Abstract
With declining system costs and assuming a short energy payback period, photovoltaics (PV) should, at face value, be able to make a meaningful contribution to reducing the emission intensity of Australia’s electricity system. However, solar is an intermittent power source and households remain completely dependent on a “less than green” electricity grid for reliable electricity. Further, much of the energy impact of PV occurs outside of the conventional boundaries of PV life-cycle analyses (LCA). This paper examines these competing observations and explores the broader impacts of a high penetration of household PV using Melbourne, Victoria as a reference. It concludes that in a grid dominated by unsequestered coal and gas, PV provides a legitimate source of emission abatement at high, but declining costs, with the potential for network and peak demand support. It may be technically possible to integrate a high penetration of PV, but the economic and energy cost of accommodating high-penetration PV erodes much of the benefits. Future developments in PV, storage, and integration technologies may allow PV to take on a greater long term role, but in the time horizon usually discussed in climate policy, a large-scale expansion of household PV may hinder rather than assist deep cuts to the emission intensity of Australia’s electricity system.
Highlights
The Garnaut Climate Change Review reports that the emission intensity of Australia’s electricity system would need to decline from its current 850 g grams of carbon dioxide-equivalent (CO2-e)/kWh to between 110 and 200 g CO2-e/kWh under Australia’s contribution to a 450 or 550 ppm CO2 scenario respectively by 2045 [1]
There is a dearth of rigorous analysis demonstrating that such a transformation offers the most promising pathway to a near-zero emission electricity supply within the time frame discussed in climate policy
Conventional PV life-cycle analyses (LCA) analyses are expressed in terms of primary energy, but since fuels have differing quality and usefulness, there is an argument that the EROI should include some provision to account for the varying usefulness [123]
Summary
The Garnaut Climate Change Review reports that the emission intensity of Australia’s electricity system would need to decline from its current 850 g CO2-e/kWh to between 110 and 200 g CO2-e/kWh under Australia’s contribution to a 450 or 550 ppm CO2 scenario respectively by 2045 [1]. The manufacture and installation of PV incurs an energy debt through its embodied energy [5], and few analyses include the full upstream costs of PV [6,7], or attempt to capture a pro-rata allocation of the downstream costs of distribution and ancillary services. It seems that much of the discussion around PV is focused on exploring theoretical potential, assuming ipso facto that a high penetration of PV is desirable. May accelerate a path-dependence towards a sub-optimal generation mix, undermine the economic case for low-emission baseload, and hinder efforts to delivering the deep emission cuts recommended towards the middle of the century
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