Monday Study – The Smart Way To Handle EV Charging

More EVs, Fewer Emissions How to Maximize Emissions Reductions by Smart Charging Electric Vehicles

Lynn Daniels, Britta Gross, Christy Lewis, Laurie Stone, March 2022 (Rocky Mountain Institute) ,p> Executive Summary

Transportation emits more carbon than any other sector in the United States. To limit global temperature rise to 1.5°C, we must reduce carbon emissions from transportation 45% by 2030. To do this, we must decrease the number of vehicle miles traveled and put 70 million electric vehicles (EVs) on the road by the end of the decade.

In the US today, EVs already deliver about 60%–68% fewer emissions than internal combustion engine (ICE) vehicles. When those EVs are optimized with smart charging to align with the lowest emissions rates on the electricity grid, they further reduce emissions by an additional 2%–8% and even become a grid resource.1

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In fact, when 70 million EVs are on the road (one in four cars), emissions-optimized smart charging is the equivalent of taking an additional 5.73 million ICE vehicles off the road. Even today, charging 1 million EVs at the right times is equivalent to taking between 20,000 and 80,000 ICE vehicles off the road. Smart charging and electric vehicles, combined with increasingly accurate real-time models for what is happening on the electricity grid, are facilitating this interaction between the electric utility and transportation sectors.

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As more accurate models are developed that provide dynamic signals about the costs and emissions associated with power generation in real time, there is a significant opportunity for utilities and EV owners to control EV charging according to an emissions signal. This leads to:

• Reduced costs—utilities can take advantage of low-cost moments of renewable energy curtailment by encouraging EV drivers to shift their load to these times.i

• Reduced emissions associated with driving and charging EVs.

• A faster transition to renewables

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In this report, we explore the factors that maximize emissions reductions when EVs are charged according to an emissions signal, in other words, when the marginal emissions rate is lowest.ii We find two key factors that are most critical to maximizing CO2 savings:

1. The local grid mix: The more zero-emissions generation available on a given grid, the greater the opportunity to reduce CO2 emissions. The highest possible savings found in this study are on grids with high renewable generation penetration. However, even on grids with relatively high carbon intensity, if there is a large difference between the emissions factors of that grid’s fuel sources, emissions-optimized charging can significantly reduce emissions when the cleaner fuels are available.

2. Charging behavior: EV drivers should charge using faster charging rates but over longer dwell times (the amount of time a vehicle is parked at a charger).

There are also other factors to take into consideration. These include transmission capacity, which is critical to ensure that zero-emissions electricity can be dispatched to where it is needed (i.e., so that charging EVs can use it), and the potential for EVs to mitigate renewable energy curtailment.

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These factors point to a set of actions that we recommend utilities explore:

1. When appropriate, prioritize Level 2 charging with longer dwell times, maximizing the flexibility of EVs as a grid asset.iii

2. Incorporate transportation electrification into integrated resource planning, going beyond simply projecting EV adoption to considering how EVs can be used as a flexible asset.

3. Align transportation electrification programs and offerings with the grid generation mix.

4. Complement investment in new transmission lines that move renewable energy to load centers and can provide a structural solution for curtailment, with technology that optimizes charging around the marginal emissions rate to avoid curtailment in the near term in advance of new transmission coming online.

5. Continually re-evaluate time-of-use tariffs as real-time grid data becomes readily available. For example, rather than just considering rates that reflect peak and off-peak loads, adjust rates to incentivize EV charging when there is likely to be curtailment.

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Fleet operators who are transitioning to electric vehicles can also take advantage of emissions-optimized charging. Leading fleets, especially those electrifying to directly reduce their Scope 1 emissions, should consider emissions-optimized charging to maximize these direct emissions reductions… click here for more

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