Conclusions

Picture from SciLogs

Over the past few weeks, we have explored the history of fossil fuel use and reviewed various alternative energy technologies (AETs) such as hydropower, solar, wind, geothermal and nuclear. We also looked into its economic implications, as well as surveyed the approaches taken by various developed and developing countries' to reduce dependence on fossil fuels. 

In evaluating the various AETs, Turconi (2013) found that greenhouse gas (GHG) emissions from plant operation itself would not be adequate to represent its environmental performance. A wholistic picture could be presented by using all three life cycle phases, namely fuel provision, plant operation, and infrastructure. The life cycle analysis (LCA) would reveal that majority of GHG emissions would arise from plant operations for fossil fuel technologies, from fuel provision for biomass technologies and nuclear power, and from infrastructures for renewables. 

Table 1 complied by Sovacool (2008) suggests that renewables (wind, hydropower, solar and geothermal) along with biomass fair generally well in the LCA. Nonetheless, the context for biomass would need to be carefully considered, especially in situations where peatland forests may be involved. Evans et al (2009) and Varun et al (2009) share similar views that the renewable energy technologies have a strong potential based on indicators such as availability of renewable sources, land requirements, water consumption and social impacts, on top of GHG emissions from LCA. Evans et al (2009) assessed that wind power is the most sustainable, followed by hydropower, photovoltaics and then geothermal. 

Technology	Capacity/configuration/fuel	Estimate (gCO2e/kWh)
Wind	2.5 MW, offshore	9
Hydroelectric	3.1 MW, reservoir	10
Solar thermal	80 MW, parabolic trough	13
Biomass	Forest wood steam turbine	22
Solar PV	Polycrystalline silicone	32
Geothermal	80 MW, hot dry rock	38
Nuclear	Various reactor types	66
Natural gas	Various combined cycle turbines	443
Coal	Various generator types with scrubbing	960
Coal	Various generator types without scrubbing	1050

Table 1: Life cycle estimates for electricity generators (Sovacool, 2008)

With renewables leading the table, Jacobson and Delucchi (2009) suggests that nations could set a goal of generating 25 percent of their new energy supply with wind, water and solar (WWS) sources in 10 to 15 years and almost 100 percent of new supply in 20 to 30 years. Based on their calculations, all existing fossil-fuel capacity could theoretically be retired in 40 to 50 years. Meanwhile, Ghoniem (2011) suggests that nuclear energy and renewable resources are necessary components of the energy source mix, and they are relatively carbon free. For rural communities, biomass technologies could be considered. 

Apart from the LCAs, decision makers would also have to consider other factors such as public opinion and the economic viability of the AET. For example, policy makers would need to be mindful of the potential catastrophic consequences arising from any nuclear incidents, and the high upfront costs of construction for the nuclear power infrastructure. 

While it may seem like a page out of a fiction novel, space-related energy technologies that run into prohibitive costs in today's context, could become a reality within the next few decades with technological advances that can drive down related launch costs. Meanwhile, some of the leading edge technologies such as the Liquid Fluoride Thorium Reactor (LFTR) could help tilt the balance towards nuclear energy by employing safer technologies (Hargraves and Moir, 2010).

On a slightly different tune, apart from economics and technical considerations of AETs, we may also ponder over the outcomes of the Warsaw climate change talks in Nov 2013, and wonder if climate change could ever be solved being embroiled in the quadmire of politics and controversy. I would suggest the advice of Jacobson and Delucchi (2009) that clear leadership would be needed, so that meaningful and achievable energy goals could be agreed upon, as one of the many solutions towards the climate change problem.

Before concluding, I would also like take this opportunity to thank my dear friends who have been following this blog, and the many suggestions on how I could make this blog better. 

We have only one Earth. Let's treasure it!