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.

Photo by Nathan Anderson on Unsplash

It’s the 9th annual National Drive Electric Week (NDEW)! More than 300 events—mostly throughout the United States, but also in a growing number of locations around the world—will offer consumers a chance to learn about, test drive, and even buy an electric vehicle. Undoubtedly, electric vehicles (EVs) are surging in popularity right now. It’s a trend that shows little sign of slowing down.

There were already more than 1 million EVs on the road in the U.S. by the end of 2018. By 2030, that number is forecast to reach nearly 19 million, according to a report from the Edison Electric Institute. Similarly, Bloomberg New Energy Finance’s 2019 Electric Vehicle Outlook notes that annual EV sales totalled just a few thousand in 2010, and reached more than 2 million globally last year. BNEF forecasts global annual EV sales to hit 10 million by 2025 and 28 million by 2030.  

Delivering against the green promise of EVs

Nearly two-thirds of prospective car buyers in America have interest in electric vehicles (EVs), according to a recent survey from Consumer Reports and the Union of Concerned Scientists (UCS). Not surprisingly, some 73% say that EVs can help reduce oil use and 72% believe EVs can help reduce pollution. Those are both true statements. But how much cleaner can EVs become vs. their internal combustion engine counterparts? UCS and others, including us here at WattTime, have looked at the emissions associated with charging EVs on various grids—some with more polluting fossil-fueled generation and others with more clean renewably-generated electricity. The good news is that, relative to the U.S. light-duty fleet average fuel economy of 22 MPG, EVs are cleaner everywhere.  But it turns out that EVs can be even cleaner, and sometimes, much cleaner.

Emissions-optimized charging unlocks EVs’ full potential

At a time when annual changes in overall electricity demand are pretty much flat (thanks in part to the effectiveness of energy-efficiency programs), EVs represent a unique source of new demand for utilities and our power grid. Meanwhile, it’s pretty much common knowledge that from coast to coast we’ve been rapidly adding more and more renewable energy to the power grid. These two forces present a golden opportunity for EV charging.

First, as we add more renewable energy to electricity grids that are transitioning away from their legacy fossil-fueled generation, we’re seeing stronger and stronger variation in emissions rates from the grid. Sometimes the grid is cleaner, and sometimes it’s dirtier, depending whether polluting power plants or clean renewables are making up the mix.

Second, with new demand from EVs, every time you plug in an EV charge, the electricity grid has to ramp generation up or down to account for that change in load. But what power plants are responding? Does the utility have to turn on an inefficient, heavier-polluting, fossil-fueled peaker plant? Is surplus wind or solar generation being thrown away because there isn’t enough demand at that moment to absorb the emissions-free electricity?

With the right kind of insights into real-time grid conditions—and the ability to send that information via software signal to EVs—they could time their charging to sync with moments of clean electricity and avoid moments of dirty energy, making EVs cleaner than they already are.

A new WattTime report shows EVs’ emissions-saving capability

Just on the eve of this week’s NDEW, we released a new report that analyzed the emissions-saving capability of smarter EV charging. We looked at four representative grids across the country, and two common charging scenarios: daytime workplace charging and at-home overnight charging. Our findings were nothing short of exciting. Using an emissions-optimized charging cycle, such as WattTime’s Automated Emissions Reduction software, EVs could become up to 20% cleaner annually and 90% on individual days… incredibly through nothing more than smart software that modulates when an EV starts and stops charging within its allotted charge window (while still leaving you with a full battery, of course).

This is a gamechanger for EVs. Without ever touching their already-superefficient powertrains, it’s like giving them a big MPGe boost. They can drive just as far, but with fewer associated grid emissions. Which in the end delivers on one of the big reasons why drivers flocking to EVs in the first place: they’re green.  Now, they can be greener still. With EV awareness on the rise—thanks in part to  high-profile events such as NDEW—it’s good to remind drivers that EVs are a solid bet for reducing your eco footprint. With emissions-optimized charging, that bet can pay ever higher returns.

If you could hold planet Earth in the palm of your hand, it would feel nearly as smooth as a billiard ball. Up close, features such as Mount Everest and the Marianas Trench become more formidable. An August 2018 McKinsey study on the how electric vehicles could impact demand on power grids showed a similar dichotomy between the big picture and the details in which the devil feels so at home.

Using a Monte Carlo simulation of EVs in Germany as a frame of reference, McKinsey researchers found that as EV adoption rises—from <1% of vehicle stock today to 7% by 2030 to 40% by 2050—EV-related electricity demand (kWh of consumption) would add just 1% to total German power demand by 2030 and about 4% by 2050.

So the big picture looks smooth and no cause for major alarm from a grid operations perspective. But EV adoption is unlikely to be uniform, and national averages will hide sharper geographic differences. Especially when it comes to suburban ‘hot spots’ where EV adoption is expected to be greatest.

In suburbia, surging EV demand could also spike grid demand

When the McKinsey team looked at postal-code-level EV penetration, it found that, in suburban areas where EV uptake is expected to be strongest, peak load would spike about 30% in the evening hours after commuters return from work and plug in their wheels.

That model, based on load profiles for a September day in the U.S. Midwest, assumed a typical residential feeder circuit for 150 homes, each home with two cars. One in four cars would be an EV charging at an average plug-in power of 3.7 kilowatts. Without corrective action, the analysists say, the associated 30% bump in peak demand would be enough to require grid upgrades costing several hundred dollars per EV to alleviate overloaded feeder circuits.

A second analysis considered the load profile of a fast-charging station. That one came back with more startling results yet. According to the authors, “a single fast-charging station can quickly exceed the peak-load capacity of a typical feeder-circuit transformer.” No surprise there, when one considers that a single EV using a high-end fast charger sucks as much juice as the peak demand of 80 households.

A role for coordinated EV charging and complementary strategies

Fortunately, there are solutions less formidable than scaling Everest or plumbing the depths east of the Mariana Islands. Among those the McKinsey team suggests include collocating an energy storage unit with the transformer (or, alternatively, pairing batteries with EV charging stations, as ChargePoint is doing with its PowerBlock fast-charging system).

The big one McKinsey suggests, though, is implementing time-of-use rates for electricity users. That at least provides a business case for load shifting in the form of a price signal for EV drivers to bulk shift EV demand from on-peak times to off-peak hours. But that still doesn’t solve the problem of myriad EV drivers all plugging in around the same time—even if at off-peak hours—and surging grid demand beyond what local circuits have been built to handle.

Moreover, for many grids across the country, existing time-of-use pricing doesn’t always correlate with grid emissions, so EV drivers could inadvertently be economically incented to shift their charging to times of higher grid emissions. We need to solve the demand-price-emissions equation as a set, rather than focus on one or two at the expense of the others.

To avoid dozens of EVs simultaneously draining the local grid during what would historically have been an off-peak time, doing this right will require “centrally coordinated, intelligent steering of EV-charging behavior,” the McKinsey team says. Or perhaps a blend of central coordination by utilities, distribution system operators, and EVSE network operators and decentralized coordination via EV drivers, automakers, and others at the grid edge.

Doing more with smart EV charging

Fostering smart EV charging behavior would offer myriad benefits, the authors say. Of course, it would shave peak demand at the heart of McKinsey’s study findings. Second, it would provide a new lever for managing system demand and offer valuable system-balancing services to grid operators (akin to a flavor of vehicle-to-grid services sometimes written about but not yet realized). And, it could crank up charging at times of high solar and wind generation (or, similarly, times of low marginal emissions rates) and ramp it back down when generation and marginal emissions get dirtier.

This last point is important. McKinsey is saying that centrally coordinated, smart EV charging done right should involve more than shaving peaks and taming the roller coaster of grid demand. It should take into account the mix of electricity being produced in a way that favors renewables over fossil energy sources, a need that will persist even as coal-fired electricity generation continues to wane. McKinsey has separately estimated that roughly 80 percent of the forecast growth in U.S. electricity demand is expected to be met with natural gas generation.

Here is where technologies such as WattTime’s Automated Emissions Reduction (AER) system can play a vital role.

It’s not hard to estimate average EV emissions based on overall grid mix in a particular region—calculators such as this one by the Union of Concerned Scientists can do that for you. But that’s like viewing Earth as cue-ball smooth; averages show a general picture but lack the details necessary for impactful decision making.

The electricity mix—and especially those generators that are on the margin—in a given locale varies minute-by-minute with the ebbs and flows of demand, winds gusting through turbine blades, clouds passing between solar panels and the sun, and so on.

Built into EVSE networks, EV chargers, and EVs themselves (or some combination), WattTime’s AER software keeps tabs on power generation and marginal emissions rates in real-time. That opens the door to the tracking marginal emissions of power consumption in fifteen-minute increments—and, more importantly, using that knowledge to optimize charging not only based on peak-load considerations, but also on the environmental impact of charging at a given moment.

There are, after all, counterintuitive times when it could actually better to charge an EV during times of peaking grid demand. For one example, imagine that peak demand aligns with a particularly windy day, where surplus wind generation is being curtailed. Or perhaps early afternoon on a late spring or early fall day, when solar PV is cranking but even the grid’s peaking demand isn’t enough to suck up all those sun-powered electrons. Normal time-of-use rates might push EV charging demand off peak and miss an opportunity to charge during that time of surplus wind or solar.

Without smart, flexible charging and the insights of technologies such as WattTime AER, peaks and troughs will be as ingrained in EV charging as they are in our planet’s crust. Fortunately, we have the tools to navigate the ups and downs in the cleanest possible way.

Electric vehicles (EVs) are more efficient and less polluting than comparable rides powered by traditional internal combustion engines—even when EVs are charged on relatively dirty grids; plus, the greener that grids get with renewables, the cleaner EVs get with their associated emissions.

But there’s been the nagging question of whether, as sales continue to ramp up, EVs could become too much of a good thing for the power grid. For example, after 1.1 million new electric vehicles hit the roads globally in 2017, Bloomberg New Energy Finance forecasts that worldwide annual EV sales will hit 11 million by 2025 and 30 million by 2030. Can the electricity grid handle the coming wave of EVs and all the charging—some slow, some fast, and some superfast—that will come along with it?

A 2018 study from the UK’s Office of Gas and Electricity Markets (Ofgem) found reason for optimism—assuming that mass EV uptake comes hand-in-hand with intelligent charging systems. Ofgem found that “smart, flexible” charging solutions could allow at least 60% more EVs to connect to the existing UK power grid than would be the case without intelligent charging systems. With flexible fast charging, up to six times more EVs could connect, the authors found.

That’s possible, Ofgem says, because unlike inflexible EV charging—which blindly fills a big battery from the time it’s plugged in until it’s either topped off or the plug is pulled—flexible EV charging pays some attention to what’s happening beyond the outlet.

Charging flexibility makes all the difference

Inflexible EV charging, the authors say, increases peak demand, risks local outages, reduces system diversity, constrains areas that are already constrained, and forces all energy consumers to pay for new electrical infrastructure needed because of the added demand of EV owners.

Flexible EV charging, on the other hand, lowers the increase in peak demand, enables the more efficient use of existing assets, improves system diversity, defers or avoids power-infrastructure expansion, and can reward consumers—in pounds and pence (or dollars and cents, on this side of the Atlantic)—for their flexibility.

That’s a lot of cons and pros, but the big one has to do with peak demand. Depending on when peak demand occurs, and—more importantly—what power plants are called upon to meet that demand (often an expensive, polluting, fossil-burning peaker plant), there could be big implications for marginal grid emissions that risk casting a bit of a cloud over the clean EV story.

Keep in mind that the above doesn’t take into account vehicle-to-grid technology, which could harness EVs as a stored energy source, tapping into parked cars rather than peaking plants. For example, a Tesla Model 3 battery stores four to five times more electricity than a Tesla Powerwall battery. And overall, EVs that charge using a 240-volt outlet draw about as much power as six microwave ovens running simultaneously. Then imagine all that energy and capacity at coordinated scale. “As a pooled resource, the growing number of EV batteries could provide a wider range of valuable grid services, from demand response and voltage regulation to distribution-level services, without compromising driving experience or capabilities,” the Ofgem team explains.

How flexible charging unlocks greater grid value—while reducing emissions

Closer to home, the U.S. Department of Energy’s INTEGRATE study has estimated that with 3 million EVs—half of them using flexible charging and EV batteries as energy storage—peak demand would fall 1.5 percent. You read that right: adding 3 million electric cars could cut peak demand. Electricity costs would decline by 1 percent to 3 percent. In addition, renewable-energy curtailment would shrink by 25 percent and overall grid emissions could shrink, too.

That last bit about renewable energy curtailment and grid emissions is vitally important. Curtailment means wasting renewable energy that would otherwise be generated because the grid can’t accommodate it at a particular time.

Renewable energy’s contribution to the grid can change minute-by-minute. So, when we consider how to do smart, flexible charging of EVs for the optimization of power delivery, we should be asking not just if and how the grid can handle that demand but also what sources of generation are on the margin and/or at risk of curtailment at any point in time. In other words, how can smart, flexible EV charging help electricity grids from the UK to the U.S. not only handle more EVs but potentially do so while lowering their marginal emissions by charging at times of cleaner energy and avoid times of dirtier energy.

This sits squarely in the sweet spot of WattTime’s Automated Emissions Reduction (AER) technology. The software—including a recently updated EV charging module—uses a combination of real-time grid conditions and historical emissions data to track the precise mix of renewable and fossil energy coursing through a device such as an EV charger, in 5-minute increments.

This is especially important when it comes to EVs and marginal emissions. Yes, we can measure EV emissions based on overall grid mix in a particular region. But what arguably matters much more is marginal emissions. When I plug in my EV to charge (or unplug my EV to drive away), what power plant turns on or off in response to that demand? And can we ensure—through a combination of smart, flexible charging and the right signal, such as AER—that EVs are using as much clean energy as possible while avoiding dirty energy?

With the kind of smart, flexible charging envisioned in the UK Ofgem report and WattTime’s AER technology, the answer is yes. And that’s as big a story, we’d argue, as the UK grid being able to handle 60% more EVs.