Series of articles: The Path to Climate-Neutral Heavy-Duty Transport – The symbiosis of MCS charging and photovoltaics – What is possible?
To achieve Germany’s climate protection goals, emissions from heavy commercial vehicles must be reduced to net zero by 2045. With increasingly powerful batteries, a growing charging infrastructure, and rising economies of scale, the conditions are favorable to initiate the transformation towards climate-neutrality in the heavy commercial vehicle sector. This transformation is no longer a niche topic. The logistics industry is deeply engaged with the transition and is awaiting the entry of climate-neutral vehicles into the mass market.
The transformation faces both technical and infrastructural problems as well as energy and economic challenges. On the technical and infrastructural side, the primary issues are the lack of charging infrastructure and the associated speed of energy infrastructure expansion. Economically, the high initial investments for infrastructure and vehicles are the biggest obstacles. However, there are ways to address these challenges. Optimized, bidirectional charging at depots can help reduce costs. Additionally, the symbiosis of PV systems and public charging during midday presents a promising solution to meet charging needs.
In this five-part series, we will delve into various aspects of the transformation to a climate-neutral commercial vehicle sector, focusing primarily on battery-electric commercial vehicles.
Articles:
- Ramp-up pathways to climate-neutral heavy-duty transport
- Fast-charging infrastructure in Germany – Needs and potentials
- The symbiosis of MCS charging and photovoltaics – What is possible?
- Down with the Cost – Bidirectional Charging in a Truck Depot
- The future of climate-neutral commercial vehicles
In the previous parts of this article series on heavy-duty electrification, we outlined the future requirements for charging infrastructure on the path to climate-neutral heavy-duty transport along with the challenges involved. In addition to the required energy, the resulting peak load resulting midday from fast charging processes is going to be a significant challenge facing the energy system. The charging pattern, which involves charging the required energy at midday during pauses, results in a typical load curve at service stations in the shape of a bell curve (see Figure 2 in article 2). A second peak occurs in the evening due to public charging overnight. The bell curve is strongly reminiscent of the feed-in characteristics of PV systems. Their electricity generation also peaks at midday. This raises the possibility of a “symbiosis” between PV generation and MCS charging around highway service stations. The following, third article in our series of articles addresses this subject.
As described in the previous article, the predicted peak load resulting from the fast charging of commercial battery electric trucks during midday will be approximately 11 GW. The individual service stations will each have to provide several MW of charging power for this purpose. In order to reduce expansion costs associated with connection capacity, the question arises as to what extent local power generation from PV systems and the installation of large battery storage systems in the immediate surroundings of service stations are suitable for covering or reducing peak loads and energy requirements for fast chargers.
An analysis by the FfE GeoDataLab of the spatial potential available at and around service stations in Germany is examining the compatibility of PV systems and fast charging in more detail. The option of a PV shelter covering the truck parking lots at service stations is evaluated in order to exploit the potential of direct local generation. When calculating the potential of the surrounding sites, radial surfaces at a defined distance from the service area are analyzed in terms of their PV suitability and the potential PV power that can be installed at these sites is calculated. In this context, Figure 1 shows an example of a service area near Meynbach in Mecklenburg-Western Pomerania, for which the PV potential is shown in a radius of 500, 1,000 and 1,500 meters.
The next step involved the application of this method to all 351 service stations that are currently published as locations in the Federal Ministry for Digital and Transport’s (BMDV) planned fast-charging grid for trucks and a comparison of the projected charging power with the local PV potential. The planned charging power published at each of these locations is analyzed. Figure 2 presents an aggregated comparison of the installed power and the possible PV potential (shown in absolute values) for the charging site in Figure 1.
It is evident that the installed power of the charging infrastructure and consequently peak loads could be covered by a pv site development in a radius of significantly less than 500 m around the service station in appropriate weather conditions. Applying this methodology to the planned locations of the fast-charging grid (see Figure 3), it becomes apparent there is considerable ground potential around the majority of service stations. Figure 3 shows at which locations and to what extent the planned charging power can be “covered” by roofed PV areas as well as radial development within a radius of 500 – 1,500 m (exclusive consideration of installed power in the case of photovoltaic area development). Consequently, the majority of the areas around the service areas are generally suitable for PV systems and can therefore contribute to reducing the peak load.
The analysis of only the installed power, however, only indicates the potential to reduce the local peak load under appropriate weather conditions. For a comprehensive classification, it is essential to analyze the temporal dimension. Assuming an average of 1,000 hours of full utilization per year in Germany, this results in a generated energy of approx. 6.9 – 17.1 TWh for the land use of 500 – 1,500 m around service stations shown in Figure 3. Compared to the energy requirements of 15 – 50 TWh calculated in article 1 for 2035, a not insignificant proportion can be covered by PV systems around service stations, without taking into account the seasonality of PV generation.
On the basis of the previously acquired insights, the question arises as to how “symbiotically” the temporal and seasonal PV generation and potential charging requirements of battery electric long-distance vehicles relate to each other. A more general approach was adopted to answer this question. A first step is the analysis of characteristic, weekly mobility profiles of long-distance vehicles (daily route > 400 km), which were evaluated with the FfE Markow mobility model. Figure 4 displays the sites at which long-distance vehicles are located on average over the course of a week. The restriction to vehicles with a daily mileage >400 km results from the assumption that these vehicles cannot complete their trips on a single battery charge and thus are the primary factor for fast public charging in the heavy commercial vehicle segment.
It is evident that the trucks are at the home depot almost exclusively overnight on weekdays meaning a significant share of the intermediate charging demand required throughout the day is external. While both the time of day and the seasons strongly influence PV generation, the seasonal trend in the charging requirements of commercial vehicles is relatively less significant. An annual charging load profile is therefore approximated in a simplified approach by sequencing the average weekly charging load profile. This weekly load profile is determined using 100 generically generated driving profiles from the Markow mobility model. Influencing factors such as increased consumption at low temperatures were only considered secondarily via the average consumption of the vehicles. The resulting average charging load profile for long-distance vehicles is presented in Figure 5. As an example, it shows how each vehicle in the current fleet of electrified long-distance trucks would impact the grid over the week, which means that this profile can be scaled by reference to sheath quantities.
From the weekly load profile of an average long-haul truck in Germany shown in Figure 5, the share of publicly charged power (blue curve) can be utilized to approximately calculate the load profile of a electrified long-haul vehicle fleet in 2035 in relation to PV generation. For this purpose, the publicly charged weekly profile is multiplied by the forecast number of the electric truck scenario AE35 for the year 2035 from the first article in this series (120,000 long-distance vehicles in 2035), resulting in an approximate load profile of the vehicles for entire Germany. It is important to consider that today’s mobility behavior (see Figure 4) is projected unprocessed to 2035 and expected efficiency developments are also neglected. This is compared with the calculation of the generation curve from the calculated areas with irradiation data from 2012, which is used to determine the percentage of the weekly charged energy that can be covered directly by the PV systems. The degree of self-coverage is also determined for each week, taking into account an appropriately dimensioned storage system. Figure 6 demonstrates this evaluation for the 52 weeks and three site scenarios.
As anticipated, the coverage of the (assumed constant weekly), publicly charged energy demand of long-haul trucks in winter from PV systems is negligible. The coverage with a developed area with a 500 m radius also contributes to a maximum weekly coverage of approx. 70 % of the demand. It must be taken into account that only the 351 tendered locations of the truck charging grid are covered with PV installations (see Figure 2) and that the charging requirements of a largely electrified long-haul commercial vehicle fleet in 2035 stand in contrast to this. The comparison of direct and weekly self-consumption coverage shows that there is significant potential for stationary storage systems, which could shift up to 2,196 GWh across Germany from the use case of self-consumption optimization alone. These storage systems also have other use cases, such as peak load reduction (through slow charging at times of low load and discharging at times of high load), participation in energy markets or even a possible future “grid-supporting” use, whereby the location contributes to the stabilization of the local grid. This analysis thus provides an initial indication of the significant potential of “integrated charging locations”, although there are still a number of obstacles to overcome.
One of the obstacles, analyzed in this concluding excursus, is the number of potential “negotiation partners” involved in implementing an “integrated charging site”. To harness the potential and develop the calculated PV potential within a radius of 500 – 1,500 meters around rest areas, significant areas need to be developed with PV systems. A land analysis evaluates, using the example of service stations in the state of Bavaria, how many parties would need to be involved per site for PV development at most. For this purpose, the number of cadastral parcels in the considered locations was calculated. This analysis does not directly clarify the absolute number of parties that would need to be involved in the negotiation, as it is highly likely that multiple parcels could belong to the same owner. However, it provides an initial indication. Figure 7 illustrates this for the locations in Bavaria for service stations and area within a radius of 500 meters around the considered sites.
On average, this results in a number of 55 cadastral parcels, highlighting the scale and complexity of implementing an “integrated charging site”. It is important to consider that these projects, with connections at the medium to high voltage level, represent a significant intervention in the local distribution and transmission grid. As we have illustrated in another discussion paper, projects of this nature require significant lead time (several years) for realization. Therefore, to implement potential “integrated charging sites”, one thing is needed above all in the near future – speed to actionism!
In the next, fourth article of this series, we will look at the other side of charging and take a look at the (optimized) charging of commercial vehicles at the home depot.
Further Information
- Electrification and Integration of Heavy Commercial Vehicles (NEFTON)
- Influence of the ramp-up of battery electric commercial vehicles on distribution grid planning
- SPIRIT-E – Shared private charging infrastructure and reservation for bidirectionally integrated truck elektrification
- Bid-E-V – Bidirektionale elektrische Vans