Can electric vehicles provide some flexibility to the grid?
Can electric vehicles provide some flexibility to the grid?
The flexibilization of our consumption patterns will be key to integrating more renewables and electric vehicles could be part of the solution.
Renewables are going to increase drastically in the coming years. We have presented such a prospect in previous posts and we have highlighted the risk of price cannibalization. One way to reduce such risk is to increase the flexibility of our consumption, or in other words, to ensure that the demand follows the generation. But practically, what does it mean? And can electric vehicles be an important part of the solution? Let’s explore.
This post has been summarized in the following Twitter thread.
A week in Germany in June 2023
Let’s take the example of the week of Monday 29 May to Sunday 4 June 2023. We see that during the weekend and on Monday (an official holiday in Germany) the load is between 35 GW to 52 GW. For the other days, the load is between 42 GW and 64 GW. The maximal load is therefore around 50% more than the minimum load.
We observe that the residual load (the load minus wind and solar) is very low on some occasions. This has the direct consequence to push the day-ahead and intraday prices to very and even negative levels (especially on Monday 29 May).
A week in 2035
Let’s look at a week in 2035 according to the study from Agora Energiewende. By 2035, Germany would have 309 GW and 215 GW of respectively solar and wind capacity.
Such capacity would result in hours with peak generation above 200 GW as we can observe n the graph below. The study is presenting two cases, one with high flexibility and one with low flexibility. In the first case, we observe a maximal load above 200 GW and a minimum load of 50 GW1. For the second case, the maximal load is around 140 GW and the minimum is slightly above 50 GW.
In case the system is with low flexibility2, the level of curtailed renewables would be much higher. The white area in the figure below is showing the curtailed energy. Two things are remarkable:
With low flexibility, the quantity of curtailed power is far from negligible. Solar peaks are almost not captured by flexible consumption.
Even with high flexibility, there is still some curtailed energy. Curtailment makes only sense if the market prices are dropping to zero or below, meaning that we should expect some serious cannibalization effect, especially for solar as curtailment seems to be concentrated when solar is important.
Electric vehicles: a potential solution
A major trend that we are observing is the rapid uptake of electric vehicles. It is expected that by 2030, 30 million cars will be electric. More than half of them will be fully electric (BEV) and the rest would be plug-in hybrids (PHEV).
EU road passenger transport must reach 30m electric vehicles by 2030, close to six times more than the 5.3m registered today.
Let’s assume an average battery size of 40 kWh3 for BEV and 14 kWh for PHEV. We also assume a 60% penetration of fully electric cars. The total energy content would therefore be 888 GWh. Of course, not all electric cars would be connected to the grid. Let’s assume that 50% would be, incentivized by cheaper electricity. Then, let’s assume that they are on average 50% charged already. Practically, it means that 222 GWh could be consumed in a low price period4. Compared to the forecasted EU solar capacity of 920 GW (SolarPower Europe) or 750 GW (REPowerEU), this is only 15 to 18 minutes of peak solar production5.
Electric vehicles would be part of the solution to absorb the renewables surplus but only to a limited extent. In addition, it would require proper legislation and incentive tariffs.
In Germany, batteries of electric cars have a combined capacity above 60 GWh already and are leading by far, compared to other batteries such as home storage, industrial storage, and large-scale storage. We published a piece on large-scale storage already here.
Tariffs to enable smart charging
Nevertheless, to be able to incentivize people to consume when electricity on the markets is cheaper, dynamic tariffs must be generalized. Dynamic tariffs refer to tariffs that are set closer to the instantaneous value of electricity, for example, with an hourly price indexed on the day-ahead market. Interestingly, a front-runner in dynamic pricing is Norway, which is also a leader in electric cars.
And smart meters
But to enable the generalization of dynamic tariffs, we need to urgently roll out smart meters across the EU. Hereunder is the situation in the EU in December 2021 (be careful with the strange color coding). Some countries are well-advanced, while others, such as Germany, have no smart meter. Without smart meters, there cannot be dynamic pricing, and without dynamic pricing, there is no financial incentive for people to consume when there is a renewable surplus.
In conclusion
The need for flexibility in our consumption pattern is clear and it will only increase in the coming years. The rollout of electric vehicles can be a key solution, even though the potential is not infinite and other sources of flexibility should be used as well6. But at least two elements should happen: the installation of smart meters and the generalization of dynamic tariffs.
This is quite extreme as the maximal load is 4 times higher than the minimal load.
The system with low flexibility is nevertheless with a much higher flexibility than currently.
Battery size can vary greatly from 20 to 100 kWh.
This is relatively optimistic and should be considered as a higher range.
Producing the peak installed capacity will not happen. Most probably, the peak generation would be close to 60% of the installed capacity, meaning a potential flexible use of 25 to 30 minutes.
Electric storage, flexibility in the use of heat pumps, etc.