Author: Prof Eugene Coyle, a Fellow of Engineers Ireland, was the recipient of a visiting Fulbright scholarship to Purdue Univeristy in 2011/12, representing the College of Engineering and Built Environment at the Dublin Institute of Technology, and is dean of the Military Technological College, Muscat, Oman. He is the lead author of 'Understanding the Global Energy Crisis' , which brings together experts in energy policy, social science, power systems, solar energy, agronomy, renewable energy technologies, nuclear engineering, transportation, and the built environment from both sides of the Atlantic to explore the future of energy production and consumption from technological, political, and sociological perspectives.
Climate variability is one of the great discussion points and climate change one of the great concerns of humankind today. Research in climate science and meteorology is an advanced and well-established field of study. It is fitting to recall that in the 1860s Irish scientist and Fellow of the Royal Society John Tyndall (1820-1893) identified the radiative properties of water vapour.
Among his findings he reported that moist air absorbs 13 times more heat than dry, purified air. He observed that waves of heat travel from Earth’s surface through our atmosphere towards outer space and in so doing dash in their passage against atoms of oxygen and nitrogen and against molecules of aqueous vapour.
It is interesting to recall that it is only in very recent years that there has been an emerging global acceptance of the influence of particles generated by man-made processes into Earth’s atmosphere, in particular the negative impact of carbonaceous fuel emissions emerging from the stacks of coal, oil and gas power plant generators.
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Figure 1: click to enlarge[/caption]
Equally disruptive to Earth’s atmosphere is the resultant of tailgate gases emerging from the world’s ever growing automobile fleet. World energy demand today is in excess of 13 Mtoe (million tonnes of oil equivalent), with an expected increase of at least one hundred per cent by the year 2035. These figures are based on anticipated population growth in the developing world. While future world population growth is difficult to predict there are indications that it may stabilise at approximately nine to 10 billion by the end of the century.
Figure 1 provides a profile of world total primary energy supply by fuel type, indicating that coal, oil and natural gas continue to be the principal global generation fuel sources.
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Figure 2: click to enlarge[/caption]
Figure 2 profiles CO2 emissions per fuel type. It is clear that there is a direct correlation to burning of fossil fuels and greenhouse gas emissions to Earth’s atmosphere.
While a new paradigm in shale gas production over the past few years has tipped the scales in favour of increased production of gas, with particular benefits to the US economy, it is nevertheless important to note that while natural gas is cleaner than oil, it is nevertheless a major contributor to greenhouse gas emissions.
Further developments in clean coal technologies and carbon capture and storage proffer some hope in the knowledge that coal is still likely to feature prominently in the global energy mix for some decades to come, however such innovations are at an early stage in development and are unlikely to result in emission reductions in the order required to make a genuine decline in the rising carbon emissions graph characteristic.
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Figure 3: click to enlarge[/caption]
Prior to modern industrialisation concentration levels of carbon dioxide in Earth’s atmosphere remained relatively stable at approximately 280 ppm (parts per million). Over recent decades there has been a steady rise in emissions, with levels now at 400 ppm (a 40 per cent increase) and rising on average 2.4 per cent per annum (Figure 3).
Figure 3: Atmospheric increase in carbon dioxide (CO2) concentration
In 2009 the International Energy Agency (IEA) proposed a plan entitled the '450 scenario', with an aggressive timetable of actions that would be required to limit the long-term concentration of greenhouse gases to 450 ppm, and in so doing setting a limit of global temperature rise to 2°C above pre-industrial levels.
There have been concerted efforts from commencement of the Kyoto Protocol in 1997 with ensuing developments to date spearheaded by members at the principal meeting of signatory counties, including Marrakesh (2001), Copenhagen (2009), Cancún (2010, Durban (2011), Warsaw (2013), Lima (2014), and to be followed by the important United Nations Framework Convention conference to be held in Paris in 2015.
Hydro-generation world's largest carbon neutral renewable electricity resource
As noted by Dr Arden Bement, energy sustainability is a complex, 'wicked problem' that is interrelated with other complex issues, such as environmental sustainability, economic sustainability, and water and soil sustainability (in relation to biomass-derived) fuels. In reviewing current and potential future carbon reduced (or carbon neutral) energy sources, hydro-generation remains the world’s largest carbon-neutral renewable electricity resource.
Comprising 20 per cent of total world renewable capacity, global installed capacity reached 1,000 GW in 2014. Contributing to electricity generation in more than 60 countries, installed capacity is increasing significantly in large countries including China, Indonesia and India.
Global wind installation is on a rapid growth curve, with up to 40 per cent year on year growth and currently standing at 370 GW. The majority of wind installations to date have been on-shore and the technology, although still developing, has reached a relatively mature status. Off-shore wind farms offer greater power (watts/m
2), but such installations are more technically challenging and costly to install and maintain.
Off-shore farms can produce up to 50 per cent more electricity than on-shore equivalent farms. Wing spans for off-shore turbines of up to 160 m are now possible. Advances in off-shore wind is a likely growth area. There is potential for development of near-shore deep water zones in countries including the USA, the western coast of South America, Spain, Norway, China, Japan, India, and the eastern coast of Australia.
Wind turbine power rating is determined by Betz Law: P = 0.5
cρAV
3 Importantly power output is proportional to wind velocity cubed and to blade swept area. As the area is proportional to the square of the radius (r
2 or D
2/4), holding other conditions constant, a doubling of the radius will increase power output fourfold.
Ireland's installed wind capacity of 3,000 MW a 'formidable achievement'
Ireland currently has installed wind capacity of 3,000 MW. In spite of challenges, both socio and technological, installation to this level on a relatively small island grid represents a formidable achievement.
Exciting developments in wave and tidal energy in Ireland and the UK also hold promise, however technological developments are still at an early stage and grid penetration to date is small. The Marine Renewable Industry Association (MRIA) plays a key role in policy developments and information dissemination; the MRIA Annual Energy Industry Forum is a key calendar event in this important sector.
Geothermal energy is the energy contained in Earth’s interior in the form of heat. Earth’s inner core reaches a maximum temperature of approximately 4000°C. To extract heat it is necessary to have some carrier to transport heat to an accessible depth below Earth’s surface. At certain locations increased temperature gradients occur, indicating significant geothermal resources. These may be commercially exploited within depths of approximately 5km and fluxes of 10 to 20 W/m
2.
The sun is the largest entity of our solar system and is either the direct or indirect source behind almost all forms of energy we use on Earth today. Electricity generated from solar photovoltaic (PV) and concentrated solar power (CSP) therefore has the potential to allay resource constraints and emission concerns associated with the combustion of fossil fuels, and introduce more environmentally sustainable watts to the global energy supply going forward.
At the end of 2012, Solar PV reached a significant milestone, exceeding 100 gigawatts of installed capacity worldwide. PV devices convert sunlight directly into electricity, whereas CSP collects the thermal energy from focused sunlight via a working fluid that subsequently provides heat or electricity. With 100 gigawatts of installed capacity worldwide, nevertheless in 2013 solar electricity accounted for less than half a per cent of the global share of electricity.
PV solar generation could account for 11% of global electricity generation by 2050
Predictions, on the other hand, forecast that PV solar generation could account for 11 per cent of global electricity generation by 2050. The biggest economic challenge solar PV faces is in achieving grid parity, or competitiveness with retail electricity prices on a per kilowatt-hour basis.
Biofuels are categorised as either first or second generation. Ethanol production as a transport fuel has been the domain of first generation biofuels. Production commenced in the 1970s and has grown to relatively substantial proportions in Brazil and the USA. As a flexi-fuel, average blends of 20 per cent have been achieved in Brazil, with permission for much higher percentage blends as required in meeting market demands. Owing to policy restrictions a maximum bend of 10 per cent has been permitted in the USA. Biodiesel has featured in the EU with permitted blends of up to 20 per cent.
Second-generation biofuels are derived from a variety of advanced feedstocks including cellulosic sources of agricultural resides such as corn stover, wheat straw, and forest residues. They may also be comprised of dedicated energy crops such as miscanthus, switchgrass, poplar, and willow. These feedstocks may be converted to biofuels via biochemical, thermochemical, or hybrid sources. The technology in second generation fuels has been slow to develop and has not lived up to its expected market penetration to date.
Nuclear energy is an ultra-concentrated source of energy; one tonne of natural uranium is capable of producing 44,000,000 kWh of electricity. By comparison, to produce the same amount of electricity would require 20,000 tonnes of coal, or 8.5,000,000 cubic-metres of natural gas.
Nuclear is meanwhile controversial in the public arena, principally due to its related association of atomic weaponry, its operational safety records and the radioactive waste materials it produces. These concerns have seriously undermined the progress of nuclear over recent decades.
Nuclear power carbon-emission-free and economically competitive alternative
Estimates by the International Atomic Energy Agency (IAEA) reveal that annual generation of nuclear power has been on a 2 per cent year-on-year downward trend. A significant advantage of nuclear power is that it is carbon-emission-free. It may be argued that commitment to low carbon economics makes the nuclear option cost attractive since other non-carbon free sources, such as coal-fired and gas-fired plants, will necessitate development of more advanced (and hence more expensive) technologies in order to achieve a reduced carbon emission footprint. The International Energy Agency suggests that nuclear power remains an economically competitive alternative.
The Achilles heel in energy for transportation is its disproportionate reliance on oil. While the oil dependency of major consuming countries varies, the USA is not unique with a transportation sector that accounts for nearly 30 per cent of total domestic energy consumption and a similar percentage of greenhouse gas (GHG) emissions. It is estimated that there are nearly a billion vehicles on the road today, with expectations that the global fleet will exceed 1.3 billion by 2020.
In China alone, the vehicle fleet grew tenfold from about two million in 1980 to 20 million by 2005. Any discussion seeking to advance an understanding of the global energy crisis must include an analysis of the transportation sector and the central role played by oil.
With regard to ground transportation, improvements to vehicle efficiency, diversification of alternative fuel supplies, and realistic scale-up of hybrid, electric, and advanced vehicles over the long term constitute key strategic developments. An eventual transition to hydrogen as an alternative fuel may also become technically and economically viable in the long term, though many significant challenges loom.
In addition to passenger cars, transportation segments such as aviation, rail and maritime represent areas of considerable opportunity for reducing reliance on traditional petroleum fuels and reducing the sector’s carbon footprint. Technology deployment will be the driving force behind this strategy, but this will take time and will be costly.
Prof Eugene Coyle is a Fellow of Engineers Ireland, dean of the Military Technological College in Muscat, Oman, and lead author of 'Understanding the Global Energy Crisis'.
Downloading the book for free
The book, 'Understanding the Global Energy Crisis', is arranged in three parts. Part 1 considers the global energy crisis in context with individual chapters featuring i) historical perspectives of energy and greenhouse gas emissions, ii) global energy policy perspectives, and iii) social engagement and responsibility by the engineer.
Part 2 reviews energy conversion technologies with four chapters dedicated to iv) wind, hydro, ocean and geothermal energy, v) solar power and nanotechnology, vi) biofuels, and vii) nuclear engineering. Part 3 explores energy distribution and use, with 3 chapters featuring viii) issues in taking renewables to market, ix) energy and transportation, and x) energy and the built environment.
An electronic version of the book is freely available, thanks to the support of libraries working with Knowledge Unlatched, an initiative designed to make high quality books Open Access for the public good. More information about the initiative and links to the Open Access version can be found at: www.knowledgeunlatched.org