Be ready to read a lot about transmission lines, batteries and pumped hydro. This holy trinity is supposed to enable intermittent inputs from the sun and the wind to do the heavy lifting that coal is doing at present.
To appreciate the challenge, look at the power supply at dinnertime last night after the sun and wind achieved a record 50% of the power supply in the middle of the day. The black line at the top of the chart indicates the total for supply and demand, near 23GW from late morning until after dinner. The point of the story is that Unreliable Energy Fails in the Evening.
The inputs from the wind (green), field solar (red) and rooftop pv (yellow) grew from sunrise at 6am to the point at lunchtime when they matched the contribution from the conventional sources black coal, brown coal, gas and hydro (blue).
The chart below shows all the sources of supply up to midday. The low point in the middle of the night is about 17GW compared with 23 to 24GW at the high points during the day.
Reverting to the first chart in this post, you can see RE contributing 50% in the middle of the day and 13% – less than 3GW towards to total demand of 23GW in the evening. 87% of the supply was coming from conventional sources, overwhelmingly coal.
Grand Designs to Decarbonize the Power Supply
The grand scheme is to install some 30GW of large-scale RE plus more rooftop PV to replace 15GW or more of our existing 20-22GW of coal stations. Even at the most preliminary level of analysis you have to discount field solar by 80% and windpower by 70% but the real crunch is the next to zero level of supply for dinner on windless evenings, not to mention the situation at breakfast time.
Transmission lines, batteries and pumped hydro.
All the new capacity will be dispersed from far North Queensland to Tasmania, hence the need for massive expansion of transmission lines to get power form places where the wind is blowing and the sun is shining to places where it is not. That does not get over the common situation where the wind is hardly blowing anywhere – like the lengthy periods observed most recently in June and July.
Batteries? Tell us more about the capacity of batteries.
Pumped hydro? Where in the world can we find pumped hydro schemes operating at grid scale of production without support from conventional power?
Back to the drawing board.
PS Don’t mention grid stability issues.
Or environmental damage.
Or the massive amount of extra power required for the electric vehicle fleet.
Don’t expect cheaper power any time soon.
Liberty Quote – There is no art which one government sooner learns of another than that of draining money from the pockets of the people — Adam Smith