Tag Archives: power

Energy independence for sewage-eating robot

This story’s all over the place, at venues as diverse as Hack-A-Day and Mike Anissimov’s blog… and with good reason. Here’s the lede from PhysOrg:

UK researchers have developed an autonomous robot with an artificial gut that enables it to fuel itself by eating and excreting. The robot is the first bot powered by biomass to be demonstrated operating without assistance for several days. Being self-sustaining would enable robots of the future to function unaided for long periods.

Yup, you read that right – this machine eats a kind of organic slurry, digests the nutrients in it and then craps out the waste. Not quite so elegant (or do I mean sinister?) as the proposed rat-eating household bot we mentioned a while back, eh?

Joking aside, this is quite a big deal – energy-autonomous machines could do all sorts of amazing things, and some scary ones too. It also stirs up the same arguments about “artificial life” as the Venter announcement, albeit coming from a very different angle: if I remember my GCSE biology right, eating and excreting are two pillars of the scientific definition of biological life, and there’s a machine that does both as well as being capable of independent movement. Interesting times, people, interesting times.

Speaking of sewage and energy, we could probably be getting some of our household wattage from human waste, and there’s a pilot scheme for biomethane recapture from sewage here in the UK at the moment. But gas is tricky and dangerous to store and pipe – why not cut out the middle man and just get the energy out of the sewage directly? To be truthful, there’s still a middle man… billions of them, in fact. Apparently certain nanoparticle coatings applied to graphite anodes in sewage tanks encourage certain bacteria to proliferate, eating sewage and releasing electrons all the while. Your biowaste gets cleaned up, and you produce electricty at the same time! Sounds almost too good to be true… but they’ve got it working in a lab environment, so you never know.

Sing the body electric: be your own batteries

Back in the early eighties, my father had a joke he loved to tell non-engineers about the then nascent technology of mobile phones; the punchline sees the customer, heretofore staggered by the miniaturisation of the handset he’s just bought, daunted by the ludicrous size of the power supply.

While those days are long behind us (and my father should be posthumously forgiven, as he started working with computers when they still filled entire floors), the problem remains: the more electronic hardware we want to carry around with us, the more reliable and equally portable a source of juice we need to keep it running. And given that our near future is posited to be crammed with everyware, ubicomp, body area networks and cyberpunkish augmented reality contact lenses, there’s money in being the first to come up with the solution.

Money or military advantage, perhaps… indeed, good ol’ DARPA who are one of the big players in this field, because the amount of hi-tech kit the average soldier has to cart about is becoming a serious issue (not least for the soldiers themselves). Their proposed solution? Scavenge the wasted energy from the human body carrying the kit [via BoingBoing]:

Obviously, our bodies generate heat—thermal energy. They also produce vibrations when we move—kinetic energy. Both forms of energy can be converted into electricity. Anantha Chandrakasan, an MIT electrical engineering professor, who is working on the problem with a former student named Yogesh Ramadass, says the challenge is to harvest adequate amounts of power from the body and then efficiently direct it to the device that needs it.

In the case of harnessing vibrations, Chandrakasan and his colleagues use piezoelectric materials, which produce an electric current when subjected to mechanical pressure. For energy scavenging, ordinary vibrations caused by walking or even just nodding your head might stimulate a piezo material to generate electricity, which is then converted into the direct current (DC) used by electronics, stored in solid-state capacitors and discharged when needed. This entire apparatus fits on a chip no larger than a few square millimeters. Small embedded devices could be directly built onto the chip, or the chip could transmit energy wirelessly to nearby devices. The chip could also use thermoelectric materials, which produce an electric current when exposed to two different temperatures—such as body heat and the (usually) cooler air around us.

It’s a good idea (though it remains to be seen how useful it’ll be; I suspect the efficiency of gadgets will need to increase in order to meet the available energy harvest halfway), but it begs the question: how much wasted energy could we harvest if we were sufficiently motivated to do so? Think of it as a kind of energy freeganism – dumpster-diving for watt-minutes. Wind, solar and tidal power are two taps on the natural world, but what about the environment we’ve made in our own image?

People have thought about harvesting the energy of footsteps to power subway stations; why not do the same with shopping malls (hence ensuring that the energy used is directly proportional to the actual throughout of shoppers)? Might there be some way of harnessing the gravitational flexing of very tall buildings, in addition to covering them with solar cells and heat exchangers and hell knows what else? I reckon we’d be able to think of lots of sources of energy we currently overlook as too trivial, if only we really needed to… necessity is the mother of frugality, after all.

Japanese plan space-based solar power

714px-Space_solar_powerThe Japanese government has taken another step towards actually building a space based solar power plant. Mitsubishi Electric Corp and industrial design company IHI Corp are to develop a design for a SBSP plant to be up and running at some point in the next three decades:

By 2015, the Japanese government hopes to test a small satellite decked out with solar panels that beams power through space and back to Earth.

There are still a number of hurdles to work through before space-based solar power becomes a reality though. Transportation of the solar panels into space is too expensive at the moment to be commercially viable, so Japan has to figure out a way to lower costs. Even if costs are lowered, solar stations will have to worry about damage from micrometeoroids and other flying objects. Still, space-based solar operates perfectly under all weather conditions, unlike Earth-based panels that are at the mercy of the clouds.

It makes sense to start moving in this direction, but will practical implementation arrive fast enough to help reduce global warming emissions?

[from Inhabitat, via Slashdot][image from Wikimedia]

Fusion on a budget

fusionreactorCanadian company General Fusion are developing a fusion reactor that is based on a process called magnetized target fusion:

The reactor consists of a metal sphere with a diameter of three meters. Inside the sphere, a liquid mixture of lithium and lead spins to create a vortex with a vertical cavity in the center. Then, the researchers inject two donut-shaped plasma rings called spheromaks into the top and bottom of the vertical cavity – like “blowing smoke rings at each other,” explains Doug Richardson, chief executive of General Fusion.

The last step is mainly well-timed brute mechanical force. 220 pneumatically controlled pistons on the outer surface of the sphere are programmed to simultaneously ram the surface of the sphere one time per second. This force sends an acoustic wave through the spinning liquid that becomes a shock wave when it reaches the spheromaks in the center, triggering a fusion burst.
General Fusion has just started developing simulations of the project, and hopes to build a test reactor and demonstrate net gain within five years. If everything goes according to plan, they will then build a 100-megawatt prototype reactor to be finished five years after that, which would cost an estimated $500 million.

Like general artificial intelligence, generative fusion power is one of those technologies that always seems to be 10-20 years in the future.

It is good to see alternative techniques to the well-known ITER project or Inertial Fusion Energy being adopted as it increases the chances that some genuinely practical approach will be found.

It’s also heartening to see (relatively) smaller operations engaging in generative fusion research.

[from Physorg][image from Physorg]