WHITEPAPER

Increase your grid independence

Posted on March 01, 2025

Executive summary

What

Charging station for electric vehicles (EV) with ten fast chargers along the highway

Where

Germany

Why

Germany has among the highest rates for on-grid energy in the world. The use of renewable energy solutions enables increased grid independence and reduces costs. It also supports sustainable, climate-smart development.

Main benefits

Energy cost optimization; Reduction of CO₂ emissions; Provision of sufficient high-power charging power; “All-Day“-Charging

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Sustainability is a key driver for electric mobility. Given the opportunity, drivers would rather charge their cars with renewable energy. Fast charging hubs along the highway equipped with photovoltaics (PV) and a battery energy storage system (BESS) allow more cars to fuel up with renewable energy while also reducing costs.

Optimizing energy costs with microgrids

To demonstrate the savings potential for electric vehicle (EV) fast charging hubs along the German Autobahn with renewable energy systems, we have calculated two scenarios using HOMER Grid® simulation software.

Making full use of solar power

EV charging hubs have an intermittent energy load profile. High loads during the day when multiple cars need charging alternate with periods of little to no load at night and in the mornings.
A photovoltaic (PV) system produces ample power for self-consumption during daylight hours. For full utilization, however, the addition of a small battery energy storage system (BESS) plays a key role. It enables self-consumption to be further increased and makes sure that no energy is wasted.

         

Results of the use case

As the comparison illustrated, electric vehicle (EV) fast charging hubs using renewable energy systems enable significant reductions in energy costs.

Maximizing savings with a combined PV and BESS setup
Roadside locations for fast charging hubs generally have plenty of space for ground-mounted solar panels, allowing for a nondisruptive, low-cost installation. With an available area of approx. 6000 m², as in our use case, a photovoltaic (PV) system is limited to 750 kWp.

By adding an energy storage system (ESS), self-consumption of solar energy can be increased to maximize energy cost savings. Costs for the chargers themselves, as well as grid connections, are not considered at this stage.

CAPEX Assumptions:
Case 1: 750 k€               Case 2: 960 k€

Scenario 1 & 2 savings summary

The initial situation’s costs are comprised of energy consumption charges (generation and grid costs, taxes and levies) as well as demand charges.

In scenario 1, self-consumption of PV power enables significant savings on grid consumption charges – by 26% or € 122k per year. Further savings could be possible through feed-in tariffs depending on the daily production and the load demanded. These savings are slightly offset by the PV system’s operational and maintenance (O&M) costs of approx. €5k, resulting in total reduced energy costs of € 117k per year.

In scenario 2, grid energy usage can be reduced even further – by up to 27% or € 136k per year. Additional savings of € 30k are achieved through demand charge reductions. After factoring in the O&M costs for PV and ESS of € 12k, total savings still amount to € 154k per year.

Payback Period

In scenario 1, the investment in a PV only system for an EV charging hub enables energy costs savings of €117k per year with a payback period of 6.6 years.

In scenario 2, investing in a combined PV and energy storage system can lead to savings
of €154k per year, thanks to optimized self- consumption of renewable energy. The payback period is 6.3 years*.

In addition to the financial advantages of Case 2, it has the following benefits for operators:
—   Sufficient buffer for high-power-charging (HPC)
—   Provision of “all-day” charging

Case 2 could even be further improved using advanced value stacking (e.g. adding trading or grid services).

Microgrid services, system integration and smart control

Our microgrid systems offer a wide variety of solutions and services. Each can be individually designed to serve specific needs. Special microgrid services we offer include consulting, planning, the single-source supply of hardware and software, as well as installation and maintenance.

Start saving costs with microgrids

Are you curious if microgrids can help your facilities save on energy costs?

Contact us today at
info@ps.rolls-royce.com
Or call +49 7541 90-7 7777

Rolls-Royce Group
www.mtu-solutions.com

Rolls-Royce provides world-class power solutions and complete lifecycle support under our product and solution brand mtu. Through digitalization and electrification, we strive to develop drive and power generation solutions that are even cleaner and smarter and thus provide answers to the challenges posed by the rapidly growing societal demands for energy and mobility. We deliver and service comprehensive, powerful and reliable systems, based on both gas and diesel engines, as well as electrified hybrid systems. These clean and technologically advanced solutions serve our customers in the marine and infrastructure sectors worldwide.

Within its Net Zero at Power Systems program, Rolls-Royce has set out to sustainably reform its product portfolio so that by 2030, new technologies can save 35% of greenhouse gas emissions compared to 2019. This near-term target plays a significant role in Rolls-Royce Group’s ambition to achieve net zero by 2050 at the latest. A key element in achieving these goals is the release of the highest volume mtu engine products and systems to run on sustainable fuels as quickly as possible.

Increase your grid independence

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