3 ms·

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 tur

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

filmor 8y ago
This sounds very odd to me. Most wind turbines built today with a capacity of over a few hundred kW are not synchronised to the grid frequency. They run at whatever speed they can run at with the current wind speed, which is converted to DC, goes down to the root of the wind mill and gets converted back to regular 50Hz AC when it's put into the grid. They only thing that could happen there is that this converter station blows up. Also, those modern turbines always have turnable rotors that can just be moved into a longitudinal position relative to the airflow, stopping immediately.
- hyperman1 8y ago
  My knowledge of turbines is about a century out of date, so please be so good to add everything you know to this discussion. As I understand it:. It used to be that every turbine on the grid was synchronized and people found out how the grid communicated its energy behaviour by changing frequency. This happened as emergent behaviour, almost by accident. As the grid operators came to rely on it, newer technology has to emulate it. But today, most of Europe shares the same grid, which was impossible at the time. There have to exist technological advances to make this possible. And solar doesn't even have an inherent frequency, it's DC. So what you say sounds very reasonable. But I hope never to see from close by what happens if modern energy equipment fails catastrophically.
madez 8y ago
> In practice, the non-renewable energy turbines like gas are the easiest to control so these are used to balance the grid. You can use energy from the renewable sources to charge up storage systems, which in turn can be controlled more easily. That way you achieve flexibility without relying on non-renewable energy sources.
cesis 8y ago
Nitpicking, but the easiest generation to control is hydro - few seconds to change power output dramatically. For gas it is a few minutes at least. Nuclear and coal mostly can be used just as baseload.
makomk 8y ago
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 8y ago
  > 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).

filmor 8y ago

This sounds very odd to me. Most wind turbines built today with a capacity of over a few hundred kW are not synchronised to the grid frequency. They run at whatever speed they can run at with the current wind speed, which is converted to DC, goes down to the root of the wind mill and gets converted back to regular 50Hz AC when it's put into the grid. They only thing that could happen there is that this converter station blows up. Also, those modern turbines always have turnable rotors that can just be moved into a longitudinal position relative to the airflow, stopping immediately.

hyperman1 8y ago
My knowledge of turbines is about a century out of date, so please be so good to add everything you know to this discussion. As I understand it:. It used to be that every turbine on the grid was synchronized and people found out how the grid communicated its energy behaviour by changing frequency. This happened as emergent behaviour, almost by accident. As the grid operators came to rely on it, newer technology has to emulate it. But today, most of Europe shares the same grid, which was impossible at the time. There have to exist technological advances to make this possible. And solar doesn't even have an inherent frequency, it's DC. So what you say sounds very reasonable. But I hope never to see from close by what happens if modern energy equipment fails catastrophically.

madez 8y ago

> In practice, the non-renewable energy turbines like gas are the easiest to control so these are used to balance the grid. You can use energy from the renewable sources to charge up storage systems, which in turn can be controlled more easily. That way you achieve flexibility without relying on non-renewable energy sources.

cesis 8y ago

Nitpicking, but the easiest generation to control is hydro - few seconds to change power output dramatically. For gas it is a few minutes at least. Nuclear and coal mostly can be used just as baseload.

makomk 8y ago

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 8y ago
> 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).