Results 1 - 10 of 28
Results 1 - 10 of 28. Search took: 0.014 seconds
|Sort by: date | relevance|
[en] A set of model experiments was performed to analyze the role of technology development on energy system responses to a global uniform carbon tax. The B2 baseline scenario as implemented by IMAGE 2.2 was used as the starting point for the analysis. Stabilization at a carbon dioxide concentration of 550 ppmv from this baseline was shown to be technically feasible at limited costs. In the first decades, improved energy efficiency and fuel switching play an important role in reducing greenhouse gas emissions. In the longer term, introduction of carbon-free options account for the bulk of the reductions. Technology development is demonstrated to play a crucial role for the mitigation costs (measured as the required level of the imposed carbon tax) by decreasing the gap between the (currently) more expensive low/zero carbon options and their fossil alternatives. For example, technology development, modeled as learning by doing, increases the global carbon reduction in 2030 as a result of a US$300/tC tax from nearly 40% to 60%. Three different aspects of technology development, i.e. technology development under baseline conditions, induced technology development and inertia caused by lifetimes of technologies were identified as important factors in explaining the different responses under different conditions. The relative importance of these factors is of crucial importance for the 'optimal' timing of abatement efforts. Finally, for long-term responses not only has technology development been shown to be important, but also other dynamic processes in the energy system, like depletion. They can sometimes work in the opposite direction
[en] A high probability of limiting temperature increase to 2 deg. C requires a radiative forcing below 3 W/m2, around the end of this century, according to current knowledge. This paper identifies conditions under which achieving such low radiative forcing levels is feasible. Calculations here show that such targets could be achieved, based on technical and physical considerations, provided some key conditions are met. These key conditions include early participation by major sectors and regions in sufficiently stringent policy regimes, and a wide portfolio of mitigation options. Bio-energy and carbon capture and storage (CCS) play an important role in achieving low stabilisation targets. This would require optimistic assumptions with respect to the expansion of the area needed for food production, to allow space for bio-energy crops, and a significant increase in the efficiency of second-generation biofuels. The sensitivity analysis shows that if certain technologies are removed from the available portfolio, low targets - especially the 2.6 W/m2 target - are no longer within reach.
[en] In this article, we assess the potential development of energy use for future residential heating and air conditioning in the context of climate change. In a reference scenario, global energy demand for heating is projected to increase until 2030 and then stabilize. In contrast, energy demand for air conditioning is projected to increase rapidly over the whole 2000-2100 period, mostly driven by income growth. The associated CO2 emissions for both heating and cooling increase from 0.8 Gt C in 2000 to 2.2 Gt C in 2100, i.e. about 12% of total CO2 emissions from energy use (the strongest increase occurs in Asia). The net effect of climate change on global energy use and emissions is relatively small as decreases in heating are compensated for by increases in cooling. However, impacts on heating and cooling individually are considerable in this scenario, with heating energy demand decreased by 34% worldwide by 2100 as a result of climate change, and air-conditioning energy demand increased by 72%. At the regional scale considerable impacts can be seen, particularly in South Asia, where energy demand for residential air conditioning could increase by around 50% due to climate change, compared with the situation without climate change
[en] Using the results of a recent model comparison study performed by the Energy Modeling Forum, we have shown in this paper that including non-CO2 gases in mitigation analysis is crucial in the formulation of a cost-effective response. In the absence of climate policies, the emissions of non-CO2 greenhouse increase from 2.7 GtC-eq/year in 2000 to 5.1 GtC-eq/year in 2100 (averaged across all the models). A multi-gas reduction strategy stabilizing radiative forcing at 4.5 W/m2 (compared to pre-industrial) reduces the emissions (on average) to 2.5 GtC-eq. Such an approach leads to a cost reduction of 30-40% compared to a CO2 only reduction strategy for the same target. The choices of a target and how the gases are valued form an essential part of developing multi-gas strategies. Model results show that using IPCC global warming potentials (GWPs) as basis for substitution has large consequences for the timing of methane reductions. In this context, further research and assessment on multi-gas metrics, going beyond the mere physical aspects, are important for both research and policy-making
[en] The hikes in hydrocarbon prices during the last years have lead to concern about investment choices in the energy system and uncertainty about the costs for mitigation of greenhouse gas emissions. On the one hand, high prices of oil and natural gas increase the use of coal; on the other hand, the cost difference between fossil-based energy and non-carbon energy options decreases. We use the global energy model TIMER to explore the energy system impacts of exogenously forced low, medium and high hydrocarbon price scenarios, with and without climate policy. We find that without climate policy high hydrocarbon prices drive electricity production from natural gas to coal. In the transport sector, high hydrocarbon prices lead to the introduction of alternative fuels, especially biofuels and coal-based hydrogen. This leads to increased emissions of CO2. With climate policy, high hydrocarbon prices cause a shift in electricity production from a dominant position of natural gas with carbon capture and sequestration (CCS) to coal-with-CCS, nuclear and wind. In the transport sector, the introduction of hydrogen opens up the possibility of CCS, leading to a higher mitigation potential at the same costs. In a more dynamic simulation of carbon price and oil price interaction the effects might be dampened somewhat.
[en] In this article we explore several scenarios that aim at meeting radiative forcing targets at 4.5, 3.7, 2.9 and 2.6 W/m2 by 2100. These scenarios are run under the assumption of participation of all countries by 2012 in climate policy and under the assumption of a significant delay in the participation of Russia and non-Annex I countries (up to 2030 and 2050). The study finds the lowest radiative forcing categories to be feasible under full participation, certainly if overshoot of targets is allowed and when bio-energy and carbon-capture-and-storage is added to the mitigation portfolio. In cases with severe delay in participation, the lowest targets become infeasible. For less strict targets (e.g. 3.7 W/m2), delayed participation leads to considerable costs increases (up to 90% for the stabilisation case). As a next step, scenarios with less delay in participation need to be explored.
[en] The risk of human-induced climate change and the volatility of world oil markets make non-fossil fuel options important. This paper investigates the potential for wind, solar-PV and biomass (WSB) to deliver energy. The focus is on land opportunities and constraints and on production costs as a function of resource availability and depletion and of innovation dynamics. The context is provided by the IPCC SRES scenarios as simulated with the IMAGE 2.2 model. We explicitly consider several sources of uncertainty, aspects of the food vs. energy trade-off and the effects of interaction between the three options through their claims on land. We show that 'potential production' concepts are strongly dependent on the chosen land-use scenario-and should therefore be used with an indication of the underlying assumptions. Our results indicate a potential for liquid biofuels in the order of 75-300 EJ year-1 and for electricity from WSB options at production costs below 10 cents kWh-1 of 200-300 PWh year-1. Theoretically, future electricity demand can be amply met from WSB sources in most regions by 2050 below 10 cents kWh-1, but major uncertainties are the degree to which land is actually available and the rate and extent at which specific investment costs can be reduced. In some regions, competition for land among the three WSB options may significantly reduce the total potential as estimated from simple addition-which is another source of uncertainty
[en] Potentials for bio-energy have been estimated earlier on the basis of estimates of potentially available land, excluding certain types of land use or land cover (land required for food production and forests). In this paper, we explore how such estimates may be influenced by other factors such as land degradation, water scarcity and biodiversity concerns. Our analysis indicates that of the original bio-energy potential estimate of 150, 80 EJ occurs in areas classified as from mild to severe land degradation, water stress, or with high biodiversity value. Yield estimates were also found to have a significant impact on potential estimates. A further 12.5% increase in global yields would lead to an increase in bio-energy potential of about 50%. Changes in bio-energy potential are shown to have a direct impact on bio-energy use in the energy model TIMER, although the relevant factor is the bio-energy potential at different cost levels and not the overall potential.
[en] So-far, most climate mitigation studies look at climate policy strategies in a so-called first-best world, i.e. using the least expensive emission reduction options in all world regions and sectors. To explore the impact of limited participation of countries, we have run a set of scenarios that explore the impact of introducing a carbon tax in OECD, the BRIC countries (Brazil Russia, India and China) and the rest of the world. The results show that carbon taxes can effectively reduce greenhouse gas emissions. However, if low greenhouse gas concentration levels are to be achieved, early participation (in some form) of large developing countries is important to increase reduction potential. It should be noted that global carbon taxes (without additional assumptions) lead to relatively high costs in low-income regions. Cap-and-trade regimes have more flexibility to create a comparable distribution of costs amongst countries.
[en] A methodology is presented here to assess the potential long-term contribution of non-CO2 greenhouse gases in mitigation scenarios. The analysis shows the future development of the mitigation potential of non-CO2 gases (as a function of changes in technology and implementation barriers) to represent a crucial parameter for the overall costs of mitigation scenarios. The recently developed marginal abatement cost curves for 2010 in the EMF-21 project are taken as the starting point. First-order estimates were made of the future maximum attainable reduction potentials and costs on the basis of available literature. The set of MAC curves developed was used in a multi-gas analysis for stabilising greenhouse gas concentrations at 550 ppm CO2-equivalent. Including future development for the non-CO2 mitigation options not only increases their mitigation potential but also lowers the overall costs compared to situations where no development is assumed (3-21% lower in 2050 and 4-26% lower in 2100 in our analysis). Along with the fluorinated gases, energy-related methane emissions make up the largest share in total non-CO2 abatement potential as they represent a large emission source and have a large potential for reduction (towards 90% compared to baseline in 2100). Most methane and nitrous oxide emissions from landuse-related sources are less simple to abate, with an estimated abatement potential in 2100 of around 60% and 40%, respectively