Alternative energy - when, where, how, why?
October 22, 2008 7:31 PM   Subscribe

What would it take of an alternative energy to make a serious impact in current global energy consumption? What cost/benefits would it need to demonstrate over and above existing sources? Who would need to seriously start using it? Anybody have some good sources of information or discussion on this topic?
posted by zaebiz to Technology (19 answers total) 4 users marked this as a favorite
 
What would it take of an alternative energy to make a serious impact in current global energy consumption?

This seems unanswerable to me. If you define 'serious impact', someone might be able to answer it.

eg: According to the figures here, renewables supplied 1.03% of world supply. Is that 'significant'? If so, the answer is 1.03%. If not, it's whatever percentage you're defining....

What cost/benefits would it need to demonstrate over and above existing sources?

Marginal. By definition.

Who would need to seriously start using it?

No-one in particular. I suppose one answer would be "energy hogs", ie the West, but really, it's not important who is using it.
posted by pompomtom at 7:59 PM on October 22, 2008


I don't mean for this to come off sounding like a glib answer, but I think it hinges completely on how you define "serious impact".

The switch to 55W "Energy Miser" bulbs (instead of standard 60W) probably had a significant impact on energy consumption over time since they were introduced (back in the 70s IIRC). I suspect that the companies marketing them have lots of figures involving how many tons of coal they've saved, etc. However, I'm not sure anyone could say with a straight face that they have really changed our course as a society tremendously; we're still burning fossil fuels at a tremendous rate. Depending on how low you set the bar, those bulbs might or might not be "serious."

If you're looking purely at what would constitute a game-changer, I'd say it would be any energy source that doesn't involve the oxidation of hydrocarbons and has a cost per watt, delivered to the customer over existing infrastructure, that is within 5% or so of fossil sources before any sort of subsidies or incentives. Of course, that might arguably include nuclear power and a lot of existing technologies, so while it's probably a necessary condition, it's probably not sufficient.

Unfortunately, when you start asking for requirements on an alternative energy source, you start to get a list of requirements that's awful similar to what you get if you ask a bunch of Windows users what they'd like in a Linux distribution: the requirements boil down to (1) be the product we're using today, while (2) not being the product we're using today. That, IMO, is a sign of people who are not really ready or open to alternatives, because they're not willing to change anything in any significant way.

I don't know if that was too chatfiltery of an answer, but it's sort of a broad question.
posted by Kadin2048 at 8:03 PM on October 22, 2008


Though the above respondents are correct in that your definition of "serious impact" is significant, I don't think they're really answering your question, which seems to me to be about what characteristics a given alternate energy source would need to possess before it would see widespread adoption.

The simplest answer is that it has to be cheap. The world uses an incredible amount of energy, and consumer use is only a tiny fraction of that: commerce, and especially industry, are by far the largest consumers. To constitute a significant percentage of the world's energy supply, a potential energy source needs to:

1) Be plentiful enough to actually supply a significant percentage of the world's energy needs, and,

2) Provide that percentage at a cost which is at least close to being competitive with current sources of energy.

It need not actually be the same price or cheaper, because many users are willing to pay a premium for "green" energy, but the number of those users and the premium they are willing to pay is rather small, especially for large users. Though you might be willing to pay an extra 10% of your energy bill, a corporation that spends a few million dollars on energy probably isn't.

Most alternative energy sources fail at either or both. For example, wind and hydroelectric power are both relatively cheap, but there just isn't that much energy to be had here. Solar power is plentiful, but not cheap. Ethanol is neither plentiful nor cheap. Absent subsidies, we'd be using it for its intended purpose: inebriation. A cheap but rare source of power will be used, but won't constitute any significant percentage of our energy consumption. A plentiful but expensive source generally won't be used, which is why there are so few solar plants. Rare and expensive sources only get used when congresscritters, encouraged by ignorant pundits, decide to bring home the bacon.

The only real "alternative" energy source with any real promise is nuclear, but we've regulated that so heavily that it's no longer cheap, i.e. the regulatory hurdles are so high that it's just not worth it. We need to change this. Now. Actually, about twenty years ago, but now will have to do.
posted by valkyryn at 8:33 PM on October 22, 2008


Okay, actually, sunlight isn't that abundant. If you covered every square inch of Earth's surface with 100%-efficient solar cells, you could only produce about 40% of the 101,600 trillion BTU that the United States alone consumed in 2007. Sunlight is about 120W/m^2, which isn't anywhere close to being enough power to run an industrial, let alone post-industrial, society. Granted, no industrial/post-industrial society seriously considers getting 100% of its energy from one source, but given the numbers, there really isn't any way that sunlight can ever contribute more than a percentage point or two of our annual consumption.

You can see the actual breakdown here. Note that renewable energy makes up less than 10% of annual electricity production, while nuclear makes up slightly more than 10%. "Biomass," which I take to mean burning wood, manure, etc., contributes more than all other renewable forms of energy, including hydroelectric, combined.

So until you've got an energy source that can produce a few quadrillion BTU, it really isn't worth talking about.
posted by valkyryn at 8:59 PM on October 22, 2008


An alternate energy source would have to have the following five characteristics:

1. It has to be huge (in terms of both energy and power)
2. It has to be reliable (not intermittent or unschedulable)
3. It has to be concentrated (not diffuse)
4. It has to be possible to utilize it efficiently
5. The capital investment and operating cost to utilize it has to be comparable to existing energy sources (per gigawatt, and per terajoule).

Wind power, for example, fails #2 and #5.

Fusion fails because after 50 years of research, no one can make fusion energy-positive. Also, at this point it looks like fusion will be too expensive even if they can make it work.

Fission power passes the test. Unfortunately, the US has at this point tied up fission power in so many rules and regulations that it isn't possible to untangle the red tape in order to build a fission plant, which is why there hasn't been a fission plant built in the US since the mid 1980's.

Biomass fails #3. It also partially fails #1. The energy available is unlimited, but the power is bottlenecked in several ways, most notably by available arable land, and competition for other uses for that land (such as growing food).

Solar electrical generation fails #2, #3, and #5.

My general test is this: I won't pay any attention to claims about a form of alternate energy unless someone can show me a practical plan to use that form of energy to produce 1% of current American energy consumption, implemented in 15 years.

The US uses energy at an average rate of about 3.6 terawatts. So to pass this test a proposed alternate source of energy has to produce 36 gigawatts average.

The reason I use that test is that most fans of "alternate energy" don't understand the scale of the problem. They see some sort of test project, that produces a few hundred kilowatts or a few dozen megawatts and say, "See? The solution is right before your nose!" But when they look at what's required to scale it up to 36 gigawatts, it ceases to look as easy. A lot of fashionable alternate energy forms can't scale up. (Also, I usually end up having to explain the difference between "average power generation" and "peak power generation". If a windmill farm produces 500 megawatts when the wind blows and nothing when it doesn't, then 500 megawatts is peak, not average.)

So what is there, in the future, which might do it? One of the most interesting is called a "core tap". It's a hole drilled deep into the ground, to where it can reach heat from the mantle. You pump water down the hole, let steam come up, and run the steam through a standard turbine and use that to produce electricity.

They aren't practical now, because current drilling technology can't go deep enough. It'll require a couple of advances in materials science, and a breakthrough in drilling technology (possibly involving using big lasers to do the drilling) but it could all come together in 30 years or so if we really wanted it to.

Presumably the capital cost of drilling the hole would be immense, but once that's done, the operating cost should be less than for a coal plant of equivalent power output, since you don't have to buy fuel for the core tap.
posted by Steven C. Den Beste at 9:15 PM on October 22, 2008 [2 favorites]


Jesse Ausubel published a controversial study last year estimating the amount of land different energy sources would have to consume to provide electricity to large populations.
posted by driveler at 9:31 PM on October 22, 2008


If you covered every square inch of Earth's surface with 100%-efficient solar cells, you could only produce about 40% of the 101,600 trillion BTU that the United States alone consumed in 2007. Sunlight is about 120W/m^2, which isn't anywhere close to being enough power to run an industrial, let alone post-industrial, society.

This is completely incorrect. I don't really want to prognosticate on the future of solar energy, but anyone can do the calculation and see that only a very small fraction of the earth's surface would need to be covered in the case valkyryn gives above.
posted by ssg at 9:58 PM on October 22, 2008


valkyryn: Okay, actually, sunlight isn't that abundant. If you covered every square inch of Earth's surface with 100%-efficient solar cells, you could only produce about 40% of the 101,600 trillion BTU that the United States alone consumed in 2007.

I think you are seriously challenged in your mathematics. The area of the United States, let alone the rest of the planet, is 10 trillion square meters. You would need to generate 10,000 BTU per square meter per year to supply the total U.S. energy needs. At 120 W per square meter this would require less than 30 hours to supply the power for the entire year.

Another way to state it is that you could supply the entire country's energy needs if you had 100% efficient solar cells on just 1% of the country's surface working 8 hours a day. That's right, the sun supplies 100% of the country's energy needs on only 1% of the country's land.

Contrary to your statement, solar energy is extremely abundant. However it requires more efficient and cheaper solar cells to harvest that energy.
posted by JackFlash at 10:21 PM on October 22, 2008 [1 favorite]


ditto ssg. i just did the calculation and to produce 1e20 joules ( = 101,600 trillion btu) you'd need about 10,000 square miles of solar panel. which is a lot, but not an impossible sort of lot.
posted by sergeant sandwich at 10:25 PM on October 22, 2008


Fission power passes the test. Unfortunately, the US has at this point tied up fission power in so many rules and regulations that it isn't possible to untangle the red tape in order to build a fission plant, which is why there hasn't been a fission plant built in the US since the mid 1980's.

Nope, regulations are not the problem. Nukes are not being built in the U.S. because they simply aren't cost competitive with current fossil fuel plants. Investors are not interested in risking $5 to $10 billion for a nuclear plant that might take 20 to 30 years to pay off. Nuclear plants are economical in France which doesn't have the abundance of cheap fossil fuels as in the U.S.

---

So what is there, in the future, which might do it? One of the most interesting is called a "core tap". It's a hole drilled deep into the ground, to where it can reach heat from the mantle. You pump water down the hole, let steam come up, and run the steam through a standard turbine and use that to produce electricity.

Drilling a hole in the ground is not a practical solution for tapping geothermal power. Solid rock is a very poor conductor of heat. It can take a year for heat to travel 10 meters in solid rock. If you drilled a hole in the ground and pumped in water, you would get heat for only a short time before all the surrounding rock was chilled.

Natural geothermal areas are unique and very limited because they overlie cubic miles of naturally fractured rock through which water can flow. They work because they gather heat over a wide volume of fractured rock. Just a hole drilled into solid rock won't work.
posted by JackFlash at 10:56 PM on October 22, 2008 [2 favorites]


Some things to look out for when people do these sorts of calculations.

1. Math errors.
2. Treating all energy sources as equivalent, without considering how they are consumed.

As an example, nearly 1/3rd of US energy consumption goes to transportation. Most of this is oil products that are burned in internal combustion engines, and at least 2/3rds of that power ends up as waste heat, rather than doing useful work.

If electric motors were doing the same work, they'd be dramatically more efficient, and so they'd require less total energy. This remains the case when taking into consideration transmission losses from a solar or wind farm. It likely even holds true in the case of an efficient fossil fuel fired steam power plant.

This brings us to:
3. Glossing over some missing piece of technology or infrastructure when talking up their favorite option.

For example, current battery technology is quite efficient. The downside is that the energy density is pretty low, which means that useful range on a charge is a lot less than a tank of gas. (On the other hand, its probably enough for most daily commutes, and while people don't generally have gas pumps at home, pretty much every home and office has a connection to the electrical grid, which is usually way below peak capacity at night).

On a related note:
4. Assume everything else is standing still while their favored solution matures.
Not to pick on Steven, but 30 years for core tapping to achieve commercial viability is a long time. While we are waiting for advances in materials science and major breakthroughs in drilling technology, photovoltaic efficiencies could double (as they have over the past 30 years), and/or prices could drop significantly. Similarly, battery energy density would improve (though not likely double without a major breakthrough)

5. Assume demand patterns can't change.
Yeah, it would be great to find drop in replacements, but infrastructure is upgraded and replaced, and industries evolve as their cost structures change. In the 30 years since the Arab oil embargo, US industry adapted away from oil. The US now generates 2x the GDP per barrel of oil consumed compared to 30 years ago. The transportation sector is the last to have a major direct dependence on oil. Furthermore, the amount of energy consumed from any source per $ of GDP has declined steadily.

We can also adapt to the supply patterns of things like wind, and solar. The grid could be upgraded, and interconnected coast to coast to take advantage of peak load lagging peak solar generation during the summer months, or let wind power be used more widely.

Smart appliances can drop their power consumption automatically to help cope with spikes in demand or sags in supply. Similarly, industrial processes and control systems can similarly adapt to be more amenable to interruptions of service.
posted by Good Brain at 11:16 PM on October 22, 2008 [1 favorite]


It's already happening, and it's not going to stop. Look outside the USA though - alternative energy is hugely hampered in the USA because the whole country is almost made out of solid coal, so alternative energies have to be price-competitive with "free". The US traditionally hasn't paid attention to climate change issues, so another big advantage of renewables is meaningless there.

Conversely, Denmark for example, currently gets 20% of it's power from wind, and is working to expand this to 50% in less than 20 years. (In terms of wind use, Denmark is the biggest today, but quite a few countries get over 5% of their power from wind - today - not in the far-flung future.)

Once these economies have adapted, the infrastructure in place, etc. they will reap ongoing dividends that will greatly aid their competitiveness. That will draw others into the fold.


Production electric cars hit the market in 2010. These will be small numbers at first, but as they eat away at gasoline's fleet-share, net energy use will drop, because hardly any of the BTUs from a gasoline engine actually reach the driveshaft, whereas almost all of the energy put into an electric car, reaches the driveshaft.

It looks like alternative energy has an uphill battle, but that's because old energy is subsidized by such vast existing infrastructure. However, clean technology is so inherently vastly superior in so many ways that it is managing to make headway despite being at such a colossal disadvantage. I suspect that the fact that this headway is being made at this point means the battle is already won. The rise of alternatives is inevitable. As the infrastructure advantage is nibbled away over decades, old energy won't be able to compete, and the almighty dollar will prevail.
posted by -harlequin- at 1:37 AM on October 23, 2008


Sustainable Energy - Without The Hot Air is a soon-to-be-published book by a Cambridge physics professor about some of the numbers behind sustainable energy. It's really a case study on what green energy means for the UK in terms of renewable infrastructure and changing usage habits, but much of the information is easily generalised. The book is available free here, along with slide sets from talks the author has given on this topic.
posted by Jakey at 1:56 AM on October 23, 2008 [1 favorite]


nothing is going to happen unless oil stays about $150/barrel on a consistent basis.
posted by any major dude at 5:48 AM on October 23, 2008


Stephen C. Den Beste, wind power provides just over 1.5% of the US’s electricity. In 2007, the average installed cost was $1710/kW with an average capacity factor of 33% (both from a DOE report [PDF]).

So, alternative energy: is there an alternative to sustainability? When? Now. Where? Here (for all values of here: you just have to use the appropriate technology). How? Ask your local wind/solar/hydro association - this stuff's the opposite of rocket science. Why? As I asked, is there an alternative to sustainability?
posted by scruss at 5:52 AM on October 23, 2008


I have always found error in the thinking that an energy source must supply x% of demand in order to be worth discussion. I say rather, the more alternatives (green and sustainable) the better. Hundreds of alternatives that supply a small portion of demand would add up.
posted by Goofyy at 9:38 AM on October 23, 2008


My general test is this: I won't pay any attention to claims about a form of alternate energy unless someone can show me a practical plan to use that form of energy to produce 1% of current American energy consumption, implemented in 15 years.

This is a pretty silly test. Even if the laws of physics rearranged themselves to allow a perpetual motion machine that provided unlimited free energy, I doubt even that machine could pass this test. Change in energy infrastructure at these massive scales is SLOW! Fifteen years is the bat of an eye. Hell, it can take that long to get just a single power plant from drawing board to reality.

The question was re current global energy consumption. But I think people need to stand back and appreciate the scale - and timescale - of what we're dealing with. Adsent some kind of new huge race-to-the-moon national push, national energy infrastructure does not, and should not, change overnight.
posted by -harlequin- at 9:39 AM on October 23, 2008


Scruss, the 20 gigawatts of generation capacity cited in that report is peak, not average.
posted by Class Goat at 4:37 PM on October 23, 2008


Class Goat, I wasn't quoting the installed capacity, I was quoting the %age supply. I am acutely aware of the difference between peak and average capacity of wind farms.
posted by scruss at 10:27 AM on October 28, 2008


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