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Renewable Energy: Clean Tech Solutions | California Academy of Sciences


♪ (music) ♪ You know, it’s hard keeping up with all the new
clean and green technologies for generating renewable energy. Tell me about it. There are so many awesome innovations
with great potential. Wave and tidal energy, bird proof wind power,
paint that gathers solar energy, What will we think of next? And some of these renewables
aren’t so new. Take wind power,
it’s been around for centuries. And some form of the hydropower
has been around since late 1800s. In California, we currently receive
around 15% of our energy from this source each year. Unless there’s a drought. Renewables count on the fact
there will always be water, wind and waves to gather energy.
Or sunshine. Take solar energy. The Sun powers the Earth’s system
and more than meets our energy needs. And there’re so many ways
to harness energy from the Sun. Large-scale concentrated solar power uses mirrors to direct huge amount
of sunlight to a smaller area. Electricity is generated
when the light is converted into heat, which drives a turbine
connected to a generator. Photovoltaics, the solar energy
that’s most familiar, can be small or big scale. Take San Francisco’s Sunset Reservoir here. The Sunset Reservoir solar array
generates about 5 megawatts of renewable energy for San Francisco. That’s the equivalent
to about 500 homes a year that it powers. Photovoltaic cells
actually absorb the energy of the sun. This energy hits the solar cells, exciting electrons in a semiconductor. These electrons can be captured
and converted into clean electricity. That’s so cool,
I never knew what was going on here. Why aren’t solar cells on every roof?
Especially if it’s good for environment? Well, I heard that solar energy
can be expensive to install. How can we provide
this source to every home?Grid Alternatives
is a nonprofit organization that has a mission of bringing
renewable energy technologies to under served populations. For the last 10 years we’ve done a total of more than
6,300 installations across the country. So the 6,300 systems that we’ve installed will save the families
that we’ve installed them for more than $165 million,
over the course of their lifetime. It will also offset
greenhouse gas emissions, to the equivalent of almost
to half a million tons. And that is also the equivalent
of taking 91,000 cars off the road, or planting 11 million trees. I am in. Solar can save the world! I don’t mean
to literally rain on your parade, but solar can’t always
be our energy source. What happens if it’s night time
or if it’s cloudy? There are ways of extending
solar’s reach beyond sunny days, but don’t take my word for it,
let’s hear from an expert. You can store solar energy
either as electricity or as heat.The most obvious place you thinkof storing that electricity
is in a battery,
but that’s still pretty expensive.There are actually less expensive ways
to store solar electricity.
One is called
pumped hydroelectric storage,
where you have two reservoirs–
one higher reservoir, one lower reservoir,
and when you produce electricityoften, when you don’t need it
for something else,
then you can use that electricity
to pump the water up to a hill
to the second reservoir,
and then, when you need the electricity,
you can allow the water
in the upper reservoir
to drain down, run through a turbine
to generate electricity.
So that’s a method of storagethat’s less expensive
and actually pretty common
throughout the world today.It seems like we’re going to needmany sources for our power in the future.Speaking of other sources– Wait, where the heck are you? I’m at the Geysers geothermal power plant. Geothermal is energy
way from way deep in the earth.(John Avery) The Geysers is the largest
geothermal power plant in the world.
We produce approximately 725 megawatts.We have approximately 350 steam wells
that collect the steam
from below ground
in the geothermal reservoir,
and then those wells feed pipelinesand eventually gather to our main lines,
for example, this pipeline here
which goes
into our turbine building there and enters the steam turbine generatorand that turbine
is coupled to the generator
which is rotating
at 3,600 RPM, or 60 hertz, supplying the electricity to you. Wow, there are a lot of renewable options. Yeah, we didn’t even tell you guys
about this dance floor that generates the electricity by,…
well, dancing. But remember, in addition
to all these new technologies, we have to consume less energy
and use it more efficiently. So that there’s enough to go around. ♪ (music) ♪ So if we cut down our energy use,
does that mean we can stop dancing?

Bernard Jenkins

2 Comments

  1. Yes, wind pwr really made us progress as a nation. Ha. And if the green energy didn't need government subsides it wouldn't exist.

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