Future Energy Mix Research Articles

The case for organic photovoltaics

Increasing demand for energy worldwide, driven largely by the developing world, coupled with the tremendous hidden costs associated with traditional energy sources necessitates an unprecedented fraction of the future global energy mix come from sustainable, renewable sources. The potential solar energy resource dwarfs that of all other renewable sources combined, yet only two photovoltaic technologies are known to have the potential to be scaled up to make dramatic impact on the overall energy mix: silicon and organic photovoltaics. In this paper, we present the long-term sustainability advantages of organics when compared to silicon and other photovoltaic technologies in terms of energy payback time and global warming potential while also discussing the outlook for transitional applications of organic solar cells.

Thermodynamic analysis of combined cycle gas turbine power plant with post-combustion CO2 capture and exhaust gas recirculation

Natural gas is expected to make up a significant proportion of the future global energy mix. Therefore, reducing greenhouse gas emissions from gas-fired processes is very essential for most countries, before emission reduction targets can be met. This article aims to carry out thermodynamic analysis of combined cycle gas turbine power plant with post-combustion CO2 capture through modelling and simulation. The combined cycle gas turbine power plant and the CO2 capture plant were simulated in Aspen Plus®. The combined cycle gas turbine power plant model was validated with simulation data from GateCycle® and the CO2 capture plant model was validated with experimental data from the pilot plant at the University of Texas at Austin. The CO2 capture plant was scaled up from pilot plant to commercial scale to process flue gas from a 250 MWe combined cycle gas turbine power plant. The integrated model for combined cycle gas turbine and CO2 capture plant was further used for performance study. Exhaust gas recirculation has been proposed to increase CO2 concentration in flue gas and reduce the flue gas flow rate. Its effect on combined cycle gas turbine power plant performance and capture plant sizing has been investigated. The analysis indicated that exhaust gas recirculation can reduce penalty on thermal efficiency without any major modification to the original power plant.

Global and regional potential for bioelectricity with carbon capture and storage

Among technological options to mitigate greenhouse gas (GHG) emissions, biomass energy with carbon capture and storage technology (BECCS) is gaining increasing attention. This alternative offers a unique opportunity for a net removal of atmospheric CO2 while fulfilling energy needs. Empirical studies using bottom-up energy models show that BECCS has an important role to play in the future energy mix. Most of these studies focus on global BECCS potential, whereas it is of interest to understand where this mitigation option will be deployed. This key issue will strongly depend on regions’ biomass resources and possession of storage sites. The aim of this study is to assess the global and regional potential of BECCS up to 2050 in power generation. This analysis is conducted using the multiregional TIAM-FR optimization model. The climate policy scenarios investigated lead to a considerable expansion of renewable energy and CCS and BECCS technologies in the power sector. CCS from fossil fuel is mainly deployed in fast developing countries (India and China) and BECCS is highly distributed in developing countries, even though biomass resources are widely available in all regions.

An analysis model for small-scale rural energy service pathways — Applied to Jatropha-based energy services in Sumbawa, Indonesia

The potential role of bioenergy in the future energy mix and the performance of bioenergy conversion and use is a controversial issue. Life cycle assessment (LCA) is the key tool to assess the performance and impacts of bioenergy systems and services. As a fairly complex and costly tool, LCAs are rarely applied on small-scale rural settings, which at the same time make up for the largest share of global bioenergy demand. This study proposes an analytical model for rural energy service pathways (RESPs), which supports a simplified and manageable small-scale bioenergy planning by comparing energy and cost efficiencies as well as by pre-assessing possible livelihood impacts of rural energy service pathways for lighting, cooking and mechanical power. The model has been applied on a case study on the Indonesian island Sumbawa that uses the oil bearing scrub Jatropha curcas L. to provide rural energy services. Results of the quantitative and qualitative analyses are combined to evaluate different energy service pathways. Results show strong differences for the investigated service pathways. Cooking with plant oil or biogas cannot compete with firewood from the energy and cost analysis while the negative health impact of particulate matter support liquid and gaseous fuels as long as no low-emission wood stoves are available. Lighting with plant oil or biogas is not supported by both the quantitative and qualitative analyses. The provision of mechanical power shows the greatest potential if the technical service pathways can be further optimised and the institutional challenges can be solved.

An evaluation of Substitute natural gas production from different coal gasification processes based on modeling

Coal and lignite will play a significant role in the future energy production. However, the technical options for the reduction of CO2 emissions will define the extent of their share in the future energy mix. The production of synthetic or substitute natural gas (SNG) from solid fossil fuels seems to be a very attractive process: coal and lignite can be upgraded into a methane rich gas which can be transported and further used in high efficient power systems coupled with CO2 sequestration technologies. The aim of this paper is to present a modeling analysis comparison between substitute natural gas production from coal by means of allothermal steam gasification and autothermal oxygen gasification. In order to produce SNG from syngas several unit operations are required such as syngas cooling, cleaning, potential compression and, of course, methanation reactors. Finally the gas which is produced has to be conditioned i.e. removal of unwanted species, such as CO2 etc. The heat recovered from the overall process is utilized by a steam cycle, producing power. These processes were modeled with the computer software IPSEpro™. An energetic and exergetic analysis of the coal to SNG processes have been realized and compared.

Assessing wave energy effects on biodiversity: the Wave Hub experience

Marine renewable energy installations harnessing energy from wind, wave and tidal resources are likely to become a large part of the future energy mix worldwide. The potential to gather energy from waves has recently seen increasing interest, with pilot developments in several nations. Although technology to harness wave energy lags behind that of wind and tidal generation, it has the potential to contribute significantly to energy production. As wave energy technology matures and becomes more widespread, it is likely to result in further transformation of our coastal seas. Such changes are accompanied by uncertainty regarding their impacts on biodiversity. To date, impacts have not been assessed, as wave energy converters have yet to be fully developed. Therefore, there is a pressing need to build a framework of understanding regarding the potential impacts of these technologies, underpinned by methodologies that are transferable and scalable across sites to facilitate formal meta-analysis. We first review the potential positive and negative effects of wave energy generation, and then, with specific reference to our work at the Wave Hub (a wave energy test site in southwest England, UK), we set out the methodological approaches needed to assess possible effects of wave energy on biodiversity. We highlight the need for national and international research clusters to accelerate the implementation of wave energy, within a coherent understanding of potential effects-both positive and negative.

Comments: The Prize, Updated

Editor's column The history of the energy industry is a study in technical innovation, entrepreneurs, political figures, and how singular decisions changed not only the oil and gas industry, but also the world at large. That history is captured particularly well in the writings of Daniel Yergin, chairman of IHS Cambridge Energy Research Associates. He recently published a sequel to The Prize: The Epic Quest for Oil, Money, and Power, which is titled The Quest: Energy, Security, and the Remaking of the Modern World. Published in 1991, The Prize told the story of the history of oil—the technologies, people, and politics that changed the modern world. The new book tells how the current modern energy world came to be and how it might look different in the future. Much has happened since the first book was written—the conclusion of the Gulf War, the collapse of the Soviet Union, the wave of oil industry consolidation in the late 1990s, and the sharp growth in Chinese and other developing countries’ energy demand. Energy was greatly affected by or central to all of these events and will continue to play a leading role on the world stage, writes Yergin, who addresses several significant contemporary issues in the book: Peak oil theory is nothing new and this is the fifth time in modern history that there has been widespread fear that the world is running out of oil. The first time was in the 1880s when oil production was primarily concentrated in the US state of Pennsylvania. But the theory greatly discounts the industry’s ability to innovate and invest as it finds new and better ways to develop resources. The growth in shale gas production, and the use of technologies such as hydraulic fracturing and horizontal drilling, are one of the industry’s most significant advances and have permanently changed the global gas landscape in a remarkably short time. He believes the industry will continue to innovate and make progress to try to satisfy some of the public concerns about hydraulic fracturing. One natural or geopolitical event can change the energy industry overnight. An example is the nuclear power accident at Fukushima in Japan earlier this year after a tsunami hit the country. That may have ended thoughts of a nuclear power renaissance meeting the needs of a growing global demand for electricity. Concerns about energy supply, and energy demand, will continue to drive geopolitical discussion, including how nations can become energy secure from natural disasters and cyber security threats. And political discussion of climate change could significantly affect the world’s future energy mix. Sometimes overlooked, he writes, is the promise of energy efficiency, which he believes “has the potential to have the biggest impact of all” in satisfying future energy demand. Both the industry and environmental groups agree that the issue is critical and it may become the “first fuel” in any future discussion of balancing global demand with climate change.

World natural gas endowment as a bridge towards zero carbon emissions

We use a global energy market (GEM) model to show that natural gas has the potential to help stabilize global carbon emissions in a span of about 50–100years and pave the way towards low and zero carbon energy.The GEM provides a close fit of the global energy mix between 1850 and 2005. It also matches historical carbon and CO2 emissions generated by the combustion of fossil fuels. The model is used then to forecast the future energy mix, as well as the carbon and CO2 emissions, up to the year 2150.Historical data show relative decarbonization and an increase in the amount of hydrogen burned as a percent of fossil fuel use between 1850 and 1970. The GEM indicates that with a larger contribution of natural gas to the future energy market, the burned hydrogen percentage will increase. This decarbonization will help to advance economic and environmental sustainability.

Life cycle comparison of a wave and tidal energy device

Tidal and wave energy devices are often discussed as a future contributor to the UK’s energy mix. Indeed, marine energy resources are said to have the potential to supply up to 20 per cent of the nation’s electricity demand. However, these technologies are currently at the development stage and make no meaningful contribution to the national grid. A number of devices have been developed, but no single method has emerged as the leading technology. This paper aims to compare two promising devices, one wave device and one tidal device, and assess the life cycle properties of each. A life cycle assessment of the Oyster wave energy device was conducted as part of this study, and a comparison of this and the SeaGen marine current turbine was undertaken. In both cases a ‘cradle-to-grave’ assessment was carried out, calculating emissions from materials, fabrication, transport, installation, lifetime maintenance, and decommissioning (including recycling). The SeaGen tidal device was calculated to have an energy payback period of 14 months, and a CO2 payback period of 8 months. The equivalent figures for the Oyster device were 12 and 8 months, respectively. The respective energy and carbon intensities for the two devices were 214 kJ/kWh and 15 gCO2/kWh for the SeaGen and 236 kJ/kWh and 25 gCO2/kWh for the Oyster. The calculated intensities and payback periods are close to those of established wind turbine technologies, and low relative to the 400–1000 g CO2/kWh of typical fossil fuel generation. With further developments in construction and deployment efficiency these intensities are expected to fall, so the devices appear to have the potential to offer a viable contribution to the UK’s future energy mix.

High and very high temperature reactor research for multipurpose energy applications

Ten years ago, the European High Temperature Reactor (HTR) Technology Network (HTR-TN) launched a programme for developing HTR Technology, which expanded so far through 4 successive Euratom Framework Programmes. Many projects have been performed – in particular the RAPHAEL project in the 6th Euratom Framework Programme and presently ARCHER in the 7th – in line with the Network strategy that identified cogeneration of process heat and power as the main specific mission of HTR. HTR can indeed address the growing energy needs of industry presently fully relying on fossil fuel combustion with a CO 2-lean generation technology, thanks to its high operating temperature and to its unique flexibility obtained from its large thermal inertia and its low power. Relying on the legacy of the former European leadership in HTR technology, this programme has addressed specific developments required for industrial process heat applications and for increasing HTR performances (higher temperatures and fuel burn-up). Decisive achievements have been obtained concerning fuel manufacturing and irradiation behaviour, key components and their materials, safety, computer code validation and specific HTR waste (fuel and graphite) management. Key experiments have been performed or are still ongoing: irradiation of graphite, fuel and vessel materials and the corresponding post-irradiation examinations, safety tests and isotopic analyses; thermal-hydraulic tests of an Intermediate Heat Exchanger mock-up in helium; air ingress experiments for a block type core, etc. Through Euratom participation in the Generation IV International Forum (GIF), these achievements contribute to international cooperation. HTR-TN strategy has been recently integrated by the “Sustainable Nuclear Energy Technology Platform” (SNE-TP) as one of the 3 “pillars” of its global nuclear strategy. It is also in line with the orientations and the timing of the “Strategic Energy Technology Plan (SET-Plan)” for the development of CO 2-lean energy technologies, and thus strengthens the nuclear option in a future European energy mix. Nuclear cogeneration for industrial process heat applications is a major innovation and a major challenge, requiring large-scale demonstration to prove its industrial viability. To enable demonstration, it is necessary not only to develop an appropriate nuclear heat source, but also to develop coupling technologies and to adapt industrial processes to the coupling with a HTR. This requires a close partnership between the conventional and the nuclear technology holders as the base of a Nuclear Cogeneration Industrial Initiative. Recently the project EUROPAIRS initiated by HTR-TN together with process heat user industries has set the bases of such a strategic partnership.

Aerosol loading in an urban environment from a biofuel based CHP plant: assessment and mitigation

This study presents outcomes from a preliminary dispersion modeling exercise for the extent of aerosol loading owing to enhanced biomass combustion in the future energy mix. Secondary aerosol generation potential from photochemical interactions between the precursor emissions from a typical biomass based combined heat and power (CHP) plant and the associated local emissions from harvest and transportation of the biofuels has been estimated for a peri-urban site in the UK. The study provides results for two options – one, direct firing of the energy crop (miscanthus) i.e. base case; two, biomass gasification prior to combustion i.e. mitigation. We demonstrate that on considering the main life cycle stages of biofuel use i.e. harvest, transportation and combustion, the overall effect of the mitigation option is trivial. This is primarily due to increased emissions from harvest and transportation stages while meeting additional biomass feedstock demands incurred in achieving identical energy output as the base case.

Photovoltaics: Status and Perspectives until 2020

AbstractSince 2000, total PV production increased almost by two orders of magnitude, with a compound annual growth rate of over 55%. The most rapid growth in annual cell and module production over the last five years could be observed in Asia, where China and Taiwan together now account for more than 60% of world-wide production. Prices for photovoltaic electricity generation systems have more than halved over the last five years making the technology affordable to an ever increasing number of customers worldwide. The photovoltaic industry is in a process to mature and in this course increasing industry consolidation takes place. This process presents a risk as well as an opportunity at the same time, opening more and more markets. Various installation scenarios published during the last three years vary significantly depicting photovoltaic electricity generation from insignificant to a major energy source. With worldwide 50 GW cumulative installed photovoltaic electricity generation capacity installed in September 2011, photovoltaics still is a small contributor to the electricity supply, but its importance for our future energy mix is finally acknowledged.

Techno-economic assessment of flexible solvent regeneration & storage for base load coal-fired power generation with post combustion CO2 capture

Abstract CO 2 capture and storage has the potential to significantly reduce man made CO 2 emissions from large point sources consuming carbon containing fuels. The share of fossil fuels is expected to remain significant in future global energy mix, driven by the energy consumption of power generation facilities. At the same time, an increased demand for flexible electricity supply is expected as a result of more intermittent renewable sources of power generation. In this work the concept of flexibility and associated plant operation parameters are evaluated on an economic basis by performing analysis on the effect of flexible solvent regeneration and storage for a base load coal fired power plant with post combustion CO 2 capture in a market with cyclical electricity price patterns. An MILP model for generating the optimum operating strategy by maximizing weekly profit was developed and results presented. The model and subsequent analysis highlights the potential value of flexible solvent regeneration and storage. The work also shows a positive correlation between weekly profits and electricity price volatility.

Carbon Capture; Transport and Storage in Europe: A Problematic Energy Bridge to Nowhere?

This paper is a follow up of the SECURE-project, financed by the European Commission to study “Security of Energy Considering its Uncertainties, Risks and Economic Implications”. It addresses the perspectives of, and the obstacles to a CCTS-roll out, as stipulated in some of the scenarios. Our main hypothesis is that given the substantial technical and institutional uncertainties, the lack of a clear political commitment, and the available alternatives of low-carbon technologies, CCTS is unlikely to play an important role in the future energy mix; it is even less likely to be an “energy bridge” into a low-carbon energy future.

‘Energy security’ and ‘climate change’: Constructing UK energy discursive realities

Recently, in the United Kingdom, two issues have dominated the energy policy agenda: effective climate change mitigation and energy security. Whilst evolving government policy has led to government support for new build nuclear power as part of the nation's future energy mix, limited attention has been devoted to examining how arguments were constructed to lead ‘naturally’ to nuclear new build as an option for addressing these two issues. Using Critical Discourse Analysis this paper analyses the struggles within the climate change mitigation and energy security discourses in generating and/or replacing meanings. In particular, it examines how construction of the dominant (hegemonic) discourses led ‘naturally’ to the necessity of new build nuclear power. This paper draws upon 24 stakeholder interviews to examine the hegemonic and counter-hegemonic discourses. It outlines how climate change and energy security were perceived as motivators for energy policy; it shows how the combination of the dominant construction of climate change as an environmental issue and the construction of energy security as a ‘ gas gap’ lent weight to the argument for nuclear new build. Struggling against these discourses is a counter-hegemonic discourse centred around climate change as a symptom of unsustainability and energy security as a lack of energy diversity. The latter, rather than ‘naturally’ proposing an urgent need for nuclear new build, lead to the argument for readdressing the focus of, and use of resources by, society – reducing energy demand and increasing energy supply diversity.

Combustion Characteristics of Biomass Residues and Biowastes: Fate of Fuel Nitrogen

Biomass residues and wastes will have an important role in the future energy mix. Residues from agriculture or industrial processes are usually cheap, widespread, and continuously produced, and their heating value is comparable to that of wood. However, many of these materials are rich in proteins and, thus, nitrogen. Therefore, to be able to exploit these materials in an efficient way, fundamental research on their nitrogen chemistry is essential. In the work presented here, the release of gaseous compounds from five biomass residues from different processes was tested in a bench-scale single-particle reactor. The tested fuels were dry distiller’s grains and solubles (DDGS), palm kernel cake (PKC), rapeseed cake (RC), fermented sewage sludge (FSS), and chicken manure (CM). All of these materials have sufficiently high heating values and are either already used or projected to be used soon in industrial-scale boilers. The setup allowed us to study the total C and N release and the nitrogen partitioning be...

Comments: Betting on Gas

Editor's column ExxonMobil’s purchase of XTO Energy last month—one of the largest merger and acquisition deals this decade—is another sign that future prospects for gas appear brighter than ever. The supermajor’s buyout of a leading developer of unconventional gas resources in North America gives it a major foothold in what has become the hot E&P play of the moment. In a panel session at last month’s International Petroleum Technology Conference (IPTC) in Doha, Thomas Walters, president of ExxonMobil Gas and Power Marketing, laid out his company’s view of the future of gas, a week before the XTO deal was announced. Gas demand will see strong growth over the next 20 years and resource holders must find new ways of developing supplies to meet this demand, he said. Presenting information from ExxonMobil’s 2009 Energy Outlook, Walters said that fossil fuels would continue to be the main energy source for decades and that gas demand would grow faster than demand for other hydrocarbons. Global demand for natural gas will challenge the industry to deliver, from developing unconventionals such as shale to massive liquefied-natural-gas (LNG) projects, such as those that have been built in Qatar, panelists said during the IPTC session. Gas, in particular, will play an important role in the future energy mix because of its abundance, smaller environmental impact, and its desirability as a fuel for power generation. Since its founding in the mid-1980s, XTO has grown by acquiring mature assets and expanding reserves through technology know-how. It owns large interests in major US shale, tight gas, and coalbed methane plays, and has reserves estimated at 45 Tcf of gas equivalent. ExxonMobil said it plans to create an upstream organization to manage global unconventional resources. Other companies are betting on a bright future for unconventionals as well. BP, Statoil, and Eni all have bought significant shale gas assets in the US in the past year. And Devon Energy announced in November that it was selling all of its Gulf of Mexico and non-North American E&P assets to focus on US and Canadian onshore. Devon holds key stakes in several of the largest US shale plays. Although projects in North America have drawn the most attention, other regions have begun estimating the huge potential of unconventional resources. Poland has attracted the interest of Marathon and ConocoPhillips for potential shale development. Saudi Arabia is also eyeing tight gas and shale projects, Abdulla Al-Naim, vice president of Exploration with Saudi Aramco, said during IPTC. He predicted that the exploration staff of the future would be focused on unconventionals. The rise of gas as a future fuel source continues to boost the prospects of a global gas producers’ association similar to OPEC. The 11 member countries of the Gas Exporting Countries Forum met in Doha during the week of IPTC to discuss strategy. Although gas has had limited scope as a global commodity, the growth of LNG has contributed to gas becoming a more fungible and less regional commodity.

A geological disposal facility for the UK’s radioactive wastes

Nuclear power is an essential part of our future energy mix. However, to be fully credible, an active and visible programme of work is needed to demonstrate that radioactive wastes will be disposed of safely. In the UK, a programme for managing historic and committed wastes is being developed and the success of this programme will affect the management of all future waste arisings. Higher activity and longer lived wastes will be consigned to a deep geological disposal facility designed to provide passive isolation of the wastes after it has been sealed and closed. This article begins by considering how such a facility and the barriers that it comprises will contain and isolate radioactivity. It then considers the committed inventory of UK wastes and the repository engineered design options that might be available for them, in the diverse range of geological environments that may emerge from the government’s current voluntary siting process. Much support and information can be gained from over 30 years of international effort on geological disposal and this article sets this in the context of some specific issues facing the UK waste management programme. The article concludes by looking at confidence in repository safety and at where repositories may be built in Europe over the next decades.

Hydroelectric Power in Developing Countries

Over the last two decades, global electricity production has more than doubled and electricity demand is rising rapidly around the world as economic development spreads to emerging economies. Not only has electricity demand increased significantly, it is the fastest growing end-use of energy. Therefore, technical, economic, and environmental benefits of hydroelectric power make it an important contributor to the future world energy mix, particularly in developing countries. This article deals with policies to meet increasing energy and electricity demand for sustainable energy development in some developing countries such as Brazil, China, India, and Turkey.

The Role of Hydropower for Sustainable Energy Development

The global debate about large dams is at once overwhelmingly complex and fundamentally simple. It is complex because the issues are not confined to the design, construction, and operation of dams themselves but embrace the range of social, environmental, and political choices on which the human aspiration to development and improved well-being depend. Over the last two decades, global electricity production has more than doubled, and electricity demand is rising rapidly around the world as economic development spreads to emerging economies. Not only has electricity demand increased significantly, it is the fastest growing end-use of energy. On the other hand, the hydropower industry is closely linked to both water management and renewable energy production, and so has a unique role to play in contributing to sustainable development in a world where billions of people lack access to safe drinking water and adequate energy supplies. Therefore, technical, economic, and environmental benefits of hydroelectric power make it an important contributor to the future world energy mix, particularly in the developing countries. This article deals with policies to meet increasing energy and electricity demand by using hydropower for sustainable energy development in the world.