Although the global RES-E potential capacity of wind and biomass is significant, there is little doubt that the generating potential of the world’s solar resource is much larger. As shown in Table 2.11, an evaluation of global renewable energy resources by De Vries et al (2007: 2607) found that the world’s solar generating potential, generated by solar PV technology, was five to 15 times that of wind and 13 to 16 times that of biomass. This finding is in line with those of a similar evaluation published by the United Nations Development Program in 2000 (‘World Energy Assessment’ in Table 2.11).
Table 2.11: Comparison of the long-term global generating potential of wind, biomass and solar PV electricity as reported by de Vries 2007 and the World
Energy Assessment.
Source: De Vries et al 2007.
Solar technology can be divided into solar photovoltaic (PV) and concentrating solar thermal (CST) types. Silicon based solar PV is reasonably mature (although greater efficiencies are being sought) however it may evolve into a second-generation of technology, thin film technology, which is reasonably immature. Although CST technology underwent significant development during the 1980s, the technology was fairly dormant until the ‘Solar One’ generator was opened in Nevada (in the USA) in 2006. The two major types of CST technology – trough and point-concentrated – are both experiencing significant refinement in terms of energy conversion efficiency and generator size though through technology is more mature and favoured by generators. Another major front of refinement is the usage of storage mediums (particularly molten salts) to allow 24 hour-a-day generation.
Like the world in general, the extent of Australia’s solar resource dwarfs that of its wind and biomass resource. The country is particularly well endowed with solar resources compared to most other countries. Graham et al (2008: appendix 1, p. 24) argue that an area measuring 35 km by 35 km, located in a region in Australia with good sun and little cloud cover, could generate enough electricity to meet all of the country’s current electricity consumption needs if covered with a CST generation system. This could be achieved with a 70% capacity factor (requiring storage) and a 14% solar radiation to electricity conversion rate. Lovegrove and Dennis (2006: 791) argue that Australia receives the highest average amount of solar radiation of any continent on earth. They also say that an area 138 km by 138 km covered in solar generators could generate enough electricity to supply all of Australia’s energy needs (including heat and transport). However, as shown in Table 2.7, solar PV generators currently account for less than 1% of Australia’s RES-E generating capacity. CST technology currently has no significant generating capacity in Australia.
Study Wind (PWh/yr) Biomass (PWh/yr) Solar PV (PWh/yr) Total (PWh/yr) De Vries et al A1 scenario 80-39 72-58 1188-607 1341-705 De Vries et al A2 scenario 62-23 25-20 317-0 403-38 De Vries et al B1 scenario 80-38 63-51 945-603 1089-692 De Vries et al B2 scenario 74-32 49-39 623-0 745-62 World Energy Assessment 53 62-35 13844-438 13959-526
Given the national abundance of sunny sites, the long-term marginal cost of Australia’s solar generation is mostly tied to the long-term trend in solar technology costs. This means it is probably safe to assume solar’s long-run marginal cost will decrease in Australia, although access to transmission infrastructure could affect its future marginal cost trends (as discussed in s5.6).
Figure 2.20 show Australia’s solar exposure (both direct and diffuse (ie scattered by cloud)) across a full year. However, even though the northern half of Australia has the best average annual solar exposure, its exposure is less than in the southern half of the country when the monsoon season is underway (from November to March). This means that the most commercially attractive solar sites in the country are not
necessarily in its north: they may be in areas with more consistent, but weaker, annual exposure. This is particularly so given that northern Australia has poor transmission infrastructure.
Figure 2.20: Average annual solar exposure (direct and diffuse) in Australia
Source: Bureau of Meteorology 2009.
Australia has a very large solar generating potential. The CSIRO (2006: 18) only estimated it as being ‘very large’. Table 2.12 shows the solar electricity generating potential of 1% of the country’s land area. At 44.3 TWh/day it is equal to 59 times Australia’s current level of electricity generation. This is equal to about 16,170 TWh/yr. If, eventually, a significant proportion of this solar generating potential is
rather than solar PV, despite it being currently being less mature, as shown in Table 2.8. This is because, as long as there is transmission access, CST technology can be located away from coastal areas where it can receive direct sunlight which can be converted at higher temperature, and therefore greater efficiency, than diffuse sunlight. Diffuse sunlight (made diffuse by cloud cover) is the most common type of sunlight received in Australia’s coastal areas where most of its urban development is located and where most solar PV can be expected to be installed.
Table 2.12: Calculation of the solar generating potential of 1% of Australia’s land surface
Quantity description Quantity amount
1% of Australia’s land surface 76,000 km2
Daily solar energy received by 1 %
of land surface at 15 MJ/m2/day 1,140,000 TJ/day
Electricity generation potential of solar energy at 14% conversion efficiency
159,600 TJ/day Equivalent electricity generation
potential in TWh
44.3 TWh/day Australian daily electricity
generation
0.75TWh/day
Source: author calculations.
There are two types of geothermal electricity technology: hydro thermal and hot rock geothermal. In both cases, electricity is produced by underground superheated water, but in the case of hydro-thermal electricity, the water comes to the surface naturally. In the case of hot dry rock electricity, deep holes have to be drilled through which water is pumped to exploit the subterranean heat. Hydro-thermal is a
reasonably mature type of RES-E and is used extensively in countries close to tectonic plates, like New Zealand and Iceland. However, as shown in Table 2.8, hot rock geothermal is not mature and has significant potential for future generating cost reduction. The Australian hot rock industry believes there is significant capacity for reducing the generation cost of hot dry rock generation in the country as the
technology moves from a demonstration to a commercial phase (MMA 2008a). Using the definition of energy technology development stages devised by Foxon et al
(2005), hydro-thermal technology is at a commercial stage, whereas hot rock technology is only at a ‘demonstration’ stage because it is still at a prototype stage with few units installed to date. Currently hot rock geothermal demonstration plants are being developed in France, Japan and Australia (Nicholson 2009: 68). Australia
(Sandeman 2006: 725). Australia does have some hydro-thermal potential under the Great Artesian Basin (in the middle of the country), and two remote small scaled generators have used it to generate electricity (Needham 2009: 9). However, most of its hydro-thermal resource is in remote locations and its water temperature is
relatively low (Harries et al 2006b: 816). ). As shown in Table 2.7, geothermal generators currently account for less than 1% of Australia’s RES-E generation capacity.
Like its solar resource, Australia is well endowed with geothermal generating potential. It has been claimed that 1% of Australia’s geothermal energy could supply 26,000 times the country’s current total annual electricity demand (Ferguson 2008: 1). The CSIRO (2006: 18) said Australia’s total identified hot rock resource was equal to 2,500 EJ: if this potential was used each year with a 90% capacity factor, and a 15% conversion efficiency, then it could generate 821,249,460 TWh/yr; therefore just 1% of it (the proportion assumed in Table 2.13, below) would generate 8,212,495 TWh/yr. Figure 2.21 shows the distribution of Australia’s hot rock geothermal resource. The largest, hottest resource is concentrated in the remote eastern part of central Australia in the north-east of South Australia and the south-west of
Queensland. The remoteness of this resource has major transmission access implications, discussed in chapter 5.
Figure 2.21: Geothermal heat potential of Australia
2.3.7 Australia’s overall RES-E generating potentials and why they justify extra