Renewables Just Keep Getting Better

On Sun, 13 Oct 2019 22:53:35 +1100, Sylvia Else <sylvia@email.invalid>
wrote:

On 13/10/2019 7:23 am, Rick C wrote:
I ran across this article about an Indiana utility having rejected a bid for fossil fuel generation based on cost and risk.

"Vectren’s 2016 proposal to replace coal with a gas plant was declined as too large and financially risky for the small utility, requiring a new bid – which recently came in showing wind, solar and storage dominating the list of offers."

In addition it seems another Indiana utility is going hard on for renewables...

"The Northern Indiana Public Service Company (NIPSCO) learns fast. In 2018, the utility published research suggesting that closing coal plants early, and replacing them with renewables and energy storage, would save customers $4.3 billion. Around the same time as the above bids, the utility announced it would be closing a majority of its coal facilities by 2023 (thus the need for the following procurement), and all coal facilities by 2028. Coal lobbyists, expectedly, have flooded the state’s legislature."

They are looking at adding "2.3 GW of capacity from solar power plants coupled with energy storage". The costs they are expecting to see...

"A preview of where pricing might come in could be seen in the below image, from a summer of 2018 NIPSCO RFP, where we saw bids for solar power at 3.57˘/kWh for 1.3 GW-AC, and 705 MW-AC of solar+storage at an extra charge of $5.90/kW-Mo."

If I understand the storage costs, they seem pretty trivial. I'd love to have my power supplied this way. It would cut my electric bill in half. Good thing my power is local, but not so local it comes from the expensive nuclear power plant next door.

I'm wondering how soon it will be until no one even thinks of any other energy source. Certainly nuclear is a bad idea going forward.


Their desire to get rid of coal seems to be related to some issues
specific to them regarding coal supply. They wouldn't apply world-wide.

The referenced 2018 document is

https://www.in.gov/iurc/files/2018%20NIPSCO%20IRP.pdf

From that document I have extracted the following diagram

https://www.dropbox.com/s/dg09th5086y6d7i/capacity.png?dl=0

DSM stands for demand side management - essentially, some customers
agree to stop using power if necessary.

I find it difficult to see how the diagram on the right for 2028 can
possibly represent a secure supply. Or even a supply during the evening
and night. The battery storage component is very small - it's really
just about levelling out the short term variations in solar. It
certainly doesn't represent storing solar generated energy for use at
night, or during prolonged periods of rain [*].

Sylvia

[*] My own solar panels do reasonably well under cloud, but their output
drops to pretty much zero in rain, presumably because the drops of rain
on the panels mess them up optically.

Storage is one big problem with solar and wind. We are now having big,
week-long, deliberate [1] blackouts in big regions of California, and
I hear people talking about getting residential batteries. They
haven't done the math.

Even funnier, they are talking about using the batteries in their
electric cars to power up their houses.

[1] PG&E is delivering a public lesson on the value of electricity.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

On Sunday, October 13, 2019 at 12:18:09 AM UTC-7, upsid...@downunder.com wrote:

On Sat, 12 Oct 2019 16:25:28 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

On Saturday, October 12, 2019 at 7:01:59 PM UTC-4, upsid...@downunder.com wrote:
On Sat, 12 Oct 2019 13:23:24 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

I ran across this article about an Indiana utility having rejected a bid for fossil fuel generation based on cost and risk.

Indiana again, the Indiana legislators once tried to define pi as
exactly 3.2 by a law


"Vectren’s 2016 proposal to replace coal with a gas plant was declined as too large and financially risky for the small utility, requiring a new bid – which recently came in showing wind, solar and storage dominating the list of offers."

In addition it seems another Indiana utility is going hard on for renewables...

"The Northern Indiana Public Service Company (NIPSCO) learns fast. In 2018, the utility published research suggesting that closing coal plants early, and replacing them with renewables and energy storage, would save customers $4.3 billion. Around the same time as the above bids, the utility announced it would be closing a majority of its coal facilities by 2023 (thus the need for the following procurement), and all coal facilities by 2028. Coal lobbyists, expectedly, have flooded the state’s legislature."

They are looking at adding "2.3 GW of capacity from solar power plants coupled with energy storage". The costs they are expecting to see...

"A preview of where pricing might come in could be seen in the below image, from a summer of 2018 NIPSCO RFP, where we saw bids for solar power at 3.57¢/kWh for 1.3 GW-AC, and 705 MW-AC of solar+storage at an extra charge of $5.90/kW-Mo."

If I understand the storage costs, they seem pretty trivial. I'd love to have my power supplied this way. It would cut my electric bill in half. Good thing my power is local, but not so local it comes from the expensive nuclear power plant next door.

I'm wondering how soon it will be until no one even thinks of any other energy source. Certainly nuclear is a bad idea going forward.

While implementing any increased demand with renewable, talking about
replacing 22 GW of coal power plants doesn't make sense.

Since both solar and wind have a capacity factor of 20-35 %, in order
to produce the same energy as the coal plants, the renewable nominal
capacity needs to be 3-5 times or 60-100 GW. If 60 GW would be
implemented with 3 MW wind turbines, 20000 turbines would be
required, thus the distance between turbines would be 2 km if evenly
spread out across the state. I guess this would cause a strong NIMBY
effect

Yeah, a wind turbine every mile is a lot like cell phone towers, eh? People hate those things. Maybe it would be better to put them all in a few locations kinda like growing crops on farms rather than a plant here and a plant there. We can call them "wind farms"... my idea.

Unfortunately you can't put wind turbines too close together, since
they will "shadow" each other.

Wind turbines can be installed pretty close into a line that is
perpendicular against the prevailing winds, but you need to leave
quite a lot of space, before you can install the next line.

If there are no prevailing winds, you need to keep the turbines well
apart.



Even with even distribution between solar and wind, there are several
days each year when production is much lower than expected. For
instance thick clouds for a week and low winds. Thus energy storage
for a week would be required.

The realistic really large scale storage system is hydroelectricity,
but there is no way that it could handle the deficiency. The current
installed hydro capacity is less than 0.1 GW and since Indiana is so
flat, it would be hard to build more.

Since they have companies bidding on the job and already have an idea that the storage cost will be around a cent per kWh, I think your rational is not complete in some way.

So the battery capacity for the 100 kWh Tesla would cost a full
dollar???

Yes, too expensive, right? Cost more than the Tesla for a 10 years contract.

Hour: $1
Day: $24
Month: $720
Year: $8640
Decade: $86400

Rental rate is $1 per hour, whether it's used or not.

 

[Rick C]

On Sunday, October 13, 2019 at 5:37:19 AM UTC-4, upsid...@downunder.com wrote:

On Sun, 13 Oct 2019 00:55:34 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:


Even with even distribution between solar and wind, there are several
days each year when production is much lower than expected. For
instance thick clouds for a week and low winds. Thus energy storage
for a week would be required.

The realistic really large scale storage system is hydroelectricity,
but there is no way that it could handle the deficiency. The current
installed hydro capacity is less than 0.1 GW and since Indiana is so
flat, it would be hard to build more.

Since they have companies bidding on the job and already have an idea that the storage cost will be around a cent per kWh, I think your rational is not complete in some way.

So the battery capacity for the 100 kWh Tesla would cost a full
dollar???

That's the storage cost added to the kWh of generation, not the capital investment to be able to provide the kWh of storage over and over and over. Did I really need to explain that to you? I did provide the original quote.

Sorry I missed that point.

Still your numbers sound way too optimistic.

What is the cost of 1 kWh storage ? $300 ?

They don't give that number, but I have to assume that is factored into the prices quoted. If someone sells you apples, do you care what they paid for the truck that delivers them?

How many cycles does the battery last ? 1000 full cycles or 3000
partial cycles ? Thus the battery could store 1000-3000 kWh before
being replaced. Thus the added cost for each kWh stored would be 10 to
30 cents.

Again, do I care if I am buying the storage and not the storage facility?

Some energy is lost in charging (rectifying) electronics, some in
discharging (inverting) electronics and in the battery itself.
Multiple this loss with electricity cost. Unless you assume that the
electricity is completely free, this will add to the storage cost.
Thus, your 1 cent/kWh is off by a least one order of magnitude.

Order of magnitude??? You must be used to working with Edison era electronics. Please show your assumptions and math.

--

Rick C.

-+ Get 2,000 miles of free Supercharging
-+ Tesla referral code - https://ts.la/richard11209

 

[boB]

On Sun, 13 Oct 2019 08:13:40 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Sun, 13 Oct 2019 22:53:35 +1100, Sylvia Else <sylvia@email.invalid
wrote:

On 13/10/2019 7:23 am, Rick C wrote:
I ran across this article about an Indiana utility having rejected a bid for fossil fuel generation based on cost and risk.

"Vectren’s 2016 proposal to replace coal with a gas plant was declined as too large and financially risky for the small utility, requiring a new bid – which recently came in showing wind, solar and storage dominating the list of offers."

In addition it seems another Indiana utility is going hard on for renewables...

"The Northern Indiana Public Service Company (NIPSCO) learns fast. In 2018, the utility published research suggesting that closing coal plants early, and replacing them with renewables and energy storage, would save customers $4.3 billion. Around the same time as the above bids, the utility announced it would be closing a majority of its coal facilities by 2023 (thus the need for the following procurement), and all coal facilities by 2028. Coal lobbyists, expectedly, have flooded the state’s legislature."

They are looking at adding "2.3 GW of capacity from solar power plants coupled with energy storage". The costs they are expecting to see...

"A preview of where pricing might come in could be seen in the below image, from a summer of 2018 NIPSCO RFP, where we saw bids for solar power at 3.57˘/kWh for 1.3 GW-AC, and 705 MW-AC of solar+storage at an extra charge of $5.90/kW-Mo."

If I understand the storage costs, they seem pretty trivial. I'd love to have my power supplied this way. It would cut my electric bill in half. Good thing my power is local, but not so local it comes from the expensive nuclear power plant next door.

I'm wondering how soon it will be until no one even thinks of any other energy source. Certainly nuclear is a bad idea going forward.


Their desire to get rid of coal seems to be related to some issues
specific to them regarding coal supply. They wouldn't apply world-wide.

The referenced 2018 document is

https://www.in.gov/iurc/files/2018%20NIPSCO%20IRP.pdf

From that document I have extracted the following diagram

https://www.dropbox.com/s/dg09th5086y6d7i/capacity.png?dl=0

DSM stands for demand side management - essentially, some customers
agree to stop using power if necessary.

I find it difficult to see how the diagram on the right for 2028 can
possibly represent a secure supply. Or even a supply during the evening
and night. The battery storage component is very small - it's really
just about levelling out the short term variations in solar. It
certainly doesn't represent storing solar generated energy for use at
night, or during prolonged periods of rain [*].

Sylvia

[*] My own solar panels do reasonably well under cloud, but their output
drops to pretty much zero in rain, presumably because the drops of rain
on the panels mess them up optically.


Storage is one big problem with solar and wind. We are now having big,
week-long, deliberate [1] blackouts in big regions of California, and
I hear people talking about getting residential batteries. They
haven't done the math.

Even funnier, they are talking about using the batteries in their
electric cars to power up their houses.


[1] PG&E is delivering a public lesson on the value of electricity.
Yes ! absolutely !

In California where the sun actually kind of works, home solar and
batteries with inverters can help carry them through times of power
outages like this just fine... But those people would have to
conserve on their electric usage compared to how cheap and
uninteruptable their utility electricity normally is.

Limited to TV, lights, cold beer and a hot soldering iron.

 

[Bill Sloman]

On Monday, October 14, 2019 at 12:49:07 AM UTC+11, upsid...@downunder.com wrote:

On Sun, 13 Oct 2019 05:29:40 -0700 (PDT), Bill Sloman
bill.sloman@ieee.org> wrote:


[*] My own solar panels do reasonably well under cloud, but their output
drops to pretty much zero in rain, presumably because the drops of rain
on the panels mess them up optically.

Seems unlikely. Rain clouds are usually thicker and darker than regular clouds - there has to be a thick enough layer of suspended small water droplets in a cloud to give them a chance to collide and fuse into droplets big enough to fall fast enough to survive until they hit the ground.

A layer of water on top of a solar panel would be an extra optical interface, but only reflects about 4% of the incident light. The rest would go straight through.

If we assume that light clouds scatters light in all directions, half
of the incoming radiation will be scattered back to space and newer
reach the ground.

The water-air interface scatters about 4% of the incident radiation, so it takes a long series of interactions to scatter light back into space.

If there are a lot of them, a lot more than 50% of the incoming radiation can end up scattered back into space.

An empirical test, why do you have to turn indoor lights on much
earlier on a cloudy evening compared to a clear evening?

Depends how thick the clouds are, which was the point being addressed.

--
Bill Sloman, Sydney

 

On Sun, 13 Oct 2019 13:10:48 -0700, boB <boB@K7IQ.com> wrote:

On Sun, 13 Oct 2019 08:13:40 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Sun, 13 Oct 2019 22:53:35 +1100, Sylvia Else <sylvia@email.invalid
wrote:

On 13/10/2019 7:23 am, Rick C wrote:
I ran across this article about an Indiana utility having rejected a bid for fossil fuel generation based on cost and risk.

"Vectren’s 2016 proposal to replace coal with a gas plant was declined as too large and financially risky for the small utility, requiring a new bid – which recently came in showing wind, solar and storage dominating the list of offers."

In addition it seems another Indiana utility is going hard on for renewables...

"The Northern Indiana Public Service Company (NIPSCO) learns fast. In 2018, the utility published research suggesting that closing coal plants early, and replacing them with renewables and energy storage, would save customers $4.3 billion. Around the same time as the above bids, the utility announced it would be closing a majority of its coal facilities by 2023 (thus the need for the following procurement), and all coal facilities by 2028. Coal lobbyists, expectedly, have flooded the state’s legislature."

They are looking at adding "2.3 GW of capacity from solar power plants coupled with energy storage". The costs they are expecting to see...

"A preview of where pricing might come in could be seen in the below image, from a summer of 2018 NIPSCO RFP, where we saw bids for solar power at 3.57˘/kWh for 1.3 GW-AC, and 705 MW-AC of solar+storage at an extra charge of $5.90/kW-Mo."

If I understand the storage costs, they seem pretty trivial. I'd love to have my power supplied this way. It would cut my electric bill in half. Good thing my power is local, but not so local it comes from the expensive nuclear power plant next door.

I'm wondering how soon it will be until no one even thinks of any other energy source. Certainly nuclear is a bad idea going forward.


Their desire to get rid of coal seems to be related to some issues
specific to them regarding coal supply. They wouldn't apply world-wide.

The referenced 2018 document is

https://www.in.gov/iurc/files/2018%20NIPSCO%20IRP.pdf

From that document I have extracted the following diagram

https://www.dropbox.com/s/dg09th5086y6d7i/capacity.png?dl=0

DSM stands for demand side management - essentially, some customers
agree to stop using power if necessary.

I find it difficult to see how the diagram on the right for 2028 can
possibly represent a secure supply. Or even a supply during the evening
and night. The battery storage component is very small - it's really
just about levelling out the short term variations in solar. It
certainly doesn't represent storing solar generated energy for use at
night, or during prolonged periods of rain [*].

Sylvia

[*] My own solar panels do reasonably well under cloud, but their output
drops to pretty much zero in rain, presumably because the drops of rain
on the panels mess them up optically.


Storage is one big problem with solar and wind. We are now having big,
week-long, deliberate [1] blackouts in big regions of California, and
I hear people talking about getting residential batteries. They
haven't done the math.

Even funnier, they are talking about using the batteries in their
electric cars to power up their houses.


[1] PG&E is delivering a public lesson on the value of electricity.
Yes ! absolutely !

In California where the sun actually kind of works, home solar and
batteries with inverters can help carry them through times of power
outages like this just fine... But those people would have to
conserve on their electric usage compared to how cheap and
uninteruptable their utility electricity normally is.

Limited to TV, lights, cold beer and a hot soldering iron.

And oxygen generators?

<https://www.newsweek.com/california-man-dependent-oxygen-died-12-minutes-after-pge-power-shutoff-1464766>

 

[Rick C]

On Sunday, October 13, 2019 at 9:26:40 AM UTC-4, upsid...@downunder.com wrote:

On Sun, 13 Oct 2019 03:57:14 -0700 (PDT), Bill Sloman
bill.sloman@ieee.org> wrote:

On Sunday, October 13, 2019 at 9:20:06 PM UTC+11, upsid...@downunder.com wrote:
On Sun, 13 Oct 2019 10:03:46 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

On 13/10/19 08:18, upsidedown@downunder.com wrote:
If there are no prevailing winds, you need to keep the turbines well
apart.

The magic number is 5 times the rotor diameter.

A consequence is that larger windmills don't extract
more power per unit of land area, because the distance
between them increases.

In the UK you can expect to get about 2W per square
metre, but that depends sensitively on the typical
windspeed; over much of the UK it would be only
0.6W per square metre.

Some back of the envelope calculations: To replace the Indiana 22 GW
coal production with wind, at least 60 GW (nominal) wind power needs
to be installed due to low capacity factor.

The area of Indiana is 94 000 km², thus 0.64 MW/km² or 0.64 W/m². If
the wind speeds are similar to the UK, you could barely fit those wind
turbines when equally spaced across the state of Indiana.

Taller windmills help, to an extent which is very
dependent on location and surface texture.

http://withouthotair.com/cB/page_263.shtml
and succeeding pages.

One interesting note is that the power density obtainable from solar
panels is much higher for a specific land area. Even at high
latitudes, in which you have to use ample space between panels in
north/south direction to avoid shadowing other panels during the
winter. Tens of watts / square meter land area can be obtained, but is
not of much use, if there are clouds for many months :-(

Light cloud doesn't matter for non-centrated solar cells. Clouds scatter light rather than absorbing it, though enough cloud eventually scatters most of the incident sun-light back into space.

Inland areas don't see that much cloud cover - by the time an air mass has gotten over any coastal ranges, most of the water it has picked up over the oceans has fallen out as rain.

Indiana is close to lake Michigan and based of the snow figures, they
get quite a lot of rain and hence they also have a lot of clouds, i.e.
conditions similar to the Baltic sea basin area.

You are really reaching this time. Why not actually consult a climate reference rather than trying to extrapolate with invalid assumptions?

"All that water picked up from the lake normally travels no further than about 25 miles away before falling, but it can sometimes travel as far as 100 miles away!"

So 25 miles is a given, 100 miles is a reach. Only a small portion of Indiana will be impacted by the lake effect.

--

Rick C.

--- Get 2,000 miles of free Supercharging
--- Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Sunday, October 13, 2019 at 9:19:03 AM UTC-4, Tom Gardner wrote:

On 13/10/19 14:14, upsidedown@downunder.com wrote:
On Sun, 13 Oct 2019 11:39:57 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:


One point about windmills vs solar is that the land
underneath windmills can be used for other purposes,
especially growing food. Solar cannot.

While at low latitudes you can pack the panels so densely that not
much light will reach the ground, but at medium to high latitudes you
have to leave some space between panels in north/south direction to
avoid shadowing each other during the winter, so at least grass will
still grow quit well beneath the panels.

In practice rows of east/west panel rows can be built and animals can
graze between these rows. It might be a good idea to leave some space
between panels in the east/west rows too, so that the animals don't
feel too claustrophobic. Alternatively, mount the panels higher up so
that animals can freely graze below them.

To overstate the counterpoint, if enough light is reaching
the plants to grow, then the solar plant is inefficient.

Basically you can use the energy in the light for
photosynthesis or electricity; make your choice

Solar cells are optimized by assuring they receive direct light from the sun as much as possible. Land is not the quantity to be optimized in most installations, so you will want to leave space between rows to prevent one row shading the other. This naturally will leave some land not covered with solar cells and will receive diffuse light from other parts of the sky. Grass won't grow great, but it will grow. Not sure it will be robust enough for animals to graze on. I know sheep grazing messes up the grass because they don't cut it, they pull it up by the roots. Cows not so much. Cows like to rub against things and will knock over anything that isn't pretty firmly in the ground, like fences.

So while solar panels at latitudes away from the equator will have room for light to reach the ground, it's not particularly useful for either solar power or crop growth other than selected species.

--

Rick C.

++ Get 2,000 miles of free Supercharging
++ Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Sunday, October 13, 2019 at 8:29:44 AM UTC-4, Bill Sloman wrote:

On Sunday, October 13, 2019 at 10:53:42 PM UTC+11, Sylvia Else wrote:

[*] My own solar panels do reasonably well under cloud, but their output
drops to pretty much zero in rain, presumably because the drops of rain
on the panels mess them up optically.

Seems unlikely. Rain clouds are usually thicker and darker than regular clouds - there has to be a thick enough layer of suspended small water droplets in a cloud to give them a chance to collide and fuse into droplets big enough to fall fast enough to survive until they hit the ground.

A layer of water on top of a solar panel would be an extra optical interface, but only reflects about 4% of the incident light. The rest would go straight through.

Would rain reflect significantly more light than the glass? Every smooth surface will reflect some light when that light is not coming in perpendicularly. I forget the name of that law, but it varies from no reflection at perpendicular to total as a grazing angle is approached. Or is there other reflection from the material being water?

--

Rick C.

+- Get 2,000 miles of free Supercharging
+- Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Sunday, October 13, 2019 at 8:31:12 PM UTC-4, k...@notreal.com wrote:

On Sun, 13 Oct 2019 13:10:48 -0700, boB <boB@K7IQ.com> wrote:

On Sun, 13 Oct 2019 08:13:40 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Sun, 13 Oct 2019 22:53:35 +1100, Sylvia Else <sylvia@email.invalid
wrote:

On 13/10/2019 7:23 am, Rick C wrote:
I ran across this article about an Indiana utility having rejected a bid for fossil fuel generation based on cost and risk.

"Vectren’s 2016 proposal to replace coal with a gas plant was declined as too large and financially risky for the small utility, requiring a new bid – which recently came in showing wind, solar and storage dominating the list of offers."

In addition it seems another Indiana utility is going hard on for renewables...

"The Northern Indiana Public Service Company (NIPSCO) learns fast. In 2018, the utility published research suggesting that closing coal plants early, and replacing them with renewables and energy storage, would save customers $4.3 billion. Around the same time as the above bids, the utility announced it would be closing a majority of its coal facilities by 2023 (thus the need for the following procurement), and all coal facilities by 2028. Coal lobbyists, expectedly, have flooded the state’s legislature."

They are looking at adding "2.3 GW of capacity from solar power plants coupled with energy storage". The costs they are expecting to see...

"A preview of where pricing might come in could be seen in the below image, from a summer of 2018 NIPSCO RFP, where we saw bids for solar power at 3.57¢/kWh for 1.3 GW-AC, and 705 MW-AC of solar+storage at an extra charge of $5.90/kW-Mo."

If I understand the storage costs, they seem pretty trivial. I'd love to have my power supplied this way. It would cut my electric bill in half. Good thing my power is local, but not so local it comes from the expensive nuclear power plant next door.

I'm wondering how soon it will be until no one even thinks of any other energy source. Certainly nuclear is a bad idea going forward.


Their desire to get rid of coal seems to be related to some issues
specific to them regarding coal supply. They wouldn't apply world-wide..

The referenced 2018 document is

https://www.in.gov/iurc/files/2018%20NIPSCO%20IRP.pdf

From that document I have extracted the following diagram

https://www.dropbox.com/s/dg09th5086y6d7i/capacity.png?dl=0

DSM stands for demand side management - essentially, some customers
agree to stop using power if necessary.

I find it difficult to see how the diagram on the right for 2028 can
possibly represent a secure supply. Or even a supply during the evening
and night. The battery storage component is very small - it's really
just about levelling out the short term variations in solar. It
certainly doesn't represent storing solar generated energy for use at
night, or during prolonged periods of rain [*].

Sylvia

[*] My own solar panels do reasonably well under cloud, but their output
drops to pretty much zero in rain, presumably because the drops of rain
on the panels mess them up optically.


Storage is one big problem with solar and wind. We are now having big,
week-long, deliberate [1] blackouts in big regions of California, and
I hear people talking about getting residential batteries. They
haven't done the math.

Even funnier, they are talking about using the batteries in their
electric cars to power up their houses.


[1] PG&E is delivering a public lesson on the value of electricity.
Yes ! absolutely !

In California where the sun actually kind of works, home solar and
batteries with inverters can help carry them through times of power
outages like this just fine... But those people would have to
conserve on their electric usage compared to how cheap and
uninteruptable their utility electricity normally is.

Limited to TV, lights, cold beer and a hot soldering iron.

And oxygen generators?

https://www.newsweek.com/california-man-dependent-oxygen-died-12-minutes-after-pge-power-shutoff-1464766

My aunt was in a nursing home on oxygen that she was paying for. My uncle had them use an oxygen bottle rather than the generator because it was a fraction of the cost. Given there is no guarantee that power even under the best of circumstances will remain on, why would someone who critically needed oxygen be on a machine rather than a bottle? Or why would a machine not have a bottle as a backup?

But then they don't know the power cut was what caused the death and they don't even know for sure he was a PG&E customer.

--

Rick C.

-+- Get 2,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Monday, October 14, 2019 at 12:04:37 AM UTC-4, Bill Sloman wrote:

On Monday, October 14, 2019 at 2:35:12 PM UTC+11, Rick C wrote:
On Sunday, October 13, 2019 at 9:19:03 AM UTC-4, Tom Gardner wrote:
On 13/10/19 14:14, upsidedown@downunder.com wrote:
On Sun, 13 Oct 2019 11:39:57 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:


One point about windmills vs solar is that the land
underneath windmills can be used for other purposes,
especially growing food. Solar cannot.

While at low latitudes you can pack the panels so densely that not
much light will reach the ground, but at medium to high latitudes you
have to leave some space between panels in north/south direction to
avoid shadowing each other during the winter, so at least grass will
still grow quit well beneath the panels.

In practice rows of east/west panel rows can be built and animals can
graze between these rows. It might be a good idea to leave some space
between panels in the east/west rows too, so that the animals don't
feel too claustrophobic. Alternatively, mount the panels higher up so
that animals can freely graze below them.

To overstate the counterpoint, if enough light is reaching
the plants to grow, then the solar plant is inefficient.

Basically you can use the energy in the light for
photosynthesis or electricity; make your choice

Solar cells are optimized by assuring they receive direct light from the sun as much as possible. Land is not the quantity to be optimized in most installations, so you will want to leave space between rows to prevent one row shading the other. This naturally will leave some land not covered with solar cells and will receive diffuse light from other parts of the sky. Grass won't grow great, but it will grow. Not sure it will be robust enough for animals to graze on. I know sheep grazing messes up the grass because they don't cut it, they pull it up by the roots. Cows not so much. Cows like to rub against things and will knock over anything that isn't pretty firmly in the ground, like fences.

So while solar panels at latitudes away from the equator will have room for light to reach the ground, it's not particularly useful for either solar power or crop growth other than selected species.

There are farmers in Australia who are grazing sheep between solar panels.. One advantage is that any weeds don't get tall enough to shade the solar panels.

That doesn't mean the panels are crammed as close together as possible. If the grass receives sufficient sun and the sheep are sufficiently sparse the grass can recover. Indirect light only is not likely enough. Heck, it's hard to get grass to grow at all under dense tree cover.


> Presumably one can drive the flock from one paddock to the next and leave it fallow for long enough to let the grass recover, but not long enough to allow any weeds to get inconveniently tall.

The devil is in the details.

--

Rick C.

-++ Get 2,000 miles of free Supercharging
-++ Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Sunday, October 13, 2019 at 4:10:52 PM UTC-4, boB wrote:

On Sun, 13 Oct 2019 08:13:40 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Sun, 13 Oct 2019 22:53:35 +1100, Sylvia Else <sylvia@email.invalid
wrote:

On 13/10/2019 7:23 am, Rick C wrote:
I ran across this article about an Indiana utility having rejected a bid for fossil fuel generation based on cost and risk.

"Vectren’s 2016 proposal to replace coal with a gas plant was declined as too large and financially risky for the small utility, requiring a new bid – which recently came in showing wind, solar and storage dominating the list of offers."

In addition it seems another Indiana utility is going hard on for renewables...

"The Northern Indiana Public Service Company (NIPSCO) learns fast. In 2018, the utility published research suggesting that closing coal plants early, and replacing them with renewables and energy storage, would save customers $4.3 billion. Around the same time as the above bids, the utility announced it would be closing a majority of its coal facilities by 2023 (thus the need for the following procurement), and all coal facilities by 2028. Coal lobbyists, expectedly, have flooded the state’s legislature."

They are looking at adding "2.3 GW of capacity from solar power plants coupled with energy storage". The costs they are expecting to see...

"A preview of where pricing might come in could be seen in the below image, from a summer of 2018 NIPSCO RFP, where we saw bids for solar power at 3.57¢/kWh for 1.3 GW-AC, and 705 MW-AC of solar+storage at an extra charge of $5.90/kW-Mo."

If I understand the storage costs, they seem pretty trivial. I'd love to have my power supplied this way. It would cut my electric bill in half. Good thing my power is local, but not so local it comes from the expensive nuclear power plant next door.

I'm wondering how soon it will be until no one even thinks of any other energy source. Certainly nuclear is a bad idea going forward.


Their desire to get rid of coal seems to be related to some issues
specific to them regarding coal supply. They wouldn't apply world-wide.

The referenced 2018 document is

https://www.in.gov/iurc/files/2018%20NIPSCO%20IRP.pdf

From that document I have extracted the following diagram

https://www.dropbox.com/s/dg09th5086y6d7i/capacity.png?dl=0

DSM stands for demand side management - essentially, some customers
agree to stop using power if necessary.

I find it difficult to see how the diagram on the right for 2028 can
possibly represent a secure supply. Or even a supply during the evening
and night. The battery storage component is very small - it's really
just about levelling out the short term variations in solar. It
certainly doesn't represent storing solar generated energy for use at
night, or during prolonged periods of rain [*].

Sylvia

[*] My own solar panels do reasonably well under cloud, but their output
drops to pretty much zero in rain, presumably because the drops of rain
on the panels mess them up optically.


Storage is one big problem with solar and wind. We are now having big,
week-long, deliberate [1] blackouts in big regions of California, and
I hear people talking about getting residential batteries. They
haven't done the math.

Even funnier, they are talking about using the batteries in their
electric cars to power up their houses.


[1] PG&E is delivering a public lesson on the value of electricity.
Yes ! absolutely !

In California where the sun actually kind of works, home solar and
batteries with inverters can help carry them through times of power
outages like this just fine... But those people would have to
conserve on their electric usage compared to how cheap and
uninteruptable their utility electricity normally is.

I guess week long electrical outages will be the new normal. Sounds like a huge incentive to install wind/solar and backup. Just make sure the system is the type that will power your home when the grid is down.

I'm wondering if this outage is PG&Es way of Enroning California again. This is because they can't make their system work without starting fires?

--

Rick C.

--+ Get 2,000 miles of free Supercharging
--+ Tesla referral code - https://ts.la/richard11209

 

[boB]

On Sun, 13 Oct 2019 20:31:06 -0400, krw@notreal.com wrote:

On Sun, 13 Oct 2019 13:10:48 -0700, boB <boB@K7IQ.com> wrote:

On Sun, 13 Oct 2019 08:13:40 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Sun, 13 Oct 2019 22:53:35 +1100, Sylvia Else <sylvia@email.invalid
wrote:

On 13/10/2019 7:23 am, Rick C wrote:
I ran across this article about an Indiana utility having rejected a bid for fossil fuel generation based on cost and risk.

"Vectren’s 2016 proposal to replace coal with a gas plant was declined as too large and financially risky for the small utility, requiring a new bid – which recently came in showing wind, solar and storage dominating the list of offers."

In addition it seems another Indiana utility is going hard on for renewables...

"The Northern Indiana Public Service Company (NIPSCO) learns fast. In 2018, the utility published research suggesting that closing coal plants early, and replacing them with renewables and energy storage, would save customers $4.3 billion. Around the same time as the above bids, the utility announced it would be closing a majority of its coal facilities by 2023 (thus the need for the following procurement), and all coal facilities by 2028. Coal lobbyists, expectedly, have flooded the state’s legislature."

They are looking at adding "2.3 GW of capacity from solar power plants coupled with energy storage". The costs they are expecting to see...

"A preview of where pricing might come in could be seen in the below image, from a summer of 2018 NIPSCO RFP, where we saw bids for solar power at 3.57˘/kWh for 1.3 GW-AC, and 705 MW-AC of solar+storage at an extra charge of $5.90/kW-Mo."

If I understand the storage costs, they seem pretty trivial. I'd love to have my power supplied this way. It would cut my electric bill in half. Good thing my power is local, but not so local it comes from the expensive nuclear power plant next door.

I'm wondering how soon it will be until no one even thinks of any other energy source. Certainly nuclear is a bad idea going forward.


Their desire to get rid of coal seems to be related to some issues
specific to them regarding coal supply. They wouldn't apply world-wide.

The referenced 2018 document is

https://www.in.gov/iurc/files/2018%20NIPSCO%20IRP.pdf

From that document I have extracted the following diagram

https://www.dropbox.com/s/dg09th5086y6d7i/capacity.png?dl=0

DSM stands for demand side management - essentially, some customers
agree to stop using power if necessary.

I find it difficult to see how the diagram on the right for 2028 can
possibly represent a secure supply. Or even a supply during the evening
and night. The battery storage component is very small - it's really
just about levelling out the short term variations in solar. It
certainly doesn't represent storing solar generated energy for use at
night, or during prolonged periods of rain [*].

Sylvia

[*] My own solar panels do reasonably well under cloud, but their output
drops to pretty much zero in rain, presumably because the drops of rain
on the panels mess them up optically.


Storage is one big problem with solar and wind. We are now having big,
week-long, deliberate [1] blackouts in big regions of California, and
I hear people talking about getting residential batteries. They
haven't done the math.

Even funnier, they are talking about using the batteries in their
electric cars to power up their houses.


[1] PG&E is delivering a public lesson on the value of electricity.
Yes ! absolutely !

In California where the sun actually kind of works, home solar and
batteries with inverters can help carry them through times of power
outages like this just fine... But those people would have to
conserve on their electric usage compared to how cheap and
uninteruptable their utility electricity normally is.

Limited to TV, lights, cold beer and a hot soldering iron.

And oxygen generators?

https://www.newsweek.com/california-man-dependent-oxygen-died-12-minutes-after-pge-power-shutoff-1464766

WoW ! Geeez ! Yeah, I would definitely put O2 generator on my list of
critical circuits. Never trust only the grid for somethlng as
important as that ! At least a UPS !

 

[Bill Sloman]

On Monday, October 14, 2019 at 2:35:12 PM UTC+11, Rick C wrote:

On Sunday, October 13, 2019 at 9:19:03 AM UTC-4, Tom Gardner wrote:
On 13/10/19 14:14, upsidedown@downunder.com wrote:
On Sun, 13 Oct 2019 11:39:57 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:


One point about windmills vs solar is that the land
underneath windmills can be used for other purposes,
especially growing food. Solar cannot.

While at low latitudes you can pack the panels so densely that not
much light will reach the ground, but at medium to high latitudes you
have to leave some space between panels in north/south direction to
avoid shadowing each other during the winter, so at least grass will
still grow quit well beneath the panels.

In practice rows of east/west panel rows can be built and animals can
graze between these rows. It might be a good idea to leave some space
between panels in the east/west rows too, so that the animals don't
feel too claustrophobic. Alternatively, mount the panels higher up so
that animals can freely graze below them.

To overstate the counterpoint, if enough light is reaching
the plants to grow, then the solar plant is inefficient.

Basically you can use the energy in the light for
photosynthesis or electricity; make your choice

Solar cells are optimized by assuring they receive direct light from the sun as much as possible. Land is not the quantity to be optimized in most installations, so you will want to leave space between rows to prevent one row shading the other. This naturally will leave some land not covered with solar cells and will receive diffuse light from other parts of the sky. Grass won't grow great, but it will grow. Not sure it will be robust enough for animals to graze on. I know sheep grazing messes up the grass because they don't cut it, they pull it up by the roots. Cows not so much. Cows like to rub against things and will knock over anything that isn't pretty firmly in the ground, like fences.

So while solar panels at latitudes away from the equator will have room for light to reach the ground, it's not particularly useful for either solar power or crop growth other than selected species.

There are farmers in Australia who are grazing sheep between solar panels. One advantage is that any weeds don't get tall enough to shade the solar panels.

Presumably one can drive the flock from one paddock to the next and leave it fallow for long enough to let the grass recover, but not long enough to allow any weeds to get inconveniently tall.

--
Bill Sloman, Sydney

 

[Robert Baer]

upsidedown@downunder.com wrote:

On Sat, 12 Oct 2019 16:25:28 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

On Saturday, October 12, 2019 at 7:01:59 PM UTC-4, upsid...@downunder.com wrote:
On Sat, 12 Oct 2019 13:23:24 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

I ran across this article about an Indiana utility having rejected a bid for fossil fuel generation based on cost and risk.

Indiana again, the Indiana legislators once tried to define pi as
exactly 3.2 by a law
* But the Bible says it is exactly three.

"Vectren’s 2016 proposal to replace coal with a gas plant was declined as too large and financially risky for the small utility, requiring a new bid – which recently came in showing wind, solar and storage dominating the list of offers."

In addition it seems another Indiana utility is going hard on for renewables...

"The Northern Indiana Public Service Company (NIPSCO) learns fast. In 2018, the utility published research suggesting that closing coal plants early, and replacing them with renewables and energy storage, would save customers $4.3 billion. Around the same time as the above bids, the utility announced it would be closing a majority of its coal facilities by 2023 (thus the need for the following procurement), and all coal facilities by 2028. Coal lobbyists, expectedly, have flooded the state’s legislature."

They are looking at adding "2.3 GW of capacity from solar power plants coupled with energy storage". The costs they are expecting to see...

"A preview of where pricing might come in could be seen in the below image, from a summer of 2018 NIPSCO RFP, where we saw bids for solar power at 3.57¢/kWh for 1.3 GW-AC, and 705 MW-AC of solar+storage at an extra charge of $5.90/kW-Mo."

If I understand the storage costs, they seem pretty trivial. I'd love to have my power supplied this way. It would cut my electric bill in half. Good thing my power is local, but not so local it comes from the expensive nuclear power plant next door.

I'm wondering how soon it will be until no one even thinks of any other energy source. Certainly nuclear is a bad idea going forward.

While implementing any increased demand with renewable, talking about
replacing 22 GW of coal power plants doesn't make sense.

Since both solar and wind have a capacity factor of 20-35 %, in order
to produce the same energy as the coal plants, the renewable nominal
capacity needs to be 3-5 times or 60-100 GW. If 60 GW would be
implemented with 3 MW wind turbines, 20000 turbines would be
required, thus the distance between turbines would be 2 km if evenly
spread out across the state. I guess this would cause a strong NIMBY
effect

Yeah, a wind turbine every mile is a lot like cell phone towers, eh? People hate those things. Maybe it would be better to put them all in a few locations kinda like growing crops on farms rather than a plant here and a plant there. We can call them "wind farms"... my idea.

Unfortunately you can't put wind turbines too close together, since
they will "shadow" each other.

Wind turbines can be installed pretty close into a line that is
perpendicular against the prevailing winds, but you need to leave
quite a lot of space, before you can install the next line.

If there are no prevailing winds, you need to keep the turbines well
apart.



Even with even distribution between solar and wind, there are several
days each year when production is much lower than expected. For
instance thick clouds for a week and low winds. Thus energy storage
for a week would be required.

The realistic really large scale storage system is hydroelectricity,
but there is no way that it could handle the deficiency. The current
installed hydro capacity is less than 0.1 GW and since Indiana is so
flat, it would be hard to build more.

Since they have companies bidding on the job and already have an idea that the storage cost will be around a cent per kWh, I think your rational is not complete in some way.

So the battery capacity for the 100 kWh Tesla would cost a full
dollar???

 

[Bill Sloman]

On Monday, October 14, 2019 at 2:22:16 PM UTC+11, Rick C wrote:

On Sunday, October 13, 2019 at 8:29:44 AM UTC-4, Bill Sloman wrote:
On Sunday, October 13, 2019 at 10:53:42 PM UTC+11, Sylvia Else wrote:

[*] My own solar panels do reasonably well under cloud, but their output
drops to pretty much zero in rain, presumably because the drops of rain
on the panels mess them up optically.

Seems unlikely. Rain clouds are usually thicker and darker than regular clouds - there has to be a thick enough layer of suspended small water droplets in a cloud to give them a chance to collide and fuse into droplets big enough to fall fast enough to survive until they hit the ground.

A layer of water on top of a solar panel would be an extra optical interface, but only reflects about 4% of the incident light. The rest would go straight through.

Would rain reflect significantly more light than the glass?

Less. It has a lower refractive index.

> Every smooth surface will reflect some light when that light is not coming in perpendicularly. I forget the name of that law, but it varies from no reflection at perpendicular to total as a grazing angle is approached.

Probably Snells Law

https://en.wikipedia.org/wiki/Snell%27s_law

but that emphasises changes of propagation direction.

> Or is there other reflection from the material being water?

No. Water is a lot more easily deformed than glass, which can male life more complicated.

--
Bill Sloman, Sydney

 

[Rick C]

On Monday, October 14, 2019 at 3:04:49 AM UTC-4, Tom Gardner wrote:

On 14/10/19 04:35, Rick C wrote:
On Sunday, October 13, 2019 at 9:19:03 AM UTC-4, Tom Gardner wrote:
On 13/10/19 14:14, upsidedown@downunder.com wrote:
On Sun, 13 Oct 2019 11:39:57 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:


One point about windmills vs solar is that the land underneath
windmills can be used for other purposes, especially growing food.
Solar cannot.

While at low latitudes you can pack the panels so densely that not much
light will reach the ground, but at medium to high latitudes you have to
leave some space between panels in north/south direction to avoid
shadowing each other during the winter, so at least grass will still grow
quit well beneath the panels.

In practice rows of east/west panel rows can be built and animals can
graze between these rows. It might be a good idea to leave some space
between panels in the east/west rows too, so that the animals don't feel
too claustrophobic. Alternatively, mount the panels higher up so that
animals can freely graze below them.

To overstate the counterpoint, if enough light is reaching the plants to
grow, then the solar plant is inefficient.

Basically you can use the energy in the light for photosynthesis or
electricity; make your choice

Solar cells are optimized by assuring they receive direct light from the sun
as much as possible. Land is not the quantity to be optimized in most
installations, so you will want to leave space between rows to prevent one
row shading the other. This naturally will leave some land not covered with
solar cells and will receive diffuse light from other parts of the sky.
Grass won't grow great, but it will grow. Not sure it will be robust enough
for animals to graze on. I know sheep grazing messes up the grass because
they don't cut it, they pull it up by the roots. Cows not so much. Cows
like to rub against things and will knock over anything that isn't pretty
firmly in the ground, like fences.

So while solar panels at latitudes away from the equator will have room for
light to reach the ground, it's not particularly useful for either solar
power or crop growth other than selected species.

What crop do you think you could grow or harvest in a farm like this:
https://www.google.co.uk/maps/@51.5995191,-2.4819898,3a,45.9y,92.69h,92.27t/data=!3m6!1e1!3m4!1skjLH3UuIwSRu-7wMhdJQeg!2e0!7i16384!8i8192

I'm not sure, but it won't matter when some of those drivers start driving on the right side of the road and the rest run smack into them! The horror!

--

Rick C.

+-- Get 2,000 miles of free Supercharging
+-- Tesla referral code - https://ts.la/richard11209

 

[Bill Sloman]

On Monday, October 14, 2019 at 3:26:01 PM UTC+11, Rick C wrote:

On Monday, October 14, 2019 at 12:04:37 AM UTC-4, Bill Sloman wrote:
On Monday, October 14, 2019 at 2:35:12 PM UTC+11, Rick C wrote:
On Sunday, October 13, 2019 at 9:19:03 AM UTC-4, Tom Gardner wrote:
On 13/10/19 14:14, upsidedown@downunder.com wrote:
On Sun, 13 Oct 2019 11:39:57 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:

<snip>

So while solar panels at latitudes away from the equator will have room for light to reach the ground, it's not particularly useful for either solar power or crop growth other than selected species.

There are farmers in Australia who are grazing sheep between solar panels. One advantage is that any weeds don't get tall enough to shade the solar panels.

That doesn't mean the panels are crammed as close together as possible. If the grass receives sufficient sun and the sheep are sufficiently sparse the grass can recover. Indirect light only is not likely enough. Heck, it's hard to get grass to grow at all under dense tree cover.

Dense tree cover blocks a lot more sunlight.

And grass also needs water to grow (which trees are better at extracting than grass).

Over a lot of Australia, how much you can grow is determined by how much rain you get.

Solar panels aren't going to stop rain getting into the ground and the ground they shade doesn't lose as much water by evaporation.

You may end up getting almost as much grass out of the areas between the solar panels as you got out of the area when it was an open field.

Presumably one can drive the flock from one paddock to the next and leave it fallow for long enough to let the grass recover, but not long enough to allow any weeds to get inconveniently tall.

The devil is in the details.

And there are lots of them.

--
Bill Sloman, Sydney

 

[Tom Gardner]

On 14/10/19 04:35, Rick C wrote:

On Sunday, October 13, 2019 at 9:19:03 AM UTC-4, Tom Gardner wrote:
On 13/10/19 14:14, upsidedown@downunder.com wrote:
On Sun, 13 Oct 2019 11:39:57 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:


One point about windmills vs solar is that the land underneath
windmills can be used for other purposes, especially growing food.
Solar cannot.

While at low latitudes you can pack the panels so densely that not much
light will reach the ground, but at medium to high latitudes you have to
leave some space between panels in north/south direction to avoid
shadowing each other during the winter, so at least grass will still grow
quit well beneath the panels.

In practice rows of east/west panel rows can be built and animals can
graze between these rows. It might be a good idea to leave some space
between panels in the east/west rows too, so that the animals don't feel
too claustrophobic. Alternatively, mount the panels higher up so that
animals can freely graze below them.

To overstate the counterpoint, if enough light is reaching the plants to
grow, then the solar plant is inefficient.

Basically you can use the energy in the light for photosynthesis or
electricity; make your choice

Solar cells are optimized by assuring they receive direct light from the sun
as much as possible. Land is not the quantity to be optimized in most
installations, so you will want to leave space between rows to prevent one
row shading the other. This naturally will leave some land not covered with
solar cells and will receive diffuse light from other parts of the sky.
Grass won't grow great, but it will grow. Not sure it will be robust enough
for animals to graze on. I know sheep grazing messes up the grass because
they don't cut it, they pull it up by the roots. Cows not so much. Cows
like to rub against things and will knock over anything that isn't pretty
firmly in the ground, like fences.

So while solar panels at latitudes away from the equator will have room for
light to reach the ground, it's not particularly useful for either solar
power or crop growth other than selected species.

What crop do you think you could grow or harvest in a farm like this:
https://www.google.co.uk/maps/@51.5995191,-2.4819898,3a,45.9y,92.69h,92.27t/data=!3m6!1e1!3m4!1skjLH3UuIwSRu-7wMhdJQeg!2e0!7i16384!8i8192

 

[Tom Gardner]

On 14/10/19 08:17, Rick C wrote:

On Monday, October 14, 2019 at 3:04:49 AM UTC-4, Tom Gardner wrote:
On 14/10/19 04:35, Rick C wrote:
On Sunday, October 13, 2019 at 9:19:03 AM UTC-4, Tom Gardner wrote:
On 13/10/19 14:14, upsidedown@downunder.com wrote:
On Sun, 13 Oct 2019 11:39:57 +0100, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:


One point about windmills vs solar is that the land underneath
windmills can be used for other purposes, especially growing food.
Solar cannot.

While at low latitudes you can pack the panels so densely that not
much light will reach the ground, but at medium to high latitudes you
have to leave some space between panels in north/south direction to
avoid shadowing each other during the winter, so at least grass will
still grow quit well beneath the panels.

In practice rows of east/west panel rows can be built and animals
can graze between these rows. It might be a good idea to leave some
space between panels in the east/west rows too, so that the animals
don't feel too claustrophobic. Alternatively, mount the panels higher
up so that animals can freely graze below them.

To overstate the counterpoint, if enough light is reaching the plants
to grow, then the solar plant is inefficient.

Basically you can use the energy in the light for photosynthesis or
electricity; make your choice

Solar cells are optimized by assuring they receive direct light from the
sun as much as possible. Land is not the quantity to be optimized in
most installations, so you will want to leave space between rows to
prevent one row shading the other. This naturally will leave some land
not covered with solar cells and will receive diffuse light from other
parts of the sky. Grass won't grow great, but it will grow. Not sure it
will be robust enough for animals to graze on. I know sheep grazing
messes up the grass because they don't cut it, they pull it up by the
roots. Cows not so much. Cows like to rub against things and will knock
over anything that isn't pretty firmly in the ground, like fences.

So while solar panels at latitudes away from the equator will have room
for light to reach the ground, it's not particularly useful for either
solar power or crop growth other than selected species.

What crop do you think you could grow or harvest in a farm like this:
https://www.google.co.uk/maps/@51.5995191,-2.4819898,3a,45.9y,92.69h,92.27t/data=!3m6!1e1!3m4!1skjLH3UuIwSRu-7wMhdJQeg!2e0!7i16384!8i8192


I'm not sure, but it won't matter when some of those drivers start driving on
the right side of the road and the rest run smack into them! The horror!

And so we are back to my earlier (unoriginal[1]) point:
basically you can use the energy in the light for
photosynthesis or electricity; make your choice

[1] exemplified by "Without Hot Air".

The reason "Without Hot Air" is so valuable is that it cuts
through the bullshit coming from both sides of the debate.
If forces people to get rid of statements including "huge
opportunities" and "huge problems", in favour of physics,
chemistry, biology and numbers.