A Gallery of Solar Capture Technologies

The Earth is deluged with vast amounts of energy from the sun on a constant basis. Humans have utilised solar energy from their earliest days, living on the proceeds of photosynthesis either directly or indirectly. As humans discovered fire, they cleverly enlarged their utilisation of solar energy to keeping warm on cold winter nights.

Modern humans have set their sites on powering a large part of their commercial and industrial infrastructure with solar energy, and have become extremely ingenious toward that end. Pictured below are several unconventional approaches to solar energy, which go beyond the simple silicon photovoltaic approach:

Plasmonic Photovoltaics

“The greatest significance thus far is to show an alternative method to rectennas and PV devices for IR and visible light conversion,” Melosh [Stanford U.] told PhysOrg.com. “The conversion efficiencies aren't amazingly high compared to a PV in visible, so it’s not going to replace PVs, but it could be used for energy scavenging later on.”

The new device’s MIM architecture is similar to that of a rectenna. However, whereas rectennas operate with long-wavelength light such as microwaves and radio waves, the new device operates with a broad spectrum of infrared to visible wavelengths. _Physorg

Northwestern U. Plasmonic via Brian Westenhaus
Another type of plasmonic super-absorption device comes from Northwestern U. Brian Westenhaus has more.

Nanowire Photovoltaics

The [U. Illinois] researchers found conditions for growing nanowires of various compositions of the III-V semiconductor indium gallium arsenide. Their methodology has the advantages of using a common growth technique without the need for any special treatments or patterning on the silicon wafer or the metal catalysts that are often needed for such reactions.

The nanowire geometry provides the additional benefit of enhancing solar cell performance through greater light absorption and carrier collection efficiency. The nanowire approach also uses less material than thin films, reducing the cost. _Physorg

Solar Antennas
A promising approach to solar antennas from Caltech
Another approach to solar antennas from Stanford

Super Light Absorber Nanotube Coating

The team of engineers at NASA's Goddard Space Flight Center in Greenbelt, Md., reported their findings recently at the SPIE Optics and Photonics conference, the largest interdisciplinary technical meeting in this discipline. The team has since reconfirmed the material's absorption capabilities in additional testing, said John Hagopian, who is leading the effort involving 10 Goddard technologists.

"The reflectance tests showed that our team had extended by 50 times the range of the material’s absorption capabilities. Though other researchers are reporting near-perfect absorption levels mainly in the ultraviolet and visible, our material is darn near perfect across multiple wavelength bands, from the ultraviolet to the far infrared," Hagopian said. "No one else has achieved this milestone yet."

The nanotech-based coating is a thin layer of multi-walled carbon nanotubes, tiny hollow tubes made of pure carbon about 10,000 times thinner than a strand of human hair. They are positioned vertically on various substrate materials much like a shag rug. The team has grown the nanotubes on silicon, silicon nitride, titanium, and stainless steel, materials commonly used in space-based scientific instruments. _Physorg

Thin Film Nanopillar

The cells designed by Solasta are built on a substrate forested with long, thin, vertically arrayed nanopillars. The pillars are coated first with metal, then with a thin layer of semiconducting material such as amorphous silicon, and then with a layer of transparent conductive oxide. Though the silicon layer is thin, a photon still has a relatively long path to travel down the length of the nanopillars, and a good chance of transferring its energy to an electron. Freed electrons then travel perpendicularly over a very short path to the metal at the core of each pillar, and shimmy down this electrical pole off the cell. "Electrons never have to travel through the photovoltaic material," says Zhifeng Ren, professor of physics at Boston College. "As soon as they're generated, they go into the metal." _TechnologyReview

This is only the beginning of the ingenious designs which are intended to shift Earthlings into a grand new solar age.

The problem, of course, is the diffuse and intermittent nature of sunlight. The invention of cheap and efficient electrical storage would partially solve that problem -- especially for desert areas near the equator, which receive plentiful sunlight on a regular schedule.

But even with cheap, efficient storage, the diffuse nature of sunlight requires large areas of land to be covered by solar collectors. At this time, even at 100% conversion efficiency, and at a cost of $0.00 per panel, large scale solar energy would not be practical or affordable for most parts of the globe.

Solar photovoltaic energy is instead a niche field, more suitable for small scale applications. Solar thermal is another matter. Solar thermal principles should be incorporated into the construction of every home and building which is built in the developed world from now on.

Gallery of Small Fusion Startups

Bussard IEC Fusion
Bussard inertial electrostatic confinement fusion (EMC2 Fusion) involves an electrostatic plasma confinement to achieve fusion. The history and development of the concept is explained in a video reached via the link above. The Bussard IEC has been financed almost entirely by the US Navy. EMC2 is based near Santa Fe, New Mexico.

Dense Plasma Focus Fusion
Lawrenceville Plasma Physics is based in New Jersey. The dense plasma focus approach uses a special pulsing "spark plug" to ionise a gas, and to form a plasmoid "pinch," with the emission of high energy photons, ions, and fusion neutrons.

HyperV
Hyper V Technologies utilises a spherical array of mini railguns to accelerate plasma beams into a central target of deuterium or deuterium-tritium, to achieve fusion (hopefully).

TriAlpha
TriAlpha is an Irvine, California venture, which has been fairly successful in the venture capital game. TriAlpha is a bit secretive with non-investors, but you can read their patent for yourselves. The concept seems to involve the highly sophisticated evolution from an earlier colliding beam fusion approach.

General Fusion
General Fusion is a small startup headquartered near Vancouver, BC. The compression of plasma to achieve fusion is accomplished by a coordinated spherical plasma compression, using pneumatics and advanced switching.

Helion
Helion Energy is located in Redmond, Washington. It is based on a principle of "colliding plasmas," and like all the rest of the small fusion approaches, it is a long shot.

Fusion reactors can be prolific neutron generators, and could be utilised for the transmutation of nuclear wastes into harmless compounds. They could also generate a number of differen highly energetic particles and high energy photons, and used for a number of purposes -- including as space propulsion. Another potential product of fusion reactions is heat. But what is most desired from fusion reactors is abundant, cheap, clean electrical power.

The energy from fusion is higher than the energy from fission, so that less fuel is required to generate equivalent energies. Fusion is generally safer, with less radioactive waste remaining to be disposed of.

Many billions of dollars have been spent by governments in a vain attempt to master the power of the stars on a more human scale. If one of the small startups manages to achieve with $millions what huge government budgets of $billions could not achieve, a revolution would have been ignited which would likely not stop with just cheap, clean, abundant energy.

Previously published at Al Fin Potpourri