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This picture has been floating around the internet

enter image description here

On May 8th, 2016, Germany's solar, wind, hydro and biomass plants generated so much energy, power prices actually went negative.

Is this true? I was under the impression that while renewable electricity production was on the rise it still was nowhere near enough to meet the needs of a major nation. Also, if this claim is true, how much power was produced by non-renewable means on that date?

Sklivvz
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David says Reinstate Monica
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    Note that the claim is that power (i.e. electricity) prices went negative, not "energy prices". They're different. Electricity is a minority of energy consumption. – 410 gone Jun 02 '16 at 05:35
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    Overproducing energy at a single day doesn't mean that the energy production meets the needs of a major nation. – Christian Jun 02 '16 at 08:59
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    @EnergyNumbers I know most vehicles can't use mains electricity, but I assumed most other energy consumption could. What's the actual situation? – Andrew Grimm Jun 02 '16 at 10:24
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    @AndrewGrimm in Germany, electricity is about 15-20% of primary energy consumption (as it is in Australia) – 410 gone Jun 02 '16 at 10:30
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    @Christian It wasn't even an entire day, just during the hours of peak solar input (at the longest). Getting adequate power at night is still a huge problem. – wedstrom Jun 02 '16 at 22:17
  • Reportedly it [also happens in Chile](http://www.bloomberg.com/news/articles/2016-06-01/chile-has-so-much-solar-energy-it-s-giving-it-away-for-free) — though part of the cause is inadequate transmission infrastructure. – 200_success Jun 03 '16 at 07:28
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    This is a self limiting problem; firstly there is equipment on the market that will convert excess electric power into gas that can be put into the gas grid. Then we have lots of users of heat (swimming pools, paper factories etc), that could heat with electric power if it was often cheaper then gas, switching between the two sources of heat. So if the cost of buying electric becomes low enough for a reasonable number of days each year, a market will be created for it. – Ian Ringrose Jun 03 '16 at 09:57

1 Answers1

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This is pretty much true, and has happened multiple times in the past. In fact, they were introduced in the German intraday market in 2007.

For example, the same situation occurred in May 2014, when prices for energy became negative.

enter image description here

However, the reason that renewable energy had temporarily negative prices is that it is difficult to store energy, and that only a limited proportion of excess energy can be exported due to transmission capacity constraints.

Power has to be used as it is generated, and many power plants cannot be stopped temporarily without large losses to efficiency and incurring significant costs. In those cases, the power plant operator may choose to pay for power to be consumed, in order to not have to temporarily shut their power plants down.

The EU commission document explains this:

The frequency of occurrence of negative price episodes rose in the last part of the observed period as the costs of ramping up or down of some conventional plants are significant.

Regarding your second question, according to EnergyTransition.de quoting Agora Energiewende, the renewable power production reached 95% during noon on 8th May 2016, driven by the massive amounts of solar energy production.

enter image description here

March Ho
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    Some words about WHY: As you wrote, you can't simply shut down a conventional power plant just to switch it on a few hours later again. But you can easily shut down wind plants, and solar cells even don't care if the power isn't consumed. BUT a law to support reg. energy (EEG), says ([§8](https://dejure.org/gesetze/EEG/8.html)): _The grid has to privilege power from reg. energy over conv. energy, and it always has to take all available power from reg. energy_. The grid even can't ask the plants to reduce their power output. – sweber Jun 02 '16 at 07:28
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    @sweber Thanks for the link, but it seems that the law linked is "außer Kraft" which from my limited knowledge of German, means that it is no longer in effect? – March Ho Jun 02 '16 at 07:31
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    @MarchHo: Yes and no... This law changes all few years, and I didn't notice. Sorry for that. The most recent version is EEG2014, and the old §8 now is [EEG2014 §11](http://www.buzer.de/gesetz/11230/a188269.htm) And §14 now says the grid can now also ask _larger_ reg. energy plants to reduce power output, but latest one _day before_. So the situation isn't that serious any more, but it's still existing due to the limitations. – sweber Jun 02 '16 at 08:06
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    Note: what went negative are not prices for renewable energy (those have minimum price guaranteed by state), rather prices of energy in a general market. See https://en.wikipedia.org/wiki/Feed-in_tariffs_in_Germany The minimum feed-in prices is about 9 EUR / MWh. – Suma Jun 02 '16 at 11:46
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    @sweber am I understanding correctly that "reg." is an abbreviation for "renewable"? – Dan Getz Jun 02 '16 at 13:02
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    @DanGetz: Yes, I meant "regenerative", though the correct english term is "renewable". – sweber Jun 02 '16 at 13:12
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    @DanGetz "reg." is the abbreviation for "regenerativ", which is the "German" word for "renewable" in energy context, yes. – Alexander Jun 02 '16 at 13:14
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    FYI I have a whole solar roof in Germany. At peak production the take-up by the electricity company is capped at 80%, because otherwise they have too much. This is one reason I am getting batteries, to keep my wasted 20%. – RedSonja Jun 02 '16 at 13:26
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    So how long until we see businesses that exist only to operate resistor banks? – user253751 Jun 02 '16 at 20:14
  • If the price is negative, and I have a solar roof, does that mean that the power company will charge me for supplying power into their system at that time? – Dan Henderson Jun 02 '16 at 22:16
  • Was this even solely attributable to renewables? This article suggests that a lot of renewables and COAL plants came online in 2014, and I imagine its much harder to shut down a coal plant than wind: http://www.bloomberg.com/news/articles/2014-06-26/germany-s-new-coal-plants-push-power-glut-to-4-year-high – Andy Jun 02 '16 at 22:22
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    "the power plant operator may choose to pay for power to be consumed" Say what? Do they just call up a really energy intensive business, like a factory and ask if they would like their ventilation systems powered? – Amani Kilumanga Jun 03 '16 at 00:40
  • @DanHenderson It means you power company will pay for the power their system supplied. Whether they charge you for it is up to them. – user253751 Jun 03 '16 at 07:10
  • @amanikilumanga That would not work. Because the energy intensive business needs a contract for energy that spans more than a day. – Taemyr Jun 03 '16 at 07:11
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    @AmaniKilumanga They probably do do that - or the business has a live feed of power prices and does it themselves. I know really energy-intensive businesses (like aluminium smelters) will lower production when power prices rise and pick it back up when they fall - this would just be a continuation of that. – user253751 Jun 03 '16 at 07:14
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    Based on the comments, and the misleading wording in the claim, do you think it is worth explicitly mentioning who is "paying" these negative prices, and that it is NOT the consumer. – Oddthinking Jun 03 '16 at 13:49
  • This answer continues the confusion between "electricity" / "energy" language. Try to get a negative price on gasoline. – Fattie Jun 04 '16 at 17:18
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    Why can't the power plant just build a giant laser and shoot excess energy into space? – John Dvorak Jun 06 '16 at 07:11
  • @AmaniKilumanga that's what an electricity spot market is for, Electricity is traded in (IIRC) 1MWh blocks at the Leibziger stock market. – mart Jun 08 '16 at 07:02
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    @JanDvorak they could if they wanted to but the return on investment is low. They could also use pumped hydro, a battery bank to store the energy. Maybe on this day Goldisthal Pumped Storage Station was able to buy electricity for negative money and then sell it later for positive money, win win! – daniel Apr 21 '17 at 13:56
  • I'm pretty certain that the moment a power station is having to pay to give electricity away the cost of their doing so is going to fall on the consumer. So, negative energy prices would mean ... higher energy prices. That's why the grid should be allowed to buy from whomever it wishes, and would probably favour whoever can provide a stable baseload; instead of being forced to prefer suppliers that tend to provide unpredictable slumps and spikes. – Grimm The Opiner Apr 01 '19 at 11:26