The Future of Energy: Why Power Density Matters

[wtmusic]

[div style="float: left; padding-right: 12px; text-align: center;"][br]Renewables don't have a remote chance of meeting 21st century energy needs."The twenty first century will almost certainly witness a transition to an overwhelming urban human population, and hopefully a transition to a low carbon energy system. The former however will have a significant impact on the latter, because a fundamentally urban species cannot be powered locally.

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Consider first the United Kingdom and Germany. Both use energy at a rate of just over 1 W/m2. So a back of the envelope calculation will tell you that getting all of their energy needs from onshore wind will require covering half of the UK or Germany in wind turbines. If you have ever been confused by why these countries are building wind farms in the North Sea, instead of on land where it is much cheaper, now you know why. Wind energy's low power density means you need to put it in a lot of back yards. And there are not as many of them in the North Sea.

Things are even worse in Japan and South Korea. If you covered all of South Korea in wind turbines they would generate less energy than is consumed there. Japan has a similar problem. And this ignores another difficulty: trees. Both Japan (68%) and South Korea (63%) have very high forest cover. If we ignore forested land (which should be out of bounds for large scale renewable energy generation, unless large scale biomass plantations are deemed acceptable) energy is used with a power density of almost 6 W/m2 in Japan and 7.5 W/m2 in South Korea. This calculation makes it clear that these countries can only be predominantly powered by renewable energy through the large scale utilisation of the more power dense solar energy. And social and political constraints may mean this can only happen if the efficiency of typical solar panels increases significantly from their current 10-15%.

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In contrast typical generation of fossil fuel and nuclear electricity has a power density of at least an order of magnitude greater than that of renewable energy. Power densities are comfortably above 100 W/m2 after accounting for mining etc. And conventional power plants often have power densites in excess of 1000 W/m2. A simple example of this higher power density is this small propane powered generator, providing in excess of 1000 W/m2. This is far in excess of the power density of any conceivable new method of generating renewable energy."

http://theenergycollective.com/robertwilson190/257481/why-power-density-matters?utm_source=feedburner&utm_medium=feed&utm_campaign=The+Energy+Collective+%28all+posts%29

[gtar100]

1. Reality. And why we are so stuck on fossil fuels.

I would like to see every dollar in profit from these oil companies be used to clean up their mess, find the ways and the means to virtually eliminate the toxic waste generated by their operations, and heavily fund research and development of clean energy production. And if that means we'll have fewer millionaires and billionaires in this world, I can live with that.

[intaglio]

2. I wonder which part of the hydrocarbon/nuclear industry commissioned this rubbish?

Energy density is a problem, but the fanciful assumptions about both that measure as well as about about "wind power" show this article to be pure propaganda.

Energy density varies from week to week, day to day, and hour to hour and to use "back of the envelope calculations" is utterly meaningless. The scary dystopia of imagining the whole of the land mass of the UK and Germany covered in wind turbines is just laughable as it ignores all the other forms of renewable power generation as well as off-shore siting and the huge increases in efficiency of wind turbines.

Even today wind turbines and renewables can over produce forcing grid dumps and shipping at a loss. My small and rural corner of the UK is producing sufficient energy that the local distribution company is warning of a need to increase the capacity of the grid so more power can be shipped out and wind turbines frequently stand idle because of such overcapacity.

Most of the problem of energy density vanishes if energy storage can be achieved, for wind and solar; with possible future sources such as wave, tide and hot rocks; produce at times of low demand as well as high. This sort of idea is, naturally, decried as being fanciful by opponents of renewable energy but they were similarly dismissive about the efficiencies and prices of solar cells. As an example the most familiar plaint about energy storage is that it is "thermodynamically inefficient" a laughable stance because any electricity generation system can be similarly demonised.

[kristopher]

3. The OP poster is renowned for posting false information

It is clearly a mission.

Debunking the Renewables “Disinformation Campaign”


According to Fox Business reporter Shibani Joshi, renewables are successful in Germany and not in the U.S. because Germany has “got a lot more sun than we do.” Sure, California might get sun now and then, Joshi conceded during her now-infamous flub, "but here on the East Coast, it's just not going to work." (She recanted the next day while adding new errors.)

Actually, Germany gets only about as much annual sun as Seattle or Alaska; its sunniest region gets less sun than almost anywhere in the lower 48 states. This underscores an important point: solar power works and competes not only in the sunniest places, but in some pretty cloudy places, too.

A PERVASIVE PATTERN
The Fox Business example is not a singular incident. Some mainstream media around the world have a tendency to publish misinformed or, worse, systematically and falsely negative stories about renewable energy. Some of those stories’ misinformation looks innocent, due to careless reporting, sloppy fact checking, and perpetuation of old myths. But other coverage walks, or crosses, the dangerous line of a disinformation campaign—a persistent pattern of coverage meant to undermine renewables’ strong market reality. This has become common enough in mainstream media that some researchers have focused their attention on this balance of accurate and positive coverage vs. inaccurate and negative coverage.

Tim Holmes, researcher for the U.K.’s Public Interest Research Centre (PIRC), points out press coverage is important because it can influence not only “what people perceive and believe” but also “what politicians think they believe.” PIRC’s 2011 study of renewable energy media coverage surveyed how four of the highest-circulation British daily newspapers reported on renewables during July 2009. A newspaper’s balance of positive and negative renewables coverage tended to align with its editorial ideology. The difference was astounding. In one instance, negative coverage of renewables was just 2.5 percent; in another, upwards of 75 percent.

A follow-up 2012 study by public relations consultancy CCGroup examined five of the most-read newspapers in the U.K. during July 2012. Researchers found more than 51 percent of the articles featuring renewables were negative, 21 percent positive...

http://blog.rmi.org/blog_2013_07_31_debunking_renewables_disinformation_campaign

Sad to say that this progressive forum is a prolific outlet for this same disinformation.

[oldhippie]

4. Says the Master .....

... propagandist.

[wtmusic]

5. Renewable resources are highly geographically-dependent

and specifically in regard to the UK, which has no significant hydro resources, wind is the most productive. You say that covering the UK in wind turbines is "laughable", but in fact resorting to any other resource to provide local power would be even less productive. So covering the UK in wind turbines is a best-possible scenario, and it will never happen.

On what basis are you assuming that "huge increases" in efficiency of wind turbines are physically possible? Have such increases even been demonstrated in laboratory situations?

Most of the problem of energy density vanishes if energy storage can be achieved

Indeed it does. That's roughly equivalent to saying that most of the problem of energy density vanishes if people use less energy, which is simply not going to happen either. Similarly, practical energy storage on a scale which would be useful is not here today, it won't be here tomorrow, and likely won't be here fifty years from now because of fundamental thermodynamic limits on efficiency and electrical resistance. Again, you categorize these problems as "laughable" but they are very real - all kinds of storage involve significant inefficiencies which are non-existent in direct transmission. They take the meager output of renewables and move them from meager to inconsequential.

I have always been dismissive about solar cells as any kind of solution and continue to be. After decades of development they make up a tiny fraction of power generation, they're useless at night and when it's cloudy (see storage conundrum, above), and they're land use hogs. Renewables advocates seem to think the public is going to be tolerant (or able) to spend four times as much money, and use up 10 times as much space, for an energy resource which is available sometimes and still needs to be backed up with fossil fuel peaking plants (i.e., they are not carbon-free).

Geothermal is useful in certain areas; again that's not going to cut it, and like tidal power will demand an investment of hundreds of billions of dollars with no significant promise of panning out.

Renewables advocates seem to be particularly numbers-averse and for good reason. When their fanciful dreams are put to any kind of physical test they simply don't add up. They're a false promise, a false solution, and we don't have time to waste on them.