Queensland presently has the lowest share of renewables in the National Electricity Market. In terms of wind farms, Queensland has just the 12 MW Windy Hill wind farm, compared to more than 1,200 MW of registered wind capacity in South Australia, and has only a handful of new wind projects proposed.
In September 2012, ROAM Consulting produced a report for the Department of Climate Change on the wind and solar resources in the NEM. These reports were produced as part of the ‘100% Renewables’ project being undertaken by the Australian Energy Market Operator. The study considered the areas in 43 polygons across the eastern states.
One important finding was the large amount of good wind resource available in Queensland, which is often thought to have poorer wind resources compared to the southern states.
In Queensland, the study area covers 73 per cent of the land area and represents the land in the vicinity of the existing transmission network of the NEM. The polygons do not cover the Mt Isa system in north-west Queensland or areas north of Archer Point in Queensland.
ROAM’s analysis used an extensive array of data and heuristics for determining potential wind and solar sites with suitable terrain, land use and weather conditions. Elevation, land use and population data were combined to determine an upper bound for the land available for wind and large-scale solar (PV and solar thermal) power developments.
The consultants developed conservative estimates on land use and population data in order to limit the upper bound on available land area. For example, the build density of wind turbines was not allowed to be greater than any existing wind farm in the NEM relative to the current population density of the surrounding area. For wind power, ROAM also excluded all sites with an estimated capacity factor less than 35 per cent.
ROAM then adjusted the wind and solar resource for each polygon to meet terrain and current land-use limitations. Subsequently, ROAM used its Wind and Solar Energy Simulation Tools (WEST and SEST) to develop hourly time-series of wind power and solar power for each polygon based on meteorological observations and modelling.
For the area of Queensland covered by the polygons, ROAM’s modelling found that 228 GW of onshore wind power is possible. Due to a large amount of flat land available in Queensland and high isolation, ROAM estimated that up to 8,900 GW of large-scale solar PV or 6,400 GW of concentrating solar thermal power could be installed. Considering that the current average demand in the NEM is 23 GW, with an annual peak demand around 33 GW (including about 9 GW in Queensland), the potential for wind and solar generation in Queensland is many times larger than needed.
A further benefit is that the north Queensland wind resource (the northernmost polygon) is generally uncorrelated with the wind resource of the southern states, which is a critical factor in achieving system reliability throughout the NEM.
The following figure shows the onshore wind farm build limit (in GW) by polygon, considering only wind farms with a capacity factor of 37 per cent or more.
The solar potential in Queensland is also significant: the next figure shows the build limit (in GW) by polygon for single axis tracking solar PV.
Archer Point near Cooktown in the northernmost polygon has the strongest wind resource in Queensland and a 120 MW wind farm has been proposed there. This site would require significant transmission upgrades to be viable on a large scale, as the transmission system extends only to Cairns, with distribution level supply as far as Cooktown.
Other proposals in north Queensland include the Mount Emerald wind farm, located near the existing Windy Hill wind farm, and High Road in the Atherton Tablelands. In addition to the high wind resource potential, such sites are located in an area of relatively weak generation and would be likely to receive a favourable marginal loss factor if transmission were available.
Marginal loss factors indicate the transmission loss and are measured at reference points near the capital city of each state of the NEM. Generators are paid for the energy they send out multiplied by the loss factor. It is possible for a generator to have a loss factor higher than 1 so that it gets paid for more energy than it generates, if it is in an area with high load and little energy generation. Generation at these locations displaces generation further from the load, decreasing overall transmission network losses.
In north Queensland, Windy Hill wind farm has a marginal loss factor of 1.15, the highest of any generator connected to the NEM. In contrast, Cathedral Rocks, Wattle Point and Mt Millar wind farms in South Australia have marginal loss factors between 0.8 and 0.9. Different locations in the NEM therefore have revenue differences of more than 30 per cent due to loss factors alone.
The full report on ROAM’s wind and solar modelling is available here.
AEMO is converting the wind, solar and other resource mapping into a least cost plan for grid supply from 100 per cent renewables in 2030 and 2050, which is due for release in early 2013.