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Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

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Re: Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

#61

Post by Retric »

robomartin wrote: post #37

How much air would you need to supply all the power required by all the homes in California? Here's my attempt to answer that question: The first stop is to get a sense of what the realistic energy density of these approaches might be. A quick search lands you here: http://en.wikipedia.org/wiki/Compressed_air_energy_storage#E... My take-away: 1 m3 of air = about 300,000 J How much energy does a typical house in the U…

The real problem with your analysis is you want far less energy storage than that. A reasonable goal for vary high levels of 'green' tech is ~1% or ~15 minutes of grid energy storage. Beyond that it's much more valuable to simply build some peaking power plants and have excess capacity.

Re: Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

#62

Post by cpeterso »

jacquesm wrote: post #34

Congratulations Danielle, that's absolutely awesome. I'm still very sorry that you didn't get funding for some of your more off the beaten path ideas but this is as good as it gets. If there is one person that I wish would find a connection like this it is you, I'm sure you'll amaze us all with what you're going to achieve now that your toolbox is filled. This is really great news!

> some of your more off the beaten path ideas

Any references? I'd love to read more.

Re: Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

#63

Post by pjungwir »

bbuffone wrote: post #44

An old bad idea -> Many years ago i thought up an idea of creating a FEC - A self contained unit that would convert heat from a forest fires, etc... into energy. The units would be taken by helicopter and dropped into forest fires. Once the fire was over move the units into a grid that could supply energy to millions of homes. This technology is one missing piece.

My own crazy green energy idea is . . . harvest energy from lightning! Apparently other people have thought of this too, and it doesn't look like it'd work. But if someone could figure it out, it might not be the most steady source of energy, but it'd be the awesomest.

Re: Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

#65

Post by Mvandenbergh »

rdl wrote: post #25
DaniFong wrote: post #14

Earlier quoted context omitted.

A knee-jerk reaction by poorly informed and motivated reviewers, which included a fear of: - Hydrolock (solved by default) - Corrosion (solved) - Inability to separate water and air (easy to solve and quickly solved) - a lack of understanding that water could provide heat to air on expansion (proven...) We actually disproved all of their claims within 2 weeks of their decision. The problem, however, is that you don't…

I am curious how you solve corrosion in a high pressure thermal cycling environment for what are presumably very tiny water fog nozzles. But maybe that is trade secret or whatever. Naively I'd just switch out the air for N2, since it's mechanically the same and cheap. But then, once you're using special gas, I'd look at using low and high molecular weight (say, He and maybe some long chain which isn't going to detona…

The problem with low molecular weight gasses is that they lead to embrittlement of any metal in contact with them and that they leak past your seals something fierce. Both due to their small size.

He2 is also very expensive and H2 is very reactive which is not good either..

Re: Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

#66

Post by DaniFong »

jpdoctor wrote: post #32
akiselev wrote: post #28

Earlier quoted context omitted.

Yes because only in magic software wonderland can you have millions of users before you have any money. Once you exit the software bubble, almost everything, especially new technology, becomes a lot "harder" and takes a lot longer.

> Once you exit the software bubble, almost everything, especially new technology, becomes a lot "harder" and takes a lot longer. I've done hardware in spades, so I'm well aware of the differences. In hardware, Series D was either a Mezzanine round or a something-has-gone-wrong = inside/major-dilution round Maybe the world has changed, but having no product at D is not a sign that things are going well on the biz sid…

You might be overfitting the data. The initial series A, and B were essentially a seed round. I can tell you, this was certainly an upround!

Re: Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

#67

Post by jacquesm »

cpeterso wrote: post #62
jacquesm wrote: post #34

Congratulations Danielle, that's absolutely awesome. I'm still very sorry that you didn't get funding for some of your more off the beaten path ideas but this is as good as it gets. If there is one person that I wish would find a connection like this it is you, I'm sure you'll amaze us all with what you're going to achieve now that your toolbox is filled. This is really great news!

> some of your more off the beaten path ideas Any references? I'd love to read more.

Here's one:

http://daniellefong.com/2010/02/11/how-law-shapes-the-busine...

Re: Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

#68

Post by DaniFong »

robomartin wrote: post #37

How much air would you need to supply all the power required by all the homes in California? Here's my attempt to answer that question: The first stop is to get a sense of what the realistic energy density of these approaches might be. A quick search lands you here: http://en.wikipedia.org/wiki/Compressed_air_energy_storage#E... My take-away: 1 m3 of air = about 300,000 J How much energy does a typical house in the U…

Your calculations appear be within an order of magnitude of correct :-)

One other way to think of the number of shipping containers needed: actually the average american home uses 30 kwh/day. At our target energy density and efficiency we've been attempting to reach 30 kwh per m^3. 1 m^3 is approximately the internal volume of a refrigerator. So each home gets 1 fridge worth of storage. Not so bad ;-)

Re: Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

#69

Post by DaniFong »

Retric wrote: post #61
robomartin wrote: post #37

How much air would you need to supply all the power required by all the homes in California? Here's my attempt to answer that question: The first stop is to get a sense of what the realistic energy density of these approaches might be. A quick search lands you here: http://en.wikipedia.org/wiki/Compressed_air_energy_storage#E... My take-away: 1 m3 of air = about 300,000 J How much energy does a typical house in the U…

The real problem with your analysis is you want far less energy storage than that. A reasonable goal for vary high levels of 'green' tech is ~1% or ~15 minutes of grid energy storage. Beyond that it's much more valuable to simply build some peaking power plants and have excess capacity.

Well, the aim is to best peaking plants on a levelized energy cost basis. Not an easy challenge but momentous if possible.

Re: Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal

#70

Post by DaniFong »

lutorm wrote: post #60
robomartin wrote: post #37

How much air would you need to supply all the power required by all the homes in California? Here's my attempt to answer that question: The first stop is to get a sense of what the realistic energy density of these approaches might be. A quick search lands you here: http://en.wikipedia.org/wiki/Compressed_air_energy_storage#E... My take-away: 1 m3 of air = about 300,000 J How much energy does a typical house in the U…

I didn't read the article super-carefully, but my impression was that they were using the heat of vaporization of water for energy storage, not PdV work of the air. I haven't done a calculation, but my guess is that this is much more efficient.

You have to store both. Also, you can't vaporize much air at low temperatures, which we aim for. You have to hold onto water for its sensible (no evaporation) heat capacity.
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