Solar is the most abundant, permanent energy source in the world. The surface of the Earth receives over 100 000 TW of energy from the sun every year. In comparison, the global electricity generation in 2006 was 18 930 TWh, with electricity from solar energy contributing only 3.4 TWh. Clearly solar energy as a resource is not utilised to its potential. Since the first solar cells were developed in the 1970s, energy conversion efficiencies have increased, while materials and costs for manufacture of solar cells have decreased. Conventional comparison techniques suggest that solar electricity is far more expensive than electricity derived from fossil fuels, however as the world started to introduce a cost for carbon emissions, the economics of photovoltaics are expected to compare more favourably. Other parameters of importance for consideration when advancing the technological developments of photovoltaics are environmental factors that include water consumption, land degradation and social impacts where photovoltaic technology has favourable performance. This work discusses parameters that define the sustainability of photovoltaic power technology. The sustainability of photovoltaic has been assessed using an extensive literature review, according to economic, environmental and societal impacts. The key indicators of these impacts have been defined, on a per kilowatt hour basis, as the price, efficiency, carbon emissions, water use, land use, availability, limitations and social impacts. Each of these impacts has been compared, to conclude with the most sustainable aspects of photovoltaics. The most sustainable aspect of photovoltaic electricity production was found to be its availability, with no shortage of sunlight or silicon. Carbon emissions and water consumption are favourable at only 84 g CO2/kWh and 10 kg water/kWh, the majority of which are due to the intense energy requirements in the production of silicon crystals. There are very positive social advantages from photovoltaic installation, including the provision of electricity to remote and developing areas. Negative social impacts include the toxins produced during manufacture and glare. The photovoltaic energy efficiency from potential energy to electricity is only 15% with the maximum cell efficiency achieved at 39%. Due to their low efficiency, photovoltaic cells have a large area requirement. The two solutions to this problem are building integrated photovoltaics and large photovoltaic 'farms' in desert and arid regions. Currently, the least favourable aspect of photovoltaics is the cost for production of the cells. An average price is approximately USD$4/Wp and $0.25/kWh, making it the most expensive source of electricity in standard operation.
|Title of host publication||Photovoltaics|
|Subtitle of host publication||Developments, applications and impact|
|Editors||Hideki Tanaka, Kiyoshi Yamashita|
|Place of Publication||Hauppauge, NY|
|Publisher||Nova Science Publishers|
|Number of pages||21|
|Publication status||Published - 2010|