Navigant Research Blog

We’re Asking the Wrong Question about Electrification

— September 1, 2015

At the recent Fleet Technology Expo in Long Beach, California, Tesla Motors’ co-founder and founder of Wrightspeed, Ian Wright, delivered a keynote to the gathering of fleet managers, suppliers, and consultants that turned the conventional wisdom of vehicle electrification on its ear. While mandates like the California Zero Emission Vehicle (ZEV) program and various federal and state tax incentives seek to displace millions of fossil fuel-burning vehicles with electric equivalents, Wright says we’re asking entirely the wrong question. Rather than asking how to maximize the efficiency of the mass of vehicles, Wright said we should be asking: “How do we save the most fuel per vehicle per year?”

On the surface, those might seem like the same question. However, when you actually start doing the math, the resulting answer is quite different. Vehicle emissions, including CO2, are directly related to how much fuel is consumed. Unfortunately, most people tend to think of efficiency in miles per gallon (mpg). When we plot fuel consumed versus mpg, the consumption curve asymptotically approaches zero as mileage goes up. In fact, the curve of incremental fuel savings flattens out dramatically at about 35–40 mpg. Beyond that, increasing mileage comes at a very high cost with little to actually show for it in terms of reductions in total energy use and emissions.

The big gains come when you start from very low mpg, where each incremental improvement yields much larger reductions in fuel consumption. That’s where Wright has focused his efforts in recent years. Wright joined Tesla co-founders Martin Eberhard and Marc Tarpenning and financial backer Elon Musk early on in 2003 to help the tech entrepreneurs with the technical aspects of actually building a car. While Wright left Tesla long before the Roadster finally went to customers in 2008, he continued working on electrification.

Different Solutions for Different Applications

Wrightspeed has developed a micro-turbine, range-extended powertrain system for medium and heavy duty trucks, the vehicles with the biggest potential for fuel savings because they use the most fuel. These big trucks typically only achieve 3–4 mpg running on diesel and even less on natural gas. While the Nissan LEAF or Chevrolet Volt can save individual owners hundreds of dollars a year in fuel compared to similar gasoline-fueled models, the actual amount of fuel saved is relatively small.

A refuse truck is an ideal application for hybridization since it operates at relatively low speeds and makes hundreds of stops and starts per day. In order to get the 130–150-mile range needed for its daily rounds, a fully electric version would need to carry so many batteries it would consume more than half its payload; however, a plug-in hybrid with 30 miles of electric range is entirely viable. Wrightspeed developed its geared traction drive, a 250 hp unit that integrates a traction motor, two-speed gearbox, and inverter, to provide propulsion and regenerative braking. In combination with a small 80 kW turbine range extender sized to run at its optimal efficiency, Wright claims the system delivers a 50% reduction in fuel consumption, saving $35,000 in fuel and $20,000 in maintenance per vehicle annually with a 3–4-year payback time.

Navigant Research’s Automotive Fuel Efficiency Technologies report projects that a wide variety of solutions will be required to meet future efficiency and emissions targets. In order to get the maximum overall benefit, we need to ask Wright’s question and pick the best solution for each application—not one solution for every application.

 

Electric Vehicles and the Clean Power Plan

— August 24, 2015

Power_Paddle_webPlug-in electric vehicles (PEVs) bridge the gap between transportation and electric power—two sectors that until 5 years ago were effectively disparate. Overall, the potential future synergies between the two sectors seem promising. However, because these sectors are somewhat foreign to each other, some uncertainties are likely early on. One area of uncertainty is with regard to the U.S. Environmental Protection Agency’s (EPA’s) Clean Power Plan (CPP), released August 3, 2015.

The CPP is not designed to explicitly affect PEVs; rather, it is designed to decrease electric power sector CO2 emissions from existing fossil-fuel power plants. However, depending on the method by which each state implements the policy, PEVs may present a detrimental or beneficial component to state compliance strategies.

Because each state has a different electric power generation mix, each state will have individual goals and pursue varying strategies in order to comply with the CPP. The CPP CO2 reduction goals have been developed by the EPA using a rate-based approach, which places CO2 per megawatt-hour limits on power plants, but states may also use a mass-based approach (i.e., total metric tons of CO2 from the electric power sector).

PEVs Increase Demand

The mass-based approach will likely create complications for states with fast growing PEV markets. The complication arises on behalf of the fact that PEVs increase electricity demand, which increases the total emissions from power plants, while the overall CO2 reductions achieved on behalf of the PEV are not integrated in CPP calculations. This means that while a PEV would likely reduce net CO2 emissions, PEVs could make state compliance efforts for the CPP more difficult.

The rate-based approach may produce similar complications; however, this is entirely dependent on what grid resources are used to fuel PEVs. For instance, utilities may design incentives to coordinate PEV charging with peak solar or wind generation times, which would in effect increase utilization of renewable generation assets, decreasing the average rate of CO2 emitted per megawatt-hour produced in a state.

Vehicle Grid Integration

Programs and technologies to shift PEV charging to off-peak hours and integrate PEV charging into advanced grid services are being developed in large PEV markets. BMW’s iChargeForward program, which aggregates 100 BMW i3s in the San Francisco Bay Area for grid services, launched in July. Recently, charging station manufacturer eMotorWerks and non-profit software developer WattTime debuted a charging station that can automatically schedule PEV charging when the carbon emissions from the grid are lowest.

While the load represented by PEVs is still marginal compared to overall electric power sector demand, PEVs will become an ever increasing concern. Navigant Research estimates that the average PEV can increase the average U.S. household annual energy consumption by around a third and estimates that the median state PEV market share of 0.5% in 2014 will grow to over 2.5% by 2024. By the time the CPP takes effect in 2022, this equates to 4.4 million light duty PEVs in use, each consuming around 3,000–4,000 kWh annually.

PEV Market Share (% of New vehicle sales) by State, United States: 2014, 2024

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(Source: Navigant Research)

As PEV adoption reduces overall emissions in most states and cases, state PEV adoption incentives should not run contrary to state CPP compliance efforts. Rather, states should encourage efforts to utilize PEVs as potential distributed generation/energy storage resources useful for CPP compliance.

 

To Make Fast Charging Economical, Sites Need Frequent Visits

— July 27, 2015

The number of battery electric vehicle models on offer in the United States is expected to grow significantly during the next few years, with Audi, Chevrolet, Ford, Tesla, and others all expected to add to their fleets. For these models to be successful, the expansion of direct current (DC) fast charging stations to keep the cars charged will need to keep pace. While the business model for hosting a fast charging site is improving, offering the service can become quite expensive when demand charges are incurred.

According to a new report from the Idaho National Laboratory, offering DC fast charging can increase a host site’s utility bill by 15% to 100%, depending on the rate schedule. The report, which culls data from the U.S. Department of Energy’s (DOE’s) EV Project, illustrates how charges can vary greatly depending on the service territory.

How It Works

Utilities assess demand charges each month if a business exceeds specified amounts of power consumed within peak hours during a single period, usually tracked in 15 minute increments. DC fast chargers can boost power consumption by up to 60 kW, which, depending on the rate schedule and overall power consumption, is more than enough to push many businesses into demand charge territory.  And demand charges aren’t a one-time event, as they are levied monthly for up to a year or more.

For small business owners looking to fast charge electric vehicles (EVs), the price can be especially steep. The report states that “power demanded by DC [fast charging] has a more significant impact on electric utility costs for smaller commercial businesses than for larger ones.” In one example, a single charging session that puts a location above its allotted power consumption could cost $482 for that month and subsequent months. DC fast charging locations often charge $10 or less for a single charging session (such as NRG’s growing EVgo network that charges $0.10 per minute in Denver), which could create significant losses for site owners.

Therefore, if demand charges are incurred, sharing that cost among many charging sessions will make offering EV charging more economical, according to the Idaho National Laboratory. Understanding how offering DC fast charging will impact the utility bill is complicated, as each utility offers multiple tiers and rate schedules for power consumption.

Other Options

An alternative to the often severe demand charge fees is to purchase an energy storage system that would power the EV chargers at times of peak demand. Several companies, including Nissan, are entering the energy storage market to serve this developing niche.

Demand charge rate structures are a moving target in some areas as they undergo periodic revisions, which can sometimes result in contentious public utility commission hearings, as is happening now in Austin and Oklahoma.  Simplifying and limiting the fees for offering DC fast charging, such as through separate EV metering or rates, could encourage today’s reluctant business owners who are wary of the fiscal impact to begin to offer the service.

 

EPA Looks to Make EV Charging More Energy Efficient

— July 24, 2015

The U.S. Environmental Protection Agency (EPA) wants to reduce the energy consumption of electric vehicle supply equipment (EVSE) by developing its first ENERGY STAR specification for this category of products. As we know, electric vehicle (EV) chargers are idle for the majority of the day, and the specification will address the amount of power consumed while not in use.

The ENERGY STAR program will initially focus on alternating current (AC) (Level 1 and 2) charging, but the EPA is also looking at direct current (DC) charging.

According to the EPA document:

“Emerging EVSE could include features such as the ability to receive DC power from PV panels or local storage; provide DC power to other devices in a building via USB, Ethernet, or other power transmission medium; supply AC power to a building or specific appliances; coordinate power distribution with other entities in the building; include electricity storage internal to the EVSE; and enabling transmission of power from a vehicle to a home.”

Enabling DC chargers to share the incoming power via USB, AC power, Ethernet, or other media is an interesting way of getting more value out of available power. DC chargers are only used in short bursts for fast charging, so finding ways to smartly manage them as a building resource makes sense. Building in a power converter enables the charger to integrate into other stationary devices, such as using DC power from a solar panel locally instead of sending it back to the grid where its value is often less. I haven’t seen any DC chargers that can do this today, so it will be interesting to see how manufacturers develop products with these capabilities.

Paying to Park

Car Charging is looking at increasing the utility of EV chargers through a different approach. The company is assessing a fee of $0.08  per minute to EV owners who leave their vehicles plugged in but not charging for longer than 15 minutes after the charging session ends, according to PluginCars.com. The 15-minute grace period seems sensible, as many customers receive automated alerts when charging is completed. The fee is a considerable incentive for people to be conscientious about moving their cars after a completed charge, which makes them available for other (revenue-generating) charging sessions, which is critical for EVSE to become profitable.

At the EV Roadmap Conference starting July 29 in Portland, Oregon, I’ll be moderating a panel where several industry luminaries will be discussing the latest innovations in smart EV charging. Stop by and check it out, or leave a comment here with questions for the panel.

 

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