I wonder what it the energy ROI of the whole process. It is not mentioned in the article, so it is not sure it is positive.
It's certainly very negative. The advantage is you can use things like solar, hydro or geothermal energy to heat the system. Even turning 1000MW of geothermal energy into only 100MW of crude oil can be worthwhile since you can't run an internal combustion engine on geothermal energy.
Edit: To be clear, I'm not saying there isn't a need for oil. Just wondering what the efficiencies are for each route, and whether this process means that we don't even need electric cars any more (doubtful, but I thought I'd ask)
Either way, it takes a long time. The difference is the impact to the consumer of converting it to something useful for them (gas), or having them convert it to something useful (a charged battery). The consumer doesn't notice the gasoline taking a long time, to them it takes minutes.
The other huge advantage with oil is that it is a very efficient, stable and easy to transport store of energy. Transporting and storing 1MWh worth of energy using batteries is a serious undertaking compared to transporting and storing the equivalent in oil.
It's the batteries that are sub par, in many ways.
http://www.wired.com/autopia/2013/10/worlds-largest-dumptruc...
http://en.wikipedia.org/wiki/Tesla_Roadster#Timeline
"Subsequent to completion of production car number one at Hethel, the company announced problems with transmission reliability. The development transmission, with first gear enabled to accelerate 0 to 60 mph (0 to 97 km/h) in 4 seconds, was reported to have a life expectancy of as low as only a few thousand miles. Tesla Motors' first two transmission suppliers were unable to produce transmissions, in quantity, that could withstand the gear-shift requirements of the high torque, high rpm electric motor. In December 2007, Tesla Motors announced plans to ship the initial Roadsters with the transmissions locked into second gear to provide 0 to 60 mph (0 to 97 km/h) acceleration in 5.7 seconds. The first production car was not delivered with this interim solution; P1 has both transmission gears enabled. According to the plan, the initial transmissions were to be swapped out under warranty when the finalized transmission, power electronics module (PEM), and cooling system became available. The EPA range of the car was also restated downward from 245 to 221 miles (394 to 356 km). The downward revision was attributed to an error in equipment calibration at the laboratory that conducted the original test"
DISCLAIMER: Tesla's final solution was a single-speed gearbox, combined with software and energy management upgrades. The electric motor will now run as high as 14K RPMs to achieve it's 125mph top speed while retaining it's 4 second 0-60 time.
Of course you could eat the algae straight, or feed it to hogs and then eat hogs, but variety being the spice of life its a perfectly valid alternative tech to turn sunlight into food.
A single gallon of gasoline is ~33kwh of power. At 30mpg (easy for a sedan), 10 gallons (330kwh) is sufficient for a 300 mile range. So the Tesla is ~4 times as energy efficient as internal combustion, and unlikely to get any better.
>The MAN S80ME-C7 low speed diesel engines use 155 grams (5.5 oz) of fuel per kWh for an overall energy conversion efficiency of 54.4%
>The efficiency of a combined cycle gas turbine system can exceed 60%.
http://en.wikipedia.org/wiki/Diesel_engine#Fuel_economy
In fact, it's shameful how underutilized diesel engines are in this world. Same with stirling engines.
A Toyota Camry car carries 17 gallons of fuel, which, at 6 lbs per gallon, is about 100 lbs. At 28 mpg, that's enough to travel 476 miles. The Tesla S carries a 900 lb battery which is enough to travel about 250 miles. In miles per lb, that's 4.7 for the Toyota, and 0.28 for the Tesla.
Obviously, there are a lot of other considerations than just miles per lb, but gasoline's energy density and portability are stellar.
I think planes, rockets and various military applications (e.g an infanterist carrying a zillion gadgets that have to be powered for hours) are the only examples of cases where this process might be beneficial.
You could make the whole facility mechanical - the heat from the reactor is used to heat the algae and use steam-driven pumps to create the pressure. Eliminate the electrical middleman.
So yeah you're mostly right but never going to get away from maybe 5% to 10% capacity driving steam turbines to electrolyze water and run the (insecure, of course) SCADA and hotel load for the humans running the plant etc.
A likely plant would look like two nuke generating plants backing each other up and 18 nukes cooking algae into diesel, roughly.
I'm sure environmentalists would have a field day with this concept.
http://dotearth.blogs.nytimes.com/2008/02/13/federal-lab-say...
If the algae could grow in space, and this process could occur in space, then we could wastefully convert solar to oil in space, and spacecraft could use that oil in space.
Lot of if's and speculation there, but it's an interesting line of thought.
Not as much in near-Earth orbit where we enjoy much of the Earth's magnetic field's protection. Astronauts come back with an elevated risk of cancer but not tremendously so.
> That and the relative lack of local oxygen.
Grow some photosynthetic algae too, which'll convert sunlight to oxygen.
So that was the origin of my idea that this isn't going to scale in space "in general". I'm told Europa has a lot of water, other than the whole lack of sunlight thing, I could see Europa as the "fuel tank of the solar system" in the future. Maybe it could be economically viable to mine comets and turn them into fuel while they're near the sun? Or mine icy asteroids?
I think you're going to overall have more trouble finding water in space than energy.
Lasers
Let me tell you one of my pet peeves: space solar power. Okay, the stupidest thing ever. If anyone should like space solar power, it should be me. I got a rocket company and a solar company. I should be really on it, ya know. But it's like, super obviously, not going to work because, ya know, if you have solar panels - first of all, it has to be better than having solar panels on Earth, so then you say, okay, solar panel is on-orbit, you get twice the solar energy - assuming that it is out of Earth's shadow - but you've gotta do a double conversion. You've gotta convert it from photon to electron to photon, back to electron. You've got to make this double conversion, so, okay, what's your conversion efficiency? Hmm. All in, you're going to have a real hard time even getting to 50%. [The solar cells are better.] It does not matter, put that cell on Earth then. See, that's the point I'm making. Take any given solar cell, is it better to have it on Earth, or is it better to have it on orbit? What do you get from being in orbit? You get twice as much sun - best case - but you've got to do a conversion. You've got to convert it the energy to photons - well, you have incoming photons that go to electrons, but you - you've gotta do two conversions that you don't have to do on Earth, which is you've got to turn those electrons into photons and turn those photons back into electrons on the ground, and that double conversion is going to get you back to where you started, basically. So why are you bothering sending them to bloody space. "I wish I could just stab that bloody thing through the heart." BTW - electron to photon converters are not free and nor is sending stuff to space. Then it obviously super doesn't work. Case closed. You'd think. You'd think case closed, but no. I guarantee it's gunna come up another ten times. I mean, for the love of God.
From: http://shitelonsays.com/transcript/elon-musk-panel-bta-2012-...
Space exacerbates those two issues.
Ok, here they produce 1-sun intensity by having a 10 km mirror at 1000 km height, focusing on a 10 km terrestrial array.
That's a similar angular diameter, 1/100, as the sun, so from the receiver's point of view it can appear as powerful as the sun. I'm surprised that the numbers work out like that.
Maybe you could create a huge "death ray" constellation with 10x solar intensity and whose ground track (all sats in the same ground track) was filled with liquid cooled solar panels. Over the ocean it would just kill everything in its path.
I've always thought that a rectenna[1] would be the most efficient way to send power from orbit down to Earth.
I'm not sure how effective launching literally tons of material into space will be.
You're forgetting the one plausible energy source, however: the gravitational energy that the biomass has in outerspace. If you could figure out how to capture the energy of millions of tons of material moving from orbit to the Earth's surface, that might be able to provide the large majority of the energy needed to bring it up there in the first place.
I wonder how efficient we could make space elevators.
I think if you just care about renweable EROI and not about storage in convenient petrol form then wind and solar are still the winners.
Srsly though. Liquids are extremely good at this kind of density storage trade off, it's the reason petroleum won over electric cars in 1900 ( look it up, electric cars aren't new, we just decided about a. Hundred years ago we liked oil more.)
If you can't store it, you can't use it, so it doesn't matter how green it is, it won't be used.
The ideal transportable liquid fuel is diesel with gasoline a very close second. Some peculiar and temporary engineering and economic issues make gasoline ideal for passenger cars but in a very long run perspective the whole world is going diesel, its just the future has arrived a little quicker for some parts of the world than others. A common sci fi (and tech) theme.
Originally the diesel engine was developed by the Diesel bros (no kidding) to run on nut oil not crude oil. The Diesel bros had a political axe to grind about farms having self sufficient tractors much like they had self sufficient ox drawn plows. To say things didn't turn out that way would be an understatement, but there's no scientific reason it won't work that way in the future.
The primary problem with nut based biodiesel is you can't scale the production up to reasonable economic levels by shoving entire walnut trees thru a pipeline... but you can pump algae thru a pipeline...
So that's the big pix of why people are trying to turn algae into diesel.
Biogas rather than biodiesel might appear as a farm fuel in the future, either from manure or wood gasification. But not while underground gas is still cheap enough to flare.
If you unleash a chemist and tell him to do anything he wants to make the best energy store, you end up with a liquid hydrocarbon, they really are awesome by both mass and volume energy density and working temp range and corrosion resistance and shelf stability and a bunch of other parameters, even if cost is not an issue. True, weird corner cases like solid rocket boosters do end up with weird fuel components, but they're weird, so that's OK.
The story starts with people terraforming a planet and turning it into a giant algae-growing factory, for the purpose of creating oil from it. Whole plots with interesting characters occur. Then, suddenly, towards the end, those people abandon the whole project to go fight a war in their own galaxy. Then, the story ends with the shocking twist ... somehow you find out the abandoned algae factory is Earth. :)
Its not viable to thermal crack other than weird situations (Like I don't care if its net energy positive, we need feedstock to produce methane to produce ammonia to produce fertilizer so if you want to eat next winter, get crackin' today said the Kaiser to .. somebody .. in WWI). If its ridiculously expensive to thermally crack and crude is cheap, its simpler to just refine more crude and kill the market price of asphalt by dumping it on the market. So thats how we get blacktop roads, which seems to be a stupid use of valuable crude, yet... So this is a gross generalization but you can't thermally crack as a primary energy source, you've gotta cat crack. Unfortunately catalytic cracking is still something of an art or craft rather than a science because its horrifically complicated. Since day one there has been slow continuous incremental improvement, to the point that in 2010-ish its finally reasonable to finally start cat cracking algae on an industrial scale, or at least kinda sorta.
The problem with cat cracking is the catalysts are sensitive to trace contaminants so just pitching in crap from a field is an excellent way to destroy the catalyst. It is almost exactly like how carbon monoxide kills people, in that "stuff" gets stuck in the important parts which jams the whole works up and then nothing works ever again. On the other hand algae grown in glass tubes can have all its inputs controlled to not destroy the catalyst... more or less... plus or minus required trace elements... some of which kill some catalysts...
The best HN analogy I can provide is its kind of like 3D FPS games in the early 90s, no one suddenly shockingly invented out of whole cloth "the 3d chip" and that's how we got endless WWII sequels, its more like the smooth and gradual ramp up in performance from 1800s punch card unit record equipment up to the present day, where a phase change or whatever happened in the market in 1990 where suddenly the state of the art in 1990 made 3D FPS video games a reasonable application. But nothing really "new" happened in 1990 other than a century of computational performance gains continued as usual. Its the market that shifted after a certain performance level was achieved.
True, you can point to the days before and after the bipolar transistor demonstrated amplification and say the world changed on a certain date. But smooth growth in computer performance or cat cracker performance means there is no such sudden change date for FPS video games or algae based feedstock for hydrocrackers. And thats why we've been hearing about algae crackers as a "new" thing for about two decades and probably have to keep hearing about them being "new" for at least another couple decades because it becomes commonplace for people to run their cars on algae based biofuel.
The difference in the situations makes it an interesting HN topic more so than the trivia about someones recent lab experiment.
There are lots of ways to generate local "renewable" energy optima from waste products. Unfortunately, none of them scale.
Also this is something of an enviro-slur but renewable ideas are typically horribly polluting but the small scale types handwave past it. A gasoline engine can output exhaust cleaner in some ways than its input air, especially WRT hydrocarbons in smoggy areas, but a coke/charcoal oven is just beyond filthy polluting, which scales pretty well to one dude and his one car but is a non-starter for 100M American cars. The interstate would be unimaginable.
Who knows what else that we could use that would scale.