The truth about solar power – storing energy

Renewable energy sources are getting cheaper
by the day and in some cases are the cheapest methods for producing electricity. But there’s a major downside that needs
to get solved before renewables can really take over. That’s how to distribute power evenly over
time, so things like weather and peak demand aren’t problems. This are solutions to this underway, and in
some cases already here, so let’s dive into this. But before we do take a moment and hit the
subscribe button, so you don’t miss out on future videos like this one. I’m Matt Ferrell … welcome to Undecided. It’s hard to deny that wind and solar are
a great approach to electricity production, especially with their rapidly dropping costs.

Wind and solar in many cases are half the
cost of a coal plant. In fact, 74% of existing U.S. coal plants
cost more to continue running than building replacement solar and wind farms. The prices are driving more and more utilities
to shelve plans for coal and natural gas plants in favor of wind and solar. Last year Northern Indiana Public Service
changed its plans to retire two of its five coal plants by 2023 to retiring all of them
within the next decade. However, as we add more and more renewable
sources into the grid, we’re creating a challenging electrical load problem for the
grid and utilities. The infamous duck curve. That’s right … we’re going to talk about
a duck. For a good example, we could take a look at
typical electricity demand. Here’s a graph of demand over the course
of one California day in 2016.

You’ll see that the lowest demand occurs
around 4-5 in the morning, ramps up slowly over the course of the day, and peaks at around
7-8 in the evening. Well, with something like solar production,
you’re generating power in a curve over the course daylight hours. Production typically peaks around midday and
ramps down right before peak demand occurs. The right amount of power, but delivered at
the wrong time. If we subtract that solar production from
the demand curve we start to see the infamous duck make it’s appearance. I know it’s a little bit of a stretch … I’d
love to meet the person who coined the “duck curve” name and ask them to draw me a duck. Because that’s not the shape of any duck
I’ve ever seen. Anyway, the more solar production you add
to the system, the steeper and more sloped the duck’s back gets. Why is this a problem? Well, to ensure there’s electricity available
whenever you want to flip on a light switch, there needs to be just the right amount of
electricity being generated.

The way this is handled today is with two
types of power plants: base load plants and peaker plants. Base load power plants provide energy at a
continuous level throughout the day, week, and year. They aren’t able to adjust the rate of electricity
generation quickly and are meant to just … run. These are typically something like coal or
nuclear plants. On a demand curve, you’d set this to run
around the lowest level of that curve. That’s where peaker plants come in. These are generally only run when there’s
high demand and are faster to ramp up than a base load plant.

A lot of peaker plants tend to be natural
gas or oil burning plants. The steeper the duck curve gets, the lower
you need to run the base load plant, and the more you have to spin up peaker plants to
make up the difference in demand. I’ve oversimplified it, but in a nutshell
that’s the essential problem we have on our hands with some renewables like solar. But this is a solvable problem. Energy storage can be used to spread out solar
production more evenly and replace the need for peaker plants to match demand. Anyone that watches my channel isn’t going
to be surprised by this one, but batteries are a big part of the solution. There are some great examples of different
grid-scale battery installations proving their value. Tesla made news with the 100 MW Hornsdale
project in Australia, which has saved nearly $40 million AUD in the first year of operation. That’s over 1/3 the cost of the system itself. And Australia is a great test bed for this
since roughly 1/2 of South Australia’s energy comes from renewables.[8] After that success,
Tesla is now going to be building the largest energy storage project they’ve ever done,
a 1.2 GWh system for PG&E in California.

Florida Power & Light is building a 900 MWh
battery energy storage system next to an existing solar power plant. FPL for two decades has been modernizing its
system, which has often meant replacing oil-based powerplants with natural gas units, but with
solar and batteries becoming price competitive, that’s why they’re also investing there
too. By the end of this year FPL will shut down
it’s last remaining coal plant in Florida. Flow batteries are an interesting technology. It’s a rechargeable cell that has two electrolyte
liquids circulated from giant vats and brought together. The positive and negatively charged liquids
are separated by a membrane, which is where the electricity is generated from the exchange
of ions.

In Hubei, China they’re building the world’s
largest vanadium flow battery project. This pilot project is for a 12 MWh storage
system and could lead to a system up to 500 MWh down the road. There are also flow battery systems around
the world being used in conjunction with wind farms, like the Huxley Hill wind farm in Australia
and Tomari Wind Hills in Japan. And then there are hybrid battery systems. In Niedersachsen, Germany they built a hybrid
sodium-sulfur and lithium ion battery system. It uses 20 MWh of sodium-sulfur batteries
with 2.5 MWh of lithium ion batteries, that perform different grid-balancing roles. Pumped-storage hydroelectricity is one of
the most cost effective methods to store electricity today. The way it works is to take excess, or lower
cost, electricity and pump water from a lower resevoir to an elevated reservoir.

When electricity is needed the elevated reservoir
water is released through turbines to produce electric power as it flows back down to the
lower resevoir. It’s a very simple, but effective system. In the U.K. there’s Dinorwig Power Station,
which is made up of tunnels below Elidir mountain. During times of low demand they pump water
up the mountain to a resevoir at high altitude. When power is needed they let the water flow
back down through the turbines, which is capable of about 11 GWh of electricity. Here in Virginia we have the Bath County Pumped
Storage Station, which has a maximum capacity of 24,000 MWh making it the largest pumped-storage
station in the world. The two reservoirs are separated by about
1,260 feet (380m) in elevation. It’s operated much like the Dinorwig Power
Station, using power during low demand cycles to pump the water to the upper reservoir.

Then release the water during peak demand. This one I find extremely cool. It’s not that different from the core principle
of pumped-storage, but is simpler and doesn’t require access to vast amounts of water and
space. It’s a technique that’s been around for
hundreds of years and that I’m pretty sure almost everyone has seen at some point in
their life. If you’ve seen a pendulum clock, then you’ve
seen this in action. There’s a company called Gravitricity that
is scaling this concept up … a lot. Instead of needing a large amount of space
to hold batteries or reservoirs, they want to drill or reuse old mine shafts to raise
and lower a giant weight. The clever aspect of reusing old mine shafts
greatly reduces the cost of development. With a 50 year designed lifespan, no degradation
in performance, the ability to go from zero to full power in less than a second, and produce
between 1 and 20MW peak power, it’s a very interesting solution.

This solution is still making its way to market,
but it’s a really exciting prospect for the future of energy storage. Those aren’t a comprehensive list of all
of the technologies on the market or on the way. There are things like salt water batteries,
molten salt or sodium-sulfur batteries, or even fly wheels. There are a lot of interesting things in the
works, but the point is that grid scale energy storage is possible. In many cases it’s already here and being
used every day. Most of the naysayers of renewable energy
point to irregular energy production as why it will never work. We can’t be blinded by status quo thinking
and assume that the negatives of renewable energy today can’t be overcome tomorrow. Necessity is the mother of invention, and
in this case that’s never been more true. Call me an optimist, but I find all of this
very exciting for the future of renewables like solar and wind. We all need a more nimble and resilient energy
grid.

One that can provide all the energy we need,
do so in an environmentally responsible way, and maybe save us all some money on top of
it. What do you think? Do you live in an area that’s already taking
advantage of systems like these? Or is a company in your area planning on moving
in this direction? Are you worried about the swayed back duck? I’d love to hear what you think. And if you liked this video, be sure to give
it a thumbs up and share with your friends because it really helps the channel. If you’d like to support the channel, there
are some ways you can do so.

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in going solar, you can research solar panels, solar batteries, and get quotes from installers
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And as always, thanks so much for watching,
and I’ll see you in the next one..

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