Large-scale PV with Tracking
Moree Solar Farm, in northern New South Wales, Australia, has a rated power of 56 MWAC (70 MWDC/p). The project site area is around 280 hectares. It uses 222,880 polycrystalline modules with single-axis horizontal tracking. The project, a scaled down version of a previous proposal, was the first in Australia to include tracking on such a large scale.
Energy supply is ~145 GWh annually, implying a capacity factor of 30% (based on AC capacity). Annual variation is expected to be minimal at around 5%.
The panels are approximately 2.5-3m above ground level on 2785 self-powered trackers. There are 56 inverters in 28 (2MWac) Power Blocks. There is 34.5km of HVAC cabling and 110km of DC (both underground).
Grid connection is to Essential Energy’s distribution network. A nearby substation already had the capacity to handle the power produced by the solar farm. The solar farm’s own 66kV substation is connected to that existing substation by 13km of overhead power line (4km of new line and a 9km long section of upgraded line).
A SCADA system allows for the detailed monitoring and control. For example, checking the energy production of the PV panels, as well as the correct tracker orientations. A “smart” plant controller controls the regulation of key output attributes such as active power, power factor, reactive power, voltage and frequency.
Key companies involved include:
- The plant owner, Fotowatio Renewable Ventures (FRV), a Spanish company.
- Engineering and construction was by the Green Light Contractors Pty Ltd, a subsidiary of Elecnor.
- Panels are provided by JA Solar, inverters by Ingeteam and trackers by NEXTracker.
During the construction phase of the project, more than three quarters of the 150 jobs were awarded to local workers. Five permanent employees now operate the farm.
A larger 150MW version of the project was selected as a winner of government funding. But a controversial 11th hour decision by a utility to reject a PPA meant it could not obtain finance, and its grant was forfeited.
Financial close on the current, scaled-down project, estimated to cost between $164 and $180 million. Australian Renewable Energy Agency (ARENA) invested $101.7 million (a grant). Clean Energy Finance Corporation (CEFC) committed senior debt finance of $46 million.
The Moree project broke new ground by becoming the first in Australia to be built on a “merchant” basis – meaning that it planned to sell its output into the National Electricity Market, rather than rely on a PPA contract with a major off-taker. Previous large projects had been dominated by wind, but greater predictability of solar, along with tracking, allows the project to capture a higher volume of peak priced electricity.
Along with electricity, the project would sell renewable energy certificates called LGCs (more on this below).
The farm starts feeding into the grid, February 2016 and is scheduled for full completion in April 2016.
Origin Energy, a utility, makes its first ever commitment to buy power from a large-scale solar farm by signing a power purchase agreement (PPA) for the next 15 years. Origin will buy 100% of both the electricity and the large-scale generation certificates (LGCs) generated by the solar farm.
The more unusual aspect of the deal is that the PPA was signed after Moree was already financed and constructed (the former thanks to the support from ARENA and CEFC). So it was a new PPA, not a new project.
At the time, other new projects were struggling to get finance because they were unable to secure PPAs of 15 years (most only got offers between 5 and 10 years).
Though not disclosed, the contract was believed by some sources to be around $80 per MWh. That may have been based on the suggestion by the CEO of Origin Energy that the cost of large scale solar had fallen to those levels. Some solar developers regarded that as a “forward-looking” estimate though, possibly a negotiating tactic for future PPAs.
At the time of writing, the power plant has been up and running for nearly one year.
Notes on Policy & Market Environment
Signing a PPA helps Origin meet its liability under Australia’s 2020 Renewable Energy Target legislation (the target being 25% of electricity). Renewable energy certificates (LGC’s) underpin the target. There is an obligation on utilities to purchase LGCs until 2030, though it is unclear what obligations will exist after that (or how the RET will develop after 2020).
In earlier years, uncertainty over the future of the RET had caused utilities to hesitate to commit to long-term contracts to buy renewable energy and certificates. Increased confidence around the 2020 target then drove up certificate prices, making investments more attractive.
At the time of writing, LGC prices are close to the scheme cap (at $85-$90) and considered likely to remain that high for the medium term.
In addition to inflated LGC prices, increased project commitments are also helped by a dramatic increase in wholesale power prices recently in the eastern states of Australia. These have been driven by a combination of rising fuel costs, extreme weather and the closing of ageing base load generation. As a result, the price for 2018 base load power has been sitting close to $90/MWh (almost three times levels seen only two years previously).
Among policy risks are concerns over the long-term policy on carbon, and the debate around power system security and resilience as the capacities of renewable power grow (and conventional, dispatchable capacity such as coal is decommissioned). The latter in particular has led to some large-scale commitments to PV + storage projects.
[last update April 2017]