Monday, August 6, 2012

Total Available Renewable Resource

Several commenters questioned Friday's post on the grounds that the total amount of solar and wind power potentially available is insufficient to power modern civilization

This is incorrect.

Total available wind power available on land and near shore has been estimated at 72TW.   This is close to five times current total primary energy consumption, and still more than twice as large as energy consumption in 2040 (extrapolating at the 2.7% growth rate of the last decade).

Of course, not all technically and economically feasible wind sites are politically feasible.  Thus it's important that total incoming solar radiation is also very large.  Top of the atmosphere incoming solar radiation is 174000TW.  If we just look at the world's desert areas, they represent about a third of the global land area, itself about 30% of the total surface.  Allowing 30% losses in the atmosphere over deserts, and throwing out something for Antarctica (a desert, but not a very useful one for solar power), we end up with something in the ballpark of 7000TW of available solar energy from deserts alone.  This is hundreds of times larger than current civilizational energy consumption.

Therefore, constraints on our ability to utilize renewables are political and economic, not ultimate physical ones; there is plenty of renewable energy out there.

24 comments:

Lucas Durand said...

Stuart,
In addition to "political and economic" constraints I might also add technical and time constraints...

To my knowledge no one has yet demonstrated that grid-scale energy storage systems are feasible.

The clock is ticking on the implementation of any renewable energy strategy - not only in terms of a changing climate (for example) but also in terms of how much time it will take to build out the infrastructure required to make a complete transition. If your term paper is due at 9am, its no good to start it at 8:55am.

Tom Murphy has an excellent series of posts where he estimates the feasibility of a wide range of renewable strategies... The message seems to be that while some offer real potential, that potential will probably only be realized in the context of dramatically reduced demand (political constraint).

Michael R said...

"We propose a top-down approach, such as that in Miller et al., 2010, to evaluate the physical-geographical potential and, for the first time, to evaluate the global technological wind power potential, while acknowledging energy conservation. The results give roughly 1TW for the top limit of the future electrical potential of wind energy. This value is much lower than previous estimates and even lower than economic and realizable potentials published for the mid-century (e.g. DeVries et al., 2007, EEA, 2009, Zerta et al., 2008)."

http://www.theoildrum.com/node/8322

kjmclark said...

Except that Stuart covered a potential world-wide grid PV system, back in 2008 on The Oil Drum:
http://www.theoildrum.com/node/3540

Seems like he elaborated on that in a later post I can't find.

I don't recall Tom looking at a world grid like that. The closest were http://physics.ucsd.edu/do-the-math/2011/09/dont-be-a-pv-efficiency-snob/ and http://physics.ucsd.edu/do-the-math/2011/12/wind-fights-solar/. He does go into storage, only to find that we don't have the technology to store much.

Gary said...

My concern about renewables is that they might actually succeed in allowing even further population growth. Ultimately we need to feed more people, mine more non-energy resources, etc. and it's questionable that the earth's natural regulation systems can support the disruption we have already wrought, let alone support more of us!

rjs said...

since the point of all that renewable energy is to wean us off fossil fuels in order to mitigate climate change, arent we front loading our carbon footprint by building it?

for instance, you'll need metals; both aluminum smelting & steel making are two of the most energy intensive industrial processes, & for the most part use coal generated energy...

& mining of the ores uses diesel fuel...as does your construction equipment when you're building your wind & solar infrastructure...

William Connolley said...

David McKie has some very useful calculations at http://www.withouthotair.com/

Lucas Durand said...

kjmclark,
The expansion of the actual grid to a world-wide scale seems like it may be less of technical constraint but until the storage problem is solved, it seems like a moot point in a discussion about a renewable energy transition.

There has been lots of talk about such storage systems and I know there are people who are experimenting, but it has yet to be demonstrated that any such storage system is within the realm of technical possibility.

A key point to this discussion is what Nate Hagens has called "a longage of expectations". PV and wind are useful technologies, but we are likely to be disapointed if we expect to somehow scale up their use to meet current demand. Probably better to forget about building giant centralized renewable energy systems with unproven storage technologies and focus on smaller distributed systems with proven "off the shelf" storage technologies.

Peter Vesborg said...

I recently wrote a scientific paper on constraints on energy transformation technologies based on the availability of the chemical elements (do we have enough of Xy to make a TW worth of wind turbines, PV panels, etc.)

Turns out that many technologies which are great on the GW scale run into trouble on the TW scale...

You can download the paper here
http://pubs.rsc.org/en/content/articlelanding/2012/ra/c2ra20839c
after logging in (free) otherwise send me a pm, and I'll send you the pdf.

Nick G said...

Tom Murphy's analyses are kind've interesting, but not really very useful.

For instance, his analysis of chemical batteries for stabilizing a 100% renewable grid is highly unrealistic: no one would contemplate using chemical batteries in this way. Instead, we'd use a wide variety of things like Demand Side Management and very cheap underground H2 storage.

The top down analysis of wind resource looks reasonably valid. On the other hand, current human electrical consumption is only about 2TW, and another 6TW would handle the rest of current FF consumption given the much greater efficiency of electrical systems.

So, even if we can only get 5TW from wind, that's still most of what we'd need, and solar could easily provide the rest.

sunbeam said...

I think reduced energy available spells a lot of trouble for the way we do things.

My honest take though, is that "modern" civilization is more durable than it is given credit for by most on the Peak Oil sites.

I don't question Tom Murphy's understanding of physical phenomena or ability to do math. But I think that both he and Hirsch miss the fact that very large things can actually be done.

I mean we build up a national interstate system, paved over gazillion square feet of things with roads, moved probably more than a 100 million people around the country...

Built a nationwide network of fried food shacks, suburbs, shopping malls...

I forget, did we ever have more cars than people in this country? Look at all the cars that have been produced since 1945.

Geez, I mean to me all it has to do is work. No one says it will be easy, or that the current economic and political systems will survive unscathed.

But if Civilization depends on smelters running between 10 and 2 on sunny days in Arizona, I think technological society is still workable.

I realize that an argument can be made that is was all done with fossil fuels, but I think there is easily enough to make this transition.

After all, oil supply will decline on a curve. When this is apparent I think a different attitude towards what we do with energy resources will hopefully develop.

Whether me and mine wind up as squatters in a favela, or bleeding out in the mud on a battleground in some country or other (maybe this one) is another matter.

TechGuy said...

Your analysis is purely from a theological view and does not consider economic, resource limits, and complexity constraints. I believe the original author(s) of the statement included the economics, complexity and limits of capturing all of the available energy.

Physics tells us a few pounds of matter contains more than ample amount of energy to meet global energy demand for an entire year. However its not possible to convert matter into pure energy. The argument is purely academic and serves no real purpose, except to further promote misconsceptions. This discussion is like an article written for Popular science, which is largely just a fantasy.

Another significant factor is replacing non-electrical energy resources with electric systems. For instance, we don't use electricity to smelt metals, or produce petrochemicals (fertializer, etc), or produce transportation fuels. How much electricial power is required to replace chemical systems using fossil fuels? Its certainly many times the current electrical usage. What would the infrastructure be required to eliminate fossil fuels for all transportation (Trucks, cars, trains, boats and planes)? Assuming we just powered all ground vehicles in the USA with electrical system, how much more energy would the grid need to transport. How many more transformers, high tension lines would be required to transport energy from undevelop locations where land is avail.* How long would it take to upgrade it. What new technologies would be required (super conducting long distance power lines?).


Finally we most also factor in existing economic factors that world is facing. The USA has 16 Trillion in debt and climbing at more than $1T/yr. Europe is close to defaulting, Japan is has a public Debt to GDP of nearly 300% and China is in a bubble that will go bust in a few years. There is no capital available to support a global scale renewable energy program.

* Forget sea installations since any equipment set up to capture wind will have an relatively short lifespan. Caused by severe storm weather, corrosion, erosion and other factors cause by salt water. At best a large wind system will last 20 years before its damaged beyond repair. FYI: for land based PV systems you need a large army of people equipped with squeeges to constantly remove dust from all those millions if not billions of PV panels. Localized thunder storms can also take out entire PV farms by causing an voltage differential larger than the diode breakdown voltage of PVs. Lightening does not need to strike the panels to damage them. High winds storms, hail and ice storms can easily damage solar panels.

The yearly average of full sunlight in the USA per day is about 5.5 hours, when you factor in weather, day/night and seasons. For a PV system to generate 1 KW of power, 7/24/365 would require an estimate 15 KW of PV power, if you factor in storage losses, distribution losses and other factors. so for 1 TW of demand you need about 15 TW of PV panels. As you can see scaling become a big problem trying to replace existing fossil power systems with PV systems.

Unknown said...

On an unrelated note: Dr. Dai's new drought paper is out, very interesting. open access, http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1633.html

John Weber said...

Solar and wind are extension of the fossil fuel supply line. They cannot reproduce themselves. They won't be mining the copper, aluminum, rare metals. Nor will they be processing them physically and chemically. Nor fabricate into usable form, then manufacture and include all the transportation of materials, people and their needs.
see: http://sunweber.blogspot.com/2011/12/machines-making-machines-making.html

And even if they could accomplish this, they certainly won't be making all the goodies of industrial society. This is simply wishful thinking.
see:
http://sunweber.blogspot.com/2011/10/to-make-light-bulb.html

And I agree that should this fantasy occur it would only further threaten humanity and life on the earth.

Mr. Sunshine said...

Stuart is an optimist, which is ok, as long as one understands what optimism is - a positive outlook in spite of all the data. It's a disorder, not an attribute, when dealing with global scale data and events. He knows there's no equal energy density to oil, nor a source with its portability and ease of storage, shipment or use. Nor one even close. He understands the impossibility of maintaining an ecology built upon the properties of cheap, reliable oil. He has difficulty with the outcomes that are obvious by the unwinding of that ecology. So do I. I invested a lot to become the local "miller" in my community, but for naught, since when the post-peak-oil collapse finally arrives, my thyroid replacement prescription drug "grid" will fail long before my small hydro mill does. As has been said, Nature Bats Last. :)

Lucas Durand said...

jkmclark,
Apologies, I think I misunderstood your earlier post re: the world-wide grid - a point which I now realize is not moot.

That being said, I think the concept of a world-wide grid (though possibly less technically challenging than grid-scale storage) suffers from the same drawbacks as grid-scale storage: Both ideas attempts to deal with problems of cmplexity by adding more complexity and both approaches rely on the implementation of unproven technology.

There are times in life when you only have one chance to do something properly. When those times come, it is better to stick to what you know and what is proven to work - gambling on the unknown when the stakes are this high...

yvesT said...

The only sensible policy to accelerate whatever change is possible is volume based taxes on fossiles (and raw materials in general), that is what would make sense.

petemason said...

Stuart you are quite correct. The wind power study cited above (as you know) has been discredited. Scientific America produced a special edition not so long ago showing how the entire world could run on proven renewable technology, and the transformation would not cost the world, while continuing as the political and economic system does now will cost the earth. The political will is another thing - that's where the rest of us need to concentrate, while your input on these posts is highly detailed, factual and central to understanding the world today.

Stuart Staniford said...

Kjm, Lucas: I am still in the same place on storage vs grid. Storage appears to require either a breakthrough, or people being willing to put up with very little energy usage during night/cloudy intervals - which they aren't. So I don't see (absent the breakthrough) how we can have a fully renewable world absent a grid that shares energy across distances significantly above the synoptic scale.

Obviously that poses political problems too - but they seem potentially less severe than those involved in trying to get the middle classes around the world to use orders of magnitude less energy.

Stuart Staniford said...

Mr Sunshine- I don't think your position makes any sense. Total oil production is not declining and given Iraq, shale oil, etc, it appears that a rapid decline is unlikely to materialize in the next decade or two (I still think we are on the bumpy plateau and all evidence suggests that the plateau will be long). Given that, the world has the capacity to invest in new infrastructure. In fact, the current very low interest rate environment indicates that desired savings is exceeding desired investment so there is certainly capital available to invest in renewable projects as long as the necessary subsidies are in place to make project economics work. Since costs of renewable technologies (especially solar) continue to fall very rapidly, we can forsee that the subsidies can be phased out over time.

kjmclark said...

Lucas - actually, I have to disagree that a world-scale grid "suffers from the same drawbacks as grid-scale storage". We don't have the technology for storage on the level we would need. We do have the technology for a world grid. We already understand how to do undersea transmission cables, and intercontinental cables. We mostly have the technology to do a world-wide superconducting grid if we wanted to, if we were willing to spend the money to do that. But it's a question of money, not of technology.

And spacing PV collection around the world, particularly in arid places that don't have much problem with overcast skies, solves most of the intermittency problems.

Nick G said...

Petemason,

Could you provide references that discredit the top-down wind study? The basic idea looked valid to me, despite excessively conservative assumptions for their preliminary estimate of overall wind resource.

petemason said...

Nick G:
I'm on holiday I'm afraid...
You admit the assumptions which wer questioned.
I think there was recognition of the importnance of the findings that there is a real limit to the amount of wind power available and that it is not unrelated to the total energy consumption of the plane, but that as you say, thee were excessively conservatiuve assumptions that, once revised , gave a wide range of power well within requirements, when solar and wave are added. The SciAm article, I cn only find this ref:
http://news.stanford.edu/news/2009/october19/jacobson-energy-study-102009.html

Lucas Durand said...

kjmclark,
To clarify my problem with a world-wide grid:

Sufficient technology may already exist to make it work, but the implementation or execution is unproven - nobody has ever built a world-wide grid before so how is it possible to say whether we know how to build an effective one in the time-frame allowed?
Things often look good on the drawing board only to grow warts during the execution.
Like I said earlier, if you only have one shot to do something correctly, you had better be sure you don't aim too high...

Also, it seems self defeating to select a course of action that adds more complexity to an already overly complex world.
A world-wide grid would need world-wide maintenance, parts, logistics, service, administration, regulation, etc, etc.
All of this presumes a highly functional global economy and sufficient "real" capital. It isn't clear to me that these presumptions will hold true out over the time-frame under consideration.

It's fair to say that the future is uncertain.
When faced with uncertainty, designing for increased resilience is a good strategy.
The concept of very large centralized PV or wind farms connected by such a grid is not very resilient - in fact, it could make the world's energy supply more fragile or prone to disruption.
What a shame it would be if such a plan were to be executed only to be disrupted or even brought down by a single black swan.

Mr. Sunshine said...

Stuart,

I read your work simply because I hope you're right, but I'm not an optimist, myself. The length of the "bumpy plateau" - even given the bitumen,shale oil, and Iraqi sources, which are not economically viable without high prices for oil and the additional costs of global empire C&C structures in the case of Iraq - will depend more upon lower to stagnated economic growth than anything else. Stagnation in developed economies may prolong oil's "peak" but it is not desirable in any other way that I'm aware of.

As for solar and RE overall percentage input gains: given PV is a oil-era technology, in that it can't exist without the complexity of a coal and oil-based civilization and infrastructure to produce it, and given that its output power is as intermittent as a passing cloud, the electric grid will never be able to carry a large percentage of it to a constant load, since the grid was/is designed as a tuned AC circuit that simply can't stay online without supply/demand harmony.

Sure, in theory many things are possible. In practice, optimism in the face of the reality of finance, debt saturation and simply, the scale of civilized society's load and demand for constant, cheap, instant energy to sustain itself render a transparent "overlay" of known substitutes, all less energy dense, more expensive, more intermittent grid-scale power unlikely.

More likely is a far faster than expected return to lower energy levels, with a more totalitarian command structure overseeing their distribution, a lower overall economic "lifestyle," and resurgence of local resource use.

But I'll take the continuation of all things unsustainable for as long as I can - like you, I find today's world of luxury on borrowed money, time and telecommuting much preferable to dealing with basic food needs year round! :)