Can we live nuclear free?

So far I have looked at two European case studies the Chernobyl disaster in 1986 and the recent proposal at Hinkley point in the UK. These have given me an idea of the health risk and current economic costs of building a nuclear power station. This week I am looking to up the anti and tackle the issue of whether a global nuclear phaseout is possible within the next century?

I ask this question in light of the growing anti-nuclear feeling across the international community since Fukushima. Phaseouts are in progress in Japan, Germany and Italy, and there has even been increased anti-nuclear sentiment in 'strongholds' such as India, and the United States (EESI,2011).  

Taking the question at face value what options do we have available if we decide to scrap nuclear power altogether?For one, in theory we could replace the energy shortfall by burning more fossil fuels. What effects might this entail and is it a risk worth taking?  
Let's take a look at some of the observed data:
.We have witnessed a 0.85C warming of the global land and ocean surface from 1880-2012 (IPCC, 2013). 
.The majority of warming has occurred in the second half of the 20th Century, where global population doubled, water use tripled and greenhouse gas emission quadrupled (Steffen et al, 2007). 
.Decadal temperatures have risen continuously since 1850 and the period from 1983-2012 was the warmest 30 year period globally of the last 1400 years (IPCC,2013). 

CO2 concentrations (in ppm) for the last 1100 years,1769 marks the date when James Watt patented the steam engine coinciding with the upshoot in CO2 Source:Mackay,2009

Still undeterred, one could argue that the post industrial temperature rise is attributable to natural variability, after all it was hotter during the Medieval warm period. It is true that some regions exhibited similar or higher temperatures to the present day, however the warming was more regional in nature. Scientists are 95% certain that humans are the dominant cause of warming since the 1950s(IPCC,2013) and the impacts of continued warming could be catastrophic. 

 Overview of the impacts of warming, unabated use of fossil fuels would likely lead to a temperature rise of over 3C by 2100 Source: Sagebrush Solar, 2013 

Based on the data shown, to replace nuclear energy's 14% share of global electricity with fossil fuels is out of the question. Not only for the sake of emissions but also sustainability. Countries, including the UK, will face an energy gap in the coming decades due to dwindling fossil fuel supplies (Mackay, 2009). Standard coal and gas powered plants need to be replaced and emissions cut significantly.Without nuclear energy is this realistic?

The answer to the question above surely depends on how much warming is deemed acceptable.  Two degrees above pre-industrial temperature is widely considered the safe amount of warming, albeit a target not without controversy. In the fifth IPCC report more ambitious mitigation scenarios were put forward (<3W/m2) partly as a response to a growing body of literature which indicated that stabilisation of radiative levels at lower levels would be needed to maintain a high probability of avoiding the 2 degree benchmark (Vuuren et al, 2013).

Step forward RCP 2.6, the lowest emission scenario where less than 2 degrees of warming is highly probable. Vuuren et al (2013) explored what it would take to follow this emission pathway. The recent study suggests that cumulative emissions of greenhouse gases would need to be reduced by 70% by 2100 relative to a baseline scenario, which itself is a lower trajectory than we are currently following! The graphs below summarise how this could be achieved.

Trends in global energy use for the baseline (left) and the mitigation scenario RCP2.6 (right) (CCS=Carbon Capture and Storage)   Source: Vuuren et al 2013

In Vuuren's analysis nuclear power is a significant contributor to global energy demand by 2100, yet it is far from dominant. It could be argued on this basis that it isn’t a necessity to reach a low emissions target.  Vuuren is assuming however that CCS and BECCS technology (see link) would allow for the continued use of cheaper fossils fuels. In reality this may not be the case, leaving a vacant energy gap. Therefore let's say we ignore the uncertain realisation of carbon capture and focus on the now. Could we rely on renewables to take the brunt of our future energy demands?

In his book Sustainable energy- Without the hot air, David Mackay(2009) stacks the energy available from renewables against current consumption for the UK. The energy gap appears only small, but taking into account the figure on the right, you begin to appreciate the dilemma faced by many developed nations in terms of adopting renewable energy.

 Consumption against estimate of energy available from renewables for the UK, measured in kWH/d per person Source: Mackay, 2009

Moving away from the UK, Germany is a country which has been able to invest heavily in renewable energy. It's share has increased from 6.3% in 2000 to 25% in 2012; and 26 billion euros of investments were made into the country's renewables market in 2010 (BMU,2012). 

However the transition has not been smooth, there have been power outages due to the variable nature of renewable sources like wind. In 2012 while renewable electricity rose by 10.2%, there was a 2% increase in emissions due to the reliance on coal as back up energy following the nuclear phaseout (Spiegel, 2013). 

Can we afford to live without nuclear power? Well considering the emission cuts needed, the lack of inertia behind sustainable living in many parts of the world, along with the price of renewable energy (Germany has the highest electricity prices in Europe), completely removing nuclear power is not workable, assuming ambitious CCS technologies are not implemented. Nuclear power could offer a carbon-free energy supply where there is a shortage of land for renewable sources and gives more time for consumption to fall and renewable energy to propagate. 

I am not sold on nuclear energy as our main energy source over the next millennia, but do believe it is needed to support a reduction in GHG emissions. 

Thanks for Reading