Engineering advancement are boon to the society that not only provides comfort but also smoothen the life requirement in varieties of aspects. In the last few decades the major problem of concern is the negative impact on environment because of irrational consumption of non-renewable resources and emission of the pollutants (Baharwani, 2014). Hence, it is critical to think for measures in conjunction to generating renewable energy sources like photovoltaic (PV) technology which generates electricity directly from the solar energy. The likely benefits include (i) less consumption of fossil energy and (ii) reduced GHG emission. However, during its lifecycle, the solar PV modules requires a considerable value regarding the energy emits certain GHG during certain phases of its manufacturing processes. Further according to Chapman et al. (2016), in order to enumerate for energy consumed in manufacturing process of solar PV modules the “Life Cycle Assessment” studies are important.
Scope of report
The above section discusses the need for energy conservation and sustainable strategies in order to reduce environmental impact as well as to maximise the efficacy of energy sources. The discussed PV technology is usually implemented to analyse the energy used and environmental impact from the product life cycle (Baharwani, 2014). The LCA stage of the product includes the goal and scope, analysis of inventory, interpretation of results, and impact assessment. Overall, the objective of this report is to present LCA of solar PV modules in Australia.
Description of the 2.7 kWp of solar PV system
The solar PV system (2.7 kWp) contain 36 mono-crystalline units which is attached on the rooftop with concrete blocks and aluminium supporting. From which 12 modules are attached in series for generating 900 Wp. 1.5kVA capacity of three is joined with three strings, each having 12 modules (Prasad & Snow, 2014). As the electricity sourced from the PV system is very less in quantity as compared to the building’s power demand, thus it is difficult to export electricity to the grid within the urban location of Australia (ref). To measure the electrical and meteorological data a data logger is attached to the device, whereas sensors (6 in numbers) are fixed for measurement of the temperature for the mono-crystals (Baharwani, 2014).
Life cycle assessment of the solar PV system
The total energy required for a mono-Si PV system is analysed to be 4160 to 15520 MJ/m2, whereas the energy required for the PV modules (crystalline silicon) ranges from 5300 to 16,500 MJ/m2. Based on the LCA generated distribution of 2.7 kWp solar PV system, it is estimated that the 2.2 MJ/kWh is used as the life cycle energy (Nian, 2016). While the energy conversion efficiency of multi-Si PV units is almost the similar to that of mono-Si units. The embodied energy required for the multi crystalline PV system was found to be 1145 kWh/ m2. The primary embodied energy and process energy consumed for one module is 1000 MJ and 3020 MJ respectively. The total process energy and the embodied energy for both low and high energy consumption of a-Si PV system were 491 MJ/ m2, 864 MJ/m2, and 640 MJ/m2 respectively. It was reported that the total energy needed regarding the production of C/dsCdTe PV units was approximately 1803 MJ/ m2 for 10 MW/yr as well as 1272 MJ/ m2 for 100MW/yr. 0.17 MWhe/kWp of specific energy is consumed for the production of inverters (Mayr, Schmidt & Schmid, 2014). In Australia, hidden energy is used for generation of electric current from the steam turbine plant equipped with oil-fired and it is approximately 8.8% in conjunction to the operational system’s fuel consumption. However, in regards to the use of solar PV units; there is no loss in the transmission and distribution operation.
The estimated life cycle of the GHG such as CO2, N2O, and CH4 emission from turbine (equipped with oil-fired system) is 937g-CO2/kWhc and inclusive of the T&D loss it is 976g-CO2/kWhc. The life-cycle emission from the natural gases are estimated to be 493g-CO2/kWhc. For the reduction of primary energy use of the PV solar units three scenarios are included viz., (i) use of alternative supportive systems (ii) improvement in technology of the solar PV modules manufacturing and (iii) achievement of efficient solar PV module (Sharma, 2014).
The cost incurred in the life-cycle phase of solar PV units is differentiated as asset value, decommissioning cost, and operation and cost of maintenance. The market price of solar PV units and inverters used are 7 AUD$/Wp and 0.93 AUD$/Wp respectively (Mayr, 2014). However, its total cost is estimated to be 9.5 AUD$/Wp within the functional life time is 25 years for LCCA. Because of the elimination in the fuel consumption, there is no operational cost accounted in the operational phase. The dismantling process cost of solar PV units is approximately AUD$ 9302. Thus, the cost of life-cycle of the generated electricity from the solar PV units is approximately 57 cents/kWhe (Berry & Davidson, 2015).
Impact on environment
It has been found that excessive use of solar PV system can lead to problems related to waste disposal and material availability. For example, the silver requirement in the solar PV units can lead to its lessening if overused (Nian, 2016). It has been estimated that for meeting 5% of the total electricity demand in the world, 30% of the silver production is required. Moreover, at the end of the life-cycle process of the product a certain amount of waste is also generated and it is needed to be properly disposed. In the above study, 90 tonnes of the used solar modules are generated from 1 MW of the solar plant and this is needed to be landfilled (Baharwani, 2014).
In summary, for the energy demand and emission of GHG, it has been found for the mono-crystalline, CdTe/CIS, and amorphous and for other solar PV units. It is recorded that the crystalline units possess efficiency for conversion, but the requirement for the primary energy is significant. Notably, the primary energy is also aimed to reduce with the use of alternative supportive system, improvement in the solar PV units with the help of effective manufacturing process, and overall achievement of effectiveness (performance) PV modules. The variation in the performance of different installation is because of the set of parameters, which is believed to dominate the Australian market in future times.
Baharwani, V., Meena, N., Dubey, A., Brighu, U., & Mathur, J. (2014). Life Cycle Analysis of Solar PV System: A Review. Int J Environ Res Dev, 4(2), 183-190.
Chapman, A. J., McLellan, B., & Tezuka, T. (2016). Residential solar PV policy: An analysis of impacts, successes and failures in the Australian case. Renewable Energy, 86, 1265-1279.
Prasad, D., & Snow, M. (2014). Designing with solar power: a source book for building integrated photovoltaics (BiPV). Routledge.
Baharwani, V., Meena, N., Dubey, A., Sharma, D., Brighu, U., & Mathur, J. (2014). Life cycle inventory and assessment of different solar photovoltaic systems. In Power and Energy Systems Conference: Towards Sustainable Energy, 2014 (pp. 1-5). IEEE.
Nian, V. (2016). Impacts of changing design considerations on the life cycle carbon emissions of solar photovoltaic systems. Applied Energy, 183, 1471-1487.
Mayr, D., Schmidt, J., & Schmid, E. (2014). The potentials of a reverse auction in allocating subsidies for cost-effective roof-top photovoltaic system deployment. Energy Policy, 69, 555-565.
Sharma, V., Sastry, O. S., Kumar, A., Bora, B., & Chandel, S. S. (2014). Degradation analysis of a-Si,(HIT) hetro-junction intrinsic thin layer silicon and mC-Si solar photovoltaic technologies under outdoor conditions. Energy, 72, 536-546.
Berry, S., & Davidson, K. (2015). Zero energy homes–Are they economically viable?. Energy Policy, 85, 12-21.