Last week, we discussed how renewable energy can help reduce the carbon footprint of urban areas. In sunny Singapore, solar energy appears to have the greatest potential to offset our consumption of non-renewable energy sources. But how much energy can it provide? I looked up a few sources and did some simple math to figure out a rough estimate (hopefully my calculations are correct!).
First, let’s find out how much incoming solar energy Singapore receives:
- This source by the Energy Market Authority (EMA) of Singapore estimates this at 1150 kWh/m2/year
Next, let’s see how much of that energy can be converted to a useful form:
- This link reports that the most efficient rooftop solar panels are currently around 22% – this means we can get about 22% * 1150 = 253 kWh/m2/year
According to the Energy Market Authority (2015), Singapore’s total energy consumption in 2013 was about 156 TWh. Using this value, we would have needed:
- 156TWh/(161kWh/m2) = 616.6 km2 of solar cells to sustain our energy consumption entirely in 2013
(Just out of interest, I did another calculation using the most efficient solar cells as reported by Shazan (2014). Even at 46% efficiency, we’d still need about 203km2 of land – just under a third of Singapore covered in solar cells.)
These values mean that we’d need to blanket most of Singapore in solar cells to sustain our current energy use. Of course, solar is not the only form of renewable energy but it does show the limit at which such alternative energy sources can support the population.
The main issue here appears not to be just the lack of land space but more so the density of our population and our high per capita energy consumption (Low Carbon Singapore, 2009). Together, these factors result in a high energy consumption density – meaning we need to provide more energy per area of Singapore. This has significant implications – and not just for Singapore.
As most of the world’s population moves into urban areas, population density in these areas will likely rise. By extension, it is also likely that the amount of energy we need to provide in an urban area will rise (as the energy consumption becomes more concentrated within the area). Denser cities could resort to importing renewable energy (just as we currently do with non-renewables) but transporting electricity generated in one place to another is not without its issues.
If we are to switch over to renewables then, it appears that we cannot simply increase renewable energy generation. Rather, we would need accompanying measures which help to reduce the overall consumption of energy and also improve the efficiency at which energy is used.
Energy Market Authority (2015). Singapore energy statistics 2015. Singapore: Energy Market Authority. Retrieved from https://www.ema.gov.sg/cmsmedia/Publications_and_Statistics/Publications/SES2015_Final_website_2mb.pdf
Energy Market Authority (2016). Solar photovoltaic systems. Retrieved 14 April 2016, from https://www.ema.gov.sg/Solar_Photovoltaic_Systems.aspx
Low Carbon Singapore (2009). Energy consumption per capita. Retrieved 14 April 2016, from http://www.lowcarbonsg.com/tag/energy-consumption-per-capita/
Shahan, Z. (2014). Which solar panels are most efficient? Retrieved 14 April 2016, from http://cleantechnica.com/2014/02/02/which-solar-panels-most-efficient/
Wesoff, E. (2015). ‘World’s most efficient rooftop solar panel’ revisited. Retrieved 14 April 2016, from http://www.greentechmedia.com/articles/read/Worlds-Most-Efficient-Rooftop-Solar-Panel-Revisited