
It’s always windy somewhere: Balancing renewable energy in Europe (2017) - Tomte
https://arstechnica.com/science/2017/07/its-always-windy-somewhere-balancing-renewable-energy-in-europe/
======
Animats
Wind enthusiasts keep making claims that if only they could average wind over
a huge area, it wouldn't be intermittent. But when you look at wind power
generation data for huge areas such as the CAISO (California, Oregon, etc.)
control area or PJM (New England to the Midwest), it doesn't work that way.

Here's PJM's actual wind power generation for the last 24 hours.[1] Peak,
2300MW. Valley, 250MW. A 9:1 range. Those are real numbers from real wind
turbines connected to a huge real world power grid. Today is a bad day; about
4:1 variation is normal. CAISO has similar numbers.

[1]
[https://dataviewer.pjm.com/dataviewer/pages/public/windpower...](https://dataviewer.pjm.com/dataviewer/pages/public/windpower.jsf)

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icc97
> As a result, for solar to balance out the variability of wind, European
> countries would have to install ten times the existing capacity.

> The authors consider that level of expansion unlikely, which is why most of
> the analysis is focused on wind.

Is this really so unlikely? The amount of Solar panels in use now seems so
pitifully tiny and the cost of installing them is only going downwards as well
as their power output going upwards.

I guess the article means that it's unlikely by 2030, but I think a 10x
increase in Solar power is more likely than somehow the Balkans and the North
Sea countries magically balancing their different power loads.

~~~
alephnil
One problem with solar in Europe, especially in Northen and Eastern Europe,
where heating in the winter dominate consumption, is that almost all solar
potential is in the summer, when less electricity is needed. This is basically
a result of the Northern latitude of Europe (Madrid and NY has about the same
latitude).

For wind it is the opposite. Wind is strongest in the winter when the
consumption is highest. This makes wind a much more attractive option in
Europe than solar, given that electricity can't be stored easily at grid
level.

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onetimemanytime
dumb question on power producing /usage: say that Germany (and countries
linked to it's power lines) produce 100 units of energy but only 95 are used
that moment /day or whatever. What happens to the extra power? Where does it
go? I understand that they try not to overproduce but I'm sure it happens

~~~
hyperman1
That's actually a very good question. My understanding is incomplete, but this
is what I make of it:

What you suggest turns out to be impossible. The amount of energy that goes in
and out must be identical. So this means:

* Either less goes in: The required mechanical effort to make the turbine turn goes down. It will have to dissipate the extra energy as heat and catch fire, or it will become less efficient, and have stronger winds behind it as less wind energy has been used.

* Or more goes out: The transparting cables are not perfect, they are a kind of very low resistor. They do convert electricity to heat. A short is an extreme example of this. In this case, a smaller version will happen: cables will get slightly hotter.

As I understand it, monitoring and balancing the electrical grid is a very
complicated problem.

Recently, and discussed on hacker news, the opposite happened in Europe: Not
enough power was available on the net because of political circumstances. All
the generators had to push a little harder, so they all slowed down a tiny
bit. Result was the 50HZ of the european grid went a very tiny bit down to
49.999...Hz, and some clocks lost 6 minutes of time as a result.

~~~
hyperman1
A small appendix: This is what would happen if nobody controls the grid. Of
course, humans and automatic systems do control the grid.

So if you have a gas turbine, and you see it slowing down, you feed it a
little more fuel and vice versa.

Unfortunately, solar and wind energy make this impossible. So for wind, the
turbine has brakes, but there are videos on youtube where they fail or get
overloaded, resulting in burning turbines. I guess solar does something
similar (Edit: the braking not the burning of course).

In practice, the non-renewable energy turbines like gas are the easiest to
control so these are used to balance the grid.

On top of all of this, running a turbine costs a lot, so there is a lot of
grid management going on to decide who can generate which amount of
electricity. Decisions made at this level better match the actual load on the
grid, or the catastrophic consequences of the post above happen.

Brning turbine:
[https://www.youtube.com/watch?v=6y1Ib0GM5x8](https://www.youtube.com/watch?v=6y1Ib0GM5x8)

~~~
makomk
Wind and solar is actually pretty easy to throttle back in principle; wind
turbines need to have braking capabilities anyway in order to handle high
winds, and you can literally just stop drawing current from solar panels
whenever you like. The reason this doesn't happen in practice is mainly one of
policy: we want to use wind and solar rather than fossil fuels, so they have
priority when selling to the grid and non-renewables either have to shut down
or pay penalties for not being able to do so fast enough in the form of
negative energy pricing. This pushes up the cost of non-renewable generation
which has to be made up for by charging more for it when it's needed, driving
up the overall cost of electricity for consumers. (This is why Germany has
both negative electricity prices at the wholesale level and some of the
highest consumer electricity pricing in the world.)

EDF were talking about possibly needing to change this in France in the
future, since otherwise their heavily nuclear-based power grid couldn't cope
with the increased levels of highly variable renewable power they're
predicting. The nuclear plants just can't adjust their output power fast
enough or deep enough.

~~~
cesarb
> Wind and solar is actually pretty easy to throttle back in principle; wind
> turbines need to have braking capabilities anyway in order to handle high
> winds

Also, many wind turbines are variable pitch: the angle of the blades can vary,
so the controller can put them in a less efficient position to reduce the
turbine power, or "feather" them to produce no power (the brake is also used
in this case to completely stop the rotation).

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spodek
Another way to help is for users to conserve energy. Most people and companies
can reduce their consumption while gaining quality of life by paying more
attention to their use.

While conserving doesn't solve everything, it seems an essential part of the
strategy.

~~~
eesmith
Amory Lovins' "negawatt power"
[https://en.wikipedia.org/wiki/Negawatt_power](https://en.wikipedia.org/wiki/Negawatt_power)
.

In his 1985 book he "argued that utility customers don’t want kilowatt-hours
of electricity; they want energy services such as hot showers, cold beer, lit
rooms, and spinning shafts, which can come more cheaply if electricity is used
more efficiently."

