The Potential of Concentrated Solar Power for Remote Mine Sites in the Northern Territory, Australia
Table 1
Comparison of CSP collecting technologies [1, 11–13].
Technology
Parabolic trough system
Central tower system
Linear Fresnel system
Parabolic dish system
Sketch
Description
(i) Sun rays focused by parabolic through reflectors (ii) Pipes containing heat transfer fluid run through the reflector focal points
(i) Arrays of heliostats focus sunlight on a central receiver (ii) Heat transfer fluid runs through the receiver and generates steam
(i) Sun rays are focused by an array of linear mirror strips on a line receiver (ii) Linear fixed receiver is mounted on a tower
(i) An array of point-focus collectors tracks the sun in two axes (ii) Sun rays are focused on a receiver at the dish focal point
Maturity (2012)
Commercially proven (over 25 years), 3124 MWe installed as at 2013
Pilot commercial projects (medium to high maturity), 64 MWe installed as at 2013
Pilot projects (medium maturity), 288 MWe installed as at 2013
Demonstration projects (low maturity), 1.5 MWe as at 2013
Typical capacity (MW)
10–300
10–200
10–200
0.01–0.025
Operating range (°C)
150–550
250–1200
150–500
300–1500
Power cycles considered
Steam Rankine Organic Rankine
Steam Rankine Brayton cycle
Steam Rankine Organic Rankine
Stirling engine Steam Rankine
Plant peak efficiency (%)
14–20
23
18
30
Annual solar to kWh efficiency net (%)
11–16
7–20
13
12–25
Maximum slope of solar field
Up to 2%
Up to 4%
Up to 4%
10% or more
Water requirement (m3/MWh)
3 (wet cooling) 0.3 (dry)
2-3 (wet) 0.25 (dry)
3 (wet) 0.2 (dry)
0.05–0.1 (mirror washing)
Land occupancy
Large
Medium
Medium
Small
Typical surface area (m2)
300–900
100–200
30–300
50–100
Heat transfer fluid
Water/steam and synthetic oil
Water/steam, air, and molten salt
Water/steam
N/A (Stirling engine or microturbine)
Storage system demonstrated
Molten salt
Molten salt
Pressurized steam
Only indirect storage
Other storage options
Molten salt, concrete, and phase change materials
Concrete, ceramics, and phase change materials
Molten salt, concrete, and phase change materials
Concentrated heat to catalytically break NH3 into N2 and H2 for storage to recombine for release of heat
Advantages
(i) Mature steam cycle systems (ii) Success record of 354 MW (California) (iii) Simple design (single axis tracking) (iv) Hybridization with natural gas is attractive and functional (v) Ability to connect with thermal storage
(i) High temperatures and high thermal efficiency (dual axis tracking) (ii) High capacity factor and molten salt that can be used as direct HTF (iii) Simple network (single tower) (iv) Flat mirrors easy to construct and inexpensive
(i) Understood steam cycle systems (ii) Simple design (single axis tracking) (iii) Hybridization is possible (iv) Ability to connect with thermal storage (v) Flat mirrors easy to construct and inexpensive
(i) High temperatures and high thermal efficiency (dual axis tracking) (ii) Costs benefits in mass production compared to other technologies (iii) Does not require levelled surface
Disadvantages
(i) Water requirements may become a site specific constraint (ii) Maximum temperature is limited (iii) Surface has to be flattened for troughs to be installed (iv) Sun tracking is limited in single axis systems (v) Curved mirrors are sophisticated and require special manufacturing
(i) Water requirements may become a site specific constraint (ii) Requires high capital investment (iii) Only sufficiently large units are cost effective and feasible (iv) Sun tracking can be a complex job (v) Surface has to be flattened for troughs to be installed
(i) Water requirements may become a site specific constraint (ii) Sun tracking is limited in single axis systems (iii) Surface has to be flattened for troughs to be installed
(i) Requires very high capital investment (ii) Manufacturing of parabolic dish is very sophisticated and incurs very high costs (iii) O&M costs could be very high (iv) Thermal storage is not possible (v) Surface roughness has a limitation
