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! 

Energy From Space

Depiction of a solar satellite that transmits electric energy by microwave
Picture by NASA

What then does the future hold for energy options that are both sustainable and climate friendly? To address this question, we may have to stretch our imagination, and look toward the sky for an answer. 

Faced with the problem of competition for land for solar farms, scientists have been studying the feasibility of setting up solar power satellites (SPS) that can transmit electric energy to Earth via electromagnetic beam. 

The concept was invented in 1968 by Peter Glaser (McSpadden and Mankins 2002). SPS benefit from an eightfold increase in solar flux experienced in space, compared to the flux received on earth's cloudy surface. Landis (2004) proposed that SPS could be positioned such that it has a constant view of the night side of the Earth, so as to supplement daytime ground solar power by providing night power.

Brown (1992) suggested that beamed microwave power transmission could have a theoretical efficiency of 76% and experimentally achieved 54% efficiency. Although the efficiency may appear low compared to the 7% losses on traditional transmission and distribution (T&D) lines estimated by the US Energy Information Administration (EIA), one should also consider the vast distances that can be covered via satellite technology. Access to remotely located, environmentally sound, renewable resources, and transmission across sensitive areas could become possible with satellite technology, when traditional transmission lines would have faced challenges (Woodell and Schupp, 1996).

Although early studies succeeded in establishing technical feasibility, government funding in the United States came to an abrupt halt in the 1970s given the enormous costs in excess of US$100 billion needed to realise the project (Mankins, 1996)

Nonetheless, Matsumoto (2002) argued that microwave power transmission remains as one of the new technological frontiers, and the SPS had been the central attraction of space and energy technology, which could potentially achieve 80% efficiency for both transmitting and receiving systems. In this regard, Hoffert et al (2002) opined that SPS could potentially be demonstrated in 15 to 20 years and deliver electricity to global markets by the latter half of the 21st century

A reader had commented in an earlier post on wind power that due to supply and demand issues, technologies such as wind and solar may still need to be completed by traditional sources of fossil energy to ensure adequate supply of electrical power. 

To address this supply and demand dilemma, the future could see use of power relay satellites (PRS) to transmit power from regions where the energy is generated, to other regions on the globe where the energy supply is needed. Glaser (1994) suggested that a global PRS network can help to supply energy worldwide with wireless power transmitted from generation sites on Earth, to satellites in geosynchronous orbit, which then reflect the energy to load receiving stations interfacing with terrestrial power transmission networks. 

In particular, Bockris (2010) painted the scenario where regions that receive massive amounts of sunshine such as Australia, North Africa and Saudi Arabia could act as generation centres, and the PRS could beam the energy to a country needing energy through a load receiving station. 

However, even with technical feasibility, implementation of SPS and PRS may not be straightforward. Dickinson (2002) suggested that given the likelihood of interception of power beams by aircraft and spacecraft flying through the beams, there may need to be robust space policy to assure safety given the high-power flux densities required. 

The SPS and PRS may sound like technologies from a science-fiction novel today. But who knows? Maybe the ideas can be realised commercially within the next few decades, serving as a sustainable and climate-friendly energy solution.

Thorium Reactor

Schematic from Wikipedia

We had earlier covered how nuclear technology could help mitigate carbon emissions that would otherwise arise from fossil energy use. Nonetheless, the technology relies heavily on uranium as its fuel, and thus faces risks and challenges such as reactor melt-downs, nuclear waste management and potential of nuclear proliferation.

Reuters recently ran an article that suggests thorium could replace uranium as a clean, safe and sustainable energy source for the future. Thorium is four times more abundant that uranium, and the molten salt reactor (MSR, schematic above) compatible with thorium use has the advantage of allowing the whole system to operate close to normal atmospheric pressure. This is in contrast to conventional water-cooled reactors that require heavy engineering to withstand high pressure that can result in the danger of leaks and explosions. Thorium yields less waste and is less radioactive, compared to traditional uranium reactors. 

The feasibility of thorium reactors was given a boost when former UN nuclear weapons inspector Hans Blix gave his personal support to the technology as reported by the BBC. Various countries such as Canada, China, Germany, India, the Netherlands, the UK and the US are also experimenting with thorium as a substitute fuel. 

Hargraves and Moir (2010) published a paper in American Scientist that comprehensively summarised the Liquid Fluoride Thorium Reactor (LFTR) technology. Apart from suggesting that thorium is a relatively safe option, the article also suggests that the thorium reactor would be economically viable in the long run, and the risks of nuclear proliferation is minimised compared to a uranium reactor. 

Cooper et al (2011) suggests that a LFTR program could be achieved within 5-10 years with an investment of roughly $1 billion. However, a Mar 2012 report by the UK National Nuclear Laboratory (NNL) suggests that present market conditions may not favour development of the LFTR, and it may take up to 20-30 years before the LFTR technology may become economically viable. 

The LFTR developments signal an exciting new generation of nuclear energy technology that is much safer and more sustainable to operate as compared to the existing uranium based technologies. If successful, the future may see more thorium based nuclear reactors that could help mitigate the impacts of climate change.

Artificial Photosynthesis

Picture from Scienceheath

Let's imagine, being able to harness solar energy like a leaf, without the baggage of CO2 emissions. By mimicking the natural photosynthesis process taking place in a leaf, scientists are studying how the process can be artificially replicated and transformed into a technology to harness solar power (Tachibana et al, 2012) . 

While solar energy could be tapped via biomass formation, the efficiency is low and the scale is inadequate to replace fossil fuels on a global scale and provide the huge amount of power needed to sustain future energy demand. By leveraging on the photosynthetic process which essentially involves the highly efficient chemical reaction of splitting water into its constituent elements, hydrogen and oxygen could be produced. The hydrogen generated from solar-driven water-splitting has the potential to be a clean and abundant energy source. If successful, the technology can be installed in areas such as deserts that receive high-levels of solar radiation (Barber, 2007).

Nonetheless, water-splitting devices that can harvest visible light so far have a low solar-to-hydrogen efficiency of around 0.1%. Recently, a group of scientists uncovered that cobalt(II) oxide (CoO) nanoparticles can carry out overall water splitting with a markedly increased efficiency of around 5%. (Liao et al, 2013). This discovery would hopefully contribute significantly towards the development of solar-fuel technologies.

Meanwhile, it is heartening that the energy industry has already been thinking about future energy scenarios and how CO2 emissions can be reduced while meeting future energy needs in a sustainable manner. Here's a video from Shell about the energy situation that mankind could face by 2050, and some of the strategies that can be adopted.

Asian Response

Asian City Image from Wikimedia Commons

In recent years, emerging economies such as China and India have registered high-levels of emissions growth (Peters et al, 2012). The CO2 emissions in developing countries increased 4.4% in 2008, 3.9% in 2009 and 7.6% in 2010. The measures that Asian countries will undertake to mitigate CO2 emissions will likely come under close scrutiny in the coming years. 

Trade balance difference (shaded areas) between Annex B/non-Annex B production and consumption. Bunker fuels are not included in this figure. (Peters et al, 2012)

China, which is the world's largest CO2 emitter, has given strong emphasis on renewable electricity promotion in its 12th Five Year Plan (FYP) until 2020 (Yu and Qu, 2013). Hydropower will be a key focus given the maturity of the technology and its competitive cost. China will also be developing solar photo-voltics and promoting biomass production at a growth rate of 87.9% and 18.2% respectively. However, Yu and Qin (2013) assessed that China would need to consider measures to reduce energy demand in order to be effective in combating climate change in a sustainable manner.

Turning our attention to India, existing renewable energy accounts for around 33% of India's primary energy consumptions (Kumar et al, 2010). However, the energy supply will need to increase by 3-4 times in order to sustain the growth of its economy. Taking into account energy security and the need for economic growth in the face of rising energy prices, Kumar et al (2010) opined that Indian should consider adopting more renewable energy options such as biomass, hydropower, solar and wind technologies. 

Meanwhile, Reuters reported in Nov 2013 that the Japanese government drastically scaled back its CO2 emissions reduction target to 3.8%, due to uncertainty on the future of its nuclear power program. This represents a departure from its ambitious Mamizu climate policy where Japan commited to a 25% CO2 emissions reduction target. Media reports such as the Los Angeles Times suggests that wind power may likely be the key energy resource as Japan seeks to reduce reliance on fossil fuels and nuclear energy.

Rong (2013) surmises that more than three quarters of energy-related CO2 emission growth is expected to come from China, India, and the Middle East. However, China and India are unlikely to adopt a voluntary CO2 reduction commitments in the near future. Rong (2013) suggests that a post-2012 climate change regime to help improve mitigation capabilities could help draw them to the negotiation table, such as international support to boost efficiency of coal power plants in these countries

A BBC report in Mar 2013 suggested that demand in Asia will continue to fuel economic growth and consumption, supported by demand from the US and Europe. Moving forward, the joint effort of both developed and developing countries, under the principle of common but differentiated responsibilities, will be required to mitigate the impact of climate change.