Semi-transparent solar panels allow concurrent production of crops and power • Hacker News Board

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

#221

Post by Qub3d » Mon, Aug 24, 2020, 5:45 PM UTC

khawkins wrote: post #21

Only people who spend most of their life in densely crowded cities could think that the planet has so little space that you'd need to grow crops underneath solar panels for efficiency's sake.

Yep. Same problem that plagued "Solar FREAKIN' [sic] roadways" and is mentioned in the xkcd flowchart "Should I put Solar Panels on it?": https://xkcd.com/1924/

We have flat unused ground. Lets focus on getting solar there and put our whiz-bang technical chops to work solving the more difficult problem of robust distribution and storage of power.

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

#222

Post by philipkglass » Mon, Aug 24, 2020, 6:38 PM UTC

Manfredo_1 wrote: post #220

philipkglass wrote: post #219

Earlier quoted context omitted.

Nuclear has never been inexpensive enough to be the first choice for meeting peak demand in the absence of storage. Some pumped hydro plants were built in the 20th century to be charged by nuclear generation so nuclear could effectively supply peaks too. Peaking batteries could also be charged by nuclear power. Gas turbines have a construction cost under $1/watt in the US while Vogtle's AP1000s were estimated at $6/w…

This is just factually wrong. France had generated the majority of it's electricity from nuclear since the 80s, and Belgium now generates the majority of it's power from nuclear. Nuclear had repeatedly been used to satisfy peak demand. Nobody doubts that fossil fuels are cheaper. Yes, that's why fossil fuels are still in widespread use outside of France, and several countries with lots of hydroelectric power. But if…

Per the beginning of this long thread, wind and solar can supply 75% of annual US electrical demand without storage. France supplies about that much of its annual demand from nuclear power and Belgium supplies a bit over half of annual demand with nuclear power. Both countries rely on fossil generated electricity for meeting demand peaks, both via domestic generating plants and cross-border imports from foreign fossil plants. There was never a year when France met its peak electrical demand without fossil power.

The example of France proves that electrical generation could have been largely decarbonized in the 20th century, if other leaders had made a concerted push to reduce fossil fuel dependency like France's leaders did. It's tragic that other major economies did not do the same. But even France did not eliminate all fossil generation. 10% of French electricity generation is fossil as of 2017 [1].

Getting the USA's electrical generation down to only 10% fossil would be a vast improvement. I don't think that a contemporary optimized plan for getting there involves much new nuclear power even though a 20th century plan would have. A cost optimized plan from 1985 certainly would have called for a lot more nuclear power. The costs of building American solar and wind farms have plummeted since 1985. The costs of building American nuclear plants have not.

[1] https://www.world-nuclear.org/information-library/country-pr...

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

#223

Post by xxs » Mon, Aug 24, 2020, 6:45 PM UTC

m463 wrote: post #214

xxs wrote: post #114

Earlier quoted context omitted.

Instead of inverters, there should be a push for DC network. Virtually all SMPS would be able to to work with DC (right now) and they won't even need active power factor correction either. Washing mashines with brushless DC motors, most ovens would be fine too. When I think almost everything that I have home, save for geothermal pump and three-phase appliances would be ok powered by DC(0). DC has its own issues: galv…

I see DC used in electric cars, general automotive and RVs. I will say 12v is not very useful, except maybe for LED lighting. It has high losses to travel any distance. To power anything of significance requires higher voltage (or enormous cables). I do agree that it would be really good to use DC, but I kind of wonder what the reality of efficient and useful DC would be like.

12v DC is not even useful for LEDs as it requires current limiting resistors - hence power wasted to heat. The proper (efficient) way to drive LEDs is via constant current source.

I meant DC as in 230-330V DC for home/office use. I meant generally replace AC (high voltage) lines with DC ones.

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

#224

Post by Manfredo_1 » Mon, Aug 24, 2020, 9:34 PM UTC

philipkglass wrote: post #222

Manfredo_1 wrote: post #220

Earlier quoted context omitted.

This is just factually wrong. France had generated the majority of it's electricity from nuclear since the 80s, and Belgium now generates the majority of it's power from nuclear. Nuclear had repeatedly been used to satisfy peak demand. Nobody doubts that fossil fuels are cheaper. Yes, that's why fossil fuels are still in widespread use outside of France, and several countries with lots of hydroelectric power. But if…

Per the beginning of this long thread, wind and solar can supply 75% of annual US electrical demand without storage. France supplies about that much of its annual demand from nuclear power and Belgium supplies a bit over half of annual demand with nuclear power. Both countries rely on fossil generated electricity for meeting demand peaks, both via domestic generating plants and cross-border imports from foreign fossi…

France's peak energy consumption is more than 40% higher than it's trough energy demand [1]. Most years France generates ~10% of its energy from fossil fuels. Nuclear was indeed used to supply a substantial part of the peak energy demand. The substantial majority of its peak demand was fulfilled with nuclear energy. France's share of fossil fuels actually used to be lower than 10%. France's more recent uptick in fossil fuels accompanied by a drop in the share of nuclear power generation [2]. Renewable energy production increased, but its intermittency leads to an increase in fossil fuel consumption. A real world example of how the shortcomings of renewables as compared to nuclear power results in more carbon emissions.

As per your own comments, solar and wind even with substantial overproduction leave a quarter of electricity demand unfulfilled. The places that are fortunate to have hydroelectric or geothermal power available could go carbon free, but the rest are left supplying a quarter of energy with fossil fuels. The overproduction puts their price well above the cost of nuclear when you don't cherry pick one of the most infamous cost overruns as a representative example. And let's just be generous and ignore the ecological devastation caused by covering 2-4% of the Earth's land surface in solar panels.

So we have a more expensive option that leaves a quarter of electricity demand to be fulfilled by other sources (mostly fossil fuels), requires massive amounts of land to be cleared and covered in solar panels, and is subject the challenges of intermittent power generation. And we have nuclear, which is cheaper, much less land intensive, and generates consistent energy. The superior choice is unambiguous. And real world examples demonstrate this. Look at the disparity between France and Germany. The former is the posterchild of nuclear, the latter the posterchild of renewables. France's carbon intensity of electricity is usually more than a factor of 4 times smaller than Germany's. We've already put nuclear and renewables to the test. And nuclear proves to be far superior.

1. https://www.services-rte.com/en/view-data-published-by-rte/d...

2. https://en.wikipedia.org/wiki/Electricity_sector_in_France#/...

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

#225

Post by philipkglass » Tue, Aug 25, 2020, 1:36 AM UTC

Manfredo_1 wrote: post #224

philipkglass wrote: post #222

Earlier quoted context omitted.

Per the beginning of this long thread, wind and solar can supply 75% of annual US electrical demand without storage. France supplies about that much of its annual demand from nuclear power and Belgium supplies a bit over half of annual demand with nuclear power. Both countries rely on fossil generated electricity for meeting demand peaks, both via domestic generating plants and cross-border imports from foreign fossi…

France's peak energy consumption is more than 40% higher than it's trough energy demand [1]. Most years France generates ~10% of its energy from fossil fuels. Nuclear was indeed used to supply a substantial part of the peak energy demand. The substantial majority of its peak demand was fulfilled with nuclear energy. France's share of fossil fuels actually used to be lower than 10%. France's more recent uptick in foss…

I'll be interested again when France builds new reactors cheaper than new renewables. Flamanville 3 and Olkiluoto 3, even if they don't have further cost overruns, are going to produce electricity at a higher cost per MWh than German solar farms completed in the same year.

If France does build 6 more EPRs, a proposal floated last year, they will have a chance to prove that the problems to date were merely FOAK learning experiences.

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

#226

Post by Manfredo_1 » Tue, Aug 25, 2020, 3:29 AM UTC

philipkglass wrote: post #225

Manfredo_1 wrote: post #224

Earlier quoted context omitted.

France's peak energy consumption is more than 40% higher than it's trough energy demand [1]. Most years France generates ~10% of its energy from fossil fuels. Nuclear was indeed used to supply a substantial part of the peak energy demand. The substantial majority of its peak demand was fulfilled with nuclear energy. France's share of fossil fuels actually used to be lower than 10%. France's more recent uptick in foss…

I'll be interested again when France builds new reactors cheaper than new renewables. Flamanville 3 and Olkiluoto 3, even if they don't have further cost overruns, are going to produce electricity at a higher cost per MWh than German solar farms completed in the same year. If France does build 6 more EPRs, a proposal floated last year, they will have a chance to prove that the problems to date were merely FOAK learni…

France doesn't need to build new reactors largely because it's existing reactor fleet is still enough to fulfill demand. That's one of the biggest advantages of nuclear power, it lasts for the better part of a century not a decade or two. A serial run if reactor production makes more sense once the disparity between supply and demand is greater.

I'll be interested in renewables once Germany's carbon intensity per Watt is on the same order of magnitude as France. They need to drop from ~500 grams per Watt to under a hundred.