Eternal Sunshine?
Ember really did it — they flattened solar with batteries. But it’s not enough.
The data and policy thinktank Ember sets the standard these days for good faith, inclusive clean energy analysis. While understandably saluting the particular progress of solar and wind, Ember does not disparage any other energy sources. Nuclear energy gets as fair a hearing as hydro.
Recent work featured the combination of solar and battery capacity necessary for high capacity, highly reliable supply in a selection of sunny locations.
Make sure to give it a read.
Solar electricity every hour of every day is here and it changes everything would be improved by including these two things:
1. A location in Australia
The latitude of Johannesburg is 26° South. In Australia, 240 kilometres inland from Brisbane, the 400 megawatts (MW) of solar at the Western Downs Green Power Hub is at 27° South. The total project cost is $600 million AUD and includes a 540 MW, 1,080 megawatt hour battery system. Project planning began in 2018, with operation planned for next year (8 years).
Fifteen Western Downs Green Energy Hubs would represent a total of 6,000 MW of solar plus 16,200 MWh of energy storage, matching almost exactly the capacity modelled by Ember, for $9 billion.
They would require 1,545 × 15 = 23,175 hectares in total, about the size of Lake Pedder.
$9 billion and over 230 square kilometres to potentially yield 1 gigawatt of flattened solar power for something like 95% of the year, subject to local weather. In Johannesburg, Ember estimates the levelised cost of electricity at $106/MWh (USD), equivalent to AUD $162/MWh at recent average exchange rates.
2. Lifecycle emissions
As explained in Carbon Neutrality in the UNECE Region: Integrated Life-cycle Assessment of Electricity Sources:
Most of renewable technologies’ GHG emissions are embodied in infrastructure (up to 99% for photovoltaics), which suggests high variations in lifecycle impacts due to raw material origin, energy mix used for production, transportation modes at various stages of manufacturing and installation, etc.
“Solar only” produces lifecycle emissions of about 37 gCO₂eq/kWh according to the UNECE report (with a regional variation range of 23 to 82).
“Solar with battery” consists of more material, so is obviously higher. Significantly higher? Well, that’s the big question.
Literature on this topic is shamefully sparse, as examined in a comprehensive 2020 article in Sustainable Materials and Technologies. The most detailed work reviewed by the authors was from 2016, and included a “PV Self Consumption” scenario modelled on approximately 3.5 kW of solar alongside 8 kWh of battery capacity.
At this lower proportion of battery storage — assuming lithium iron phosphate chemistry — lifecycle emissions were determined to be 150 gCO₂eq/kWh.
Likely, it will be higher with a larger battery size. Conversely, efficiency and emissions intensity of manufacturing has possibly improved since 2016. When the whole point of improving the performance of solar energy is to cut emissions, it’s quite important to know. The EU politicians who protested the limit of 100 gCO₂eq/kWh, proposed for the taxonomy for sustainable investments, would certainly be interested:
Even though facilities emitting less than 100 gCO₂eq/kWh are contributing, it is not correct to claim that they are contributing substantially to meeting the climate change objective. The requirement for a facility to be contributing substantially needs to be strict enough to compensate for the part of the energy sector which is emitting above the average now and in the future. Otherwise, the average emissions from the sector will not fall below the curve and the goals will be missed.
So, let’s hope the next edition from Ember addresses these gaps. There are definitely other issues with the report, but these are the main two.
Oscar Archer holds a PhD in chemistry and has been analysing energy issues for twenty years, focusing on nuclear technology since 2014, with a background in manufacturing and QA. Sometimes he helps out at WePlanet Australia. Find him @OskaArcher on Twitter.
