Nanotechnology solutions to climate change

(Nanowerk Spotlight) Climate change is high on the global agenda. While the United Nations Climate Change Conference in Poznan, Poland, in December 2008, is an important step towards achieving an international agreement on climate change scheduled for the upcoming Conference of the Parties in Copenhagen at the end of 2009, policy makers and practitioners alike are increasingly looking for practical solutions.
A new report by the United Nations University Institute of Advanced Studies (UNU-IAS) offers three innovative solutions in responding to climate change, namely nanotechnology, ocean energy and forestry. The 46-page report ("Innovation in Responding to Climate Change: Nanotechnology, Ocean Energy and Forestry") goes beyond the technological, biological and procedural aspects of these solutions by critically assessing the opportunities and challenges that each type of innovation presents. This report addresses the question why these innovations – despite their large potential to reduce emissions, ocean energy alone could cover the world's electricity needs – have not yet reached the stage of mass commercialization.
As far as nanotechnology's role in responding to climate change is concerned, the report correctly states that nanotechnologies are a platform technology and as such, by itself, nanotechnology will not have a dramatic impact on climate change – but its incorporation into larger systems, such as the hydrogen based economy, solar power technology or next generation batteries, potentially could have a profound impact on energy consumption and hence greenhouse gas emissions.
The report highlights the role of nanotechnology in innovation in three broad categories, namely the development of efficient hydrogen powered vehicles, enhanced and cheaper photovoltaics or solar power technology, and the development of a new generation of batteries and supercapacitors.
Here is an overview of some of the main areas of scientific research and development on nanotechnology relevant to climate change according to the UNU-IAS authors:
Main areas of nanotechnology applications relevant to climate change mitigation
Main areas of nanotechnology applications relevant to climate change mitigation (from: Innovation in Responding to Climate Change: Nanotechnology, Ocean Energy and Forestry; p.11)
Nanotechnology and the hydrogen economy
Nanotechnology plays a crucial role in generation, storage and use of hydrogen as a fuel source. Hydrogen has the potential to replace traditional hydrocarbons as a major source of energy. The most significant role of nanotechnology in the move towards the hydrogen economy appears to be in the development of hydrogen fuel cells (see our Spotlight: "Building better fuel cells with nanotechnology").
As we have done here at Nanowerk before ("Nanotechnology could clean up the hydrogen car's dirty little secret"), the report emphasizes that it is important to note that hydrogen is a carrier of energy, not a source of energy. As such the use of hydrogen fuel cells is not necessarily carbon neutral:
"As the hydrogen for fuel cells has to be produced from other sources of energy, this will result in greenhouse gas emissions. The overall impact of hydrogen fuel cells on green house gas emissions will depend very much on the source of energy used to produce the hydrogen. There are examples of R&D utilizing nanotechnology, however, that are seeking to get around this limitation. As an example, Hydrogen Solar's Tandem Cell™ technology is showcased, as well as the hydrogen fuel cell of Honda's FCX Clarity.
Nanotechnology, solar energy and photovoltaics
Generating photovoltaic energy involves converting light into electrical energy and this is achieved through the use of semiconductors or photovoltaic solar cells. These cells are generally encapsulated in water-tight modules for protection from moisture and impact and the resulting assembly is typically referred to as a solar panel or module.
While nanotechnology is relevant across a wide range of R&D on photovoltaics, there is now considerable focus on the role of nanotechnology improving the efficiency of existing silicon photovoltaic panels, which are the most common type of photovoltaic panel in use today.
"There are several different types of photovoltaic panels such as crystalline and non-crystalline or amorphous silicon photovoltaic panels. Each of these photovoltaic panels differs in their efficiency in terms of converting light energy into electrical energy. Crystalline silicon while more efficient than amorphous silicon, is also more expensive. There are also concerns about the availability of high grade silicon due to increased demand."
Nanotechnology is a central part of on-going R&D aimed at circumventing these problems.
Nanotechnology and energy storage: the next generation of batteries
The next generation of batteries, and those most relevant to responding to climate change will be re-chargeable batteries better suited for use in electric cars and other vehicles. Nanotechnology is at the core of mainstream R&D in relation to the next generation of re-chargeable batteries.
Here, the report showcases the R&D of the Japanese car manufacturer Nissan (please note that Nissan is not the only car manufacturer that has been conducting nanotechnology R&D to develop next generation battery technology for use in electric vehicles). Nissan has recently developed a new laminated lithium-ion battery for electric vehicles. According to Nissan it is the same size as a conventional car battery, but has double the capacity (140Wh/kg) and 1.5 times the power even after 100,000 kilometers usage over five years. The result is double the driving distance, achieved with no increase in battery load.
Utilizing mainstream nanotechnology R&D techniques, higher power and higher battery capacity have been achieved through modification of the negative electrode material. This increases energy density and reduces electrode resistance due to nano-level electrode design. This technology is due to be launched onto the market in 2009.
The report then goes on describe several international regulatory activities and initiatives that address the still unsolved potential environmental and safety issues related to nanotechnologies; it states that "the extent to which the public and, perhaps more importantly, civil society ... fully understands both the technology that lies behind nanotechnology and the potential risks and benefits offered by nanotechnology is unclear."
In summary, the authors recommend further detailed research on how nanotechnology can contribute to addressing climate change since it is becoming clear that it may have a major role to play in this area.
Michael Berger By – Michael is author of three books by the Royal Society of Chemistry:
Nano-Society: Pushing the Boundaries of Technology,
Nanotechnology: The Future is Tiny, and
Nanoengineering: The Skills and Tools Making Technology Invisible
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