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Green Energy Now, And On The Tide
thpr writes "The Electric Power Research Institute and its partners have completed their Offshore Wave Power Feasibility Demonstration Project, which defined potential wave energy projects off the shores of the United States. This is building off of work already done in Scotland (and elsewhere). San Francisco, New York and other areas are considering trial installations of the technology. It is interesting to note (table 1 in the report) that the energy density (kW/m^2) that can be achieved is much higher than wind or solar. In addition, harnessing 24% of available wave energy near the US at 50% efficiency is equal to all of the hydropower currently generated in the US (~7% of total electricity production). On a separate note, in the Office of Energy Efficiency and Renewable Energy's $1.2B 2006 budget the Department of Energy is closing out the Hydropower Technologies Program. Maybe that's why this technology is missing from our National Energy Policy?" Until it reaches maturity, though, U.S. readers can pay for other forms of green energy.
Yes, tidal forces DO cause the earth's rotation to slow down.
The tidal forces created by the earth on the moon have slowed the rotation of the moon down to the point that we only see one side of the moon. That is, the moon rotates about once a month. Similarly, the tidal forces of the moon are slowing the earth's rotation down, and it will eventually reach one about one rotation per month also. Assuming that the sun doesn't become a red giant first. And, speaking of the sun, there is also a tidal force that from the sun that will eventually cause the earth to rotate once per year. I'm not sure who this conflict between the moon's and the sun's tidal forces work out.
Conservation of angular momentum means that the tidal forces are causing the moon to orbit the earth faster, and thus further away.
While all these tidal forces are very small and only add up over very long periods of time, they can be measured. In particular, things like variations of the amount of snow on mountains, the amount of water in man-made lakes, the force of huricanes, and variations in the shape of the earth caused by earthquakes all add up to enough to cause the need for leap seconds.
Leap years keep the seasons from rotating through the calendar. Leap seconds keep the zenith of the sun ("noon") from rotating through the day. I forget the exact value, but there is something like an accumulated 20-30 seconds difference caused by these forces over the last 50 years, and therefore there have been 20-30 leap seconds added since then.
SPF support for most open source mail servers can be found at libspf2.
How viable is solar power? I was asking myself this question and here's the numbers I came up with.
In 2001 the USA used 96275 trillion BTUs of energy that year. This comes to 3.22 trillion watts.
Now there are about 295 million people in the US, so this comes to about 11Kw per person at any given time.
This means each person uses is responsible for 262 Kwh of power per day.
Now lets say that square meter of sunlight provides 1 kw of energy on average and the average area gets 5 good hours of sunlight per day. Looking at this chart, you can see that this assumption isn't too far off.
The typical solar panel is about 30% efficient. This means that for every square meter of solar panel would render 1.5 KwH every day.
This means that each man woman and child would need 174 square meters of panel to be responsible for all the energy made and used in their name!
If every person in the united states of America put up solar panels. We would have over 51 billion square meters of panel, that's close to 20,000 square miles of panel or the equivalent of covering most of over in panels.
Now these numbers account for all energy used both domestic, industrial, and exported. Also these numbers do not account for the added or lost efficiency of converting systems over to pure electrical power as opposed to other energy processes like those used in the internal combustion engine.
I left the links to my math in just incase I botched anything.
For those who want more, the best links on for intelligent green reading:
WorldChanging.com -- which also has an article about wave power.
TreeHugger, which is already linked in the story.
Dave Pollard, which writes very insightfully about lots of things including environmental philosophy.
Green Car Congress, where you can get the best news about green mobility, cool cars & industrial developments.
IDFuel, which is more about design but covers some of the same ground as TreeHugger.com
FuelCellWorks for all the latest news about fuel cells.
Grist Magazine, for news and a touch of humor, plus lots of interviews.
Treehugger? Treehugger... Treehugger!
The main advantages that nuclear has over solar, wind, hydroelectric, geothermal, and tidal:
This is a biggie. We know how to build nuclear power plants. Other countries have been doing so for years. Even in the US, nuclear is a proven energy source: IIRC, the US derives 24% of its electricity from nuclear power.
Look at how much energy the US uses now, and how much the US predicts it will be using. Can solar cells, wind farms, hydroelectric, or tidal replace that? It doesn't seem that wind nor solar can -- it doesn't have the capacity nor the constant power generation. Hydroelectric isn't unlimited either: sooner or later you run out of damnable rivers. Geothermal? It seems location dependent (but I'll admit, I haven't done my homework on this one). Tidal? How much coastline would we need again?
Hydroelectric power creates lakes and turns rivers into streams. It changes aquatic ecosystems. How about tidal? How many shorelines are we going to line with tidal energy power generation? What do you think that will do to the environment? (Wind power is also relatively non-disruptive.)
Nuclear has been competing with traditional electric generation for decades. We know we can generate nuclear power at a relatively low cost. The same can't be said for many other alternative energy sources.
Effective at limiting pollution.
No matter what "green" energy we use, there will be pollution. Check out the byproducts created in the manufacture of solar cells. Yes, nuclear does require some mining, and it requires proper disposal of nuclear waste. Yet, in the end, nuclear is amazingly efficient at eliminating greenhouse gases on a level with other green technologies.
So, lets sum up - Nuclear is:
Perhaps this is why noted scientists such as James Lovelock also advocate nuclear power.
The main problem is the public and the greens. They are convinced that nuclear power is unsafe, that radiation will kill us all, and they are playing a NIMBY game with nuclear waste disposal.
To be honest, nuclear power isn't my first choice for green energy: That would be orbital space platforms harvesting the energy of the sun, or fusion reactors. Perhaps one day, those technologies would be feasible. Right now, they are slightly more of a pipe dream than other green energy. Nuclear exists now, and it works. Conservation goes only so far -- the third world is slowly turning first world, and that will require an enormous consumption of energy.
We need to be realistic about our energy problem and about what solutions will work. Most alternative energy sources won't work right now. Nuclear will.
Waves are cool, but don't forget ... OTEC (Ocean Thermal Energy Conversion)
My father was a primary designer on this, so I had the "real scoop" on what was going on there in real time, it was real exciting stuff back then!
Mini-OTEC, 1979
In 1979, the first successful at-sea, closed-cycle OTEC operation in the world was conducted aboard the Mini-OTEC, a converted Navy barge operating in waters off Keahole Point.
This plant operated for three months, from August-October 1979, and generated approximately 50 kilowatts of gross power with net power ranging from 10-17 kilowatts.
Its turbine generator produced a gross output of up to 55 kW. About 40 kW were required to pump up 2,700 gallons/min of 42F water from 2200-ft depth through a 24-in diameter polyethylene pipe and an additional 2,700 gallons/min of 79F surface water, leaving a maximum net power output of 15 kW.
This was a joint effort by the State of Hawaii and a private industrial partner.
More linkage: NREL's OTEC site
Google
It's effect of ocean life (and the planet in general) is microscopic, infinitesimal, compared to the effect of the coal plants and other brown and black energy sources.
Treehugger? Treehugger... Treehugger!
Good article on Wired about a safe way to do Nuclear power. Still need to get rid of the waste, but at least meltdowns wouldn't be a problem.
We've missed out on a lot by not developong nuclear plants over the last 25 years. As other posters have said, its here now, and its the cleanest we have.
Spencer Ogden
Wait a second.
Article summary: "Nuclear is a bad idea because a lot of nuclear plants are getting old and will need to be replaced. Also, if everyone had solar and wind and personal gas turbines, we wouldn't need nuclear. Oh yeah, and politicians are evil and trying to exploit this for their own benefit."
(1) Those nuclear plants are getting old anyway, and will need to be replaced anyway. That has nothing to do with what they're going to be replaced with.
(2) Not everyone does have those, and I rather doubt everyone's going to suddenly buy those. Great idea for new houses, lousy idea for existing ones.
(3) And there aren't any politicians trying to make a fast buck off green power either? That's practically what a politician's job *is*.
Where's the section that looks at a realistic breakdown of realistic costs and goals? Where's the section that makes any attempt to compare the two besides "hey! look! NUCLEAR POWER ISN'T PERFECT!"
-1, flamebait.
Breaking Into the Industry - A development log about starting a game studio.
There is one alternative that is fully sustainable and has been working economically for decades. Brazil has been producing ethanol powered cars for 25 years. Every gas station in Brazil sells straight ethanol at a lower price than gasoline. Although the proportion is lower now, in the 1980's about 90% of the cars in Brazil were powered by straight ethanol, and the rest used a 75%/25% mix of gasoline and ethanol. Today several models of cars in Brazil come with "flex power" motors, which can burn any proportion of ethanol/gasoline mix.
The Brazilian alcohol program is the largest renewable energy program for cars in the world. The only reason why it has been pulled back a little is because the oil prices aren't as high now as in 1980, after you take inflation into account. Also, the whole country has a much better economical situation, with a lower debt, internal oil production is higher and world sugar prices are higher (Brazilian ethanol is made from sugar cane). All these factors have contributed to decrease the proportion of ethanol in the total fuel consumption in Brazil, but ethanol is the first and most viable alternative for renewable transportation fuel in the world.
http://www.jc-solarhomes.com/solar_energy_facts.ht m
Assume each square metre can receives 1 KW hr per hr. Assume 20% efficiency for photovoltaics. So 0.2 KW hr per hr per metre.
http://www.infoplease.com/ipa/A0001729.html says a kw hour is 3412 BTUs, so photo voltaics produce 0.2 * 3412 = 682.4 BTU/hr per square metre.
http://energy.cr.usgs.gov/energy/stats_ctry/Stat1. html
says the 1998 U.S. energy consumption was about 94 quadrillion BTUs
Assumong 8 * 365 hours of decent sunshine in the desert year around.
So that's 100 * 10^15 / (8 * 365 ) = 34 * 10^12 BTUs/sunshine hour.
(34 * 10^12 ) / (682.4 ) = 49 * 10^9 square metres = 49 * 10^9 / 10^6 = 49000 square kilometres = 223 KM by 223 KM or 140 miles by 140 miles.
If you "want" the entire world to consume energy at per-capita rates like the USA, then assuming the US population is 300M, and the world population is 6B, then 6*10^9/(300*10^6) * 49000 = 980000 square km. The Earth's land surface area is claimed to be 148,300,000 sq km, so 980000 / 148300000 = .006608 or less than 1% of the Earth's land surface area.
Mind you, for infrastructure that huge, you have to build roads, support buldings, etc. So even if a factor of 3 off, that's still about 2% of the surface area.
Also, once demand for photovoltaics reached 1% of the above, I imagine the industry would drive efficiency from 20% to higher levels. So 1/3 of the land surface area is way too high.
The real problem with photovoltaics is the cost. http://store.yahoo.com/sancor/50w.html will sell you a 502mm x 939mm panel for $588, or 588 / (502 * 939) * 1000000 = $1247 per sq metre. Let's be hopeful that in quantity, wholesale lots, we could buy this for $1000 per sq metre. 980000 * 1000 * 1000 * 1000 = $980 trillion. Note that the annual GDP for Earth, according to http://www.cia.gov/cia/publications/factbook/print /xx.html
is $51.48 trillion. That figure is at purchasing
power parity. I'll leave it others to speculate
whether photovoltaics can be manufactured cheaper
in third world countries or not. If you don't think so, then considering that the U.S. economy
is about $11 trillion, and that it is blamed for consuming about 1/2 the world's resources, the non purchasing power parity world GDP is probably closer to $22 trillion.
There needs to be a 10X reduction in the price/energy ratio of photovoltaics. Do that, i.e. reduce the cost of the solar energy to meet the world's needs to an investment of about $100 trillion, amortize it over 30 years, and I'm sure we can find the money and land to do this.
This is a myth. Funny how old myths refuse to die. Energy Payback Time is in the order of 1-2 years these days, and then will run efficiently for 10-20 years.
h tm l
http://www.otherpower.com/otherpower_solar_new.
Solar cells are not just "batteries" and have not been for a very long time.
Surur
Information is the location of things. Computation is moving things around.
Just FYI...
Lithuania gets 86% of electricity from nuclear power. France gets 78%. Belgium gets 57%. Sweden gets 52%. Switzerland and Slovakia get 45%. Ukraine gets 44%. Germany gets 29%. Japan gets 28%. The UK gets 23%.
The US only gets 20% of electricity from nuclear.