The Challenge Ahead For Renewables: Part 1

As we are committed by all major parties to the goal of Net Zero emissions by 2050 perhaps we need to reflect on the scale of the challenge ahead.

I shall first deal with electricity, as that is the only thing that renewables such as wind and solar can produce (except perhaps for a warm inner glow in those who love them.)

Being less of a romantic, I prefer facts and figures.  In this post I use data from the BP Statistical Review of World Energy 2021, the National Energy Market website, and by tracking down opening and closing dates for various facilities.

Figure 1 shows the total generating capacity for coal, wind, and solar electrical generation for the last 20 years.  (Gas is excluded as it makes up less than 8% of generation over a year.)  This is the maximum possible output if all plants are operating at 100% of their rated capacity.

Figure 1: Generating Capacity 2021 – 2020

Note how coal fired electrical capacity fell below 25,000 MegaWatts (MW) with the closure of power stations in SA, WA, and Victoria.  Meanwhile from a very low base wind capacity rose steadily and accelerated from 2018.  Solar generating capacity has exceeded wind since 2012 and really took off in 2019 and 2020.  Wind and solar combined now exceed coal generating capacity.

Now let’s look at how much electricity was actually produced

Figure 2: Coal Capacity and Generation 2021 – 2020

Note how coal generation is falling steadily.  The gap between generation and capacity may be regarded as wasted resources (and money).  This has remained fairly constant over the years.

Figure 3: Wind Capacity and Generation 2021 – 2020

Despite the large increase in capacity, generation is not increasing as fast.  The gap is widening.

Figure 4: Solar Capacity and Generation 2021 – 2020

Again, the gap (i.e. waste) is increasing even faster.  More on this later.

Here’s another way of looking at this problem, for solar.

Figure 5: Solar Generation as a Factor of Installed Capacity 2021 – 2020

Over the last 20 years there has been a fairly constant and close relationship between the amount of electricity generated and the installed capacity it is produced from.  This illustrates the low capacity factor of renewables.  Capacity factor is average actual generation divided by the nameplate capacity, usually expressed as a percentage. 

Figure 6: Capacity Factor 2021 – 2020

Coal has a capacity factor of between 65% and 80%.  Hydro depends on rainfall and has averaged 21% over the last 10 years.  Wind averaged 32% over the last 10 years, but solar struggles to get above 15%- mainly because it sits idle at night, there are large losses in conversion from DC to AC, and also because it produces more than the grid can handle in the middle of the day so supply is curtailed. 

Investors take heed: for every MegaWatt of solar electricity you may wish to generate, you will need to install 6.7 MW.  Every 1 MW of wind electricity needs 3.125 MW installed.  But wind takes up about 24 Hectares of land per Megawatt as against 2-3 Hectares for solar.

Figure 7 shows how much investment has been wasted over the years.

Figure 7: Wasted Capacity

Waste costs money.  In the case of wind and solar, $1.8 MILLION per MW.

I hate waste- but it can only get worse. 

Tags: , ,

2 Responses to “The Challenge Ahead For Renewables: Part 1”

  1. John in Oz Says:

    Thanks for continuing to beat your head against a wall of ignorance.

    Numbers are meaningless to the innumerate political parties.

    None of them are strong enough to go against the CAGW crowd or to go back on whatever impossible-to-achieve goal/aim they have promoted.

  2. Brian Gunter Says:

    A very good presentation Ken of the factual energy data over the past 20 years. No computer “projections” here, just historical data.

    I look forward to seeing your later Parts, particularly I hope with several different options on how the zero targets can be achieved by 2050. These options should include nuclear as well as modern coal and gas generators.

    I believe that the continued expansion of wind and solar for the next 30 years would be a disaster. Of course the big investors support wind and solar because of the huge government subsidies that guarantee their investments.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.


%d bloggers like this: