Joy for the unreliable energy boosters – but wait!

This is shaping up as a record day for solar and wind production compared with coal, aided by the lower level of demand on the weekend. Black coal is possibly at the lowest level ever at 7.2GW and brown coal is down to 2.6GW. In the last couple of years black coal has moved between 8.2 and 16.1. Brown coal  has been up to 4.7 but normally it is stable in the vicinity of 4 while black coal ramps up and down along with hydro and gas to compensate for the coming and going of the sun and wind. This is the picture this morning.

RE is up to 50% of demand and the solar component often improves after lunch. Wind is operating over 40% of capacity and contributing just over 3GW that is somewhat better than the average of  2.5. The maximum observed so far is 5GW so if the wind picks up to that level today the champions of RE will be doing handsprings.

Now for the warning. The choke point factor dictates that the grid has to have 100% of supply continuously to avoid blackouts. The sustainability of the system in the absence of coal is limited by the lowest level of RE supply – because the lights start to go when the RE supply (plus hydro and gas if gas is allowed) is less than the demand at the time.

The supply of RE at any point in time is very different from the installed capacity and it is also very different from the average (29% of installed wind capacity). The worst possible case is the limiting factor and the worst possible case is a windless evening just after dark at dinnertime (peak demand.)  As any serious wind watcher knows, the worst possible case is effectively zero RE, with the sun in bed and the wind down to 2 or 3% of installed capacity. The wind is often below 10% of installed capacity for periods over 10 hours and up to 32 hours in June and July this year.

So we will need conventional power to be available to supply 100% of demand until the very distant time (if ever) when there is a solution to the problem of feasible and affordable mass power storage.

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10 Responses to Joy for the unreliable energy boosters – but wait!

  1. MACK says:

    So what is happening to the spot prices? Is it correct that they are so low on sunny days that there is no economic case to build more solar farms? In that case we can stand back and see if investors will go for batteries or gas/coal.

  2. Rafe Champion says:

    My area of competence is wind watching and that question raises some very critical issues that I have not mastered. Be prepared for interesting times in the wind industry. One firm recently decided to give the game away. They are petrified at the prospect of living without the subsidies. Without the madate to buy RE certificates the assets would be stranded.
    The most promising development is the prospect of RE generators being forced to guarantee supply that could mean entering into contracts with coal stations to provide energy when there is not enough wind and sun! What a weird way to save the coal stations!
    Gas could help but it is next to impossible to get permission to open new wells.
    Batteries are not storage, they are local voltage regulators, people should stop thinking of them as grid scale storage.
    Watch that space!

  3. BoyfromTottenham says:

    Rafe, I just took a look at the latest annual report of the Hepburn wind farm (2 wee turbines) in Victoria.
    In FY 2018 they sold electricity valued at $1.05 million (or $91/mw), and ‘clean energy’ certificates worth $664k (or $51.00/mw, a very nice subsidy of about 63% of their electricity revenue. So they can bid to sell their electricity for almost nothing if they choose and they still earn their subsidy. This is what is driving coal generators broke – if a heavily subsidised renewable generator offers the lowest price at any time (and they do!) , all the other generators get that price during that period.
    This is just part of the dirty secret of how we regulate ‘renewables’ in Australia. The good news is that the amount of renewables (the megawatts of generation) able to claim this subsidy each year has now been capped until the LRET scheme ends in 2030. So there is now less incentive to build new renewables, except to replace worn out equipment. Unless of course the government decides that still more subsidies are necessary for some reason. Watch the Budget on Tuesday night!

  4. RobK says:

    The grid scale graphs illustrated are at half hour or longer time resolution. You can see little wiggles, mostly these are variations caused by behind-the-meter(roof top) solar. At finer time resolution and more localised monitoring these wiggles are often far more intense, particularly on intermittent cloudy days. The grid see these as massive swings in demand. It requires the addition of automatic transformers and sub-station level buffering and conditioning when RE penetration hits a critical point. Additional buffering at solar panel level is also useful.
    These are just some of the additional hidden costs of RE. More generating sources, more control gear, more regulation, more transmission capacity required . All for less stability, reliability, and safety.

  5. RobK says:

    if a heavily subsidised renewable generator offers the lowest price at any time (and they do!) , all the other generators get that price during that period.
    My understanding is that spot price market is met by the lowest bidders in a five minute block, paid at 30 minute parcels. RE comes in lowest on marginal cost every time, especially due to subsidies. The balance is generally made up by coal or gas and the last (highest) bid for the period sets the price for all in that block. So effectively the RE is paid the price of peaker power generators even though they(RE) is the cause of massive grid instability. When there is a lot of RE, the grid operator has to intervene and pay extra for spinning reserve to remain on line, so called FCAS, which is a relatively new artefact spawned by RE.
    Somehow things are supposed to be cheaper in the end, but I don’t think so.

  6. H B Bear says:

    RobK – exactly. Price is set by the marginal cost and the coal plants have no chance to earn their cost of capital (the main component of any capital intensive industry) over the day. Try explaining that to any pollie with a BA from Monash or an LLB. Might as well try and teach your dog calculus.

  7. Jonesy says:

    Why keep giving wind/solar a seat at the table. What they bring can in no way be described as dispatchable power. It can best be described as noise….random generation of unusable energy….Base load/peak load is simple math. Accommodating unreliable intermittent power requires levels of load control unheard of even ten years ago. As we create better and faster load switching and detection circuits and load up our landscape with huge roads of HT towers leading all over and every which way to interlink more and more outposts of inability..when will an engineer finally hit the reset button and question the insanity of attempting to create a better mousetrap. HINT, the cheese insn’t free!

  8. Ubique says:

    So we will need conventional power to be available to supply 100% of demand until the very distant time (if ever) when there is a solution to the problem of feasible and affordable mass power storage.

    A simple truth. Yet such is the level of misinformation about RE that very few grasp it.

  9. win says:

    If we are in an economic lock down and on week end useage what are you expecting the demand on fossil fuels to be should mr Morrisons manufacturing revolution occur and God forbid we return to full economic production.
    We are still having drying drought inducing winds in Brisbane which dry up the river dam and water features in our garden. These are periodic.

  10. cohenite says:

    Rafe, bft and robK, good comments. I can’t believe angus taylor doesn’t know this which makes him culpable; if he doesn’t know it he’s incompetent.

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