Research · Citywide Strategy · August 2026
Public L2 can't be the backbone — and doesn't have to be
Two companion analyses examine Alexandria's charging network as a system: how many shared ports the city would actually need if public Level 2 substituted for home charging, and what the portfolio looks like when home access and DC fast charging carry their natural shares. The short answer: home charging where safely feasible, fast charging as the shared backstop, L2 where cars naturally dwell.
The throughput problem in one table
Charging technologies serve different dwell times, and dwell time is destiny for shared infrastructure. A three-hour L2 session means one port serves about 7 routine drivers per year at 30% utilization; a 30-minute fast-charge session means one port serves about 66.
| Metric | Public L2 | L3, 30-min | L3, 42-min (DOE observed) |
|---|---|---|---|
| Session duration | 180 min | 30 min | 42 min |
| Sessions per port-year | 876 | 5,256 | 3,754 |
| Routine drivers supported per port | 7.0 | 65.7 | 46.9 |
| Capacity vs. L2 | 1.0× | 9.4× | 6.7× |
Try the model: how many ports does Alexandria need?
Interactive port-count model
Working fleet: 120,291 personal-use vehicles (City FY26 budget data). Defaults reproduce the paper's central case. "Cross-curb share" is the fraction of affected households enabled to charge at home under the CurbsideALX proposal.
Fixed assumptions (from the paper): 3,600 kWh/user-year; 125 three-hour L2 sessions or 80 30-minute L3 sessions per user per year; ports sized by session turnover at the chosen utilization; L3 sites assumed to have 4 ports. Alexandria currently has ~8 fast ports and a 60-port L2 program cap.
The driver's side of the ledger
Capacity is only half the comparison — the other half is what each strategy costs the driver. Even a mature L2 network (charger within 15 minutes, fully productive three-hour dwell, only a 20% occupied-or-broken failure rate) still requires 125 charging trips a year:
| Strategy | Electricity | Nonproductive time | Time cost | Total burden |
|---|---|---|---|---|
| Home / cross-curb | $468 | 0 hr | $0 | $1,128 |
| Mature neighborhood L2 | $1,080 | 78.1 hr | $4,652 | $5,732 |
| Optimistic L3 (30-min) | $1,440 | 66.7 hr | $3,969 | $5,409 |
Home total includes $360/yr equipment and $300/yr insurance. Notably, even a deliberately favorable mature-L2 scenario now costs more per driver than routine fast charging — and both cost ~5× home charging.
The pitch, restated plainly
Strip away the infrastructure vocabulary and the L2-first proposition to a resident is: "What if, instead of charging at home while you sleep, you had to go to a gas station — but you have to leave your car there for hours, and it might have no pumps available when you get there? Bonus: it will cost twice as much, before we even count the time tax. Would that help you invest in an EV?" The numbers above are that pitch, quantified. Public L2 has real roles — destinations, long-dwell blocks, multifamily streets — but as the default substitute for home charging, it is not a good investment for the City or the resident.
The scale check: Alexandria's gasoline network
Today the city's shared-fueling demand is served by roughly 32 gasoline stations with an estimated 314 fueling positions handling on the order of 10,300 transactions per day (national NACS averages). That is not a forecast of EV charging demand — most EV energy should be delivered while cars are parked at home, work, and destinations — but it is a sober benchmark for what "replace home charging with shared infrastructure" would mean. A 60-port L2 pilot is a useful experiment; it is not a substitute for residential access.
What the City's own strategy and national modeling say
- Alexandria's EV Readiness Strategy distinguishes residential/workplace charging from public L2 and DC fast, recommends matching charging power to dwell time, and projected up to 100 public chargers by 2030 and 800+ by 2050 in its strongest-policy case.
- The City cites EPRI research that ~75% of charging occurs at home, and runs Plug In Alexandria to bring charging to multifamily buildings — the same "charge where you already park" logic CurbsideALX applies to rowhouses.
- NREL's 2030 national charging model expects 64% of charging energy at single-family homes, 20% at public DC fast, and just 8% at public L2.
- DOE notes DC fast charging is particularly important for drivers without consistent off-street parking — and Alexandria's own CHARGE Alex grant narrative proposed four fast chargers at S. Pickett & Van Dorn.
The recommended portfolio
Balanced strategy
(1) Enable safe residential cross-curb charging wherever site conditions allow — every such household removes ~$4,300–$4,600/yr of burden from a resident and a routine user from the shared network. (2) Actively facilitate distributed multi-port DC fast-charging sites — the high-throughput backstop for everyone who can't charge at home. (3) Keep curbside L2 where vehicles naturally dwell for hours, measured by delivered kWh, uptime, and failed attempts during the 60-port pilot. (4) Continue multifamily charging assistance. Plan charging as a portfolio, with separate targets per tier.
Sources
- City of Alexandria, Electric Vehicles in Alexandria (2026): curbside program purpose; 60-charger initial cap; Plug In Alexandria.
- City of Alexandria, Eco-City Newsletter (Feb 2026): EPRI ~75%-at-home estimate.
- City of Alexandria, EV Charging Infrastructure Readiness Strategy: charging tiers; 2030/2050 projections.
- U.S. DOE/NREL, 2030 National Charging Network (FOTW #1335) and EVGrid Assist.
- U.S. DOE, FOTW #1319: paid DCFC sessions average 42 minutes / 22 kWh.
- NACS, Key Facts About Fueling (2026): 9.8 positions and 322 transactions/day per average fuel-selling store.
- City of Alexandria, CHARGE Alex CFI grant narrative; FY26 Budget Q&A #068 (fleet denominator ≈120,291).
Modeling caveats: the 35% no-home-charging share and 30% utilization are planning assumptions, not measured City statistics; the L2 20% failure rate is a scenario assumption; gasoline transactions are an order-of-magnitude analogue only. Full caveats in the papers.