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Despite the benefits of low-temperature fuel cell technologies, they cannot directly use biomass as a fuel because of the lack of an effective catalyst system. However, Georgia Institute of Technology researchers have developed a low-temperature fuel cell that directly converts a wide variety of biomass sources to electricity. Possible application areas are local electricity supply in developing countries

With the first ever production of synthesized "solar" jet fuel, the EU-funded SOLAR-JET project has successfully demonstrated the entire production chain for renewable kerosene obtained directly from sunlight, water and carbon dioxide (CO2), therein potentially revolutionizing the future of aviation. This process has also the potential to produce any other type of fuel for transport applications, such as diesel, gasoline or pure hydrogen in a more sustainable way.

More arguments for a lunar base? "They found the most mass-efficient path involves launching a crew from Earth with just enough fuel to get into orbit around the Earth. A fuel-producing plant on the surface of the moon would then launch tankers of fuel into space, where they would enter gravitational orbit. The tankers would eventually be picked up by the Mars-bound crew, which would then head to a nearby fueling station to gas up before ultimately heading to Mars."

There was a paper with a very similar concept (reaching Mars via DRO) at the AAS meeting in January by Conte et al. First, the total Delta V required for a trip Earth -> LLO -> MLO is higher than Earth -> MLO. The trick is that Earth -> LLO requires less Delta V than Earth -> MLO and hence less mass has to be carried along *from Earth*. Essentially what both approaches have in common is that they say "if there's a free gas station orbiting the moon, it's cheaper to fly empty and fill up there on the way". The AAS paper actually does a decent job at estimating the "real" cost by also including estimates of the cost of a lunar base. https://pure.strath.ac.uk/portal/files/44275737/Conte_etal_AAS2015_Earth_Mars_transfers_through_Moon_distant_retrograde_orbit.pdf

For the first time, researchers have shown that they can capture CO2 from the air, and convert it directly into methanol, which can then be used as an alternative fuel, as well as for hydrogen storage, in fuel cells, or as a building block for plastic.

Solar power to suck out co2 during the day and make it fuel finally solves global warming?

Solvay announced today it has successfully commissioned its 1 MegaWatt (MW) industrial demonstration Fuel Cell at the SolVin plant in Lillo, Antwerp, Belgium. This Proton Exchange Membrane (PEM) Fuel Cell converts coproduced hydrogen (H2) in the plant into electricity and is now producing for weeks at a steady rate. The Fuel Cell has generated over 500 MWh in about 800 hours of operation, which amounts to the electricity consumption of 1370 families during the same time frame.

"... they are looking to use the nanotree structure to mimic photosynthesis in a device that not only harnesses the power of the sun to produce hydrogen fuel, but also captures CO2 from the atmosphere to reduce carbon emissions at the same time."

The grass mower uses the cut grass as fuel, but can also turn the grass into dried pellets for later use, for example for heating etc.

finally a consumer application for fuel cells?

Is it safe ? How far can we go for the sake of green energy ?

Camilla: can we have a closer look into this and maybe do something further?

Carbon nanotubes could replace expensive platinum catalysts and help finally make fuel cells economical

Sandia researcher Rich Diver checks out the solar furnace which will be the initial source of concentrated solar heat for converting carbon dioxide to fuel. Eventually parabolic dishes will provide the thermal energy. Photo: Randy Montoya / Sandia Nati

"And according to his calculations, improvements in short-pulse laser systems could make this form of thruster more than 40 times as efficient as even the best of today's ionic propulsion systems that push spacecraft around. "

Dejan please have a look at this also ...

while the nuclear reaction seems to be sound at first view, I am not so sure how this would work: "Electromagnetic forces push the target and the alpha particles in the opposite directions, and the particles exit the spacecraft through a nozzle, providing the vehicle's thrust. "

Theoretized 80 years ago was Breit-Wheeler pair production in which two photons result in an electron-positron pair (via a virtual electron). It is a relatively simple Feynmann diagram, but the problem is/was how to produce in practice a high energy photon-photon collider... The collider experiment that the scientists have proposed involves two key steps. First, the scientists would use an extremely powerful high-intensity laser to speed up electrons to just below the speed of light. They would then fire these electrons into a slab of gold to create a beam of photons a billion times more energetic than visible light. The next stage of the experiment involves a tiny gold can called a hohlraum (German for 'empty room'). Scientists would fire a high-energy laser at the inner surface of this gold can, to create a thermal radiation field, generating light similar to the light emitted by stars. They would then direct the photon beam from the first stage of the experiment through the centre of the can, causing the photons from the two sources to collide and form electrons and positrons. It would then be possible to detect the formation of the electrons and positrons when they exited the can. Now this is a good experiment... :)

True, but isnt it E2=(pc)^2 + (m0c^2)^2 such that for photons E\propto{pc} and for mass E\propto{mc^2}. I agree it will take a lot of energy, but this assumes that that wont be the problem at least. The question therefore is whether the mass flow of the photon rocket (fuel consumed to create photons, eg fission/fusion) is higher/lower than the mass flow for e-p creation. You are probably right that the low e-p cross-section will favour direct use of photons to create low thrust for long periods of time, but with significant power available the ISP might be higher for e-p pair creation.

In essence the equation tells you that for photons with zero rest mass m0 all the energy will be converted to momentum of the particles. If you want to accelerate e-p then you first spend part of the energy on creating them (~511 keV each) and you can only use the remaining energy to accelerate them. In this case the equation gives you a lower particle momentum which leads to lower thrust (even when assuming 100% acceleration efficiency). ISP is a tricky concept in this case because there are different definitions which clash in the relativistic context (due to the concept of mass flow). R. Tinder gets to a I_SP = c (speed of light) for a photon rocket (using the relativistic mass of the photons) which is the maximum possible relativistic I_SP: http://goo.gl/Zz5gyC .

finally a consumer fuel cell which looks promising to actually see the markets ...

See also video

Would be nice to also push for other alternative fuel and biofuel like the ones studied at Glenn Research Center for airacraft gas turbines (Fischer Tropsch Fuel instead of JP-8) and presented an the International Workshop on Environment and Alternative Energy at ESTEC