msats per joule

So how much for your energy?

Well down the road they are selling me hydrocarbons for burning at a price of

 ~6mBTC = 1 Gallon Gasoline = 120MJ =33kWh [1]

Simple enough wouldn't you say?

1J = 6*10^5/1.2*10^8 = 5*10^{-3} sat [2]

So a Joule is a unit of energy equal to 5 millisatoshi.

OK now let's go look at ASICs for two seconds:

SP35 - Yukon Power  0.66W/GH/s

Network is at half an EH/s, so

 \frac {1 GH/s} {0.5 EH/s} = \frac {1*10^9} {0.5*10^{18}} = 2*10^{-9} [3]

1GH/s should be 2*10^-9 of network.

SP35 Expected Earnings per second E, burning 1 W (1 J/s):

 E=\frac {25*10^8 sat}{10*60 sec} * \frac {1} {0.66} * 2*10^{-9} = 0.013 sat / sec [4]

Hmm..  13 millisatoshi per Joule now.

Well I don't know about you but I am rather shocked how well that worked out.  There must be some mistake.

Looking to efficiency of generators, we see that some portable gas generators get 6 kwH / Gallon.  That's roughly 20% efficiency.  20% of 13 is close to 3 msat/J, So portable gas generators powering Spondoolies boxes lose money (energy) since we're paying 5 msat/J for the gas.  To be expected I suppose.

Anyway lets keep an eye on the millisatoshi per joule conversion factor.  It's interesting for a couple reasons.

 P = 1kg*c^2 J * 5*10^{-3} sat/J = 4.5MBTC

Yup, E=mc^2 and there's 4.5 million bitcoins worth of energy in every kilogram of matter.

How do we expect this to change?  Well if we take a look at equation 4, one obvious factor that might change is the block reward.  Probably gonna drop isn't it.  If we ignore fees, we see the price per joule is going to double every four years.  The other thing that could change is the hash rate.  Hash rate goes up, msat per joule goes down.  Miner efficiency is also important of course.  Increase GH/Joule, decrease Joule per millisat.  [Edit: remember bitcoin is backed by hash.]

In other news, Sol continues to dump energy on the open market, to the tune of 1000 Watts per square meter.  That's 1000 Joules per second per square meter.  That's 5 satoshi per square meter per second.

Got an acre of sunlit land at sea level handy?  I´ll spare you the algebra this time but you should be making 2.5 BTC per hour or so from this.

Challenge Question:

At 5 msat per Joule how much area would it take to collect enough solar energy to earn a full bitcoin in a year?

Answer:  about 0.64 square meters.