Renewable energy boom drives transformer demand
Solar, wind and energy storage projects all need transformers built for their particular duty, and the volume of those projects is rising. The transition changes not only how much transformer capacity is installed, but where it is installed and what it has to cope with.
Why renewable energy needs special transformers
Solar PV plants
Solar plants generate DC, which has to be converted to AC and stepped up to transmission voltage. The step-up transformer has to cope with the characteristics of inverter output, including harmonic content and the fact that output rises and falls with irradiance across the day.
Utility-scale solar plants are typically laid out as many inverter blocks, each with a medium-voltage step-up transformer, feeding a collector substation with a larger unit. That means a solar farm is a transformer-heavy installation even before the grid connection.
Wind farms
Wind output follows the wind, so wind farm transformers see frequent load changes and often work in difficult environments — offshore, coastal, desert, or at altitude. Offshore units in particular are specified for corrosion protection and for the cost of any intervention, which strongly favours designs that need little maintenance.
Energy storage systems
Battery energy storage systems (BESS) need transformers that handle bidirectional power flow and rapid charge and discharge cycles. The bidirectional requirement affects protection design and tap changer specification, and the cycling duty means the unit sees more thermal variation than a conventional transformer performing the same average energy throughput.
Technical requirements that differ from conventional duty
- Harmonics — inverter-fed generation and storage inject harmonic currents, which raise eddy and stray losses. A harmonic loss allowance should be written into the specification.
- Fluctuating load — repeated thermal cycling over decades affects insulation and clamping structures.
- Wide voltage variation — particularly on weak rural networks where renewable plant connects.
- High ambient temperature — solar installations are often in hot, exposed locations.
- Unattended operation — monitoring and remote diagnostics are more valuable than on a manned site.
Market trends
The International Energy Agency forecasts that low-carbon sources (wind, solar, nuclear and hydro) will account for almost half of global generation by 2026. Building that capacity requires a lot of transformers, and the market projections reflect it: global demand for power transformers is projected to grow at a compound rate of about 7.4% through 2033.
Two consequences follow for buyers. First, lead times extend, so ordering early becomes a schedule decision rather than a cost decision. Second, specifications converge — projects increasingly expect the same technical requirements, which makes a well-documented offer easier to evaluate.
Our renewable energy solutions
We supply transformers for:
Our range covers inverter step-up units, collector substation transformers and grid connection transformers, in both oil-immersed and dry-type construction. For solar and wind duty we specify harmonic loss allowance and can supply monitoring options for remote diagnostics.
What to include in a renewable energy enquiry
- Plant type and total capacity in MW
- Number and rating of transformers required
- Voltage ratio and grid connection point
- Harmonic spectrum or inverter data, if available
- Site conditions — ambient temperature, altitude, coastal or desert exposure
- Whether indoor or outdoor installation is planned
- Monitoring and communication requirements
- Destination market and the standards that apply
Browse our renewable energy transformers and power transformer range, or read our analysis of transformer market growth.
Contact us for your renewable energy transformer requirements.
Transformer arrangements in a typical renewable plant
| Position | Function | Typical type |
|---|---|---|
| Inverter step-up | Raises inverter output to medium voltage | Oil-immersed or dry-type, medium rating |
| Collector substation | Aggregates many medium-voltage feeders | Oil-immersed power transformer |
| Grid connection | Raises to transmission voltage | GSU or grid transformer with OLTC |
| Station service | Supplies the plant’s own auxiliaries | Oil-immersed or dry-type, small rating |
Because a renewable plant has many small units feeding a few large ones, the transformer count is high even for a moderate capacity. That makes standardisation valuable: fewer distinct ratings means simpler spares, simpler protection settings and faster commissioning.
Why the duty is harder than it looks
Variable output
Solar output rises and falls with the sun and wind output follows the wind, so renewable plant transformers see far more load variation than a base-load thermal station. Every load change is a thermal cycle, and repeated thermal cycling works insulation and mechanical clamping over the decades of service life.
Connecting to weak networks
Renewable projects are often built where the resource is, which is frequently where the network is weakest. Weak networks mean wider voltage variation, which means a wider tap range, and lower fault levels, which affects protection settings.
Harmonic content
Inverter-fed generation injects harmonic currents into the transformer. The resulting additional losses are real and can be significant, so a harmonic loss allowance belongs in the specification rather than being discovered from operating temperatures.
Environmental exposure
Solar plants are typically in hot, dusty or exposed locations; wind plants are often coastal, offshore or at altitude. Each environment places its own demands on cooling design, corrosion protection and maintenance access.