Nanotechnology has been hailed as promising to fix many of the problems we face in the world and the demands placed upon the environment by modern society. One of the most pressing environmental issues facing modern society is that of global warming and the reduction of greenhouse gases in the environment. Nanotechnology can be applied to a number of areas to assist in the battle to control and reverse climate change.
Reduction of CO2 Emissions
The single largest influence on climate change is the amount of CO2 in the world’s atmosphere. Reducing CO2 emissions is therefore of paramount importance. Two major areas contributing to CO2 emissions are electricity production and motor vehicles. Both of these areas can be positively improved with the application of nanotechnology.
Renewable Energy and Energy Storage
Applying nanotechnology to give a reduction in greenhouse gases generated by the energy sector of industry can be further broken down into improved electricity storage, energy savings and improved electricity production.
Renewable Energy Generation
Solar Electricity Generation
There are currently two main problems with solar electricity generation; it is expensive and inefficient. Solar cells are made from toxic raw materials in a difficult and costly process and this results in the high price. If solar cells were cheap and abundant, efficiency would not be as great an issue but nanotechnology researcher are endeavouring to improve solar cells in both areas. Commercial products are already available that create solar cells from a range of cheap materials, some of which can be painted or sprayed onto virtually any surface in order for it to generate electricity.
Hydrogen Fuel Cells
A hydrogen fuel cell takes hydrogen plus oxygen and combines then to produce electricity and pure water as a waste product. Nanotechnology is being examined as holding the key to solving the two main problems with hydrogen fuel cells; producing the hydrogen and storing it. The cleanest way to produce hydrogen is via electrolysis, but the electricity used in this process needs to come from a clean source such as solar. We are therefore faced with the issues outlined above for solar generation. In order to store the hydrogen special tanks are being developed using carbon nanotubes that absorb hydrogen like a sponge and hold it in place until required.
A problem with electricity production is that it an on demand service. That is, when more electricity is required by consumers, then the electricity producers must increase their output. This situation does not necessarily coincide with the most favourable conditions for electricity production. As an example, as householders require electricity for lighting, heating and food preparation in the early evening, it may be dark and solar systems are therefore rendered useless in meeting this demand.
Nanotechnology researchers are investigating battery technology that might be able to be improved to store electricity generated at low demand periods and then release it to the grid for use at a later stage. Current Lithium Ion, Nickel Cadmium and Nickel Metal Hydride batteries are unsuitable for this application but the intervention of nanotechnology could see large scale banks of these batteries saving electricity or this may come from a new form of battery such as Nanotube Super Capacitor Batteries. Nanotube Super Capacitor Batteries are under development by MIT and utilise nanotubes to give a battery that can be charged nearly instantly and hold the charge with little degradation over time.
One of the most wasteful parts of modern society is lighting but nanotechnology may be set to change that. Although lighting is an essential part of our lives, it is also incredibly inefficient. An incandescent bulb only uses around 10 percent of the input energy to create light, the rest is wasted as heat. Compact fluorescent and LED based bulbs are already increasing lighting efficiency, but lighting based on quantum dots is expected to be close to 100% efficient.
Super Strength Materials
Nanomaterials can have strength to weight ratios far in excess of that for traditional materials. Simply by using high strength nanomaterials in the production of products can lead to decreases in energy demands from productions of raw materials (as less are required) through to transportation of goods (as they are lighter).
Insulation and Window Films
Traditionally thermal insulation is bulky and therefore can’t be used in all areas that it possibly should. This leads to inefficiencies caused by the loss of head or cold. Nanotechnology has now been used to develop an insulating material that can be spray or painted on to a surface as a thin film. The insulating effect of this material exceeds most traditional insulating materials. Transparent films are also available for coating windows. These nanotechnology enabled solar control films reduce energy consumption by filtering solar heat and insulating windows.
Nanotechnology can be used to reduce vehicle emissions in three main ways:
• Changing propulsion systems
• Weight reduction
• Emissions cleaning
New Propulsion Systems
Simply replacing motor vehicles using internal combustion engines with solar powered cars would be an instant positive leap for the environment but many challenges block that path. As outlined above, we would need major advances to solar and battery technologies, but nanotechnology may hold the keys in those areas. Nanotechnology enhanced hydrogen fuel cell powered vehicles are also a possibility.
Batteries that exploit nanotechnology can also be introduced into hybrid powered vehicles that are now common on our roads. Improved batteries can improve vehicle performance to a degree but the major benefit of improved batteries is in vehicle range per charge and the efficiency of the battery itself i.e. how much input electricity is required to fully charge the battery.
Even relatively small reductions in vehicle weight can result in large increases in fuel efficiency. Less fuel consumed equals less carbon emissions. By making vehicles from super strong yet lightweight materials, such as nanocomposites, can lead to dramatic reductions in fuel consumption.
The introduction of catalytic converters to remove NOx emissions from vehicle exhausts has changed the skyline of major cities around the world with massive reductions in smog levels. The introduction of nanocatalysts into these systems is further increasing their efficiency while requiring less raw materials to produce them.
Researchers are currently in a race to develop a similar system to remove CO2 from vehicle exhausts. Although this research is still in it’s infancy, nanotechnology and nanocatalysts may make such systems a reality.