
Is solar thermal energy with storage ready to replace coal-fired power? - Osiris30
http://www.theguardian.com/sustainable-business/2016/may/13/tantalisingly-close-is-solar-thermal-energy-ready-to-replace-coal-fired-power
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gene-h
The problem is, no one wants to fund solar thermal power. There are worries
that advances in photovoltaics might make solar thermal power obsolete over
the 30 year life of these plants.

~~~
cjensen
The Ivanpah solar thermal plant was funded [1] and many others [2]. Why do you
say no one wants to?

[1]
[https://en.wikipedia.org/wiki/Ivanpah_Solar_Power_Facility](https://en.wikipedia.org/wiki/Ivanpah_Solar_Power_Facility)

[2]
[https://en.wikipedia.org/wiki/List_of_solar_thermal_power_st...](https://en.wikipedia.org/wiki/List_of_solar_thermal_power_stations)

~~~
PhantomGremlin
What I don't like about "cheerleading" articles like this is they didn't
mention the problem installations such as Ivanpah. A few damning sentences
from the Ivanpah Wiki:

 _In November 2014, Associated Press reported that the plant was producing
only "about half of its expected annual output". The California Energy
Commission issued a statement blaming this on "clouds, jet contrails and
weather"._

When you're blaming "jet contrails" for your problems, there's a whole lot of
hurt being swept under the rug.

~~~
chongli
In other words, they're admitting they made some drastic overestimations in
their model. They are human beings after all.

How many solar thermal plants have been built before? How much experience do
we have with estimating their output?

~~~
PhantomGremlin
_How many solar thermal plants have been built before?_

CSP has been around for a while, but not many plants have been built in the
USA. Those that have been built haven't done all too well.

Here's a plant that was operational from 1982 to 1986:
[https://en.wikipedia.org/wiki/The_Solar_Project#Solar_One](https://en.wikipedia.org/wiki/The_Solar_Project#Solar_One)

The most memorable thing about it was you could easily see it from airplanes
flying in and out of SoCal.

------
Retric
Solar thermal is terrible for electric power. Photovoltaic solar is vastly
better as it provides more power, does not need direct sunlight, and costs
less.

The real reason Solar thermal is still a thing is they can burn fossil fuels
and produce base load power, while pretending to be 'green'.

~~~
Tuna-Fish
> Photovoltaic solar is vastly better as it provides more power, does not need
> direct sunlight, and costs less.

And produces nothing during the night.

The big reason for solar thermal is that you can store hot molten salt for the
night, and use it to generate power when PV doesn't do anything.

~~~
toomuchtodo
So then it comes down to which is cheaper: having hot molten salt maintained
on site, or dropping cargo containers full of lithium batteries on-prem to
provide dispatchability for the facility.

I argue batteries will get cheaper, faster, than trying to manage hot molten
salt.

~~~
nickff
Managing a hot molten salt pool is not as difficult as trying to deal with
many lithium cells. You mention dropping cargo containers on site, but that is
not the whole problem; you need to manufacture these containers and have a way
of continuously monitoring the cells, either finding and isolating the 'bad'
ones, or replacing whole containers. In addition, the molten salt will last
far more cycles than the batteries, while costing less to replace and being
simpler to service.

~~~
toomuchtodo
[https://www.teslamotors.com/powerpack](https://www.teslamotors.com/powerpack)

That's the benefit though, right? I can write Tesla a check and they can ship
me an entire utility scale energy storage system by rail/truck multi-modal. I
can't do that with molten salt.

~~~
nickff
You are vastly underestimating the cost and complexity of running this system
at an affordable cost. You would end up with Tesla running the majority of
your facility (by cost), and consequently would not be a competitive plant.

Let's do some simple math:

An average natural gas plant seems to be around 800MW, and we might assume
that they are running somewhere around 1/2 capacity when there is not much
solar irradiation (evening and night), giving us an average power level of
400MW. Wikipedia says that Lithium Ion cells have a specific energy of about
100-240 W.h/kg, and I'll assume that Tesla uses some good 200W.h/kg cells. If
the plant has to run with no irradiation for 10 hours at half capacity, it
needs 4000 MW.h of energy in batteries, which is 4000M/200 = 20Mkg of
batteries not including any losses during discharge or wasted energy for
cooling. 20 million kilograms of batteries would be very expensive to store
and maintain; they would also take up a lot of containers. A 20' container is
usually maxed out at about 20 tons, so you would need a thousand of them.

The basic problem is that unlike molten salt, there are no economies of scale
to be had with batteries or photovoltaic panels.

~~~
Retric
There is no need for Li-Ion for grid storage as weight is a non issue it's
just a question of cost. Don't forget we ship train loads of coal across
several states just to burn it.

~~~
nickff
I mentioned weight to give some idea of the amount of batteries that would be
required, and how many containers would be needed (as I was responding to a
suggestion of using containerized batteries), not because the weight is a
significant factor.

------
woodandsteel
I'm confused. The wikipedia article says Ivanpah has greatly under performed,
but the linked article says electric companies are investing in a whole bunch
of STF plants, including from the company that built the Ivanpah plant. So is
this good idea or not?

