Clean
energy—Multiple benefits

The energy system of the future could develop in a number of different directions, depending on how society and its decision makers prioritize energy objectives, including climate mitigation, energy security, air pollution, and human health. Researchers of the Energy Program at IIASA conducted a study for the Global Energy Assessment, determining that to achieve sustainability, some options are “musts,” while others are “choices.” The findings are based on a massive modeling exercise that comprehensively evaluates the consequences of different policy choices for the future energy system. The new projections will enable policymakers to make more informed choices about the future energy pathways they need to take, and how integration of different policy objectives can help to minimize the costs of the transformation.

"Clean energy … It’s the right thing to do … for our environment, it’s the right thing to do for our national security, but it’s also the right thing to do for our economy …

So spoke President Barack Obama on a visit to Fremont, California, in May 2010 to highlight renewable alternatives to oil and the burgeoning employment opportunities offered by clean energy. Listening to him were 200 workers at a new Solyndra facility manufacturing solar photovoltaic systems, and an international audience concerned about oil from the Deepwater Horizon blowout continuing to gush into the Gulf of Mexico.

One of today’s most pressing concerns are the adverse effects that greenhouse gases (GHGs)—in particular carbon dioxide—emitted in the production and use of fossil-fuel-based energy, are having on the world’s ecosystems. With changes occurring more rapidly than previously estimated, world leaders now acknowledge that a transformation of the energy system away from fossil fuels to clean energy is needed urgently to slow and mitigate these impacts.

New work being carried out by IIASA researchers on climate mitigation, energy security, reduced air pollution and health impacts, and affordability of energy within the context of the Global Energy Assessment (GEA) would support Obama’s assertions on the benefits of clean energy. In fact, researchers would go further and say that integrating clean energy targets with other energy priorities—such as security—produces enormous synergies between the objectives mentioned by Obama, resulting in significant cost reductions.

The IIASA research is pushing the boundaries of modeling well beyond the objectives used in the GEA to describe sustainability, in one of the few attempts in the scenario literature to explore—holistically—the important relationships between the various different energy objectives. Researchers are using the MESSAGE integrated assessment modeling framework to look at a large ensemble of energy futures.

Reducing total policy costs

Decarbonization to stay below a 2ºC maximum temperature requires massive investments. However, the total energy system costs for simultaneously achieving energy security and climate mitigation objectives can be substantially reduced. As regions pursue strategies to mitigate the climate and/or enact policies and procurement strategies that prioritize domestic supplies over imports, the diversity of their energy resource mixes tends to increase. The pursuance of climate mitigation and energy security adds to total energy system costs. The costs of security, however, are significantly reduced at higher levels of decarbonization, highlighting the multiple benefits of the two objectives.

Slow Climate Change, Lower Security Costs. At lower levels of decarbonization (i.e., correspondingly low 2ºC probabilities), security costs can increase total system costs by as much as 0.6 percentage points. In contrast, under stringent climate policies, in which total global policy costs are roughly 1.7% of GDP, the added costs of security become extremely small, approaching zero.

Integrated assessment of the complex energy sector is vital. Take, for example, the challenge of reaching the commonly discussed long-term goal for climate mitigation, namely, a 2ºC maximum temperature rise relative to preindustrial levels to avoid dangerous interference with the climate system. Reaching the 2ºC target depends, above all, on making deep reductions in greenhouse gas emissions over the next several decades, a feat that will be principally accomplished by dramatically scaling up the utilization of zero-carbon energy technologies (nuclear and renewables) in the global energy mix so that at least 70 percent of energy sources will be carbon-neutral in the medium term (2050). This will require the upscaling of energy investments to about double the level of today to more than US$1.7 trillion globally—at first glance an expensive transition to make. When analyzed in a holistic and integrated perspective, however, the combined costs of climate mitigation, pollution control, and energy security may come at a significantly reduced total energy bill. In fact, climate mitigation may serve as an entry point both to achieve reductions in pollution control costs of up to 80 percent and to improve energy security, leading to savings of the order of US$800 billion in terms of energy investments.

A related problem from the governance side is that in many countries, separate policy institutions are often responsible for dealing with the different objectives. As a result, the important synergies between these objectives are either overlooked or not understood, and the costs of reaching each objective individually are often overstated. For instance, because zero-carbon energy is pollution-free and can be derived from a variety of sources, it has the potential to significantly decrease air pollution and its corresponding health impacts. Substituting domestically produced renewables (biomass, hydro, wind, solar, and geothermal) for imports of globally traded fossil commodities (coal, oil, and natural gas) reduces pollution, and minimizes impacts not only on the environment (e.g., acid rain) but also on human health (e.g., respiratory tract problems). Diversifying the energy resource mix away from one that relies too heavily on fossil energy can also simultaneously reduce import dependence and enhance energy security. And the more aggressive the levels of decarbonization under scenarios with the most stringent climate policies, the greater the decrease in environmental, health, and security costs. In the most aggressive decarbonization scenarios, the added costs may actually approach zero.

However, while a wholesale reduction in pollution may be the best strategy for minimizing human health and environmental impacts, it may not be the best strategy for the climate. Tradeoffs need to be made. The main pollution–climate tradeoff centers around the small but nontrivial impact that lower levels of air pollutant emissions, namely, climate-cooling aerosols (e.g., SO2 and OC) and their possible effects on the radiative forcing balance of the Earth—defined by the IPCC Fourth Assessment Report as “a measure of how the energy balance of the Earth–atmosphere system is influenced when factors that affect the climate are altered.” Although an “across-the-board” reduction in air pollution tends to increase warming, there are a number of different ways that pollution could be controlled. Specific pollutants are proportionally reduced more than others, for example, warming components, BC, and the ozone precursors—CH4, NOx, CO, and VOCs—are reduced more than the cooling components mentioned. Such an effort would tend to preserve the overall cooling effect of aerosols and thus produce a net gain for the climate or at least allow it to remain radiant-energy–neutral.

Last edited: 28 August 2012