DARPA Awards $53 Million for Solar Power Research

mygadgetbox writes "Defense Advanced Research Projects Agency (DARPA) will be giving a consortium led by the University of Delaware nearly $53 million in funding to more than double the efficiency of terrestrial solar cells within the next 50 months. DARPA wants the consortium to develop and produce 1,000 Very High Efficiency Solar Cell (VHESC) prototypes that are affordable and that operate at efficiencies of at least 50 percent. The goal is to create solar cells that operate at about 54 percent efficiency in the laboratory and 50 percent in production."

Comments

Meh.

[pavon]

We spent two decades wasting time trying to improve the energy efficiency of solar cells. The energy efficiency isn't what matters - it is the cost efficiency! If you are using solar cells as supplemental power to a house (their most effective application), then doubling the energy efficiency of the panel just means you get to use a smaller panel. Who cares - you have a whole roof's worth of space up there. Whereas if you get the price down, then you will decrease the amount of time it takes to pay off the cost of the cells, making it worthwhile to include them in more homes. And for other uses - cars, power plants, even if we had 50% efficient cells they still wouldn't generate enough power to be much use.

I have been getting excited about some of the recent research that is making progress towards less costly, cleaner (to produce and dispose) solar cells. I guess if you are the military, and price is not an issue than this DARPA research is usefull. They need to find some way to power all this new electronics equipment that soldiers are carrying. But it is improvements in cost efficiency that will really make a difference in real world.

Re:Meh.

[CosmeticLobotamy]

Unless you're trying to put a field of the things in a desert somewhere to supplement a city's power. Then the land costs more than the cells will, and being able to use fewer saves money and, in some cases, makes it feasible at all.

Re:Meh.

[deander2]

if you double the efficiency, you only need half as many cells.
this would reduce the cost, even if the price-per-cell remains the same.

personally, i say let's try for both.

Re:Meh.

[thc69]

That kind of land is probably cheap. In fact, power companies and government probably own loads of it, unutilized, already.

Come to think of it, isn't Area 51 surrounded by a bunch of wasteland desert?

Either way, I want solar that can pay for itself quicker than I have to pay off a loan for it, else I can't afford the capital investment. I'd plaster my whole roof with it.

Solar roof shingles and solar standing seam metal roofing are too expensive, too.

Re:Meh.

[HUADPE]

There is a key problem with putting solar cells in the middle of the desert. Nobody lives anywhere near it. Transmission of electricity uses up energy, so sending power from the Nevada/New Mexico border to Los Angeles can reduce its voltage by more than half at the end of the trip. The land is cheap, but you need to buy twice as much and put twice as many cells on it to have the same effect as a local source.

1000000 times better...

[MichaelSmith]

...than looking for ways to bury waste products in the ocean.

Photocells are already fantastic technology. Not only do you save the energy you would otherwise be drawing from a power plant, you also save the energy needed to deliver the energy to the point where it is used.

A lot of public lighting near my home is now solar powered. The big advantage is that you don't have to dig trenches to the site. Trenching is very expensive because of the associated labour costs, and labour costs feed back directly into energy costs.

TATFA (think about the article)

[PresidentEnder]

Most of what Parent says is true- for the applications in question (home use, vehicle use, consumer use in general) the cost of solar cells is the limiting factor. However, this is DARPA we're talking about here- as well as a bunch of commercial clients. The applications mentioned in the article (primarily the military) rely heavily upon efficiency and not so heavily upon cost efficiency. Yes, it would be nice if GI Joe's GPS solar cell only cost fifty cents, but if it weighs a hundred pounds? I'd rather have a five-hundred dollar solar cell producing enough in half a pound. Efficiency is important in some areas, cost effectiveness in others. Research into efficiency isn't a total waste.

Re:TATFA (think about the article)

[jmcmunn]

True, the military will care about efficient power cells but is it really worth it to go the solar route? I mean we've been hearing a lot about other small energy sources as well...in my opinion solar is a pretty bad way to go from what I know about it. They're not very rugged from what I know either, which kind of describes where most of our troops end up.

While I agree sometimes it is better to spend the money and get more efficient, I'm not sure I want my tax dollars wasted on something like this if the govt decides to buy a single expensive solar cell rather than some body armor for some troops on the ground facing suicide bombers...

Re:TATFA (think about the article)

[king-manic]

While I agree sometimes it is better to spend the money and get more efficient, I'm not sure I want my tax dollars wasted on something like this if the govt decides to buy a single expensive solar cell rather than some body armor for some troops on the ground facing suicide bombers...

Body armour may stop shrapnel. Body armour can't stop kenetic force. So it's good versus grenades, small arms, peripheral range of explosions, but piss poor against a bomb attack.

Re:TATFA (think about the article)

[NMerriam]

The solar cells used in the field are not the fragile glass units people think of. We use two flexible, folding solar arrays for our field work that are MILSPEC and they can be run over by trucks, take 7.62mm rounds, and fold down to about the size and weight of a laptop computer. Less efficient than the glass panels, but that's the tradeoff.

And being able to set up a self-supporting field communications center with a small backpack full of gear can make a LOT more difference in war than an extra piece of body armor. But the power output is not great for the surface area, while ultimately I'm sure the DoD would love to be able to make the backpacks out of solar cloth and charge everything during normal activity.

Re:TATFA (think about the article)

[Jeremi]

Have you ever thought that if the government didn't spend so much money sending troops to other countries where they are not wanted, there would be plenty of money to spend on good research such as this?

Nah, you have it backwards... if the American people weren't kept in a constant state of fear and reliance on the Pentagon to "protect" them, they wouldn't be so willing to fork over their tax dollars to support the world's largest military. That's the beauty of the system: the bigger the US military-industrial complex grows, the more the rest of the world resents and fears the USA. The more the rest of the world hates and fears the USA, the more insecure the US population becomes. The more insecure the US population becomes, the more willing they are to funnel more of their tax money into "defense", in the hopes that it will make them safer from the world that hates them so. So essentially the more money they spend, the more money they will have to spend later on.

This is good and all

[rolfwind]

But the article is almost talking as if the goal of doubling the now 25% efficency being doubled are being guaranteed to be met which is hardly the case - it's been over 30 years (where it was what 8% effieciency?) since solar cells were introduced and many other countrie/companies have been working on improving efficiency without that huge jump in performance - Germany/France in particular.

land is cheap..

[slashkitty]

compared to solar cells. Are you crazy or something? about the only place where land is more expensive is in or close to a city. Solar cells cost about $100 per sqft.. while land around here costs about $50k per acre, or about $1 per sqft. If you can get me some solar cells for less than $1 per square foot, I think we could have a good business.

A Good Start

[ckswift]

This is a good start, but we really need to be pumping money into solar power research if we ever want a carbon free energy future. A excellent post over at the Cosmic Variance recently discussed how solar power is the answer for our coming energy crises.

Be Afraid, Be Very Afraid

..."But we have nuclear fission, wind power, tides, biomass, hydro, and geothermo, and one day we'll have nuclear fusion...right?" No. First, he estimates that we need 10-30 TeraWatts (TW) of supply by 2050. Fission plants come in at about 1 GigaWatt (GW) of generation capacity (we don't know how to safely, securely and make efficient ones much bigger), and so we'll need to construct one new nuclear fission plant every other day -starting now- to meet the challenge. And then they only last 50 years... The biggest and brightest fusion project right now (in europe) is hoping to get break even several years from now, and then maybe built a working demonstration machine when it is probably already too late! He then continues to work down the list of all the other alternative sources, and you realize that they just won't even come close to what we need if we are truly going to stop dumping greenhouse gases into the atmosphere.

...

But then he reminds us that we have one source left, and it has way more energy than we can possibly need. The Sun. Two hours of sunlight hitting the whole earth's surface gives us the equivalent of the 30 TW for a year we need to be working at. Taking into account practicalities, we can expect about 600 TW or so fairly easily, and at 10% efficiency in recovering it and putting it to good use, we still are way ahead of what we need.

I really encourage you to read the whole post.

~CK

Re:A Good Start

[cameldrv]

Obviously the issue is simply cost. He dismisses fission because he says we'd have to build a plant every other day to make it work. Well, to replace that with solar, you'd have to build something like ten gigawatts of solar panels, install them, and hook them up to the grid or to individual consumers. The question is which one is harder. In a market economy, generally the way you figure that out is which one costs more. Solar costs more than Nuclear, and we would need a lot of undeveloped technology if we were relying heavily on solar, due to its variability. Nuclear is reliable, has a nearly inexhaustable fuel supply, and is well proven technology.

It can only mean one thing...

[DieByWire]

If this administration is spending money on solar, it can only mean one thing...

Halliburton now owns the sun.

Uses for solar panels

[Mishra100]

I agree with the poster that says cost efficency is the biggest problem. I'm not sure how much they cost, but my dream is to create skyscapers completely out of solar panel. I think the panels look sexy enough to be on a lot of things. They should experiment with different looks for solar panels and have entire cities dressed with solar panels. This would save a whole lot on enegry costs as would be the purpose for solar panels. They should also experiment with a impact resistant solar panel. That way we can dress our cars completely out of solar panel. Basically, I think they should focus their ideas on making solar panels dynamic so we may use them in lots of applications!

Re:Uses for solar panels

[MichaelSmith]

I agree with the poster that says cost efficency is the biggest problem.

It is a similar issue to VLSI chips. Once you have sufficent economies of scale, costs will fall rapidly.

Efficiency

[SuperBanana]

Don't I recall a recent (last year or two) announcement from a university about a high efficiency solar panel, intended to be used in building construction? The panels were small, inside little cubes, and could pivot, I think?

I'm also quite positive I remember stumbling across a webpage for a US Defense/space contractor, where they offered up solar panel "scraps" (stuff you could still assemble into working modules, with a fair bit of labor) for sale to the public. Efficiency was substantially higher than anything I've seen on the commercial market, though I don't recall figures off the top of my head. They probably cost a lot more to manufacture, but $50M amortized over -possible- solar panels sounds pretty expensive too.

Why couldn't we just give a $50M grant to homeowners to buy solar panels?

Does this not violate physics?

[solarcell]

If we are talking about traditional p-n type solarcells, they physically can't do better than ~37% IIRC. There is just no way to avoid some (alot!) charge recombination. In addition there is a lot of solar energy that is not within the absorption curve. I really hate it when people throw numbers around without a reference. All photovoltaics should be referenced to AM 1.5 (the typical energy that reaches the earth). The solar people all talk about photosynthesis as 'near 50%' but that is only over the narrow absorption range of the special pair and does not include any further electron transfer steps. I have to concur that it is all about making them cheaper. That said, while you can trade effiency for cost, the who 'nanocrystal photovoltaics' died a quite death cause the charge transfer was just SO piss poor due to it being an amorphous device. Now if someone can figure out how to add some structure (chemical self assembly) then you might have something. As with most other hyped science I would not hold your breath. Engineers are damn cleaver people and my bet is on the thin film amorphous silicon and cadmium telleuride ribbons being developed. solarcell

Alternative Energy is already here.

[Fantastic Lad]

A family I know built a geo-thermal/solar powered house.

This was not their original plan at the outset. --Basically, they bought a property, and cleared a lot far back from the road. Then they learned that to have AC lines brought to their house from the mains, the local power company would charge them over $10,000 for the job of sinking four poles and running cable.

They thought, "Wow. Ten grand? Sheesh. What other options are there?"

The result was some research and a re-jigged construction plan using alternative energy. They spent about the same amount of money installing Geo-thermal and solar panel solutions.

10 big cells cost them about $8000 CAD. The rest of the money was spent digging trenches and laying thermal transfer pipes, air ducts and house wiring. Now they have all the power they need.

Strategic spot lighting using 12 volt halogen bulbs rather than bathing entire rooms in light minimizes the impact on energy reserves. Laptops are used instead of desktop computers, and various other appliances, like radios and televisions are run with DC to AC converters. Water is pumped from a well to a reservoir at the top of the house which provides pressure. Even while feeding the needs of an active family of four, the array of 5 big chemical batteries which stores electricity from sunlight never dipped below a 95% full charge on any of the days I visited. (The power readings were set on a cool display for all to look at.) --And the house is also absolutely enormous; 5 bedrooms, plus various huge family rooms the size of small churches, etc. A total mansion, and after the initial investment, it costs exactly zero to light and power.

Cooking is done on a big gas range fed from a pair of large propane tanks which contain enough propane to last more than a year. Water is drawn from a well. Refrigeration was the only puzzle still to be worked out, and while pondering it, the family had spent two years eating fresh foods while keeping milk and other such items in a basic camping cooler in the kitchen. Half the things people normally keep in their fridges don't really need to be there; milk and beef doesn't go bad all that quickly, eggs don't need to be refrigerated at all, and chicken and fish are simply bought fresh the day they are intended for consumption. --After realizing that this worked without any problems, the family basically concluded that they didn't really need a fridge in the first place. --Though, they told me that they had found a super-efficient 12 volt DC fridge on the market for homes exactly like theirs, but that they didn't think they really needed it.

Half the problem is not the power source, but the notion that we need so much electricity in the first place. --If we change the parameters of the problem, we can start using different solutions which have already been accepted by industry. Simple.

Despite the opposition, alternative energy is here for anybody who wants it.

-FL

Solar Power is not just Photovoltaics

[necro81]

The article discusses that the goal is to improve the efficiency of solar cells to 50%. As I mention earlier in this thread, silicon-based semiconductor photovoltaics top out at a theoretical efficiency of about 25-26%. Other semiconductor technologies top out somewhere around 35%. These are the two technologies people think about when they imagine solar cells. I think the outlook for discovering and commercializing a semiconductor-based solar cell that's 50% efficient in the next 50 months to be very poor. I won't get into the physics, but the theoretical limitations have to do with the fact that semiconductor photovoltaics make inefficient use of the solar spectrum: a red photon will produce as much electrical energy as a blue photon, even though the blue photon is more energetic.

But solar power is not limited merely to what one can do with photovoltaics. When people talk about the many terawatts of solar power that falls on the surface of the earth, most of that solar goes into two things: photochemistry (like in plants) or to heating the earth's surface. Plants make very efficient use of the solar power that falls on them, and a black, nonreflective object will convert the incident solar power to heat (or reradiated infrared light) with extremely high efficiency. If we could focus efforts to developing technologies that capture sunlight first into chemistry or raw heat and converting that to electricity, rather than the direct conversion to electricity that photovoltaics do, we may have a better chance of reaching the 50% goal.

For instance, there was (is?) a solar power project that in the California desert that was a solar-thermal generator. Hundreds of mirrors focused sunlight onto a tower, much like the Archimedes death ray (which has received some press in /. lately). Instead of trying to burn a ship, the focused sunlight heated sodium to about 1200 Celcius, which liquified it. That sodium was passed through a heat exchanger to boil water, which made steam, which turned a turbine, in a similar closed-cycle technology to a nuclear plant.

I'll admit this isn't much use in the battlefield, which is what DARPA is aiming for, but it is not out of the question to consider a smaller solar thermal unit for an encampment, which used a different medium than sodium.

Solar cells are still very expensive

[rif42]

Solar cells are not now, and will not in any near term (5-10 years) be a method for general electrical energy generation.

Generating electric energy with solar cells is a great idea, but they are still a speciality, because the price of the cells are so high. Prices are falling, and have been doing so for many years, but they still have a long way to go to be competitive to other large scale energy sources.

Solar cells needs more researching and funding for R&D. It will be great once it becomes affordable. Until then it is only a niche energy source for use in special locations and applcations.

For the time being the are luckily other sources for large scale non-polluting energy production, namely electrical energy from wind power. Wind power is a proven technology that is readily available and can be installed for large scale usage. It also has the benefit of being a decentralised, scaleable technology (start small then scale up).

The installed capacity for wind energy is like 20 times larger than solar power. In 2002 the world wide capacity for wind power was 32.0 GW, for solar cells it was 1.3GW. Numbers are from report by BP (the oil/energy company).

In many countries wind power is the fastest growing energy source. In Denmark 19% of electric energy is made by windmills. In Spain it is 6%, in Germany 5%. In actual numbers for installed capacity Germany is by far the leader in the field, then followed by Spain and USA. See ewea.org and gwec.net site for further numbers.

While most European countries are racing ahead and installing windmills on land and in the sea, not much progress has been done in USA in recent years. This is especially sad due to the population size of USA and the high energy usage per person.

Actual experience

[Doug Coulter]

I have two solar powered businesses here (a computer consultancy, and a machine/plating shop), and two homes which run off the same systems. Square feet definitely matter, as I am nearly out of useful roof space now. The 1000 sq foot building that has the machine tools is covered, and could use twice what I have now (although with a 2kw array, it could also be worse - 8-10 kWh a day ain't bad). I've got room for one more rack of 4 panels (about 500w more in full sun). A 500 sq foot building has its roof completely covered as well, and usually I have to pump power from the larger system over there to back it up when things aren't ideal. Any well designed solar system has the problem of, well, February...The Solarex polycrystalline panels I have on both places (2 of the four buildings that aren't always in shade) do the best in "non full sun" or gray days of all the types and brands I've tried, and this MATTERS in real life, bigtime. Getting half or even a quarter of the full sun output is far better than nothing, for example, and there are times when one either lives on this or burns petroleum in a generator, which is very expensive. But employees expect to work and get paid no matter the weather, so one copes. Remember that lead acid batteries have lousy efficiency, down to 40%, so the generator or panels lose a lot there if you're not using the energy as it comes in. There is simply not enough room on the average building around here (SW VA) to handle the bad weather months. This is a system that can run air conditioning and BIG multi HP power tools on good days...and barely limps by on nightlights if we have a week of near darkness, which happens often enough.

More like $5 trillion needed

[b7j0c]

Not just for solar, but for alternative energy in general. With our oil supply set to become uneconomical within forty years, we are literally in a sprint to find a replacement for fossil fuels wherever we use them today, and if we don't our society is going to hit the reset button for about a century or longer. Our entire economy is based on cheap and plentiful fossil fuels, ALL OF IT. Our commitment to alternatives so far is a joke in the US. $53 million isn't even a rounding error on what we need to be dedicating to this effort, which is likely already ten years late.

Re:Orbitting powerplants

[Jeremi]

If you beam it down, it will lose energy passing through the atmosphere.

True, but since you are getting it "for free" from the sun, a certain amount of inefficiency is tolerable. The lossage can be minimized by transmitting the power on the right frequencies.

It would also need to be very precisely targeted - at those sort of distances, a fraction of a degree off could result in blasting some poor shmucks house of the face of the earth

There are several simple ways to deal with that problem:

1. Add a fail-safe feedback loop to the satellite: the receiving station broadcasts a unique signal, and the power satellite only enables the power beam when it has that signal directly in its sites. That way if anything should cause the targetting system to go off course, the beam automatically shuts off.
2. Don't focus the beam very tightly. Instead of having a laser-like "death ray", you have the beam spread out to several square kilometers by the time it hits the Earth's surface. A metal grid can be layed out over that area to collect the energy. People wouldn't want to spend lots of time in the target area, but it wouldn't be instant death for them if they did show up there -- mild discomfort, maybe.
3. .... and the obvious thing: locate the receiving station in the middle of nowhere, so that even if the beam did wander miles off course somehow it wouldn't hit anything but dirt.
   

So the problems you mention are solvable IMHO. The real showstopper, for the moment, is getting the solar arrays into orbit: our current rockets have nowhere near the amount of lifting capacity required to make the economics practical. Possible solutions for this problem might be making the solar arrays on the moon, or (my personal favorite) the Space Elevator, which would make it practical to lift large amounts of mass to GEO.

Re:Try again...

[MichaelSmith]

Solar powered lighting is about the dumbest idea possible

It is in use all over the place here in Australia. Not along every main road, but it is used where there is no easy access to mains electricity. A location in the middle of a park, or on an isolated country road easily justifies solar power.

In my former job working on road transport systems we frequently installed solar and wireless traffic monitoring systems and emergency telephones.

You save on trenching this way, and also on maintenance because underground cables are forever being dug up by people.

Re:what did they learn about efficiency?

[The Master Control P]

To deliver the same power at 12V as at 120V, you have to run 10X as many amps and thus lose 10X as much power in line losses.

Power loss is I^2R, so ten times the current is 100x the power loss.