Darwin International Airport’s new 4MW PV solar array is part of a global shift to clean energy infrastructure, writes Olivia Coldrey.

In May 2016, Darwin International Airport in Australia’s Top End switched on its new 4MW photovoltaic solar array. The project marks the first stage of the airport’s ambitious plan to harness the Northern Territory’s renowned solar energy resource to meet its energy needs. In so doing, it is one of a growing number of airports worldwide making the switch to solar energy, motivated by a desire to proactively manage electricity costs and a commitment to environmental sustainability.

The Darwin International Airport solar plant is distinguished as a fit for purpose solution developed by the airport itself, building on parent company NT Airports’ impressive track record in solar generation at Alice Springs Airport. This meant hands on involvement through feasibility, design, construction, tendering and project oversight.

“[M]ore commonly, sole providers approach airports with a development proposal and corresponding power purchase agreement,” says NT Airports CEO Ian Kew. “In the case of Darwin Solar Stage 1, Darwin Airport managed the entire project from beginning to end and consumes all the solar power generated for its own use.”

Building on its work at Alice Springs Airport, the indigenous-owned engineering and project management firm CAT Projects was engaged to develop the solar plant from concept through execution and acted as owner’s engineer and project superintendent.

Technical specifications

The 4MW plant comprises 15,000 solar panels over six hectares, forecast to produce 100% of the airport’s peak electricity demand during the day and 25% of its overall energy needs. The plant operates behind the meter as the value of energy generated is higher than the price the airport could achieve by feeding it back into the grid.

The plant is powered by high efficiency Q Cells modules, which in testing proved capable of tolerating the Top End’s high temperatures and cyclonic conditions. They are complemented by SMA string inverters, which have a history of good performance in NT and are relatively easy to swap in a “plug and play” style suited to the airport’s operational requirements. The system is backed by engineering, procurement and construction contractor UGL’s performance guarantees as part of the project’s rigid performance warranty framework.

Already northern Australia’s largest megawatt scale PV system, Darwin International Airport’s solar project is progressing to a second stage that will see a further 1.5MW of generating capacity installed. When complete, the project will be valued at $13 million and save the airport about $2 million a year, representing 35% of its total electricity cost, and offset the equivalent of 7,000 tonnes of CO2 emissions each year.

NT Airports’ stakeholders have responded very positively to its solar energy initiatives, which underpins the company’s strong social licence. “[T]he interesting thing is how this good news story appeals to a wide and varied audience,” Kew says. “Interest has come from many different industries – engineering, aviation, business, the environment and local communities.”

Problems with airport PV

Safety considerations are of paramount importance in designing a solar plant for a busy airport. According to CAT Projects Managing Director Lyndon Frearson, the multi-faceted approvals process was arguably the most challenging aspect of project development: “The land at the edge of the runway may look empty, but in reality it is covered with all sorts of invisible lines that demarcate where things can and cannot be, all to ensure safety. Designing a PV array within that area requires a lot of stakeholder awareness and flexibility.”

The solar array’s design and orientation needed to comply with the complex regulatory framework Darwin International Airport operates in. This is informed by an unusually broad stakeholder group that includes not only civil but also military aircraft from the adjacent Royal Australian Air Force Base Darwin, host to the RAAF, Australian Army and Australia’s international military partners. As a result, approvals were required from multiple aviation authorities to ensure the solar plant met the operational needs of all end users, including military aircraft not compelled to follow the same approach angles as civilian aircraft and helicopters that adopt different flight paths and approaches than fixed wing aircraft.

The array is oriented at 7.2 degrees East of North, a number that was achieved only after dozens of simulations had been carried out to identify the optimal orientation for maximising yield from the solar plant while ensuring safety through minimising glint and glare.

Obtaining and complying with environmental approvals was critical. The selected site feeds into the Rapid Creek Catchment area, which meant close scrutiny of erosion and sediment control and measures to protect rare fauna. The project team harnessed the site’s natural attributes to its advantage, for example by using cleared, mulched vegetation to control water flows. Frearson notes these regularly amounted to 125mm within 24 hours during the wet season.

Private sector primacy

The Darwin International Airport project is notable for being financed entirely by the private sector, with shareholders comprising experienced renewable energy investors Palisade Investment Partners and IFM Investors. Both firms pursue a responsible investment philosophy and in these terms the solar plant’s economics and its potential for positive environmental impact were compelling.

“Darwin International Airport continues to generate very attractive investment returns for our investors and reducing the airport’s overall carbon footprint is an important component of our sustainability objective,” says Palisade Investment Director Julian Widdup.

Michael Hanna, Head of Infrastructure Australia at IFM Investors, agrees. “From a commercial perspective, stage one of the project was delivered under budget and we will recoup our initial investment costs after seven years.”

A new Labor government in the Northern Territory led by Chief Minister Michael Gunner was voted to power in August in part on a policy platform of transitioning NT to renewable energy, including by adopting a target of generating 50% of the territory’s energy from renewable sources by 2030. If adopted, NT will join the ACT, Queensland, South Australia and Victoria among Australian states and territories announcing and pursuing clear, decisive and ambitious renewable energy targets.

International perspective

The project joins a number of airports powered by solar energy in countries as diverse as the United States and South Africa, where in May 2016 Kimberley Airport in the Northern Cape became the country’s second to run on solar power.

Cochin International Airport Limited in Kerala, Southern India, is the world’s first fully solar powered airport. It has reached this milestone in stages, first installing a 100kWp rooftop PV system in 2013 followed by an additional 1MWp then 12MWp ground-mounted PV plant on land near the international cargo complex. The system is grid-connected without battery storage, with a power banking module established with the Kerala State Electricity Board allowing the airport to feed in to the grid as much power as it produces during the day and to buy back power when required. The airport no longer pays for electricity.

Cochin’s solar initiatives have had a profound demonstration effect on how large-scale transport infrastructure can be powered. During a recent visit to the airport, Piyush Goyal, India’s Minister of State with Independent Charge for Power, Coal and New & Renewable Energy, noted the airport had created a model for solar generation in the context of India’s target to produce 100GW of solar power by 2022. Goyal indicated all Indian railway stations and airports would be instructed to install Cochin-model solar energy generation facilities. Delegations have travelled to the airport from as far afield as Liberia and South Africa to see how it’s done.

The way forward

The solar power plants at Darwin International Airport and other airports worldwide provide real evidence of renewable energy’s capacity to power large-scale, complex transport infrastructure. They demonstrate that airports can be ideal locations for solar installations given their high load profiles and typical attributes of vacant land with limited or no shading. In the case of Darwin and Cochin, airport management adopted a considered, staged approach to developing their solar energy capacity, taking the time to identify fit for purpose solutions rather than buy systems off the shelf.

The technical and economic learnings generated from these installations are substantial and have the potential to play a key role in informing design of airports and other transport infrastructure in Australia and internationally. We can only expect the value of this know-how to increase as demand for such infrastructure continues to grow.


Olivia Coldrey is a lawyer with over 15 years’ energy sector experience. She is Senior Program Manager at the Renewable Energy and Energy Efficiency Partnership (REEEP), a director of the Australian PV Institute and a member of Clean Energy Crowd’s advisory board.