The Perenjori 20MW Dispatchable Solar Tower project is a feasibility study into the construction of a 20 MWe solar thermal power station in Perenjori, WA. The plant would employ Abengoa’s molten salt tower technology with a thermal energy storage system and would be integrated into the north-eastern fringe of WA’s South Western Interconnected System (SWIS).
The study will consider the potential for the first large-scale commercialisation of CSIRO’s heliostat technology, which has been developed with ARENA support at pilot scale in Newcastle. The heliostat field will be made up of over 200,000 m2 reflectors, occupying around 100ha and concentrating sunlight to a high temperature receiver at the top of a more than 100m tall tower.
Various design strategies are being trialled in the US, Europe and elsewhere to drive towards lower costs and higher efficiencies for solar thermal systems. However more rapid cost-reduction pathways must be demonstrated for solar thermal to become more broadly adopted as a mainstream energy generation technology.
The Perenjori 20MW Dispatchable Solar Tower project includes storage and has been configured for maximum replicability and optimum capacity using technology that promises the steepest cost reduction pathway.
The project promises the widest possible replicability and relevant knowledge for future solar thermal project applications. This is due to its configuration and location at the edge of the SWIS.
A plant capacity of around 20 MWe is a logical minimum for a solar thermal plant. As shown in a recent ARENA-funded study, the cost of electricity generation sharply increases at capacities smaller than 20MWe whereas the economy of scale for higher capacities is more gradual.
The project includes a thermal energy storage system, which will allow the solar thermal plant to generate electricity when needed, for example to match the evening peak demand on the SWIS. This dispatchability provides the benefits of firm capacity to the local transmission network and would qualify for capacity credits if available.
Pathway to cost reduction
Towers with molten salt show the highest potential for cost reduction of the three main solar thermal options: parabolic trough, linear fresnel and tower. This is because they allow higher temperatures, resulting in higher efficiency and lower storage costs.
The 20 MWe solar thermal plant will generate up to 100 GWh of electricity each year, enough electricity to power over 15,000 Australian homes and reduce emissions by 100,000 tonnes per year. The project location near Perenjori in Western Australia’s mid-west region is an ideal site for the proposed plant and will provide a valuable case study because:
- the site has a world class solar irradiation resource
- fringe-of-grid connection will provide significant network benefits
- proposed off-take arrangements include a combination of an electricity retailer and potentially a large iron ore mining operation with suitable load requirements
- WA Government is supportive of such activity
- strong demand for peak and especially shoulder generation
- excellent prospects for further roll-out of solar thermal power generation with storage in end of grid and off-grid applications, with an emphasis on powering the mining sector.