solar panels have gained huge momentum over the past few decades but they have
always had an Achilles heel no matter where you place them on Earth they'll spend most
of their lives in darkness that's why we made a video on building a worldwide solar network
with solar Farms placed around the world and there was a common theme in the comment section
that would be better to build a solar farm in space now as crazy as that sounds I recently
got to meet with a Japanese company called NTT that is developing just fat a space solar farm
that collects light almost 24 hours a day and beams it down to earth using lasers so future
rocket launches with solar payloads into geostationary orbit solar power and lasers
yeah this is going to be a lot of fun I'm Ricky and this is Two Bit da Vinci
we're at ntt's r d headquarters and we are going to chat with some of the engineers and scientists
that are working on this very problem and we'll see just how feasible it is how far along they
are and how much energy potential there is in solar from space before we talk about why
something as ambitious as a solar farm in space makes sense let's talk about the limitations of
land-based solar here's a chart showing an average sunny day in San Diego you might be
tempted to think that solar panels produce energy about half the time but it's actually a fair bit
less using the maximum solar peak for summer and winter we can calculate the theoretical potential
for a 24-hour period versus what my system and my old house actually produced it turns out in
the winter it's closer to 25 percent and 33 in the summer so not 50 but 25 and 33 and it's actually a
bit more complicated still this data is for a five kilowatt solar system actually my old solar system
on my old house at its peak it was producing 4 000 Watts which is awesome more than enough
to power your whole house including AC or heating based on today's prices of three dollars per watt
a five kilowatt system would cost fifteen thousand dollars but what if you wanted pure sun power at 4
000 Watts for an entire 24 hour period the theoretical potential of the system we need
96 kilowatt hours or three times as many solar panels and 50 kilode hours of energy
storage and batteries or roughly three and a half Tesla power walls raising original cost
from fifteen thousand to ninety thousand five hundred but of course we'd also need
to consider launch costs for this system in space but we'll get back to that in a minute
entity is an Innovative global technology and Business Solutions provided with an annual r d
budget of 3.6 billion dollars their ion initiative or Innovative Optical and wireless network will
help set ultra high speed low latency and low energy standards that will all benefit from
in the coming years so when you think of ultra low latency networking you're probably thinking
Esports and yes that's an obvious application of that technology but did you know you can also do
other things like remote surgery and other really cool scientific applications but yes Esports is
one of those industries that really drives forth the future of really low latency highly reliable
really quick internet but as part of their own research they're taking their expertise
in building and launching communication satellites to developing a space-based solar system seriously
I could do three or four episodes and all the amazing things they're working on but I'll come
back to that in a little bit let's take a look at what a space-based solar farm would look like
there are three main components to such a system first the energy collection and generation then
because we can't just run copper wires to a solar array thousands of miles in Earth's orbit we need
to figure out how to transmit that energy down to earth wirelessly and lastly we need to gather that
energy transmitted wirelessly and put it to useful use here on Earth let's start by identifying how
far away from Earth the solar farm should be entities pilot program will beam down energy
to a receiver station in Japan but to predictably fly over the exact same place on Earth requires
a quick discussion of geosynchronous orbits to maintain a stable orbit requires finding a balance
between tangential velocity to Earth and the Earth's gravitational pull if a satellite isn't
traveling fast enough it'll slowly get pulled into Earth's gravitational field and crash go
too fast and you'll get flung out into the vacuum of space the International Space Station the ISS
is orbiting at 402 kilometers or 250 miles from the surface of the Earth this close in it needs to
be really zooming along to stay in orbit it is at twenty thousand four hundred kilometers per hour
the ISS revolves around the Earth every 90 minutes while great for the advancement of Science and
Technology this won't work for our solar farm we need to find an orbit and speed that matches the
Earth's perfectly using the following equations and solving for time which is 24 hours we'll see
that our orbit needs to be at 36 000 kilometers at this location traveling at 11 095 kilometers
an hour our solar farm would balance the pull of gravity and stay in the exact same spot in the sky
another benefit of being up 36 000 kilometers in space is there's no atmosphere to absorb or
refract the incoming light so up here a square meter receives 1400 watts of solar energy 140
percent as much as the 1000 Watts received at the surface of the Earth between that and the near 24
hours of sunlight our space Farm has potential to receive 10 times the solar energy of a land-based
system but notice I said potential because in truth the space-based on solar system isn't
going to reach that number that's because NTT still needs to transmit that energy down to earth
which gets us into the next part of the puzzle while other companies pursuing space-based solar
power like the European Space Agency plan on using very efficient multi-junction photovoltaic solar
panels that convert the sunlight into electricity NTT has a different idea their design doesn't use
PV panels but instead an array of mirrors that concentrate light like a thermal solar power plant
this concentrated seller is directed into a very specialized Crystal all materials emit light when
exposed to energy a filament in an old-fashioned bulb glows because the electric current passed
through it NTT has been exploring neodymium and chromium doped Atrium aluminum Garnet crystals
I know it's a mouthful but but bear with me as the mirror array reflects sunlight into
the crystal it absorbs the energy and radiates it out in infrared light to try to return to a lower
energy state but this infrared light would just spread out in all directions but what we want is
a super focused laser beam to shoot down to earth so like all lasers The Entity team will have a
completely reflective mirror on one end of the crystal and a partially reflective mirror on the
other light rays that don't line up with the axis of the cylinder get reflected and eventually exit
I'm curious what the NTT team plans to do with this light since that's how the efficiency of
the system can be increased but the light parallel to the axis of the cylinder gets intensified and
narrowed in wavelength the resulting standing wave means only light of a certain wavelength can exist
inside the cavity where it is then allowed to pass through the partially reflective mirror the end
result is a 1064 nanometer infrared wavelength laser invisible to the naked eye light is an
electromagnetic wave shown in this diagram visible light is but a tiny portion of the spectrum with
Violet around 308 nanometers to Red up to 750. a lot of research and development was put into the
specific wavelength for the following reasons shorter wavelengths have higher energy all the
way up to gamma rays that are harmful to life on Earth lucky for us the Earth's magnetosphere
blocks gamma rays and other charged particles and our ozone layer blocks UVC and some UVB rays going
back to our electromagnetic spectrum longer wavelengths have less energy but are able to
pierce the Earth's atmosphere and actually reach the surface so the 1064 nanometer infrared is an
ideal candidate for this laser beam to minimize attenuation or energy loss in transmission as it
travels the 36 000 kilometers back to Earth one of the most iconic characteristics of lasers is
a super narrow beam pattern this is in contrast to most light that we see that spreads out equally in
all directions but a laser actually isn't perfect and while narrow it does disperse as it travels
how much the best lasers have a dispersion of about 0.000166 radians or roughly 0.01 degrees
which sounds really small all and it is shine this laser from one end of an American football
field to the other and the beam would only grow about 16 millimeters or 0.63 inches but that's
just about 100 meters when we consider the 36 000 kilometers we need our laser to travel that
beam would spread to 6 000 meters across about 66 football fields wide that would require a massive
solar collector but the team is also exploring various lenses and techniques to tighten this beam
to land in a smaller area the more concentrated the beam the greater the Heat and the greater
the active cooling requirements would be but we recently did a video on a Japanese initiative
to produce red hydrogen produced to the high temperature catalytic splitting of water using
nuclear power thermal as an energy source in a similar fashion active cooling systems from the
land-based panels could be used to produce the required heat to not only produce electricity
and cool the panels but also produce hydrogen we need a new hydrogen color code for this like cyan
hydrogen for example is that taken I don't know producing hydrogen with otherwise waste heat would
really increase the overall efficiency of the system so there's one more piece to this puzzle
specialized photovoltaic panels specifically tuned for infrared light at 1064 nanometers most
traditional panels are only about 20 efficient because they can't use all the Sun's light this
is why more expensive multi-junction solar panels can increase efficiencies to 30 to 45 percent NTT
is working on panels on Specialized solar PV cells with up to 50 percent efficiency when dealing with
the nearly uniform 1064 nanometer infrared light so let's do a quick calculation on the
efficiency of the entire system NTT has tested the solar light to laser efficiency to be roughly 50
percent then there's eighty percent efficiency of the transmission of laser light through the
atmosphere finally a 50 efficiency of the infrared light to the PV panels to produce electricity
these are early estimates and NTT is currently exploring various crystals and PV cell chemistries
to increase this but using today's figures and remembering our space solar system receives 140
percent of the light that we receive here on the Earth's surface we get 20 for land-based panels
and 28 for our space system so going back to our five kilowatt system 140 of the peak of 4 000
Watts we see on Earth is now 5600 watts in space plus it's continuous over the entire day if we add
up the area under the curve we see our land system produces 31.5 kilowatt hours per day and our space
system produces 135.5 kilowatt hours per day but our space system is constant one of the most
interesting aspects about researching for this video is that there is actually two points each
year where the system wouldn't receive 24 hours of sunlight during a period three weeks before and
after the vernal equinox the first day of spring and three weeks before and after the autumnal
equinox the first day of fall the system would be shaded by the Earth for about one hour per day the
Earth is tilt it on its axis about 23.5 degrees this is what gives us our Seasons but during these
two periods in fall and spring there is a small window of time where the system will be in shade
as you can see here that's pretty cool so where is entity at with this system well they are in the
research and development phase fine-tuning every aspect of the system and Performing cost-benefit
analyzes but these advancements in areas like wireless energy transmission can have huge impacts
on our material lives sooner than you think what if it was possible to have electric Airlines with
smaller battery packs that received constant energy from laser beam stations along strategic
parts of their flight path what if we could roll a Tesla semi with a huge battery and an IR receiver
into areas hit by natural disasters and kept them charged from far away using lasers up on
mountains in our previous videos on a worldwide solar Network our biggest challenge was aluminum
wires big enough to carry enough energy around the globe but maybe with lasers we could change
change all that it's really hard to calculate the levelized cost of energy for a system like this
because there are so many variables we're living in the second Space Age where launch costs have
dropped dramatically and will continue to but some rough figures from SpaceX reveals about six
thousand twelve thousand dollars per kilogram of payload to geostationary orbit and that's today's
figures the key will be really well designed folding mechanisms an ultra lightweight reflective
surfaces to maximize Sun collection as a function of weight and volume private companies investing
in space launches reusable rockets that safely fly back to Earth further material breakthroughs
and Automation and Robotics have all helped bring these launch costs down but I think space solar
systems could be the very use case we need for future launches to help feed the demand and help
bring down prices even further the most amazing thing about the scientific process is that we get
to stand on the shoulders of giants continuing to accumulate knowledge and dream up big ideas
that were inconceivable level just a generation ago NTT is a Powerhouse r d company with billions
of dollars in annual revenue and this is how they're spending their money looking into the
future here's a really cool concept that MTT came up with for a really simple solution to how you
can protect valuable and sensitive infrastructure in the case of a lightning strike so this is a
drone that they can fly you see in this video here but then they have this really cool idea
well we're dealing with lightning which is huge amounts of energy so why not store that energy and
that's what they're starting to try to do here is an example of flywheel storage superconductivity
storage compressed air all things we've talked about before but this is a cool way they can do
this with lightning energy we as humans need stop signs and Signal lights to stop us from colliding
on to each other when you have ai and Robotics these robots have no stop signs and no stops I've
been watching for about 10 minutes and they've never collided the reason why is as they get close
to each other they'll communicate and come up with their own rule set pretty amazing technology but
Mike the teacher have no stop signs or it's traffic lights anymore it might at all just
be self-governed rules between autonomous vehicles pretty cool I had the most amazing time in Japan
and I have to thank the entire team at NTT for all their help in researching this video so how far
out is entity from actually building the system maybe five years and hopefully this video at least
helps to explain why this is such an exciting and worthwhile Pursuit I'll try to follow up
with their progress in the future and share all that with you but in the meantime don't forget
to like And subscribe and if you have questions or comments sound off in the comments below and don't
forget to check out this video on our worldwide solar Network idea which kind of ties in pretty
nicely to this one and until next week I'm Ricky Whitby DaVinci thank you so much for watching