Category Archives: Energy

Intermittent versus base load when aiming for a balanced grid: a simple test

In previous post, I assumed that a grid with a base load might be easier/better than a grid based on intermittent power sources when the aim is a balanced grid. I based this on the hypothesis that in the former system much less energy needs to be displaced than in the latter, therefor it would be easier to balance.

That is something that I can check. I could put some grid data in a model and then change a parameter in order to see which one of the two is easier/better and to what extent.

Without further ado, this is what I did:

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When the aim is a balanced grid, is intermittent power easier/better than nuclear?

While cleaning up some old files, I found a link to a tweet that I used one year ago in a post on windmills “balancing” the grid. To recapitulate, during the first lockdown in Belgium, there was a lot of solar and wind power, but there was low demand. However, nuclear produced flat out, as usual. Not wanting to produce at negative prices (because of high production and low demand), windmill owners started to shut down some of their windmills. This curtailment was then framed as wind “balancing” the grid.

Below this tweet was another one written by the same author. It is his answer to the question whether there are quantified estimates on what would eventually be realistically possible with dynamic demand response:

Tweet Dieter Jong 2020-04-21

I apparently glossed over this tweet at the time I made the post, but that is an interesting question. So, in what way is that left graph easier/better than the right one when the aim is a balanced grid at all times?

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Halfway to zero: the next “half”

According to the executive summary of the Lawrence Berkeley National Laboratory study (see previous post), the US power sector emissions were already 52% lower in 2020 than projected in 2005 and therefor the US power sector has already gone halfway to zero emissions. This cheering message was shared far and wide.

Reading further than just the executive summary, the backpedaling begins. The author(s) acknowledge on the next page that 2020 is a special year and this could skew the result. There was a worldwide pandemic in 2020 that had a devastating effect on the economy. Less economic activity means less energy use, therefor a drop in emissions that would not be there if there wasn’t a pandemic. When they take 2019 as the final year (a year without the effects of the pandemic), then they find a decrease of 46%.

Okay, although that is less than 52%, it is still roughly half of the emissions.

The backpedaling continues however.

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Halfway to zero: in search of virtual emission decreases

And now for something completely different. Via Watts Up With That I learned about a Lawrence Berkeley National Laboratory study titled “Halfway to zero: progress towards a carbon-free power sector“. The conclusion of the study is that the US power sector is already halfway to zero carbon emissions. This is their overview graphic with all the gains that were made since 2005:

Halfway to zero: emissions: bau vs actual trajectory

They didn’t look at actual emission decreases from 2005, but compared current emissions to emission projections made in 2005.

They exhausted this technique in the rest of the study. Another example is the statement that the total electricity bill in 2020 is 18% less than projected. Mind you, this again is not an actual decrease. Consumers don’t see their electricity bills drop by 18% since 2005, it was projected in 2005 that the electricity bill would be higher in 2020 than what it actually was in 2020.

That is a pretty neat technique, they basically show that things could be worse and can then declare this as a gain.

I am in a cheeky mood right now, so let me try to apply this technique in my own life and see how much gain I can squeeze out of it…

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“Cheap” batteries to the rescue?

The conclusion of the report titled “Fast Erosion of Coal Plant Profits in the National Electricity Market” (see previous post) is that a surge of cheap renewable power capacity could force some coal fired power plants to close earlier. The authors attribute this to “low bids on the wholesale spot market” due to “lower operational cost”. Solar and wind are bidding at low or even at negative prices and coal fired power plants are now competing for those moments when solar and wind can’t produce (much) power, pushing those that are the most expensive to operate out of the market.

The report states a number of things that are not included in that analysis and one of them is the need for backup capacity. The report did however mention several possible backup strategies and it seems that the authors believe the most in batteries as backup strategy, although they did not look into the economic effects of this strategy. To emphasize the viability of batteries, the claim is made that batteries are among the cheapest backup sources and battery costs are expected to decline substantially over the coming decade.

There are two graphs in the report that illustrate this point. The first one is a graph comparing the average short run marginal cost of different generation types (page 16):

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“Cheap” renewables pushing fossil fuels out of the market

Last weekend, I watched a short Youtube video about the claim that cheap renewables is forcing out fossil fuels. A new report came out finding that 5 of the 16 Australian coal plants could close earlier due to cheap renewables.

Screenshot from The Agenda: Australian coal plants unviable by 2025

The lead analyst of the report made the claim that the future closures of those plants are due to a flood of “cheap” renewables. This claim was mentioned in the title, the description ánd the interview itself. They really wanted to thoroughly rub that message in…

Most members of the public would probably understand from this claim that the cost of producing electricity by renewables is so low that it makes coal fired power plants unprofitable, but it is my experience that when an energy expert claims that solar and/or wind are “cheap” that it generally means something really different from what members of the public thinks it means…

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New South Wales batteries model: the optimal balance between deficit and surplus production

In previous post, I explored the potential impact of batteries with a total capacity of 1,350 MW / 2 GWh in replacing dispatchable power sources by intermittent power sources in a grid. It learned me that the capacity of the batteries was way too small to absorb the variability of the intermittent output. Not much surplus was produced at a low share of intermittent power, but there was always a deficit. The higher the share, the lower the deficit, but also the higher the surplus production. It however took an incredibly high share for the deficit to reach zero, corresponding to very high levels of surplus production.

That made me wonder whether it would be possible to determine the point where the batteries would be used in an optimal way, meaning finding the point where there is the least amount of surplus combined with a still reasonable amount of deficit. This would allow me to determine a more realistic share of intermittent power for this battery capacity and, more importantly, how much dispatchable power would this intermittent share actually displace.

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New South Wales batteries model: balancing with 2 GWh?

In this first (late) post of the new year, I will go back to a previous post about 18 new grid batteries that might be built in New South Wales. I estimated that the capacity to be build could be somewhere around 1,350 MW.

These batteries would most probably provide frequency control as does the Hornsdale Power Reserve in South Australia. But frequency control is just one small piece in the transition towards renewables. At some point in time, New South Wales will have to provide back-up capacity when they want to increase intermittent sources and cut back on fossil fuels. That made we wonder, if NSW would like to do this backup with batteries, how far would they jump with that 1,350 MW and how much dispatchable power could be displaced? Would that solve much of the back-up problem? Or is this just akin those proverbial gnats peeing on a fire?

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South Australia, the second cheapest electricity in Australia … or the most expensive?

Previous post detailed electricity prices of four states in Australia, coming to the conclusion that the electricity prices of South Australia were without any doubt the highest of those four states. In the meanwhile, I came across several other sources that also claimed that South Australia has the highest electricity price for consumers in Australia.

Now imagine my surprise reading the last paragraph of the Wikipedia article on “Energy in Australia” (my emphasis):

It was claimed in 2017 that South Australia had the most expensive electricity in the world [50] Another analysis claimed that South Australia has the second cheapest electricity in Australia.[51]

South Australia, the second cheapest electricity in Australia?!?!

In my limited dataset with only four states, South Australia had -by far- the highest average electricity price for consumers. This means that South Australia is at best the fourth cheapest in Australia (if all other not listed states were more expensive). How does this “second cheapest electricity” claim square with being at best the fourth most expensive, possibly even the most expensive?

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South Australia, at lonely heights

It is often claimed that energy sources like solar and wind are cheap or even cheaper than some conventional power sources like coal, gas or nuclear. If this is really true, than one would expect that energy prices in countries with more solar and wind go down or at least being less than in countries powered by conventional sources. That doesn’t seem to be the case, on the contrary. I already looked at energy prices of Denmark and Germany a couple years ago. I then came to the conclusion that these two countries not only had by far the highest share of solar and wind, but also by far the highest consumer prices.

What about South Australia? It also has a high share of solar and wind, how does its electricity price for consumers compare to the other states within Australia?

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