twice on Monday afternoon as temperatures hit the 90s across the state.
The peak load for the summer of 2005 came on July 26, when energy users across the state consumed an average 31,741 megawatts of electricity during an hour-long period.
Between 2 p.m. and 3 p.m. on July 17 the average peak load registered at 32,316 megawatts, while between 3 p.m. and 4 p.m. the peak load was 32,519 megawatts of electricity.
As such, I'll use that peak load as a starting point. I'm not sure what the average energy requirements would be.
from:
http://albany.bizjournals.com/albany/stories/2006/07/17/daily14.html
8,683.2 km^2 area for Urban Area of New York City
DrBuzz0 said:
The continental US receives about 200 watts per meter squared average solar power concentration. Do the math and you'll find problems.
Assuming that this figure can be exported to New York City solar panels (not sure if it can be)...
31 741 000 000 watts needed for the state (okay, that's a big state, but I can't find energy use needed by city quickly enough; if someone else can find it, that would be lovely)
8 683 200 square meters for the Urban area of New York City
(That last one from
http://en.wikipedia.org/wiki/New_York_City)
*200 watts per square meter = 1 736 640 000 Watts created
That's significant, I'll admit. However, that's 1.7*10^9 watts vs. 31.7*10^9 watts needed. That cuts down on requirements for all of New York State (again, I'm not sure about New York City itself), but it's a far cry from replacing them. I'm not sure how much wind energy could help, though.
One thing is, New York City is very big and has a lot of energy consumption requirements... however, it's also very environmental in that it uses
New York City's dense population and low automobile dependence help make New York among the most energy efficient in the United States.[34] The city's greenhouse gas emission levels are relatively low when measured per capita, at 7.1 metric tons per person, below San Francisco, at 11.2 metric tons, and the national average, at 24.5.[35] New Yorkers are collectively responsible for one percent of the nation's total greenhouse gas emissions,[35] though comprise 2.7% of the nation's population. The average New Yorker consumes less than half the electricity used by a resident of San Francisco and nearly one-quarter the electricity consumed by a resident of Dallas.[36]
http://en.wikipedia.org/wiki/New_York_City
So this would lower the overall energy requirements of the state of New York. Something like San Francisco would get about as much bang for their buck, but need more bucks.
Now, for cost...
Meh, I'm giving up on looking up the details for cost. Some of it goes over my head, and I would rather an expert handle it.
However, I did find this link:
http://www.dmme.virginia.gov/de/chap7c.html It seems that the more solar energy has to handle, the higher the costs per kilowatt hour rises.
The Table shows that it is difficult for even high-performance solar water heaters to be cost-effective when displacing inexpensive natural gas: systems must cost $25 or less per sq.ft. in residential applications, and $21 or less per sq.ft. in commercial applications. When displacing electricity, however, the situation is much different: even lower performance systems can be economical if costing less than $50-52 per sq.ft. in residential and small commercial applications (in Virginia Power's service area). The large general service rate case in Table 1 assumes that demand charges (costs for on-peak power) are not avoided. Where demand charges are paid by a facility, the solar system design should include a peak-load reduction strategy (including summer-daytime shutoff on the auxiliary heater), so that these charges can be avoided and system cost-effectiveness can be improved."
The three small to moderate scale systems that were evaluated in detail in the study had installed costs that ranged from $44 to $74 per square foot of collector, with an average of $59. Their average annual performance ranged from 550 to 770 Btu per sq.ft. per day, with an average of 650.
To use the Table as a decision guide, you read it from right to left. First, you must know the type and rate of energy saved. For example, let's say you have residential electricity at $.078 per kWh or $22.85 per million Btu. Second, you assume (or get a guarantee from the contractor of) the system's energy performance (let's say 600 Btu per day per square foot of collector area). Finally, you simply read from the first column the maximum cost of the system to be cost-effective. In our example, the maximum cost (or break-even point) is $67 per square foot of collector area. If a contractor bids a cost under the maximum (say $40 per square foot), the system should be cost-effective; if it is over the maximum, it will probably not be. It should be noted that this guide includes only economic benefits and not the other benefits provided by solar energy systems, such as reduced air pollution emissions, enhanced energy self-reliance, and conservation of non-renewable resources.
Now, the cost per kilowatt hour for nuclear energy... using
this chart, it seems that nuclear energy costs a little under $2.50 per kilowatt hour, including fuel costs, operation and maintenance, general overhead, system integration, carbon emissions (how do they factor that as a "cost"?), and capital expenditure.
As for energy itself for nuclear energy...
Wikipedia said:
The remaining worldwide energy resources are large, with the remaining fossil fuels totaling an estimated 0.4 YJ (1 YJ = 1024J) and the available nuclear fuel such as uranium exceeding 2.5 YJ. Fossil fuel range from 0.6-3 YJ if estimates of reserves of methane clathrates are accurate and become technically extractable. Mostly thanks to the Sun, the world also has a renewable usable energy flux that exceeds 120 PW (8,000 times 2004 total usage), or 3.8 YJ/yr, dwarfing all non-renewable resources. Even that amount is also only a minute amount of the sun's total energy output, due to the small solid angle the earth's outline makes with the sun.
http://en.wikipedia.org/wiki/World_energy_resources_and_consumption
Of course, this means that solar energy is quite significant; however, it costs quite a bit of money to export it over long distances, and would have to have methods of storing said energy when it's dark. The batteries required for such a thing would be extremely wasteful...
Also, factor in the 20% efficiency to 40% efficiency of the most top-notch (and thus much more expensive) solar panels... I think that cuts down on the usable energy actually usable, if that's not factored in anyways. I may have to retract my claim about solar energy powering the world being far fetched. The question is, is it economically or environmentally feasible? Can we create all of these solar panels, throughout the world, place them, and have little problems sustaining such a system economically or environmentally? Will exporting said power be easy over large distances?
If we store that energy into batteries, so we could use that energy even during the night time or for exporting, then that would definitely increase the amount of waste produced by such a system...
Hmm... found something rather interesting, about "low level waste":
The nuclear industry also produces a volume of low-level radioactive waste in the form of contaminated items like clothing, hand tools, water purifier resins, and (upon decommissioning) the materials of which the reactor itself is built. In the United States, the Nuclear Regulatory Commission has repeatedly attempted to allow low-level materials to be handled as normal waste: landfilled, recycled into consumer items, et cetera. Most low-level waste releases very low levels of radioactivity and is only considered radioactive waste because of its history. For example, according to the standards of the NRC, the radiation released by coffee is enough to treat it as low level waste.
http://en.wikipedia.org/wiki/Nuclear_power
Lol. Careful of that coffee!
I bumped into that last one quite by accident, and thought I'd share it.
