20% CO2 savings through intelligent charging shown by AUDI and The Mobility House
Munich, 14 January 2022
In 2020, electric cars reduced CO2 emissions in Germany already by a good 160,000 tons if the current electricity mix of 471 g CO2/kWh (2018, German Federal Environment Agency) is used to calculate the CO2 emissions. And this figure could even have been doubled if cars were charged exclusively with green electricity – at least that is the conclusion of an evaluation conducted by the energy company E.ON which compared the CO2 emissions produced by cars with combustion engines with those produced by electric cars. But since wind and solar-based renewable energy generation naturally fluctuates, more or less electricity generated from coal and gas inevitably ends up in electric car batteries depending on the time of day, which makes it not exclusively green.
While this might sound like a sobering statement at first, the unique strength of battery-powered e-mobility as a flexible consumer in the energy system harbors outstanding opportunities. Charging processes can be automatically postponed to times when an above-average amount of CO2-free electricity generated from renewables is available in the grids. E-mobility will then become an indispensable pillar as renewable energies expand further. By postponing charging to the "surplus" times (e.g. between 10.00 a.m. and 4.00 pm on sunny days), these surpluses are turned into valuable usable energy.
Pilot project shows: CO2 reduction of 20% is possible
In a pilot project, the technology company The Mobility House joined forces with the AUDI AG to conduct a year-long exploration of the emission saving potential of CO2-optimized charging processes and the additional incentives they involve. "Prioritizing electric car charging when there’s plenty of wind power and solar energy available can reduce CO2 pollution by up to 20%  immediately," explained Veronika Brandmeier, Head of Energy Supply and VGI Projects at The Mobility House.
"AUDI wants to become a provider of CO2-neutral mobility. We firmly believe that the future of mobility is electric. Electromobility is by far the most efficient way to decarbonize, which is why we are pursuing a consistent e-roadmap. By 2025, we will significantly increase the number of electric models; we plan to have more than 20 all-electric ones. That’s why it’s important that this multitude of electric vehicles is charged primarily with electricity from renewable sources, so CO2 emissions are actually brought down to zero. Through our joint project with The Mobility House, we’ve demonstrated that we can indeed control CO2 emissions, in addition to showing what added value this might bring to the system as a whole and its players," remarked Alexander Kupfer, Project Manager in the Sustainable Product Concepts Department within AUDI AG's Technical Development Division.
In addition to the environmental benefit, there are several other positive effects end consumers would find interesting, too. "Companies in particular could benefit from CO2-optimized charging processes," continued Brandmeier. "For instance, they could use flexible electricity tariffs to significantly cut their charging costs, since energy prices tend to be lower when the renewable energy-feed in is high. As our pilot project with AUDI shows, it’s possible to make pre-tax savings of up to 37% on electricity procurement costs. Or, to put it another way, up to €88 per electric car, per year, if a vehicle owner has their car connected to a charging station both during daytime while they’re at work and overnight when they’re at home." This clears the way for maximum flexibility and thus an optimum yield, too. For illustration purposes, it’s ideal to convert this figure to gas station prices: Here, the savings would correspond to the price of gasoline dropping from €1.50/liter to just €1.42/liter for an entire year. Looking at the current development of the energy market, controlled charging could lead to even greater financial benefits in the future.
"CO2-optimized charging would certainly be interesting for private customers too," remarked Brandmeier. In technical terms, it would be feasible if private customers were using digital smart meters and charging infrastructure interfaces that are already commonplace today. "However, the regulatory requirements and the availability of variable electricity tariffs, which would be easy to implement with smart metering, are still missing," Brandmeier pointed out. This would allow end customers to make the most of lower prices and the climate to benefit from lower CO2 emissions. But variable electricity tariffs would prove advantageous for grid operators too. Energy is usually particularly expensive when comparatively costly coal and gas-fired power plants have to compensate for peak loads. If drivers of electric cars moved their charging processes to off-peak times thanks to financial incentives, this would mitigate peak loads, the urgent need for regulatory intervention and expensive investments for grid expansion, not to mention the risk of blackouts. "It would create a win-win-win situation," as Brandmeier commented, "for consumers, grid operators and the climate."
CO2-optimized charging impacts on Scope2 emissions
There are even more advantages for companies, as the pilot project shows. Companies that charge their already sustainable fleet of electric cars in a way that optimizes CO2 emissions are showing how serious they are about their efforts to protect the climate – which is sure to go down well with customers, business partners, employees and talented potential applicants. It also has the potential to boost their image – a benefit that shouldn’t be underestimated. Companies that have to record and disclose their CO2 emissions for their CSR report can also use innovative technology to cut back on their Scope2 emissions.
ChargePilot, the intelligent Charging and Energy Management system by The Mobility House, already reduces climate gas emissions even without CO2-optimized charging. Load management prevents load peaks and shifts charging processes to low-load and therefore lower CO2 time windows when the proportion of renewable energies is high. Without load management, the CO2 pollution for the use cases examined would actually increase compared to the average electricity mix, as the current pilot project has shown. The reason for this is that if charging takes place at peak times as is usually the case (e.g. immediately after staff arrive at work, or at home at the end of the working day), the electric car draws electricity with an above-average proportion of CO2 from the grid.
Electric cars are arriving just in time for the renewable energy expansion
If Germany increases the share of renewable energies in electricity consumption to 65 % by 2030, this will in many cases result in a temporary oversupply of energy. A simulation produced by the Technical University of Berlin and AUDI revealed that the 10 million electric vehicles that would then be available (the German government's declared goal is now 15 million electric vehicles by 2030) could cover more than half of their demand from the surpluses. Alternatively, from the energy supply point of view, 50 % of the surpluses could be utilized – in line with the motto "Don’t switch off – use".
The expansion of renewables and increase in electric car numbers should be even higher with the European Commission’s current "Fit for 55" climate protection program. Then, the contribution of electric vehicles would be even greater.
 Simulations are based on 2018 values.