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Semi-transparent solar panels allow concurrent production of crops and power

onlinelibrary.wiley.com

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Re: Semi-transparent solar panels allow concurrent production of crops and power

#51

Post by danans »

qayxc wrote: post #33
yellow_lead wrote: post #28

Earlier quoted context omitted.

Aren't there setups that can do both as well? i.e charge battery first and send excess to the grid?

The setups have to be separate (e.g. different outlets for mains and solar) to protect the grid. Even a small home solar installation puts out enough power to easily kill unsuspecting maintenance personell working on the grid, for example. So the utility company has to have 100% control over he mains at all time for safety reasons (i.e. your meter must never run backwards). If they cut the power (e.g. for maintenance…

> So the utility company has to have 100% control over he mains at all time for safety reasons

This is controlled independently by the solar inverters's software, not the utility via any sort of signal. That software is mandated by regulation as you say for the safety of line workers. Recent batteries allow for an "islanding" mode, which allows continued backup power delivery to the house during a grid outage but cuts off the grid connection.

> your meter must never run backwards

... during a grid outage. During normal operation it's fine for it to run backwards. That's what net metering quantifies.

> said battery can either feed into the grid, or be connected to separate outlets in your house, but never both at the same time.

I think this is a technical limitation, since it would require a current divider and 2 inverters, which is a level of complexity not worth it for the application.

Re: Semi-transparent solar panels allow concurrent production of crops and power

#52

Post by bialpio »

ape4 wrote: post #11
Grakel wrote: post #2

There's no shortage of open area to put solar panels. If we put a (nearly) continuous strip in every highway median, that would be a huge step forward, and still take up practically zero useable space. Even 1% of the federally owned land in the sun belt would generate an enormous amount of power.

Vehicles often crash into things beside a highway.

Planes sometimes fall on people's roofs. Let's not optimize for edge cases here?

Re: Semi-transparent solar panels allow concurrent production of crops and power

#53

Post by dehrmann »

mrfusion wrote: post #48

Could we design one to mostly get energy from green light which plants reject anyway?

This was my first thought, but PV panels that capture 25% (I'm guessing) the energy of standard panels are only viable if the cost of land is the limiting factor.

The other complicating factor is that large-scale farming requires a decent amount of horizontal and vertical clearance, so the structure for the panels would be substantial, especially if you want to track the sun.

Re: Semi-transparent solar panels allow concurrent production of crops and power

#54

Post by pwagland »

hirundo wrote: post #7
Grakel wrote: post #2

There's no shortage of open area to put solar panels. If we put a (nearly) continuous strip in every highway median, that would be a huge step forward, and still take up practically zero useable space. Even 1% of the federally owned land in the sun belt would generate an enormous amount of power.

"if the government were to take over the Sahara Desert, there would be a shortage of sand in five year" -- Milton Friedman (exaggerating, somewhat) Better to put them on home roofs, and arrange for them to be owned by the homeowners, designed so that the occupants are (literally) empowered when the grid is mismanaged, as in California. On highway medians control is more centralized, and they would require more mainte…

> if the government were to take over the Sahara Desert, there would be a shortage of sand in five year" -- Milton Friedman (exaggerating, somewhat)

I know that this is meant to be a humorous comment, however, desert sand is not really usable for most things that we want sand for, for example, it is not suitable for concrete, since it is too fine. (https://petroleumservicecompany.com/blog/could-desert-sand-b...)

This is why, desire being in a desert, Dubai imports its sand! (https://www.bbc.com/worklife/article/20160502-even-desert-ci...)

Re: Semi-transparent solar panels allow concurrent production of crops and power

#55

Post by qayxc »

nitrogen wrote: post #47
qayxc wrote: post #33

Earlier quoted context omitted.

The setups have to be separate (e.g. different outlets for mains and solar) to protect the grid. Even a small home solar installation puts out enough power to easily kill unsuspecting maintenance personell working on the grid, for example. So the utility company has to have 100% control over he mains at all time for safety reasons (i.e. your meter must never run backwards). If they cut the power (e.g. for maintenance…

Meters run backward intentionally when selling solar back to the utility. You need a switching system that will isolate immediately if the grid fails, and resync with the grid AC before reconnecting, if you want to be able to operate on and off the grid.

That depends on the country then - in my country, you need to install a secondary meter instead.

Re: Semi-transparent solar panels allow concurrent production of crops and power

#57

Post by qayxc »

danans wrote: post #51
qayxc wrote: post #33

Earlier quoted context omitted.

The setups have to be separate (e.g. different outlets for mains and solar) to protect the grid. Even a small home solar installation puts out enough power to easily kill unsuspecting maintenance personell working on the grid, for example. So the utility company has to have 100% control over he mains at all time for safety reasons (i.e. your meter must never run backwards). If they cut the power (e.g. for maintenance…

> So the utility company has to have 100% control over he mains at all time for safety reasons This is controlled independently by the solar inverters's software, not the utility via any sort of signal. That software is mandated by regulation as you say for the safety of line workers. Recent batteries allow for an "islanding" mode, which allows continued backup power delivery to the house during a grid outage but cut…

> During normal operation it's fine for it to run backwards. That's what net metering quantifies.

Hm. Different countries, different regulations I guess. In my country you have to install a second meter instead.

Re: Semi-transparent solar panels allow concurrent production of crops and power

#58

Post by discreteevent »

brightball wrote: post #45
Retric wrote: post #19

Earlier quoted context omitted.

Rooftop photovoltaic is currently more expensive, less efficient, and surprisingly dangerous to install. Solar thermal designs actually benefit from being on rooftops. As to dust, economies of scale make a huge difference. It’s rarely worth it, but using a farm truck to spray water across miles of panels is much more efficient than tens of thousands of homeowners doing the same.

First I’ve heard of solar thermal. Any good links?

Goes back years. Simplest form is a squiggly pipe behind a pane of glass. Water runs slowly through the pipe and heats up.

Re: Semi-transparent solar panels allow concurrent production of crops and power

#59

Post by onionisafruit »

brightball wrote: post #45
Retric wrote: post #19

Earlier quoted context omitted.

Rooftop photovoltaic is currently more expensive, less efficient, and surprisingly dangerous to install. Solar thermal designs actually benefit from being on rooftops. As to dust, economies of scale make a huge difference. It’s rarely worth it, but using a farm truck to spray water across miles of panels is much more efficient than tens of thousands of homeowners doing the same.

First I’ve heard of solar thermal. Any good links?

Think rooftop solar water heaters.

Re: Semi-transparent solar panels allow concurrent production of crops and power

#60

Post by jeffbee »

bialpio wrote: post #52
ape4 wrote: post #11

Earlier quoted context omitted.

Vehicles often crash into things beside a highway.

Planes sometimes fall on people's roofs. Let's not optimize for edge cases here?

This has to be the most ignorant comment ever posted on HN. In a typical year how many aircraft crash into structures? Zero. There are more than fifteen thousand car crashes in the USA every day.
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