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Considering the enormous ecological and economic importance of the transport sector the introduction of alternative fuels - together with drastic energy efficiency gains - will be a key to sustainable mobility, nationally as well as globally. However, the future role of alternative fuels cannot be examined from the isolated perspective of the transport sector. Interactions with the energysystem as a whole have to be taken into account. This holds both for the issue of availability of energy sources as well as for allocation effects, resulting from the shift of renewable energy from the stationary sector to mobile applications. With emphasis on hydrogen as a transport fuel for private passenger cars, this paper discusses the energy systems impacts of various scenarios introducing hydrogen fueled vehicles in Germany. It identifies clear restrictions to an enhanced growth of clean hydrogen production from renewable energy sources (RES). Furthermore, it points at systems interdependencies that call for a priority use of RES electricity in stationary applications. Whereas hydrogen can play an increasing role in transport after 2030 the most important challenge is to exploit short–mid-term potentials of boosting car efficiency.
The role of hydrogen in long run sustainable energy scenarios for the world and for the case of Germany is analysed, based on key criteria for sustainable energy systems. The possible range of hydrogen within long-term energy scenarios is broad and uncertain depending on assumptions on used primary energy, technology mix, rate of energy efficiency increase and costs degression ("learning effects"). In any case, sustainable energy strategies must give energy efficiency highest priority combined with an accelerated market introduction of renewables ("integrated strategy"). Under these conditions hydrogen will play a major role not before 2030 using natural gas as a bridge to renewable hydrogen. Against the background of an ambitious CO2-reduction goal which is under discussion in Germany the potentials for efficiency increase, the necessary structural change of the power plant system (corresponding to the decision to phase out nuclear energy, the transformation of the transportation sector and the market implementation order of renewable energies ("following efficiency guidelines first for electricity generation purposes, than for heat generation and than for the transportation sector")) are analysed based on latest sustainable energy scenarios.
Based on different current long-term energy scenarios the paper discusses the future perspectives of hydrogen in the German energy system as a representative example for the development of sustainable energy systems. The scenario analysis offers varying outlines of the future energy system that determine the possible role of hydrogen. The paper discusses the possibilities of expanding the share of renewable energy and the resulting prospects for establishing clean hydrogen production from renewable energy sources. Emphasis is given to the questions of an ecologically efficient allocation of limited renewable energy resources that can only be assessed from asystems analysis perspective. Findings from recent studies for Germany reveal a strong competition between the direct input into the electricity system and an indirect use as fuel in the transport sector. Moreover, the analysis underlines the paramount importance of reducing energy demand as the inevitable prerequisite for any renewable energy system.
Using natural gas for fuel releases less carbon dioxide per unit of energy produced than burning oil or coal, but its production and transport are accompanied by emissions of methane, which is a much more potent greenhouse gas than carbon dioxide in the short term. This calls into question whether climate forcing could be reduced by switching from coal and oil to natural gas. We have made measurements in Russia along the world's largest gas-transport system and find that methane leakage is in the region of 1.4%, which is considerably less than expected and comparable to that from systems in the United States. Our calculations indicate that using natural gas in preference to other fossil fuels could be useful in the short term for mitigating climate change.
New energy efficiency policies have been introduced around the world. Historically, most energy models were reasonably equipped to assess the impact of classical policies, such as a subsidy or change in taxation. However, these tools are often insufficient to assess the impact of alternative policy instruments. We evaluate the so-called engineering economic models used to assess future industrial energy use. Engineering economic models include the level of detail commonly needed to model the new types of policies considered. We explore approaches to improve the realism and policy relevance of engineering economic modeling frameworks. We also explore solutions to strengthen the policy usefulness of engineering economic analysis that can be built from a framework of multidisciplinary cooperation. The review discusses the main modeling approaches currently used and evaluates the weaknesses in current models. We focus on the needs to further improve the models. We identify research priorities for the modeling framework, technology representation in models, policy evaluation, and modeling of decision-making behavior.
It is now widely recognized that effective communication and demand-side policies for alternative energy require sound knowledge of preferences and determinants of demand of the public and consumers. To date, public attitudes towards new transport technologies have been studied under very different conceptual frameworks. This paper gives an overview of the various conceptual frameworks and methodologies used, where four main approaches can be distinguished: general attitudinal surveys, risk perception studies, non-market economic valuation studies, and other approaches such as those based on semiotic theory. We then review the findings of the recent literature on acceptance, attitudes and preferences for hydrogen and fuelcell end-use technologies, focusing on vehicles. These studies are then contrasted with related research into alternative fuel vehicles. The paper finally discusses the main trends in research and avenues for further work in this field. We recommend, among other things, the use of approaches that build knowledge and familiarity with the technology prior to the exploration of attitudes, and the set up of studies that take a whole-systems perspective of hydrogen technologies and that look at hydrogen in the context of other competing clean technologies.
A promising candidate that may follow conventional vehicles with internal combustion engines combines hydrogen from regenerative sources of energy, fuelcells and an electric drive train. For early fleets introduced the refuelling infrastructure needs to be in place at least to the extent of the vehicles operational reach. The question arises which strategies may help to keep initial hydrogen and infrastructure cost low? Industrial production, distribution and use of hydrogen is well-established and the volumes handled are substantial. Even though today's industrialhydrogen is not in tune with the long-term sustainable vision, hydrogen production and infrastructure already in place might serve as a nucleus for putting that vision into practice. This contribution takes stock of industrial production and use of hydrogen in North Rhine-Westphalia based on a recently finalized project. It demonstrates to which extent industrial hydrogen could be used for a growing number of vehicles and at which time additional capacity might need to be installed.
Concentrated solar power (CSP) plants are one of several renewable energy technologies with significant potential to meet a part of future energy demand. An integrated technology assessment shows that CSP plants could play a promising role in Africa and Europe, helping to reach ambitious climate protection goals. Based on the analysis of driving forces and barriers, at first three future envisaged technology scenarios are developed. Depending on the underlying assumptions, an installed capacity of 120 GWel, 405 GWel or even 1,000 GWel could be reached globally in 2050. In the latter case, CSP would then meet 13–15% of global electricity demand. Depending on these scenarios, cost reduction curves for North Africa and Europe are derived. The cost assessment conducted for two virtual sites in Algeria and in Spain shows a long-term reduction of electricity generating costs to figures between 4 and 6 ct/kWhel in 2050. The paper concludes with an ecological analysis based on life cycle assessment. Although the greenhouse gas emissions of current (solar only operated) CSP systems show a good performance (31 g CO2-equivalents/kWhel) compared with advanced fossil-fired systems (130–900 CO2-eq./kWhel), they could further be reduced to 18 g CO2-eq./kWhel in 2050, including transmission from North Africa to Europe.