Germany has too many solar panels, and it's pushed energy prices into negative | Hacker News Reader

Germany has too many solar panels, and it's pushed energy prices into negative

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9 pointsrustoo11 comments

Is this a real research group?

The use, twice!, of the phrase "biiiig, cheeeap grid batteries" in a research report would make me doubt their credentials.

Plus it's just a weirdly rephrased take on the duck curve that people have talked about for over a decade. Here's a 2017 presentation on how to respond to it.

https://www.energy.gov/eere/articles/confronting-duck-curve-...

Sort of real. It's the research desk at a bank.

Sorry, for an obvious question to those who will answer, but does Germany not have energy interconnects with neighboring countries or do all those countries face the same issue of excess capacity?

Germany does share an electricity market with its neighbours, you can see the live import and export e.g. here: https://www.iea.org/data-and-statistics/data-tools/real-time....

Currently, Germany is averaging around 6.4 GW of imports and 3.2 GW of exports. During production spikes caused by e.g. wind or solar power, the price quickly drops in the whole region, sometimes into the negative in order to help stabilize the grid frequency.

World needs pillar batterys. Basically vertical drilled tunnels, that store energy as a liquid under pressure, by lifting the core of the tunnel.

Is that any better than a simple gravity battery? Because while those are very cheap, the people who complain that renewables have a low energy density will faint and/or explode when they discover how low-density gravity storage is.

That's a cute idea but it does not work, if you run the numbers.

The formula for potential energy is mgh, where m = mass, g = gravitational acceleration (approx 10 m/s2) and h is the height.

Let's say the vertical tunnel you want to build is 200 meters deep and 1m by 1m. Half of the shaft is rock, it's the thing you lift and lower. That's 100 m by 1m by 1m, which means 100 m3. You use lead, which has a density of about 11 tons/m3. Let's round to 1000 tons, or one million kg. Moving this column of lead from the lowest point to the highest requires the energy of mgh = 1 million times 10 times 100 = 1 billion Joules. Divide that by 3600 and you get about 280 kWh. For comparison the battery of a Tesla S has a capacity of 100 kWh.

I live near TVA's pumped storage facility at Racoon Mountain[1]. Until a few years ago, it was "the largest battery in the world" based on ability to store kWHs.

This one facility helps stabilize an entire xxGW US region's grid.

[1] https://en.wikipedia.org/wiki/Raccoon_Mountain_Pumped-Storag...

As both a geologist experienced in drilling and a geotechnical engineer specialised in geomechanics - this isn't nearly as clean, manageable, or good an idea as you think it is.

The best kind I saw is the sand battery, storing energy as heat : https://polarnightenergy.fi/sand-battery

Batteries

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