A strong plug-in hybrid car, truck, or commercial vehicle uses low-emissions electricity to drive a significant majority of its average annual miles.

Today’s strongest PHEVs are those with at least 40 miles of electric range (AER). By mid-decade, that minimum should be 60 miles or more for vehicles up to 6,000 lbs. The second propulsion system can be an internal combustion engine or fuel cell, preferably capable of using very low-carbon fuel. Strong PHEVs must be safe and roadworthy in any driving mode, mostly eliminate cold starts, and be tested for performance and emissions on an established test cycle that most closely matches real-world driving, preferably the US EPA test reflected on the window sticker of new vehicles. A Strong PHEV’s engine should rarely—if ever—come on with ample battery state-of-charge and require minimal or no engine maintenance. They use existing, market-established charging connectors.

Strong PHEVs:

• are complimentary to battery electric vehicles, biofuels, and hydrogen- while supporting faster market expansion
• provide on-site back-up power during catastrophes or outages
• lower the impact on and may deliver resilience to the electric grid
• reduce range anxiety and infrastructure cost
• broaden the used EV market in all vehicle classes
• expand EV opportunities for smaller, rural, and disadvantaged communities, particularly those in colder regions
• serve as a platform for advanced batteries, fuels, and engines
• provide a realistic solution for towing.

Enable more rapid EV market growth, as Strong PHEVs compliment ZEVs:

While we do not uniquely advocate for them within this group, Coalition members support Zero-Emissions Vehicles, particularly Battery Electric Vehicles (BEVs). Accordingly, strong PHEVs aren’t proposed to compete with them, but rather with traditional gasoline-only or other less-efficient, more-polluting vehicles. SPHEVs offer a compelling, near-zero-emissions option for individuals and fleets who don’t yet find BEVs viable. Specific requirements should vary with vehicle class and type, but the goal to accomplish nearly a significant majority of users’ daily driving in electric mode remains consistent. Considering battery advances, a strong plug-in hybrid car should have an AER of 60 miles by mid-decade, which will electrify about 80% of typical annual miles and have a similar GHG and emissions profile as a 300-400 mile-range BEV. Similarly, larger SPHEV trucks should also electrify about 70-80% of their annual miles.

The flexibility of strong PHEVs alleviates unique range anxiety concerns in an expanding number of use cases with varying distance requirements. Both fleets and commuters benefit from vehicles that may use—but are not dependent on—faster, more expensive DC charging, lowering capital investment and operation costs. These are particular advantages in rural and disadvantaged communities, where driving distances might be longer, budgets more constrained, and sufficient, affordable, public charging lacking. As more infrastructure is deployed, these SPHEVs will become “increasingly” electric.

Strong PHEVs can support congestion charge schemes, “emissions-free zones,” or other local vehicular pollution policy, either through a manually-enabled “hold mode” featured on many of today’s models or automatically-geofenced transition systems currently in development.

Strong PHEVs support smart grid management and integration:

Using smaller batteries than BEVs and with the flexibility to charge at lower-power 240v “L2” (or even 120v “L1”) charging speeds, SPHEVs take full advantage of overnight or other off-peak charging periods, maximizing grid asset utilization.

While strong PHEVs may not be dependent on DC charging, the inclusion of this feature provides both electric range extension and, for some models, bi-directional power capability. These vehicles may provide exportable power to a home or other site, or even to the grid itself, for emergent needs or arbitrage purposes. Using them for this purpose can alleviate the need for redundant stationary storage batteries. When crucially required, the secondary fuel in SPHEVs can also be used to extend this ability, making them ideal for municipal and other resilience needs.

Long Term Technology Solutions:

A key advantage of strong PHEVs is their political and technological common ground with both incumbent petroleum-based fuels and more renewable alternatives. While most use gasoline as their secondary fuel today, the Strong Plug-in Hybrid Coalition encourages replacing it with cleaner fuels over time. It is also critical to resilience and revolution in transportation to research, develop, and implement technologies that build on technological successes to date. 

Strong plug-in hybrids present an optimal platform to incorporate many of these developing technologies- whether renewable fuels or batteries, motors, and engines advancing with a focus on increasing efficiency, reducing the use of certain materials, light-weighting, and other goals.