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Comment by heydenberk | Hacker News Reader

I'm hopeful that future cryptocurrencies won't be so energy-intensive to mine. Bitcoin is already a non-negligible contributor to global CO2 emissions, believe it or not.

EDIT: Reversible computing (http://en.wikipedia.org/wiki/Reversible_computing) is a possible way to have computationally difficult proof-of-work while minimizing energy consumption.

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From the README of my "Cuckoo Cycle" Proof-of-Work at https://github.com/tromp/cuckoo :

Mining is generally considered to be inherently power hungry but it need not be. It’s a consequence of making the proof of work computationally intensive. If computation is minimized in favor of random access to gigabytes of memory (incurring long latencies), then mining will require large investments in RAM but relatively little power.

Cuckoo Cycle represents a breakthrough in three important ways:

1) it performs only one very cheap siphash computation for about 3.3 random accesses to memory,

2) its memory requirement can be set arbitrarily and doesn't allow for any time-memory trade-off.

3) verification of the proof of work is instant, requiring 1 sha256 and 42 siphash computations.

Runtime in Cuckoo Cycle is completely dominated by memory latency. It promotes the use of commodity general-purpose hardware over custom designed single-purpose hardware.

Other features:

4) proofs take the form of a length 42 cycle in the Cuckoo graph.

5) it has a natural notion of (base) difficulty, namely the number of edges in the graph; above about 60% of size, a 42-cycle is almost guaranteed, but below 50% the probability starts to fall sharply.

6) running time for the current implementation on high end x86 is under 24s/GB single-threaded, and under 3s/GB for 12 threads.

7) making cuckoo use a significant fraction of the typical memory of a botnet computer will send it into swap-hell, and likely alert its owner.

I'd be on board. Now we have to build it, and more importantly, build a community around it.

The next complain will be that the cryptocurrencies are so memory intensive that the RAM production is a non-negligible contributor to global CO2 emissions.

What's the defense against someone with a lot of money that can buy an ASIC farm or a memory farm or a whatever farm that is needed for the computation? How much money should the chip builders charge for that? How many energy can be used in the production of the critical item?

Essentially, if 50 BCT cost ~$25000, to create them you must just burn ~$25000 of petrol, i.e. 250 barrels. If you burn only 200 barrels, someone will find a faster method burning 201 that is still profitable. (You can choice to burn them during mining, or during the chips fabrication, or during the chip design, or any combination of them.)

There could be an ASIC for that. There's a new memory interface that works at 10 TB/sec with 16GB memory[1].Currently there's no cpu/gpu architecture in planning that's even close to needing that memory bandwidth, and the manufacturing is expensive.

All this means this tech won't fit decentralization well.

[1]http://www.eetimes.com/author.asp?section_id=36&doc_id=13209...

Bandwidth and latency are two seperate concepts, that 10TB bandwidth is probably around 100MB/second if you need truly random access to individual bytes of 16GB of ram and need to read each byte to find out which byte you need next. It's a speed of light issue where the round trip time back and forth to the individual RAM chips adds an inherent delay so RAM designers don't really focious on reducing latency as your stuck with a farly high latency anyway so bandwidth is generally more useful.

How do you make something incapable of being energy-intensive but still difficult? The more computers have to work at something, the more energy they use. I'm not the world's leading expert, but I don't see a way around that.

There is being energy intensive, and then there is being CPU intensive.

You could imagine a hypothetical coin that somehow uses proof of data storage and retrieval instead of proof of work. Producing and running tons of harddrives would still require power, but it would be a less.. direct.. requirement.

Short answer: http://en.wikipedia.org/wiki/Reversible_computing

Could you explain this a little more, I'm having a hard time seeing how it applies to mining.

You get around it by slowing down the computation with memory latencies. See http://en.wikipedia.org/wiki/Random-access_memory#Memory_wal...

Ripple's consensus algorithm pretty much has this licked.

https://ripple.com/wiki/Consensus - http://bitcoin.stackexchange.com/questions/10180/what-are-th... - http://bitcoin.stackexchange.com/questions/13330/what-is-the...

I'm Ripple Labs' Head of Tech Ops and I have to say I think it's amazing. Additionally, there's a program Ripple Labs are running which grants XRP for computing power donated to World Community Grid. So if you want to spend computing power you can, while doing some good. https://www.computingforgood.org/

I wonder if the energy spent moving/securing bitcoin is more or less than the energy we spend moving/securing cash/credit. Driving armored trucks full of cash and coins around isn't free. Nor is it free to keep the regular banking system's electronic infrastructure running.

Not a whole lot of energy spent writing a key to a USB stick and putting it in a safety deposit box.

Even though it is the dead of winter and we just had a major snow storm role though my furnace hasn't turned on in days. My mining equipment provides sufficient heat to keep my house warm on it's own.

Have you tried to calculate whether you make more money from mining than you would save by switching to a more cost effective way of heating your home, without electricity?

I'm not sure I understand your question. My mining equipment is profitable on it's own the fact that it totally eliminates my need to burn natural gas to heat my house is just an extra fringe benefit to the tune of $100 /month in the winter months.

The assumption is that heating with gas/wood/coal whatever is cheaper than heating with electricity - is the profit made from mining including that - your point stands though.

Define non-negligible and show us some numbers.

Mining is supposed to be difficult.

Here's a back of the envelope calculation. In theory (by supply-demand idea), you would make a negligible profit mining bitcoins. Each bitcoin is worth about $600. If our supply-demand assumption is true, the $2,160,000 dollars of Bitcoins that come into existence every day, that's also about $2,160,000 of electricity used. Or about 18,000,000 kWh per day. Or about 9,000,000 kg of C02 per day (9000 metric tonnes). That's about 3,285 thousand metric tonnes per year, or about the entire annual CO2 output of a country such as Papua New Guinea.

> the $2,160,000 dollars of Bitcoins that come into existence every day, that's also about $2,160,000 of electricity used.

You lost me. What?

A new block gets mined every 10 minutes, each with a 25BTC bounty. That's 600 * 25 * 6 * 24 = $2,160,000 per day. No rational person would spend more in electricity than the reward, hence the 1-to-1 conversion. (In fact, miners do spend more than they earn, collectively.)

That's based on the idea that if bitcoin mining is profitable, more people will get in on it until it eventually becomes break even with the cost of doing it.

This is of course a big simplification, and neglects things like the upfront cost of building the mining equipment.

The assertion is that there's roughly enough miners that miners make only a little profit. If your electricity costs $80 and you're likely to make $100, you're going to do it, and the OP is making an assumption that enough people have made that calculation that the amount of money made per miner is close to the cost of electricity per miner.

Therefore, the cost of electricity used should be close to the value of the bitcoins produced.

>If our supply-demand assumption is true, the $2,160,000 dollars of Bitcoins that come into existence every day, that's also about $2,160,000 of electricity used.

I have some first-gen ASIC miners and electricity is 20% of revenues at the current price and difficulty. The current-gen miners that are contributing to most of the increase in hash power are even more efficient and many large scale operations have cheap electricity.

The frantic addition of mining hardware (observable in the hash rate) contradicts this.

How so? It would seem to me to say nothing on the issue. The added hardware may be a mix of profitable and non-profitable machines. The question is where is the equilibrium now and over time?

I can't offer a strict logical proof, but I very much doubt that the hash rate is doubling month over month due to unprofitable hardware being brought online.

Most of the numbers floating around the internet and nearly every mainstream news piece about bitcoin's energy consumption are wrong. They cite an outdated statistic maintained by blockchain.info that assumed everyone was using a GPU even when nearly all of the network was ASICs.

I would estimate the current network (25Ph/s) averages around 2-5W per Gh/s, leading to 50-125MW total power use. bbosh in this thread is off by an order of magnitude.

I haven't cited any statistic from blockchain.info, and haven't considered hardware at all. All I have done is employ economic argument, which I think makes sense. It doesn't matter whether or not particular individuals are using ASICs. All that matters is that, collectively, they are making only a tiny profit (if any). This argument doesn't require consideration of hash-rate or particular hardware at all.

The problem with a lot of cryptocurrencies is that the mining is difficult and wasteful; you're doing a lot of computation that only makes economic sense if a lot of other people are also doing it, and it's plain that many of those people are trying to do it using someone else's equipment, which is a form of theft (specifically, conversion).

I like DogeCoin (much shibe) but this is still a Bad Thing. It would be much better if the problem being solved to create a blockchain were also useful in some other context, eg protein folding. Of course, some such problems are handled better than others by computers; protein folding is something that humans seem to do well but for which we haven't managed to develop great algorithms yet.

But if part of the work can be done in the human brain rather than in a CPU/GPU/ASIC, is that bad? The current computation model basically means that mining rewards go to whoever invests the most capital, ie has money to throw at the problem. This is inherently inequitable, because it means people with more money or a willingness to appropriate the equipment of others will mine/dig/discover more coin. Of course, the argument is that since mining is rather random, in theory you can start mining on your small CPU tomorrow and hit some coin, or get a random amount of coin for a fixed amount of mining. But random rewards devalue expertise and experience in favor of an unnaturally even probability distribution. I really think the computational abstraction is a barrier to cyptocurrency adoption, because ultimately your economic incentive is only as good as people's adoption of a sunk cost fallacy.

Here's the thing

You replace a "dumb heat generator" with a dogcoin miner.

That is: turn down the heating in your place and let the computer heat it up a bit.

Heh, that works in the winter but not in North American summers.

While a dogecoin miner is almost exactly as efficient an electrical heater as a standard resistive electrical heater, they are both less efficient than heat pumps (or in specific cases, such as heating a single person without having to first heat a very large and cold room, they are both less efficient than radiative electric heaters).

And of course electric heating is typically more expensive than natural gas, fuel oil, coal, municipal steam, etc... If you are turning down the natural gas and turning up the electric heaters, you are burning through money.

The problem isn't individual rigs in private dwellings; it's that entire data centers are being built purely to mine crypto currencies. At that scale heat dissipation itself becomes an energy expending task.

Energy consumption is precisely what gives proof of work its utility. It provides the economic cost to overturning ledger commitments which is at the core of bitcoin's security guarantees.

I would like to see folded coins.. That is, protein folding. I'm definitely not qualified to suggest this, but it seems like proteins are kind of like hash values in their one way process structure.. I wonder if protein foldings are finite in number like bitcoins?

http://www.reddit.com/r/Bitcoin/comments/1xgd8v/those_words_...

Stop E-Mail-Spam. This would be a huge energy saver.

Part of what makes the 'difficulty' difficult is the energy cost. If you lose that you lose some of the safety of the network.

Here you go: http://www.nxtcrypto.org/

100% Proof of stake, 1 minute blocks, no mining.

And not a clone of Bitcoin and thus no reason to presume it's not full of bugs and security exploits. Bitcoin is king for a reason, it's survived the scrutiny; any alt coin that chooses to do a complete rewrite is in for a long hard road to come anywhere close to the trust Bitcoin has earned.

Isn't that a pyramid scheme? To have any nxt, you need to buy it from someone else.

Is precious metal a pyramid scheme? o.O

But energy is money. The more money, the more energy.

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