In my previous post, I concluded that cryptocurrencies face major hurdles, but that blockchains offer promise. In an earlier series of posts, I concluded that data centres will diverge into three different types, one of which is a highly distributed global computing network that consists of low-powered computers mounted directly on solar panels.

I also said that batteries are horrid, so that global network of low-powered computers should run without batteries. That means that they’re off at night, which in turn led to a follow-the-clock type of computing in which, as the day ends in one place, the computing gets pushed ever westwards. However, I didn’t specify the mechanics of how such a grid would work, and although I think it’s do-able – and interesting to do - it’s feat a piece of engineering.

It now occurs to me that blockchain mining is that feat: the perfect application for such a network.

First, by design, all blockchain networks are distributed. There are lots of copies of the relevant blockchains living on lots of computers, and only some of those computers will respond to any given request. It doesn’t matter which ones. It doesn’t matter why a given computer fails to respond: it could be busy doing other things, it could be switched off. It could be that it’s night so the computer’s powered down as there’s no sunlight to power it.

Second, by design blockchains are fault-tolerant. If a computer fails half-way through mining, it doesn’t matter: that mining is being done by multiple other computers, and the expectation is that only a few will produce a correct result. Whether a computer drops out because it can’t produce a result in time or because a cloud passed in front of the sun doesn’t matter.

Third, storage is already designed in. The original thought was that there would be multiple copies of any given datum (photo, song, whatever) distributed around the network in such a way that there will always be a copy available somewhere where the sun is shining. Unfortunately, designing highly distributed file systems is quite an undertaking. But, with blockchains, that design is done and built-in.

So the idea is this:

1. Find NGOs that install solar panels in poor countries.

2. Find other NGOs that are keen on bringing computing to poor countries.

3. Attach Raspberry Pi computers to the solar panels, perhaps with a blockchain ASIC to speed up the processing - see here.

4. The computers attached to a given panel will use some, but not all the power. There will be plenty left over, so the communities get free power.

5. The community will get a share of the income from the bitcoin mining.

6. SolarRaspberryMining will get the remainder of the income from the bitcoin mining.

A few specifics, just to demonstrate that this is feasible.

The Raspberry Pi Compute 3 uses the ARM CMOS chips, which use tiny amounts of power compared to mainstream server chips – the model 3 uses 5.1v @ 2.5A, which amounts to less than 8W, which corresponds to about 15cm * 15cm of solar panel. Assuming a panel is 1 square meter, that could mean up to about 40 Raspberry Pi computers per solar panel.

There are ASICs to speed up blockchain processing, and speed is probably important. Those ASICs will most likely be quite power-hungry, so that reduces the number of units per panel. To avoid heating (more accurately, heat dissipation) problems, and to leave power spare for the community, say half a dozen Pis+ASICs per 1m2 panel.

That model of Raspberry Pi is about USD40, and that will probably be USD100 by the time we’ve added wireless and an ASIC. Allow for the usual fudge factors, and we’re probably looking at USD1,000 per panel. That buys half a dozen Raspberries, on a panel, and all plugged in, installed, tested and the like. It doesn’t buy the panel.

There is R&D to be done: working out how to attach the PIs, customizing the OS for various blockchains, and generally making sure the whole lot works. And then there’s the issue of finding organisations to work with. So overall, this is quite a project. If you think it’s got any legs, please get back to me on chris.maden [at] cpmc.com.hk, and we’ll see if there’s a way to make it work.