How much energy does Bitcoin require?

You hear a lot about Bitcoin these days — how it is or isn’t the future of currency… In the middle of such a discussion recently, the topic of energy usage came up: Suppose Bitcoin did take over — what would the sustainability impact be?

It’s certainly a complicated question, and I don’t think I have a good answer to it yet.  But, a first order question along the way would be: how much energy is required per Bitcoin transaction?  

There’s a nice analysis of this over at motherboard, and the answer it comes to is this: a single Bitcoin transaction uses enough electricity to power ~1.5 american households for a day!   By comparison, a Visa transaction requires somewhere on the order of the electricity to power .0003 households for a day…  

That’s certainly a much bigger gap than I would’ve guessed, and highlights that there would certainly be a lot of energy-efficiency improvement needed if Bitcoin were to grow dramatically!  Of course, it’s not clear whether that would be possible, since the security of the system depends on the difficulty of the computations (and thus large energy consumption).  So, in a sense, the significant energy usage becomes part of the protection against attacks…  I guess there are probably some interesting research questions here.

See the full article for a discussion of how they arrived at these numbers.  It’s a back-of-the-envelope calculation, but a pretty reasonable estimate in my mind.

A national strategic computing initiative

I’m still playing catchup on recent happenings after not blogging for so long…   In case you missed it, at the beginning of this month, computer science (well, high performance computing in particular) got a nod from the highest level.  President Obama signed an executive order creating a national strategic computing initiative.  The initiative basically pushes the idea that the economic prosperity and scientific competitiveness of the US depends fundamentally on pushing the limits of high performance computing. There’re some interesting nuggets in the full text, including a specific focus on defining a path forward for high performance computing in the “post-Moore’s law era.”

Given the current funding environment for fundamental research, it will be very interesting to see how this plays out in terms of concrete research calls and programs in the coming years.  There should be more details in ~90 days about how this plan will align across NSF/DOE/DOD etc.  Should be interesting.

A report from the IPAM summer school

This is an amazing few months for programs at the intersection of computer science and economics.  IPAM just finished up a summer school and the Simon’s institute is just about to start a long program.

Lucky for us in LA, both are very near by, so many of our students spent the last few weeks over at IPAM for the program, which included a parade of great talks, and are now getting ready to head up to Berkeley for the Simons program.

Now that the IPAM summer school is over, the videos have all been posted at this point, so go take a look!  There are lots of really interesting talks there, including a great sequence of talks on matchings from Rakesh Vohra & Itai Ashlagi…

I was given the dubious honor of starting off the summer school, so you can check out my sequence of talks on Networked Markets as well.  It was the first time I’ve gotten a chance to talk about our work on networked Cournot competition and networked Stackelberg competition, so it was a lot of fun (and a lot of work to put together the slides).  It was nice to do it in the context of the summer school since it gave me a chance to start from the beginning and build all the way up from standard Cournot competition models, through some of the interesting recent work on networked Cournot in a generic setting (e.g. these two papers), all the way to our work on the role of market makers in networked Cournot competition (which is motivated by electricity markets).

Now that the summer school is done, I’m looking forward to heading up to Berkeley for the Simons program this fall…

Farewells and other goings on

It’s been a while since I last wrote a post here… The spring was full of duties pulling me in lots of different directions, but now (finally) the summer has given me a chance to dig myself out and now I’m finally back.

Of course, lots has been going on at Caltech and in RSRG in the meantime…

For Caltech as a whole, the big recent news is of Gordon & Betty Moore’s $100 million dollar gift, which is particularly special because it’s a pure endowment gift with the goal of helping to provide graduate fellowships.  This takes us a long way toward our ultimate goal of providing fellowships for every grad student on campus.

For the CMS department, the exciting news is that we’ll be welcoming two new interdisciplinary faculty into our mix:

• Omer Tamuz, who falls squarely in the middle of Economics, Mathematics, and Computer Science
• Fernando Brandao, who works on quantum information/complexity/algorithms

Welcome, guys!

And finally, in RSRG, lots has been going on.  This year we sent a number of students and postdocs off into the world…

• Lingwen Gan is now happily settled in at Facebook
• Subhonmesh Bose will be starting as an Assistant Professor at UIUC this coming year after finishing his postdoc at Cornell
• Enrique Mallada will be starting as an Assistant Professor at Johns Hopkins
• Siddharth Barman will be starting as an Assistant Professor at the Indian Institute of Science (IISc)

So, we’ve said a lot of goodbyes, but we also have new faces joining our ranks:  Madeleine Udell & Hu Fu have joined as postdocs, and lots of new grad students will make their way onto campus in the coming month.