96% renewables possible

 From a Twitter thread by David Osmond, a wind engineer at Windlab

A common riposte by fossil-fuel spruikers to claims that we can get  to 100% renewables is that it is impossible.  David Osmond has done a simulation using actual data for wind, sunshine and demand in Australia's NEM (National Electricity Market) over a 3-year period which shows that we can get to 96% (including existing hydro) without difficulty.  The precise numbers will differ for each genertion region, but in principle, this analysis implies that similar percentages can be reached in any continent-wide grid.  ("Island" grids, i.e., grids not connected to other geographies, will require more storage)

Summary of my 96% renewable NEM simulation, as presented at ANU's 100% renewable workshop.  My data is based primarily on actual wind & solar generation data, using 3 yrs of data at 30 minute resolution.  It uses 24GW/81GWh of short-term storage plus Snowy2.0. 

Actual wind and solar generation has been scaled up to 38 GW of wind, 16 GW of utility PV and 35 GW of rooftop PV.  Also assumed a completed NSW-SA interconnector, Stage 1 of the Marinus cable to TAS, and the medium upgrade of the NSW-QLD interconnector. 

The remaining 4% came from "other".  In the short to medium term, "other" is likely to mean gas or demand management.  But in the longer term it could transition to biofuels/biogas, long-term storage such as Tasmania's battery of the nation, or a hydrogen based source.

During days of poor wind and/or solar resource, existing hydro and/or Snowy2.0 is run hard, which makes up much of the shortfall.  "Other" is used to fill the remaining shortfall. 

For the 24GW/81 GWh of short-term storage, it's worth noting that we already have ~1.4GW/25GWh from the existing pumped hydro projects at Tumut3, Shoalhaven & Wivenhoe.  The remainder could come from 3 million residential batteries and a small fraction of an EV car fleet. [On my (NPT's) calculation this is about 4 hours of storage]

QLD is a particularly important state, due [to] the relatively good performance of its wind on calm wintery days in the southern states. Its solar also performs relatively well on those days too.

Finally, note the negative correlation between Mt Emerald wind and solar/wind in every other state, at both 30-minute & daily timescales.  Nth QLD is particularly important to a mostly renewable NEM!

The full presentation is available at ANU's 2020 100% renewable workshop webpage.

One more tweet for @simonahac  & @gnievchenko

 A graph of the curtailed generation.  If we were able to send the curtailed generation to a hydrogen electrolyser, then the 2nd graph shows the capacity factor of that electrolyser, and how much of the curtailed power it could use.