Denmark’s wind farms generated 140% power needs on July 9

[Borgholio]

http://qz.com/450737/denmarks-wind-farm ... yesterday/

An unusually windy day gave Scandinavia another chance to show off its global superiority in clean energy yesterday. On July 9, Denmark’s wind farms generated more than enough power to meet nationwide electricity demands—with a 16% surplus of energy during the day and a whopping 40% surplus overnight.

The extra energy didn’t go to waste; it was exported to Germany, Norway, and Sweden via interconnectors between the countries’ electricity grids. (The Germans haven’t always loved those interconnectors, by the way.)
Denmark’s interconnections with other northern European countries(energinet.dk (screenshot))

“It shows that a world powered 100% by renewable energy is no fantasy,” European Wind Energy Association spokesman Oliver Joy told the Guardian.

According to The Guardian, the website energinet.dk, which gives real-time breakdowns of Denmark’s energy production, showed that the country’s wind turbines were not even operating at full capacity when they generated the surpluses.

For all of 2014, Danish wind turbines, most of which are onshore, supplied the equivalent of 39% of the country’s annual electricity consumption.

If every nation was able to be as renewable as Denmark, we wouldn't have to worry about power. Ever.

[Esquire]

Well, we wouldn't on unusually windy days. What about calm ones, or overcast ones for solar systems? Wind energy is usually only enough for 39% of Danish demand, after all.

EDIT: Spelling; phones are bad for typing.

[Borgholio]

Well naturally a combination of methods is best to make up for the weaknesses of various methods, but still.... *only* 39% just from wind? If only we could be so lucky here in the US.

[Thanas]

Yeah, renewable energies have gone up massively in Europe. It is estimated that Germany for example will be able to hit the target goal of 50% by 2025(?).

[Iroscato]

My god, we're doing it. We're actually doing it...

[Sea Skimmer]

Of course this also shows just how much you have to overbuild renewables generating capacity to even think about running your grid off them, because they still need several times the capacity to actually meet the sustained demand in less then ideal conditions. And of course Denmark is ideally placed for large offshore wind turbines, with shallow seas as 75% of the national borders, conditions shared by precious few other states, but at least the damn things work at night.

[madd0ct0r]

Of course this also shows just how much you have to overbuild renewables generating capacity to even think about running your grid off them, because they still need several times the capacity to actually meet the sustained demand in less then ideal conditions. And of course Denmark is ideally placed for large offshore wind turbines, with shallow seas as 75% of the national borders, conditions shared by precious few other states, but at least the damn things work at night.

So bloody what? Coal Power plants in the UK run an average of 60% of the days of the year, meaning you need two for running your baseload grid off them, and more to cover any peaks. It's not like all other forms of power generation don't also have that issue one way or the other.

[Darth Tanner]

Just a few points but the wind was supplying 140% of the transmission demand (at 3am when demand would be lowest), not actual demand - the Danish transmission system is relatively small (peaked around 3GW yesterday) compared to actual energy demand and is heavily reliant on embedded generation below the transmission level, although a lot of that will be solar/renewable lots of it isn’t and Denmark is still heavily reliant on coal and biomass overall.

Additionally Denmark has the highest domestic energy bills in the world, all that wind has to be paid for, although the domestic market seems to subsidise the industrial customers to a much greater extent than most of the EU.

It's not like all other forms of power generation don't also have that issue one way or the other.

Although you must have spare capacity to allow for outages on conventional despatchable plant with intermittent wind you must have a completely different plan as the entire technology type will vary uncontrollably with the wind conditions. There is a significant balancing difference between having the risk of losing a couple of coal power stations due to technical failure and having your entire wind capacity at full when you don’t need it or losing it all on a winter peak.

In the UK at least wind is at a level where it is easily managed with existing balancing services (although it has increased the pressure on them) but if we were genuinely hitting 100% of transmission demand in the UK with wind alone (say 70-80GW of wind capacity) it would be unmanageable to balance that without massive redundancy.

Still a great achievement for Denmark though.

[madd0ct0r]

Why would the entire technology fail at once? The Wind isn't constant across an area the size of a country. The more sites you have, the more consistent it becomes.


I am interested in what you say about transmission energy vs energy demand - is that including biomass for heating or just local chp for things like hospitals?

[Darth Tanner]

Wind is largely consistent across large areas. Tomorrow the UK will see wind generation go from around 380MW to 6000MW in the space of a few hours because if its windy at one field its going to be windy across most of them. Although you often see wind middling around 3-4GW it tends to swing together because the UK isnt really that large in terms of weather systems.

is that including biomass for heating or just local chp for things like hospitals?

Actually ignore me! I’ve looked again at their transmission website and they are actually providing (I assume estimates) of embedded generation in not only their CHP but solar as well! Although I presume their electrical demand is being suppressed through the use of non-transmission connected assets. Denmark has massive amount of CHP burning both fossil fuels and biomass, they are only reporting 299MW of it running now but presumably this is the generation spilling out onto the transmission system rather than an actual total – either that or their CHP systems all shut down for the summer.

From today’s generation they are meeting 55% of demand with wind alone, with their conventional plant only generating 306MW… I don’t see how that is sustainable for the conventional plant unless they are mostly carrying out their summer maintenance at the moment – if they’re not getting the volumes to stay in business or a subsidy to make space for the wind then they will shut and Denmark will lose its despatchable capacity for when the wind is generating at a low level.

[madd0ct0r]

ehh, I'd bet heavily on the summer maintenance story. Same for the CHP. If you're not using the heat output over the summer it might be cheaper to buy in the leccy then keep the delivieries of woodchips flowing

[Broomstick]

Well naturally a combination of methods is best to make up for the weaknesses of various methods, but still.... *only* 39% just from wind? If only we could be so lucky here in the US.

Well, we had up to 100-110 kph winds in my area the past two days, I'm sure that generated some energy for the local wind turbines (we do have some)... but that's the other problem. There has to be a mechanism for keeping the turbines from over-speeding in such conditions.

And some days we don't have any wind.

That's the problem with most renewables - there isn't a constant and consistent supply. You lose some efficiency by trying to smooth that out.

[salm]

Well, we had up to 100-110 kph winds in my area the past two days, I'm sure that generated some energy for the local wind turbines (we do have some)... but that's the other problem. There has to be a mechanism for keeping the turbines from over-speeding in such conditions.

The blades are adjustable so that the rotor allways turns at a similar speed. Unless there is too little wind of course.

[Borgholio]

That's the problem with most renewables - there isn't a constant and consistent supply. You lose some efficiency by trying to smooth that out.

Oh sure, a balanced system is critical. Have wind turbines in places where there tends to be at least a fairly consistent breeze, solar power on rooftops and in open areas, hydro power if you happen to have the right topography in the area, tidal power if you have big enough tides... Just add in a few natural gas or nuclear plants for backup or peak power and you're set.

[Purple]

Or you could, you know go nuclear and not have to worry about plastering every millimeter of your country with the electric equivalent of one of those 1000 piece puzzle traps from Tom and Jerry.

[Borgholio]

Or you could, you know go nuclear and not have to worry about plastering every millimeter of your country with the electric equivalent of one of those 1000 piece puzzle traps from Tom and Jerry.

Don't knock Tom and Jerry.

But I agree, nuclear would be the best way to go if we weren't such pussies about it.

[salm]

Or you could, you know go nuclear and not have to worry about plastering every millimeter of your country with the electric equivalent of one of those 1000 piece puzzle traps from Tom and Jerry.

Yeah. You´d just have to worry about not getting elected and then someone else putting up wind and solar plants.

[Thanas]

Or you could, you know go nuclear and not have to worry about plastering every millimeter of your country with the electric equivalent of one of those 1000 piece puzzle traps from Tom and Jerry.

Don't knock Tom and Jerry.

But I agree, nuclear would be the best way to go if we weren't such pussies about it.

Or if energy companies like the ones of Germany and Japan had not been caught repeatedly with not giving a shit about things like security protocols.

[Darth Tanner]

There has to be a mechanism for keeping the turbines from over-speeding in such conditions.

I believe all modern turbines have the capability to either apply brakes or rotate their blades to avoid excess spin. Those brilliant photos of them bursting into fire are usually a result of their brakes failing although again most modern turbines have very high maximum wind speed tolerances.

If their generation is not required on the grid (or won't fit) they are paid to apply those breaks which in the UK is called constraint payments, I guess the US has similar arrangements.

Just add in a few natural gas or nuclear plants for backup or peak power and you're set.

Gas or diesel only I'm afraid. Nuclear is terrible for use as backup or peaker as you destroy the economics of nuclear by not getting it to output every last KWh it can as the vast majority of its costs are fixed regardless of site output... most older reactors are also pretty limited in ramping capacity... some of the geriatric UK fleet can take several days to get to full load.

[Borgholio]

some of the geriatric UK fleet can take several days to get to full load.

That long? You mean they can't simply retract some of the control rods and start heating up steam?

[madd0ct0r]

funnily enough, I think getting huge generators up to full speed from stationary safely might be more complex

The other issue is, as Darth Tanner said, a nuclear power plant continues to cost money by just existing. Any day it isn't making money by generating electricity it's losing money.

[Darth Tanner]

Our oldest unit is Wylfa and she is 52 years old, to be fair she is closing this winter but it took her 3 days to increase load by 200MW last week - a lot of that is likely because she is so old and obsolete (being the last standing MAGNOX plant) that her management are being very gentle with her. The newer AGR/PWR designs can likely achieve several hundred MWs a minute (I think 7% of capacity/minute is industry standard on modern designs) ramping speeds though but economically they don't want to as anything but maximum output is wastage of capacity.

[Borgholio]

Yeah I didn't expect to be able to do it instantly but slowly ramping up the power over the course of an hour or two doesn't seem unreasonable to my (admittedly) untrained eye. Good point about the cost though, nuclear fuel decays even if not generating electricity.

[Darth Tanner]

Its not really the cost of the fuel... its the cost of your reactor building itself, all your staff and safety inspections & licences, your armed police units, your fuel depo and storage facilities and financing costs on top of all that. Actual fuel is pretty much irrelevant to nuclear, I think it makes up less than 1-2% of the MWh export cost on most plant operations.

I suppose thats another reason not to use nuclear to backup wind... you would be much better off just not having the wind and using the nuclear flat out. Like France.

[Broomstick]

Well, we had up to 100-110 kph winds in my area the past two days, I'm sure that generated some energy for the local wind turbines (we do have some)... but that's the other problem. There has to be a mechanism for keeping the turbines from over-speeding in such conditions.

The blades are adjustable so that the rotor allways turns at a similar speed. Unless there is too little wind of course.

There is also a mechanism to "feather" the blades so they don't turn in the wind, usually used for when the thing is off-line for repairs/maintenance/whatever.