I am in the camp of those expecting that Investor Day will be about Master Plan Part Troix, i.e. how to scale for a global transition to renewables. So far, I abstained from such speculations but
@wdolson wrote in a
post in the Russia/Ukraine thread [emphasis mine]:
Europe has some pretty significant challenges converting completely to renewables. I don't think they can do it without also adopting nuclear power.
[...]
The cost of installing enough renewables to serve all of the UK at a level of 50KWH per person per day had dropped from 93K Euros to 18K Euros.
My immediate reaction was like "We're a household of 3 with an electric car and we use less than 15kWh per day on average. This 50kWh number has to be the entire country's consumption divided by # of UK citicens".
Living in Germany, I was curious now how my personal use of electricity compares to the entire country's consumption divided by headcount.
Gross electricity consumption in 2020 for Germany was 559 TWh per [1]. In the same year, Germany had 83.1 million residents.
That equates to 559 billion kWh / 83.1 million / 365 = 18.45 kWh per person per day or about 6.700 kWh/year.
According to [2], private households consume about one quarter of all electricity and other sources saying that the average private use of 1300 kWh per year and person corroborates that.
Renewables contributed 246TWh or about 50.5% of electricity generation in Germany for the year 2020 (down to 47.5% in '21). Renewables need to roughly double in order to fully replace non-renewables. Btw, nuclear contributed 12.5% in '20 and 13.3% the year after.
All of the above is just the tip of the iceberg if we look at overall energy consumption. According to [3], Germany's gross overall energy consumption in 2020 was 11.504 PJ (Peta Joule). According to [4], industrial use was 3.747 PJ, out of which 12% or 448PJ were used as feedstock to chemical processes. If we put these aside to be tackled later, this leaves us with 11.056 PJ used for energetic purposes. To get the delta, we can also subtract half of the 559 TWh = 276,7 TWh renewables. We all know that 1TWh = 3.6 PJ. With that, I calculate 996 PJ of renewables in '20 and a remaining 10.060 PJ of fossil (and nuclear) sources to replace.
As we're talking about gross electricity, we can assume 100% efficiency for renewables. For fossils, efficiency varies widely. Thermal power plants can have a thermal efficiency around 40% and more if waste heat is used for heating purposes. In everyday use, cars tend to be in the low 20s if one doesn't go with official but looks at actual fuel consumption. A lot of gas is used directly for heating, be it domestic or in industrial processes. Heat pumps produce between 2 and 5 times the invested electrical energy as heat.
With considerably more research, it might be possible to calculate how much electricity would be needed to replace all fossil energy but an average factor of 33% should be at least in the right ballpark.
With that, we have to generate an additional 10060/3 = 3353PJ = 931 TWh of renewable electricity to match Germany's energy consumption in 2020.
TL;DR; Renewables covered about 21% of all energy needs in Germany in 2020 if we assume that 1 kWh of electricity can displace 3 kWh of crude fossil energy. In other words, we need about 5x of today's renewables for a full transition.
Is this achievable? I did not investigate but there's a lot of untapped potential for onshore wind, domestic and grid-scale PV and offshore wind is only a matter of funding.
How many batteries will be needed?
Tony Seba calculated 110 hours of storage for a least cost solution at 400 GW of installed renewable power [5]. We had 63MW of wind and about 50 MW of PV in 2020. If that were equally scaled by 5x, we may need less storage. Vice versa, his demand for 400 GW looks reasonable with additional storage in place as surplus capacity today gets sold or wind power is shut down.
Therefore, I won't come up with my own calculation but consider his 6.2 TWh demand for storage (in Germany) to be a good estimate. As he demonstrates, the amount of storage for a least-cost solution depends on local availability and variability of wind and solar. Therefore, it's not easy to extrapolate global demand from the case studies in his presentation.
My hope is that investor day will be used to share Tesla's plans for this decade and the 2030s with respect to installing production capacity, sourcing raw materials and how to address any other challenges that they identified.
[1]
Stromverbrauch
[2]
Anteil am Stromverbrauch nach Sektoren in Deutschland 2021 | Statista.
[3]
Indikator: Primärenergieverbrauch
[4]
Energieverbrauch in der Industrie 2020 um 1,9 % gegenüber dem Vorjahr gesunken
[5]