Renewables.

Two separate regimes govern MV-equipment country-of-origin for renewables: the IRA's domestic-content bonus credit and the Build America Buy America Act (BABA).

The IRA bonus is a 10% adder on the Investment Tax Credit (or its equivalent under the tech-neutral Section 48E credit) for projects that meet a US-content threshold on steel, iron, and manufactured products. Iron and steel must be 100% US-melted-and-poured. The "adjusted percentage" threshold for solar, onshore wind, and BESS is 40% for projects beginning construction before 2025, 45% in 2025, 50% in 2026, and 55% thereafter.

IRS Notice 2024-41 (May 2024) introduced an Elective Safe Harbor that lets developers use IRS-assigned cost percentages for each component, including transformers, capacitors, inductors, bus and cables, and circuit protection inside the "Electrical Parts" Manufactured Product Component for solar PV ground-mount projects. Notice 2025-08 (the "First Updated Elective Safe Harbor") refined that table.

BABA applies separately, and governs MV equipment purchased for federally funded projects (DOE loan-program awardees, federal-agency installations, certain transmission projects). BABA and the IRA bonus can both apply to the same project.

The "One Big Beautiful Bill Act" (July 2025) altered parts of the clean-energy tax landscape; verify current credit terms with tax counsel for each project.

Wood Mackenzie's Q2 2025 survey put standard power-transformer lead times at 128 weeks (about 2.5 years) and generator step-up transformer lead times at 144 weeks (about 2.8 years).

Distribution-class units under 10 MVA have improved to 8–16 weeks for standard configurations; medium-power units 10–100 MVA run 12–18 months. Pad-mount three-phase units common in solar and BESS are projected to tighten further through 2026 and 2027 per Wood Mackenzie's outlook.

Wood Mackenzie pegged the national supply deficit at 30% for power transformers and 10% for distribution. The DOE finalized new distribution-transformer efficiency standards in April 2024 with a five-year compliance window, leaving about 75% of the market on grain-oriented electrical steel.

Order No. 2023 (effective November 6, 2023) replaced "first come, first served" serial interconnection studies with "first ready, first served" cluster studies. Project developers now have to demonstrate commercial readiness — including showing site control and posting study and readiness deposits — to enter and progress through the queue.

Cluster study deposits are $35,000 plus $1,000 per MW for facilities 20 to 80 MW, $150,000 for 80 to 200 MW, and $250,000 for 200 MW and above. An initial commercial readiness deposit equal to twice the study deposit is required to enter the cluster study. Withdrawal carries a penalty tied to the cluster phase: during the cluster study, the greater of the study deposit or twice the study cost; during restudy or later, 5% of the identified network upgrade costs.

For procurement, the change pulls the long-lead equipment decision forward. Cluster award and the network-upgrade scope drive the POI substation design, which in turn drives the MV transformer and switchgear ratings. With transformer lead times still over two years, the practical sequence is to lock the cluster-study assumptions and place orders against them well before the GIA executes.

Order 2023-A (March 2024) made minor adjustments. FERC reported in early 2026 that supplemental fast-track pathways have moved more than 50 GW of shovel-ready generation through the queue.

A complete pad-mount or station transformer spec under IEEE C57.12.00 (general requirements) and C57.12.34 (three-phase pad-mounted compartmental) needs the following.

Ratings. kVA. Primary voltage including configuration (e.g., 12,470 GRDY/7,200 wye; 34,500 delta) and primary BIL. Secondary voltage and BIL. Frequency. Impedance (%Z) — tolerance ±7.5% per ANSI C57.12.00.

Construction. Cooling class (ONAN, KNAN — natural-ester fluid — or others). Insulating liquid (mineral oil vs. natural ester / less-flammable). Tap arrangement (number of taps, ±2.5%, no-load vs under-load). Live-front vs. dead-front. Loop-feed vs. radial-feed. Enclosure paint and finish.

Service conditions. Indoor vs. outdoor. Altitude. Ambient temperature range. Required sound level.

For renewable projects, also send. Inverter manufacturer and model (for impedance match and harmonic loading). Whether the unit is inverter-duty for collector system, station service, or POI step-up. Domestic-content target for the project. Required UL listings.

Send what you have through Contact — Hawk MV Supply will fill in any remaining ratings against the cluster-study and inverter-vendor documents you provide.

The inverter and the inverter-duty transformer are a coordinated pair. The inverter's switching frequency and output filter shape the harmonic content the transformer sees; an inverter-duty unit is designed and de-rated for that harmonic load rather than a clean utility sine wave.

Several spec items must match across the inverter and the transformer: the transformer impedance has to fall within the inverter manufacturer's allowed window, the secondary winding configuration has to match the inverter output (grounded wye, ungrounded, delta-tertiary), and the reactive-power range — many jurisdictions require 0.95 leading to 0.95 lagging at the point of interconnection — has to be deliverable at all defined operating points.

The pair also has to deliver fault ride-through, the requirement that the plant stay connected and support the grid during voltage dips rather than tripping offline. Sending the inverter make and model with the transformer spec is how the impedance, winding, FRT, and reactive-power coordination get confirmed before the unit is built.

Co-located PV+BESS now attaches to roughly 38% of 2026–2027 queue projects per NREL's tracking. The two architectures used are AC-coupled (separate inverters for PV and BESS, simpler, dominant in the field today) and DC-coupled (PV and BESS share one bidirectional inverter — NREL's ATB models the utility-scale case as 130 MWdc PV plus a 71.5 MWdc 4-hour battery feeding a shared 100 MWac inverter).

For the medium-voltage scope, co-location shares the POI substation, the GSU transformer, the protective relaying at the POI, and the collector-tie hardware — the cost saving that drives the economic case. The collector itself changes: BESS power flow is bidirectional, so collector-system protection, transformer thermal sizing for round-trip charging, and the protective-relay settings at the POI all account for net export and net import. The transformer feeding a BESS block sees a different duty cycle than a transformer feeding a PV string and is specified accordingly.

DC-coupled systems also capture PV energy that would otherwise be clipped at the inverter — improving round-trip efficiency on the charge side and shifting how the collector-system transformer is loaded across the day.