Thread: Grid can go 75% renewable

Ask the Californicationers what they think about renewable energy now.
Regards PhilipA

not mine but sums up my thought nicely

If you like to have hot coffee in the morning and a hot dinner at night you had better be thankful that there is enough conventional power available because your coffee and your dinner would be cold if we had to depend on the wind and the sun to heat them.
Four factors make it hard for RE to work in Australia. First the frequent and prolonged wind droughts (see June for example) and also WA, SA and Victoria today. Second is the “choke point factor’ that means the sustainability of RE is limited by the lowest points of supply, not the installed capacity, the high points or the average (think about our need for a constant supply of air to our lungs and what happened when we are choking or drowning). Third is the island effect, we have no neighbours to help out if we are short, unlike most places in the developed world. California has rolling blackouts but it will not go completely black because it is not an island. Finally, there is no grid scale storage in sight for the foreseeable future. Please don’t refer to the Tesla batteries as storage at grid scale. And pumped hydro? Believer it when you see it

Australian coal plants 'on a hiding to nothing' and likely to close before schedule | Energy | The Guardian

Soooo.
we seem to want rolling blackouts like California then. A new warning was issued Yesterday.

The problem is that it is hot in other states so they cannot do the usual sleight of hand and import power from Arizona etc.

Renewables are Ok if you have a backup gas or coal or nuclear to bail you out. And California is planning to close existing gas plants because they use seawater for cooling. CRAZY STUFF!

BTW I am not going to subscribe to the Guardian in a million years. Let them go broke.
Regards PhilipA

I'm struggling a bit to square the Guardian's comments about coal fired power stations being on a hiding to nothing when I see that in 2018, Queensland's (largely coal fired) state owned power stations paid dividends to the Qld government of 1.65 billion dollars.

I have scanned the report to which the Guardian article refers. It largely takes as a given that older coal fired plants will retire 'as scheduled' and then discusses how the grid might respond to the problems caused by an increased reliance on intermittent renewables, including the need to manage demand, increase energy storage and replace the frequency control supplied for free by spinning turbines in fossil fuelled power stations. In fact it rather highlights the problems that an intermittent supply of electricity places on the grid. As one might expect it takes a fairly optimistic view of how this would be resolved, but provides no costing on what the replacement of services like guaranteed availability and frequency control that come from thermal power plants will be. I guess we'll find out whether the technological optimists are correct over the next decade or so!

This is a bit of a surprise.

Queensland top state for breakdowns of fossil fuel power stations | Mirage News

Originally Posted by Old Farang

Several years ago I read about what happens in power station control rooms in the UK when there is a sudden demand. The scenario was when there was a major football match, such as a final being broadcast. As soon as the match finished the millions watching it on TV made a dash for the kitchen and turned on their electric kettles to make a cup of tea. Oops!

With a conventional thermal power station you can keep units running on low load ready to take up the surge, but unless you have a direct line to the almighty, that is going to be a problem with a wind farm.

I posted previously about the lack of "inertia" in a grid relying on both wind and solar, and it is still a problem.

Its interesting. France is about 70% nuclear but is aiming to reduce the need for it to 50% by 2035. German has gone from over 20% nuclear to just over 10%. nuclear is very stable output as ramping up or down is not the done thing with that generation.

Love your kettle comment. My work kettle, microwave on top of all my computers, lights and AC turning on at 8am every day was a drip to far if my Hot water service kicked in . I added a timer to the hot water service so it can only come on at midnight. Coal fire power is dead/dying here and elsewhere.



RE your comment batteries are cheap for storage Mick. Not really true I think. The South Oz ones for example are expensive short term minnows. That said a big school of minnows can be rather large. SA on that one with a 18 million investment in a Virtual power plant mad up of hundreds of Solar PV and Batteries they have a hand on.

I like my batteries as a back up. Suspect I will add another 5kws to make a 10kw Solar PV and be off grid most days at work soon. It pays for it self very quickly if you self consume all or most.

It doesn't really matter what fuel is used in a thermal power station; coal, gas, nuclear, wood chips, cows farts or whatever will burn. In all of them the energy conversion is to produce steam, which in turn is used to drive a bloody great rotating mass configured as an electrical generator.

As a big rotating mass it possesses a lot of inertia, which directly influences stability, resulting in the ability to absorb grid surges and sudden fluctuations. There also seems to be a lot of misunderstanding about grid frequency. EVERY AC generator connected to a power grid, be it a couple of diesel generators in an outback town off the grid, up to multi MW grid power stations, HAS to run at the SAME frequency, as once connected they are all synchronised by by the simple rotating rising and fall of the voltage, know as a sine wave. They will all stay synchronised regardless of their actual load output, even to the point of becoming a motor if their energy input is less than that required to output power into the grid.

The point here is that the present state of both solar and wind generation does NOT possess these attributes, and will rapidly disconnect to protect the equipment, which has been proven the case in many countries that have big solar, and more particularly wind powered grids.