Sep 26th, 2019
In the wake of last Friday’s global climate strike, this week’s NYC Climate Week, and the forthcoming UNFCCC COP25 climate conference in Chile later this year, all eyes are focused on rapidly decarbonizing the worldwide economy. Of the many levers to pull, two in particular often sit front and center in the conversation: slashing power sector emissions with renewables and transportation electrification to get mobility off oil.
As the thinking goes, they are most effective when used together as a one-two punch: 1) electrify vehicles (EVs) to eliminate tailpipe emissions and adopt hyper-efficient powertrains and 2) charge those vehicles on cleaner grids to drastically reduce their associated emissions. It’s a powerful combo, exemplified by a recent study focused on the state of Colorado.
Electric vehicles are Colorado’s biggest emissions-reduction opportunity
Vibrant Clean Energy conducted the Colorado study, and Vox last month had a fabulous summary dissecting the findings. Vibrant modeled three scenarios through 2040:
–Business as usual: Colorado’s electricity grid and transportation sector look in 2040 much as they do today, and emissions remain essentially unchanged
–Cleaner grid: coal plants are shuttered and replaced with oodles of wind, solar, and some natural gas, slashing power-sector emissions 55% and statewide emissions 16% overall
–Cleaner grid + EVs: power-sector emissions fall a more modest 46% (thanks to natural gas generation meeting some of the increased demand from EVs), but statewide emissions overall drop an impressive 42%, thanks to an 80% decrease in transportation-sector emissions
These are exciting findings, to be sure. Yet they only scratch the surface of possibilities.
Emissions-optimized EV charging can further slash Colorado’s climate profile
For one, emissions-optimized EV charging can further slash transportation emissions above and beyond the electrification switch from gasoline- and diesel-burning internal combustion engine (ICE) cars to EVs. The idea is wonderfully simple in theory, though it takes some sophisticated software wizardry behind the scenes to implement in practice.
Several of the most-common EV charging scenarios—namely level 2 workplace charging during the day and overnight charging at home—don’t require the full charging time window in order to top off an EV’s battery. That difference between time needed to charge and time the EV remains plugged in to the grid allows an opportunity to optimize. More specifically, you can sync charging with moments of cleaner energy and pause EV charging during moments of dirtier energy.
A recently released WattTime analysis examined just how much cleaner EVs could be with smart emissions-optimized charging vs. traditional “dumb” charging. Two of the four representative grid balancing areas WattTime analyzed included WACM (a good proxy for historically coal-heavy western Colorado) and SPP (a good proxy for Xcel Energy’s wind-rich service territory up and down Colorado’s Front Range and High Plains).
The study found that EVs could be up to almost 18% cleaner annually and up to 60% cleaner on individual days. Remember: these are incremental additional emissions savings on top of the beneficial switch from ICE autos to EVs. That’s huge.
As Colorado’s grid gets more variable, emissions-optimized charging becomes even more important
For another, the Vibrant study’s view out to 2040 and Colorado’s potential grid mix reveals another key insight. As Colorado’s grid mix becomes dominantly wind and solar, supported by natural gas-fired generation, that grid will start to exhibit high emissions variability. To quote Vox article author David Roberts, Colorado’s “dispatch becomes much more volatile, with wind and solar providing almost 100 percent of energy at some points and natural gas almost 100 percent at others.”
This is highly consistent with WattTime’s findings in its study: “We should expect more grids across the country and around the world to exhibit emissions variability and emissions-reduction opportunities as they add more renewables to legacy fossil-fueled systems.”
That variability is a twofold opportunity for emissions-optimized EV charging: a) It enables even deeper emissions savings as the grid exhibits greater amplitude in its moment-to-moment swings from “very clean” to “dirtier.” b) It also presents opportunities for EVs to aid further grid integration of renewable generation, reducing curtailment and absorbing what would otherwise be wasted surplus wind and solar, helping to reduce the total need for natural gas to balance renewables’ variability.
Demand flexibility—whether from EVs or other smart technologies—is the crucial arbiter of tomorrow’s electricity grid supply and demand
At the end of the day, “emissions-optimized EV charging” is a transportation-specific name for a term that has gained increasing traction in recent years: demand flexibility. In a future world—whether within Colorado or beyond—in which we have a renewables-rich and variable grid supply and a robust fleet of electric vehicle demand, flexibility sits at the dynamic interface between them.
It is an elegant software-based solution that does more than complement renewables and EVs and other advanced energy technologies; it downright unlocks their fuller potential in a transformational turnover in hardware infrastructure—solar panels and wind turbines in lieu of coal and natural gas power plants, electrified powertrains in lieu of internal combustion engine automobiles and other light-duty vehicles.
Yes, a cleaner grid and electrified transportation can drastically reduce Colorado’s climate impact. But both can be even better versions of themselves if flexible demand, vis-a-vis emissions-optimized EV charging, is at the heart of their dance together.