Built to last: The groundwork behind Malaysia’s solar expansion

Malaysia is preparing for another major expansion of renewable energy through the Large Scale Solar 6 (LSS6) programme, which will deliver 2,500MW of solar capacity supported by 1,250MW of battery energy storage. An additional 150MW quota has been allocated to Bumiputera companies, further broadening participation in the country’s clean-energy sector. With full commercial operation targeted by Dec 31, 2029, the programme will prioritise strategic locations with growing electricity demand, particularly in southern Peninsular Malaysia, while strengthening the stability and reliability of the national power system.

While attention centres on solar panels, batteries and investment, the long-term success of every solar farm depends on something less visible: the ground beneath it.

Thousands of foundations, one unpredictable ground

A large solar farm may contain thousands of steel posts supporting photovoltaic panels, together with substations, transformers, access roads, drainage systems and battery facilities. Although each foundation appears relatively small, minor errors in soil assessment can become major project-wide problems.

Ground conditions are rarely uniform across an extensive site. One area may contain firm residual soil, while another consists of loose sand, soft clay, peat, uncontrolled fill or shallow rock. Groundwater conditions may also change between dry and monsoon seasons. Early geotechnical investigation is therefore essential to prevent foundation failure, installation delays and costly redesign.

Reading the ground before construction

A proper investigation should begin well before foundation installation. Soil boreholes help identify subsurface layers, soil strength, compressibility and groundwater conditions. Cone penetration testing, or CPT, provides continuous information on soil resistance and helps detect changes across large areas. Trial pits, laboratory testing, geophysical surveys and groundwater monitoring may also be required.

These investigations allow engineers to determine whether piles can penetrate safely, whether shallow rock may cause premature refusal, whether weak soils can resist wind uplift, and whether foundations may settle or tilt over time.

The findings guide the selection of driven piles, helical or screw anchors, shallow concrete footings or ballasted systems. Driven piles are economical where adequate penetration and resistance are available. Helical piles may suit soft or variable soils, while ballasted systems may be considered where pile driving is restricted or shallow rock prevents penetration.

There is no universally suitable foundation. The correct choice must reflect the soil profile, structural loads, installation method, groundwater conditions and expected service life.

Soft soil, settlement and drainage

Soft clay, organic soil and peat present particular risks because they may compress gradually under loading. Uneven settlement can disturb panel alignment, strain electrical connections, damage drains and affect tracking systems.

Reactive soils may shrink during dry periods and swell when moisture returns. Repeated cycles can loosen shallow foundations and alter pile-soil interaction. High groundwater can reduce soil strength, complicate pile installation and weaken construction roads. Poorly planned earthworks may also interrupt natural drainage, leading to ponding, erosion or flooding around electrical equipment.

Geotechnical design must therefore address not only foundation capacity, but also grading, drainage, erosion control, slope stability and access-road performance.

Corrosion below ground

Steel piles are expected to remain functional throughout the solar farm’s service life, often spanning several decades. Their durability, however, depends heavily on the chemical and electrochemical properties of the surrounding soil. Tests for soil resistivity, pH, chloride, sulphate and salinity help engineers assess the likelihood and rate of corrosion, particularly in coastal areas, reclaimed land, former agricultural sites and locations influenced by saline groundwater.

Where aggressive ground conditions are identified, appropriate protection must be incorporated into the foundation design. Measures may include increased steel thickness, protective coatings, galvanisation, corrosion-resistant materials or sacrificial allowances to compensate for long-term material loss. Drainage and groundwater control may also help reduce prolonged exposure to corrosive conditions.

Unlike visible structural damage, underground corrosion can progress silently and remain undetected for years. Over time, the gradual loss of steel thickness may reduce the pile’s load-bearing capacity and resistance to wind, uplift and lateral forces. A foundation designed to support clean-energy infrastructure for decades must therefore be protected against the hidden risks beneath the surface.

Testing the design in the field

Calculations alone are insufficient. Test piles should be installed using the proposed equipment and verified under actual site conditions. Compression tests assess downward-load resistance, pull-out tests measure resistance against wind uplift, and lateral tests evaluate horizontal movement. These tests confirm the required pile length and embedment depth before mass installation begins.

Construction quality control is equally important. Pile depth, alignment, driving resistance, installation torque and damage should be recorded systematically. Unexpected pile refusal, excessive penetration or changing installation behaviour should trigger immediate engineering review.

Solar farms may be powered by the sun, but their safety and durability depend on sound geotechnical decisions. When ground investigation is treated merely as a formality, problems may later emerge as delays, redesign, settlement, corrosion and structural failure.

Powering up as conclusion

As Malaysia accelerates towards a cleaner energy future, every solar farm must be built not only with advanced technology above ground, but with sound engineering below it. Thorough geotechnical investigation, appropriate foundation design and rigorous field testing are not secondary considerations, they are the safeguards that turn ambitious renewable-energy targets into safe, durable and dependable infrastructure.

The sun may provide the power, but the ground must provide the confidence.