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Opinion Volume 1 Issue 1
What’s the best way to use solar energy?
Jose Goldemberg,
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Jose R Moreira
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Institute of Energy and Environment, University of Sao Paulo, Brazil
Correspondence: Jose Goldemberg, Institute of Energy and Environmental, University of Sao Paulo, Av. Prof. Luciano Gualberto, 1289, 05508-010-Sao Paulo, SP, Brazil, Tel +55 11 3091-5053
Received: July 14, 2017 | Published: September 5, 2017
Citation: Goldemberg J, Moreira JR (2017) What’s the Best Way to Use Solar Energy? Open Acc J Photoen 1(1): 00004. DOI: 10.15406/mojsp.2017.01.00004
Opinion
Solar energy in its various forms supplies most of the energy we use. Harvesting this energy can be accomplished in several ways, ranging from photovoltaic’s (PV) for the production of electricity to biomass (through photosynthesis) and ultimately fossil fuels.
The choice among such energy sources was determined in the past by availability and cost. More recently, however other dimensions were added to such choices the most important being sustainability and an important quality index which is the continuity of supply.
Sustainability imposes severe limitation on fossil fuels use. Green House Gas emissions mitigation requires that available fossil resources will never be used in its totality as technological development with potential to transform known reserves in further resources loses interest.1 As an alternative developed and developing countries alike have encouraged the development and use of solar energies through mandates and subsidies.
The result has been decreasing costs through impressive “learning curves” and today most solar energies are competitive in comparison with traditional fossil fuel sources of energy.
As a consequence, the contribution of renewable energy sources such as wind and photovoltaic’s is increasing significantly but suffers from a fundamental problem, which is intermittence and require backup from fossil fuels with the consequent emission of Green House Gas. Hydroelectricity based on hydro reservoirs as backup is an attractive possibility but is region and seasonally specific.2
A very attractive solution, particularly for tropical countries, is electricity produced from biomass. Some types of biomass such as sugarcane are able to provide simultaneously liquid fuels and electricity, and such co-production explains their high quality energy at fulfilling sustainability requirements.3 Biomass residues can be stored for months and used when electricity demand requires. It is worth mentioning that carbon capture and storage (CCS) has been considered as one of the important technologies to guarantee the accomplishment of world compromises assumed in the Paris agreement. CCS, initially devised as a technology to improve sustainability of fossil fuels, has been seen more recently as more effective for biomass based energy sources because the net effect can result in negative Green House Gas’s emissions. Thus, instead of just another mitigation technology, negative emissions means that as more energy is used, more CO2 will be removed from atmosphere.4
It has been argued however5 that “the productions of biofuels constitute an extremely inefficient land use. Michel based his point in the comparison of the low efficiency of photosynthesis in converting solar energy (bellow 6%) with the efficiency of photovoltaic cells (about 15%) and states that the combination of photovoltaic cell/electric battery/electric engine uses the available land 600 times better than the combination biomass/fuel/combustion engine”.
Such claims have been critically analyzed by6 and proved to be highly exaggerated. Furthermore, the combination of biofuel production and electricity production, which is feasible when using sugarcane as the feedstock plus CCS, provides a powerful alternative for the capture and storage of solar energy providing thus a negative carbon route with continuity of supply.
Conclusion
In conclusion, what one can say is that solar energy capture in some of its forms, particularly bioenergy, can meet the criteria of sustainability as well as energy quality.
Acknowledgements
None.
Conflicts of interest
There is no conflict of interest.
References
- Stocker TF, D Qin, GK Plattner, et al. Climate Change IPCC 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, USA;2013:1−1535.
- REN21. Renewables 2016 Global Status Report. 2016;1−272.
- Environmental Protection Agency. Renewable Fuel Standard Program RFS2-Regulatory Impact Analysis, USA. 2010.
- Smith P, Steven JD, Felix C, et al. Biophysical and economic limits to negative CO2 emissions. Nature Climate Change. 2016;6:42−50.
- Michel H. Editorial: The Nonsense of Biofuels. Angew Chem Int Ed Engl. 2012;51(11):2516−2518.
- Nogueira H, Augusto L, Moreira JR, et al. The rationality of biofuels. Energy Policy. 2013; 61:595−598.
©2017 Goldemberg, et al. This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and build upon your work non-commercially.