Climate Change Mitigation Technologies

This year has seen the development -- albeit not yet the commercialization -- of a number of new technologies that could substantially reduce the cost of and expand the potential for global GHG emissions reductions. These technologies range from new electric generation (solar electricity) to alternatives to gasoline for the transport sector (e.g. through new nano-technologies for biodiesel) to technologies that may help minimize some of the impacts from climate-related increases in disease. Other technologies with mitigation potential are being developed that are not discussed here because they are either proprietary or not open to peer review. Collectively, these and other technological developments, coupled with adequate additional resources for commercialization, could allow significant reductions in global GHG emissions, and given the likely rise in climate impacts from existing (and already locked in) climate effects, help reduce likely climate- related damages.

Researchers at the Oregon Nanoscience and Microtechnologies Institute and Oregon State University are in the process of creating a small chemical reactor that could decrease the time required for and substantially lower the cost of biodiesel production. The reactor is comprised of nanotechnologies (most of the component parts are substantially smaller than the width of a human hair) which rapidly convert vegetable oils and alcohol into biodiesel. This new device is faster -- up to ten to a hundred times -- than current processes. The microreactor system would replace conventional biodiesel production methods, which involve dissolving a catalyst and a waiting period of up to 24 hours while a slow chemical reaction occurs.

Implications: The new microreactor is highly portable, and if commercialized, might be easily distributed to the farm, eliminating the step of transport and lengthy production processes for biomass inputs. This in turn will reduce energy input, as well as costs. The technology, however, is still in the experimental stage and does not yet have commercial scale investments.

Ethanol is produced in a fermentation process that adds yeast to plant material. Currently, there is a limit to how much ethanol can be produced with available yeast strains. However, taking advantage of a mutant strain with higher glucose/ethanol tolerances, researchers from the Massachusetts Institute of Technology (MIT) created a new form of yeast that can accelerate ethanol production. In a novel technique called transcription machinery engineering (gTME), the scientists were able to alter the transcription factors -- which control the expression of multiple genes -- and enhance the ability of yeast to persist in higher ethanol environments. Alper et al.'s yeast strain was approximately 150 percent as efficient as conventional strains. This boost in ethanol production efficiency could speed production processes.

Implications: While grain-based ethanol production yields only minor climate benefits in a full root-to-tank analysis, such new technologies could alter the equation, making ethanol a significantly less CO2 intensive fuel source, and an attractive alternative to gasoline.

As nations look toward biofuels to replace CO2 intensive fossil fuels, questions have been raised as to the most efficient source crop. Researchers from the University of Minnesota contend that not one species -- but a mix of species -- is more energy efficient and has more ancillary benefits for the environment, such as biodiversity conservation. Tilman et al. collected a decade's worth of data from 16 prairie species and demonstrate that when planted in degraded agricultural areas, an assortment of prairie grasses can produce 238 percent more energy than any one of the studied 16 species alone. For example, when grown in poor soil, switchgrass produced less than a third of the energy than the mixed species yielded, and did not outperform any of the other species planted by itself. Large gains are also found on nutrient-rich land, where the prairie grass mix produced 51 percent more energy than corn.

Implications: The researchers claim that if mixed species of prairie grasses were planted on all of the world's degraded agricultural lands, 13 percent of petroleum consumption could be displaced and 19 percent of electricity needs could be met by this source alone. Moreover, a diversity of native crops can yield additional benefits, including species protection and reduced water contamination.

Ethanol produced from biomass, or plant-derived material, is limited in part by fermentation inhibitors, which are byproducts of production and impair the sugar-to-alcohol process. A new organism, developed by Honda R & D Co., Ltd. and the Research Institute of Innovative Technology for the Earth (RITE), reduces the level of fermentation inhibitors and, as a result, boosts the yield of alcohol during the fermentation process. This supplemental alcohol can be used for energy production. The new "RITE strain" microorganism not only increases efficiency of ethanol production from biomass but it also makes some previously impractical species, such as rice straw, viable for ethanol production.

Implications: The partners developing RITE strain organisms are in the process of developing a pilot project to deploy the technology on a larger scale. If successful, the enhanced cellulosic ethanol production could not only increase supplies of ethanol but could also employ previously unused species for production.

Researchers from Massachusetts Institute of Technology (MIT) are now in the process of experimenting with carbon nanotubes in capacitors, which are commonly used to store electricity in electric circuits, to make a "supercapacitor". Capacitors can recharge in a small fraction of the time needed by traditional batteries -- within a few seconds -- and can be recharged a hundred times more often than a battery can be recharged in its lifetime.

Implications: While the researchers point out that the supercapacitor has a few more years before commercial availability, if successful, this new use of capacitors could make the electric car more cost effective and long-lasting, as battery lifetime and recharging time becomes greatly enhanced.

While batteries are excellent vehicles for storing energy, they cannot deliver electric charge rapidly. Instead, capacitors are commonly used, such as in electronic technologies. Capacitors produce power rapidly, but fail to store charge well. Researchers Palmore and Song of Brown University recently set out to combine the best of both worlds: a capacitor-battery hybrid. The hybrid was created by dipping two plastic strips with gold covering into chemical compounds that have different conductive properties. One side could act like a battery, while the other could serve as the capacitor.

Implications: While the technology is not yet fully worked out (for example, it displays considerable storage losses after recharging), the new hybrid capacitor/battery can deliver more than 100 times more charge, or power, than a conventional battery made of alkaline materials. In addition, it is as thin as a few pieces of paper and smaller than a credit card, which could lead to many commercial applications.

Solar energy holds tremendous potential for mitigating climate change, but solar cell technologies struggle to commercially compete with conventional fossil fuels. However, a recent breakthrough by chemist Pam Shapiro of the University of Idaho has developed a new way of reorganizing solar cells, which could lead to high boosts in energy efficiency, paving the way for solar technologies to enter the market with greater ease. Shapiro and her colleagues developed a solar cell arrangement that layers quantum dots -- composites of copper, selenium, and indium -- between solar cells. Typically, solar cells overheat and lose energy during the electricity-generating process; with Shapiro's new arrangement, however, the quantum dots absorb the energy that might have been lost and store it within the unit for future use.

Implications: The new quantum dot technology has more than doubled the energy efficiency of standard solar cells. Energy savings could reduce the price per kilowatt hour of a solar cell, and, as a result, solar energy may become more cost effective and commercially viable in the future.

Solar cells collect and convert the Sun's energy into electricity. However, until now, solar cell engineers could not surpass a conversion efficiency of 40 percent . A new research project funded by the U.S. Department of Energy was able to exceed this goal and attain an efficiency of 40.7 percent . The new solar cell uses an optical concentrator and is a multi-junction cell, which is designed with several layers. As the sunlight passes through each layer, energy is repeatedly captured, storing more energy than a non-layered cell.

Implications: According to the Department of Energy, this boost in energy efficiency will drop solar electricity prices to 8 to 10 cents per kilowatt hour and make solar energy more competitive. The Department predicts that by 2015, 1-2 million houses in the nation could be powered by solar energy if prices decline to this level.

Another solar energy efficiency barrier has been broken with the enhancement of the class of ultrathin solar cells. Solar cells that are ultrathin, such as those used in paints and window coatings, cannot gain the same efficiency as more conventional technologies -- usually reaching only a 4 to 5 percent efficiency. However, Swiss chemists have developed a new efficient ultrathin solar cell that uses titanium dioxide arranged in nano-crystal formations which act as semiconductors and which has an efficiency of 11 percent . The ultrathin solar cells (known as Graetzel's cells) are expected to be commercially available in two to three years. The researchers suggest that the films of solar cells will be low cost and flexible and can be applied to many surfaces.

Implications: The energy efficiency gains could reduce the price of solar power and potentially allow this thin film technology to be applied more widely in building.

Malaria results in more than a million deaths each year, the large majority of which occur in sub-Saharan Africa. Management of the malaria epidemic in part depends on lead time to prepare for the height of the mosquito vector populations, as well as the length of gestation time. A new technique proposed by Thomson et al. incorporates the use of a climate forecast model to predict when malaria risk will be at its peak, by examining climatic variables which influence the proliferation of mosquitoes. They deployed their system in Botswana and were able to give policy-makers and health program officers up to four months of additional notice.

Implications: One of the effects of climate change deemed extremely likely is an increase in the range of malaria-carrying mosquitoes. Techniques that can provide advance warning of malarial risk will be critical in combating this particular climate-generated impact. While developed using traditional climate variability analytic tools, the technique clearly has enormous value in a world of changing climate.