Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Germany outfitted half a million balconies with solar panels

grist.org

Post reply on HN
Print view View original

111–120 of 651 posts

Re: Germany outfitted half a million balconies with solar panels

#111

Post by slow_typist »

nebula8804 wrote: post #87

Has anyone done any studies on the co2 emission of manufacturing one panel like this? Curious how long it will take to offset.

585 kWh/m^2 median energy consumption for production according to a 2013 study cited on the Wikipedia article on energy return on investment. 440 W panel has about 2 m^2. It is probably a tad better now, because lower mass of silicon per meter squared. That translates to roughly 2.5 years of energy payback time in Germany under good conditions (azimuth SE to SW and elevation about 30 to 60 degrees, no shadow). Give a few extra months for the inverter and system losses. If you want to know exactly there are commercial databases used for LCA calculations.

The carbon emissions depend on the energy mix of the supply chain (which is mostly in China, since Germany totally butchered domestic production). And the total climate effect is amplified by other emissions (leaking of technical gases in silicon production? But now I am way out of my field of expertise.)

OTOH hand to calculate the offset of emissions you need to know what is going on in the grid. If windmills are shut down around noon to make room for PV, the offset is zero.

Re: Germany outfitted half a million balconies with solar panels

#112

Post by kragen »

GaggiX wrote: post #82
plantain wrote: post #68

Earlier quoted context omitted.

Paying contractors to climb on rooftops one at a time and cable up a million distinct houses is clearly not comparable to an industrial installation. Similarly the generation from a balcony on a bad angle, and from walking around Germany, typically shaded, makes no sense.

You are completely ignoring the biggest cost: land. In a dense country like Germany, using millions of existing, "free" rooftops is vastly more efficient and economical than buying and dedicating scarce, expensive land for an industrial-scale farm. Also rooftop solar generates power at the point of consumption. This significantly reduces the need for new, expensive high-voltage transmission lines.

No, land is not a significant cost, not even in Germany. You're in completely the wrong order of magnitude.

Re: Germany outfitted half a million balconies with solar panels

#113

Post by AnthonyMouse »

gpm wrote: post #107
AnthonyMouse wrote: post #99

Earlier quoted context omitted.

But in that case the regulations would only have to apply to plugging in something that doesn't do that. There shouldn't be any forms or approvals or fees for someone who buys a product that does.

I agree there shouldn't be, but I don't think it's surprising that in many places there are . It takes active work for the regulator to look at the product and say "this design is sound, we're sure it won't kill anyone".

It takes active work to do that but not to manually approve zillions of individual installations?

Re: Germany outfitted half a million balconies with solar panels

#114

Post by ffsm8 »

kragen wrote: post #102
echoangle wrote: post #47

Earlier quoted context omitted.

China is also 30 times larger in area than germany.

Yes, but until recently, Germany produced more electricity than China did.

You're not getting his point.

Germany has a space problem. There aren't large swaths of land available to put solar panels on. Added to that you have to realize just how far north Germany is, and consequently how... Bad solar is because of that.

Seriously, dropping down the same amount of panels gets you significantly less electricity in Germany then where China is building them, much closer to the equator.

Overall, Germany is in a shit place for renewable energy

Re: Germany outfitted half a million balconies with solar panels

#115

Post by slaw »

kragen wrote: post #103
slaw wrote: post #79

Earlier quoted context omitted.

Inner Mongolia is so far from populated areas that China build 2000 km electric power lines, as long as a car drive from Munich to Sicily.

The Messina Strait Bridge doesn't actually exist. Perhaps you are driving a hovercraft.

Ferries don't exist.

Re: Germany outfitted half a million balconies with solar panels

#116

Post by slow_typist »

kragen wrote: post #96
slow_typist wrote: post #88

Earlier quoted context omitted.

True, the cut of 19% VAT on panels, inverters (which is applicable to any household PV installation, not only on the balcony) are a subsidy but in the meantime prices came down so much that it’s not really relevant anymore. (440 Wp panels go for 60 EURO a piece and a 800 W Hoymiles inverter for around 120 so total subsidy is around 50 EURO.) Other subsidies paid for by the communal bodies are long gone. Cutting the V…

Are those retail prices? Are you buying them in a store, or what? 440Wp/60€ is only 0.136€/Wp, which is higher than the wholesale 0.100€/Wp price reported on Solarserver, but only barely. The word "diffusion" does get used in this way in English, but many native English speakers may be unfamiliar with it.

Yeah retail prices. And yes you can buy them in a store like home depot or order them on the internet but shipping is prohibitively expensive for small amounts. Cheapest source are local firms that install PV professionally and sell via kleinanzeigen.de as a side business or to get rid of excess stock.

Thanks for the clarification, also on the use of the word diffusion. In social sciences it is common though, there is even a book titled “Diffusion of Innovations”.

Re: Germany outfitted half a million balconies with solar panels

#117

Post by hedora »

melasadra wrote: post #19

Some people laugh at the 800W output. However, in Indonesia, roughly half of the 300 million people live in homes with an electricity capacity of 900W or less. Wish these kind of panels were available at that price here. We have pretty much 12 hours of sunlight every single day but household solar panel is discouraged by the state owned utilities.

The sunlight is going to follow a bell curve. Assume 800W at noon, and pessimistically approximate the curve with a triangle. That’s 400W * 12 hours. That’s 4.8 kwh per day.

If your house is provisioned for 900W peak, you aren’t running a furnace, a/c, electric heat, or an EV. 4.8 kWh will go a long way in those circumstances. (It’d handle a fridge or two if you could time shift the power, or got one that’s designed to hold cold over night with no power)

I don’t think you strictly need utility approvals to install balcony solar. Usually, you can either not wire them into the house at all, or have a switch to switch the house between grid and solar. (It’s better to back feed into the grid, but that requires utility cooperation. If properly installed the switch I describe is safe but maybe illegal.)

Re: Germany outfitted half a million balconies with solar panels

#118

Post by GaggiX »

plantain wrote: post #100
GaggiX wrote: post #82

Earlier quoted context omitted.

You are completely ignoring the biggest cost: land. In a dense country like Germany, using millions of existing, "free" rooftops is vastly more efficient and economical than buying and dedicating scarce, expensive land for an industrial-scale farm. Also rooftop solar generates power at the point of consumption. This significantly reduces the need for new, expensive high-voltage transmission lines.

A hectare of land is a few hundred euros per year to rent - https://ec.europa.eu/eurostat/statistics-explained/index.php... Power consumption in the EU has flatlined and is even falling. New HV transmission lines are not needed - put the solar farms next to some of the shut down nuclear plants (as we now do with big batteries in Australia and decrepit coal plants).

>A hectare of land is a few hundred euros per year to rent

Acquiring land-use rights, permitting, environmental reviews, and zoning changes for an industrial power plant costs far more than the raw rent.

>Power consumption in the EU has flatlined

This is dangerously short-sighted, the mass adoption of electric vehicles and heat pumps will place enormous new demands on the grid.

> put the solar farms next to some of the shut down nuclear plants

Solar is much more land demanding than what the decommissioned sites of nuclear power plants can offer.

Re: Germany outfitted half a million balconies with solar panels

#119

Post by marcosdumay »

plantain wrote: post #55

This is such a total failure of state capacity. Why can the government or industry not build solar power at an industrial scale, and then bring it to people's homes via the existing infrastructure at a price that makes this kind of micro-scale setup completely uneconomical? It's bad enough when we have to put solar panels on actual roofs to reduce electricity bills. This is just absurd. Where are the economies of sca…

The cost of solar power is close to independent of scale, so the benefit of doing those industrial scale plants is often smaller than the one for repurposing some bit of underused land.

There's nothing absurd about it.

Re: Germany outfitted half a million balconies with solar panels

#120

Post by oceanplexian »

Kim_Bruning wrote: post #27
monero-xmr wrote: post #11

Earlier quoted context omitted.

Maybe these can pull 700 watts on a sunny day? And you’d need a battery to store it. Would likely make 50 cents a day or less in electricity, on perfect days. The cost for a battery, panels, and install would be ~1000 euro (or more if it’s a bureaucratic mess).

I just did some modelling with the help of claude (which can write 200LOC+ numpy code faster than I can) 300 Euros crappy setup, 600 euros mid-range setup, 1200 with storage. (Extra) regulations is zilch, it's legal to plug and play these things up to 800W nameplate capacity. I went with numbers for mid-range, vertical south orientation and offsetting 200W (without battery, any overproduction is wasted). This nets yo…

I built one in Utah which is the only part of the US where it's currently legal, so I can give you the numbers.

- 4x Hyundai 435W Solar Panels @ 167$ each for $670 total

- 1x EcoFlow Stream Microinverter for $257.

- Various cables, MC4 crimping kit, etc.. about $150

Grand total was $1077, I set them in direct sun on my patio and have generated 6-8kWh per day. At Utah energy prices (0.12 where I live), they will pay off in about 4 years. Somewhere like California with 4x the energy prices as here, it would probably pay for itself in <1 year.

Post reply on HN