Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

techcrunch.com

Post reply on HN
Print view View original

171–180 of 201 posts

Re: Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

#171

Post by cmdkeen »

phaemon wrote: post #165
mschuster91 wrote: post #163

Earlier quoted context omitted.

> However, 15% of UK energy is generated from renewables (excluding nuclear), which would mean that currently one seventh of the landmass of the UK was covered in wind turbines etc. Which it isn't. Most likely brought in from other countries, and the wind parks in the North Sea. Many local utilities in Germany hold stakes e.g. in a Norwegian (iirc) dam project, so they recieve a given amount of electricity output. Th…

Nope, Scotland over produces and sells to England, but that's still UK, at least for another month ;-) Offshore wind was included in the impossible. There's something off in his figures. Perhaps wind turbines have become more efficient since he first made his calculations?

It may also be diminishing returns, not all land is equal for wind turbine placement. If all the "good" spots can't generate enough for the UK's needs you might need to start using less suitable locations.

Re: Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

#172

Post by grondilu »

cpihl wrote: post #68
grondilu wrote: post #58

When talking about breaking even, does that include the energy needed to make the deuterium? Or rather to collect it, considering it has to be extracted from water or something. IIRC deuterium costs quite a lot of energy to produce and as a result for a while it was only produced by countries having large amount of hydroelectricity available. Not exactly related, but this made me wonder : inside a tank full of liquid…

That's a good question. The short answer is the energy that it takes to extract D2 from water is so small compared to the fusion energy released it isn't a factor. That is reflected in the cost of D2O at about $0.70 per gram. In a fusion reactor, even with inefficiencies, that gram of D2O will create about $1000 worth of electricity.

Yeah that makes sense. Now that I think about it, I realise the energy needed to extract deuterium is related to the chemical energy binding water molecules together. This chemical energy is orders of magnitude lower than the nuclear energy released by fusion. So the cost of fuel production will likely be irrelevant for fusion power.

Re: Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

#174

Post by reitzensteinm »

phaemon wrote: post #162
wamatt wrote: post #137

Earlier quoted context omitted.

It's insanely cool that YC is now part of this. Also love that pg credits Sam for making it happen. On a somewhat related note. Despite the setbacks and the bad rep nuclear gets, fusion really could be a better future. The energy density is in a class of its own, compared to that of renewables. Prof David MacKay demonstrates this quite effectively here[1]. This of course is not to take anything away from renewables o…

Prof Mackay's talk pretty much says that in order to use renewable energy the whole UK would have to be covered in electricity generating equipment. However, 15% of UK energy is generated from renewables (excluding nuclear), which would mean that currently one seventh of the landmass of the UK was covered in wind turbines etc. Which it isn't. You'd be able to tell. So, one of us has made a mistake with our calculatio…

To start with, you're talking about electricity generation, where he is talking about total energy requirements. So your 15% figure doesn't include the energy consumption of cars, aeroplanes, many types of heating etc.

I believe he also includes the embodied energy of imports (this was in his book), where if goods are manufactured overseas and imported, it may make sense to count the energy used to manufacture them, depending on what you're measuring exactly.

For example, there's little difference between importing aluminium, or importing energy and bauxite and smelting it yourself.

Also, area use will not increase linearly with the addition of many renewables, because in many cases the best sites are taken first. Hydro can generate a lot of energy around the clock, but you quickly run out of the best locations. Wind strength varies across the country.

In a small country like the UK, solar isn't going to vary much by latitude, and you can probably build it out all over the country. But time shifting of demand isn't always possible, so even if the panels were free, using them to push from (say) 50% of energy from renewables to 100% is going to involve some kind of storage system, which is either going to be very expensive (probably exceeding GDP) and unproven (eg hydrogen fuel cells, lithium ion batteries), or require a ton of space and specific terrain, like pumped water. So that's going to cost a lot of space.

Lastly, electricity isn't always the desired final form. If you're powering jet planes, you're going to need some type of biofuel, which is very inefficient per unit area. If and when hydrogen planes are developed, this will stop being an issue (electric cars have already proven their viability).

I highly recommend his book. It's a brilliant read, he nicely boils down the issues, and is thoroughly committed to stopping global warming - it's not some doom and gloom oil industry sponsored thing. But he doesn't have his head in the sand about how hard a switch to renewables is going to be, unlike (unfortunately) a ton of the green movement seems to.

Re: Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

#175

Post by michaelt »

phaemon wrote: post #162
wamatt wrote: post #137

Earlier quoted context omitted.

It's insanely cool that YC is now part of this. Also love that pg credits Sam for making it happen. On a somewhat related note. Despite the setbacks and the bad rep nuclear gets, fusion really could be a better future. The energy density is in a class of its own, compared to that of renewables. Prof David MacKay demonstrates this quite effectively here[1]. This of course is not to take anything away from renewables o…

Prof Mackay's talk pretty much says that in order to use renewable energy the whole UK would have to be covered in electricity generating equipment. However, 15% of UK energy is generated from renewables (excluding nuclear), which would mean that currently one seventh of the landmass of the UK was covered in wind turbines etc. Which it isn't. You'd be able to tell. So, one of us has made a mistake with our calculatio…

According to [1] in 2012 for the UK renewables provided 11.3% of electricity demand and 3.94% of total energy demand. It's an important distinction, because petrol natural gas and jet fuel aren't renewable.

MacKay is the author of a book - "Sustainable Energy without the hot air" - which lays out all his calculations and the rationales behind the inputs. And it's available online [2]. So if you want to audit his calculations, have at it!

[1] https://en.wikipedia.org/w/index.php?title=Renewable_energy_... [2] http://www.withouthotair.com/

Re: Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

#176

Post by cycrutchfield »

netcan wrote: post #173

Slightly tangental but "end energy dependance on other nations" grates me. It sounds so nationalistic.

It's not really a nationalistic sentiment, but rather one of economic independence. See, for example, Europe kowtowing to Russia because they supply a large fraction of their natural gas.

Re: Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

#177

Post by ansible »

syntern wrote: post #99
cwal37 wrote: post #77

Earlier quoted context omitted.

I was trying to be nice. I'm a strong environmentalist via academics (BS/MS in environmental science), and currently a research analyst in renewable energy economics, so I have very strong feelings (and I like to think a well-grounded sense) about how fucked the environment and incentives around it are. I was giving a (very) charitable reading of the occasional claim that Uber will change the way everything works via…

Maybe offtopic, but what do you think about the economics of plug-in hybrid cars (like the Chevy Volt)?

You didn't ask for my opinion, but I'll give it anyway. We need cheaper batteries, period. That's the limiting factor to wider spread adoption of electric vehicles.

Re: Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

#178

Post by exDM69 »

wamatt wrote: post #137
rdl wrote: post #23

It's interesting that you can justify this investment in at least four separate ways, independently: 1) Even if there is a low chance of success, it would be wildly profitable if successful, and investing early gets you a good share if it's successful. 2) Fusion power would make the world a better place; investing in this way, when you already have huge returns and it's someone else's money, is actually rational even…

It's insanely cool that YC is now part of this. Also love that pg credits Sam for making it happen. On a somewhat related note. Despite the setbacks and the bad rep nuclear gets, fusion really could be a better future. The energy density is in a class of its own, compared to that of renewables. Prof David MacKay demonstrates this quite effectively here[1]. This of course is not to take anything away from renewables o…

> On a somewhat related note. Despite the setbacks and the bad rep nuclear gets, fusion really could be a better future.

It sure could be a better future but the "bad rep" problem is bigger than I ever thought. The coalition of green parties in the European council (or Commission? Parliament? EU bureaucracy is confusing-) have the following in their program (paraphrased): "Cancel the funding of all nuclear power projects, like the ITER project".

This is a purely political move that is made solely to appeal to the feelings (not intelligence) of their voters. Nuclear fusion should be the project for the Green movement, but instead they are doing the complete opposite, just because of the reputation issues.

Re: Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

#179

Post by JVIDEL »

ChuckMcM wrote: post #39
rdl wrote: post #23

It's interesting that you can justify this investment in at least four separate ways, independently: 1) Even if there is a low chance of success, it would be wildly profitable if successful, and investing early gets you a good share if it's successful. 2) Fusion power would make the world a better place; investing in this way, when you already have huge returns and it's someone else's money, is actually rational even…

The risk of #3 is that they don't create fusion but they do develop a machine that can emit streams of hot plasma which is then turned into the Navy's weapon of choice for close weapons support on carrier battle groups. That said, I am looking forward to at least one of the fusion efforts bearing fruit. I'm something of an optimist here but I expect a durable solution to the 'energy problem' to emerge from our develo…

The biggest fear of carrier groups are mach 7 ramjet antiship missiles launched from hundreds if not thousands of miles away, way too fast to destroy with anything even laser (you barely see them coming at you) and on top of that relatively cheap at maybe half a million a piece compared to the billions a carrier costs, meaning the enemy could launch tens of them at each ship.

Re: Y Combinator And Mithril Invest In Helion, A Nuclear Fusion Startup

#180

Post by drjesusphd »

kumarski wrote: post #86

The reasons Nuclear Fusion presents a difficult problem: 1.) There's no chain reaction mechanism. 2.) The probability of a reaction constrains reaction size. 3.) The absurd amount of heat generated by fusion. I think I once heard it was 100M degrees. Curious, anybody know how they design around this? Are they using some form of magnetized containment? Excited to see this funded.

> 1.) There's no chain reaction mechanism.

There's something like it. Fusion happens because plasma is hot -> fusion products heat the plasma to keep it hot -> more fusion happens. A chain reaction is exactly what you don't want in a nuclear reactor.

> 2.) The probability of a reaction constrains reaction size.

Can you be more specific? The probability of reaction does constrain the design, but via the Lawson criterion [1].

> 3.) The absurd amount of heat generated by fusion. I think I once heard it was 100M degrees.

That's about right, but temperature != heat. Even though the plasma has a very high temperature, it is also extremely diffuse: about 3 million times less dense than air.

The main concern is keeping it hot in the proximity of colder stuff and managing the electromagnetic energy (the fields have many times more energy than the thermal energy, and has the potential to all be dumped in a single spot), not necessarily worrying about the heat.

[1] http://en.wikipedia.org/wiki/Lawson_criterion

edit: lots of silly typos

Post reply on HN