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At the nanoscale, where the dimensions of matter are below 100 nanometres (nm), materials begin to exhibit unique properties. This defines the basis of nanotechnology. It is the level where the essential behaviour of matter is determined. FEI is involved in the science and manufacture of electron microscopes for characterising and analysing these critical properties for the advancement of nanotechnology. The application of nanotechnology to the energy sector can offer new ways to generate, store and conserve energy – bringing benefits to the environment and the potential to make an impact on climate change.

Nanoscience – the ability to explore and discover the basic blocks of our universe – has been a research discipline for decades, but the first wave of real nanotechnologies is just beginning to break and it is impressive. Nanotechnology is already demonstrating how it can help us identify and use clean alternative, sustainable fuel sources, including hydrogen, wind and solar power.

Figure 1: FEI Titan™ 80-300 Transmission Electron Microscope – the most powerful commercially-available microscope in the world

Hydrogen power – The Pacific Northwest National Laboratory (PNNL) in the US is using nanotechnology to develop a new hydrogen storage medium to fuel future transportation needs. Hydrogen is a way to reduce our reliance on carbon-based fuels. It is abundant in our atmosphere and has more energy per unit of mass than any known fuel. It can be used as a replacement for traditional fuels or to power fuel cells which convert hydrogen into electrical energy and heat. Although the concept of a hydrogen economy has been around for many years, there are several technical barriers to the wide-scale adoption of hydrogen energy. The greatest of these is storage. PNNL scientists are using solid ammonia borane (AB) compressed into small pellets to serve as a hydrogen storage material. Each millilitre of AB weighs about three-quarters of a gram and harbours up to 1.8 litres of hydrogen. Researchers expect that a fuel system using small AB pellets will occupy less space and be lighter in weight than systems using pressurised hydrogen gas, thus enabling fuel cell vehicles to have room, range and performance comparable to today’s automobiles.

Wind power – One of the problems associated with wind power is reliability. Wind turbines are huge, rotating objects that are expected to operate in all conditions. They often accumulate rain and sea water which then freeze, increasing weight and the force required to move the turbine’s fibreglass blades, reducing turbine efficiency by as much as 10%. But new coatings, built atom by atom, can help the blade materials repel water effectively. Scientists are using electron microscopes to understand how to replicate the natural water repellent surfaces of leaves and plants. One company has developed a method of covering surfaces with nanoscale wax crystals that quickly bead water, to reduce water absorption.

New self-cleaning surfaces are built on the same principle, using the characteristics of nanoscale particles – for example, titanium dioxide – to encourage the removal of dirt from exposed surfaces. Dirt on turbine blades has a similar effect to ice, but titanium dioxide particles react with the sun’s UV rays and break down surface dirt, which can then be washed away by rainwater.

Solar power – Nanotechnology is helping the development of cheaper solar panels, which could encourage more people to invest in solar power. Solar panels take advantage of the photovoltaic effect, converting sunlight into electricity. Solar power became popular in the 1970s but has fallen out of favour following fluctuations in the savings available over fossil fuels. Nanotechnology is helping to reduce the cost of producing solar panels by removing the need to build them from silicon. Thin films of new photovoltaic substances just 1 nanometre thick can generate as much electricity as a 200-300 nanometre thick silicon wafer. These thin-film cells offer similar conversion efficiencies to those based on silicon but can be manufactured more cheaply.

Figure 2: Atomic resolution image of nanoparticles of a solid oxide fuel cell

Using existing fuels more efficiently

Nanotechnology is helping us understand how fuels work. With a better understanding of the properties of different fuels we can manipulate them to deliver energy with greater efficiency. Many companies and research institutions are already demonstrating how manipulation at the nanoscale can improve the way we use existing fuels. These include lighting homes and offices with light emitting diodes (LEDs) instead of traditional bulbs, developing catalysts for diesel fuel to increase engine efficiency and identifying new methods of delivering electricity.

	Figure 3: Atomic resolution image of a carbon nanotube. Courtesy of Prof. N. Kiselev, Institute of Crystallography, Moscow, Russia

Research at the University of Cambridge suggests that by replacing inefficient light sources with high efficiency gallium nitride (GaN)-based LEDs, the United Kingdom (UK) could reduce the electricity used for lighting by 33%. These high-quality LEDs can be made routinely and have been commercialised, but white LEDs, widely used in torches and on bike lights, produce a light too harsh for our eyes. Cambridge is using powerful electron microscopes to understand how to improve the colour rendering of the phosphor coating, so that a daylight-like white light can be produced that is suitable for homes and offices.

Oxonica, a leading nanomaterials company based in Oxford, has developed a fuel-borne catalyst that improves fuel economy and reduces emissions. It has been adopted by Stagecoach Group across its 7,000 vehicle UK fleet to increase the fuel efficiency of its coaches and buses.

Nanotechnology can help us become less reliant on local electricity generation. Carbon nanotubes – tiny tubes of carbon grown for their strength and lightweight properties – are better conductors of electricity then traditional copper wires. Nanotubes can carry over a billion amps of current per square centimetre and lose very little of that energy as heat. In theory, they could carry electricity over thousands of miles. With the ability to conduct electricity efficiently over such long distances, cities could use energy generated by giant solar farms in deserts or by wind farms off coastal shores rather than relying on local coal, gas or nuclear power plants.

These examples are just some of the ways in which viewing and manipulating material at the nanoscale can influence the way we manage energy supply and demand. There are a finite number of energy sources on the planet, but measurable ways we can improve our use of them and our energy efficiency. By viewing substances atom by atom, we will understand more about them and how best to exploit their traits. By manipulating them at this scale, we will also be able to develop new materials and products which can support our drive for a cleaner, more energy-efficient world.

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