Future of Renewable Energy

Nanotechnology and the Future of Renewable Energy

Nanotechnology operates at such a fundamental level that there is very little of a technological nature that it will not impact. Thus its effects on energy generation, transmission, storage and consumption are numerous and diverse. Some will be incremental and some quite possibly revolutionary.

So, greenhouse nightmare or an emission-free future? Nanotechnology can enable them both. Barring a global wave of forward planning unseen in mankind's history, economics will probably make the decision for us.

Rather than trying to sketch the whole landscape, a few examples will hopefully illustrate the variety.

At the mundane end of the scale you have anti-fouling paints for wave or tidal power, or materials with a higher tolerance for radiation in nuclear reactors. I did say mundane.

In wind power, the potentially enormous improvements in strength-to-weight ratio of composite materials used in blades could pay back surprisingly well because the relationship of blade length to efficiency is not linear but follows a power law -- though there is much argument about how this pans out in the real world.

At the other extreme of nanotech impact, you have solar energy. We are children in this area, and the playground is built on the nanoscale. Almost any development is going to involve nanotech -- an intriguing recent exception being the use of lenses to focus light on old-fashioned silicon photovoltaics, thus demanding less of this expensive material.

But what makes for a revolution in energy generation? Two things: availability and economics. The fact that solar energy is so bountiful -- enough hits the Earth in a minute to meet our global requirements for at least a week -- makes it potentially revolutionary; it's just the cost of capturing that energy that has been standing in the way. Reduce that enough, or increase the cost of the alternatives, and you have a winning scenario.

One other energy source could, I believe, be equally revolutionary. Not fusion, which, despite the dreams of my youth, I sadly have to relegate to a distant future, not that the ongoing experiments aren't worthwhile. But geothermal energy, boring as hot rocks and steam may sound, has revolutionary potential for the same reason as solar -- an essentially unlimited supply of energy untapped only because of economics.

The nanotech connection is not as direct here as with solar -- you have tougher materials to cut drilling costs or thermoelectric tunneling for efficient low-grade heat conversion -- but it only takes the right conjunction of developments and geothermal power stations will be springing up, or down, all over the place.

I've only considered here principal power generation, but this should already give some sense of the breadth and potential scale of impact. I'd be surprised to find any reader of this unaware of the excitement surrounding developments in fuel cell and battery technology. Nanotechnology figures almost without exception in the cutting edge of both.

So how do nanotechnology-based solutions apply to environmental concerns and energy security issues?

From an energy security point of view, nanotech developments are invariably positive since, at the very least, they can help save energy -- aerogels for better insulation, IR-reflective window coatings, low-grade heat conversion in cars, etc. They also assist to varying degrees in the development of alternatives to the fossil fuels upon which so many of us are now so dangerously dependent. I've already mentioned the potential of solar and geothermal energy.

On the environmental front the answer is not so clear. We live in a world where short-term economics have an overwhelming influence on decision making.

The good news for those who worry about things like global warming, is that the increasing cost of oil -- a long-term trend that will not stop, oil being a finite resource -- and the decreasing cost of alternative sources such as solar energy, give renewables an ever more favorable economic position. When you look at the diverse spread of nanotech-related impacts they are almost always supporting technologies with an improved environmental profile.

Unfortunately, there is a rather big exception to this. Nanotechnology has helped improve the effectiveness of catalysts. Fuel cells and catalytic converters are among the welcome beneficiaries.

But catalysis is also at the heart of gas-to-liquid and coal liquefaction technologies that promise oil independence for those with access to previously uneconomical gas reserves or to coal reserves. Energy security is a big carrot and it so happens that two highly populated countries that rank among the fastest-growing economies in the world, and thus the fastest-growing energy consumers, are coal-rich: China and India. North America too is coal-rich.

If such countries can start to economically run their cars, trucks and buses on diesel made from coal -- which ironically is low-emission compared with normal diesel at the vehicle end but overall produces more CO2 than oil-based diesel -- then we could be looking at a greenhouse gas nightmare scenario since there is enough coal in the world to supply our energy needs for hundreds of years.

So, greenhouse nightmare or an emission-free future? Nanotechnology can enable them both. Barring a global wave of forward planning unseen in mankind's history, economics will probably make the decision for us.

Making the Transition from Old to New Energy

I think that the likeliest difference between "old" and "new" energy, and the generator of greatest debate, will be systemic rather than one particular technology or another. The question of when and how the transition to new energy occurs is also intriguing -- as the coal liquefaction scenario above shows, we could in theory be stuck with the old, or pretty similar, for some time to come.

Only coal and nuclear fission are potential candidates for maintaining the uniform and monolithic energy network we have now in the developed world. There are good reasons to avoid both, if we can -- some would argue that we cannot.

All the alternatives involve a mix of technologies and energy sources, with energy not always being produced where you want and when you want, thus producing a far more complex system than we have now. The phrase 'intelligent grid' is often held up as an example of how this complexity will operate, with buying, selling and saving of energy being possible at many scales.

I'd rather do away with the 'grid' word altogether because it evokes the electricity grid that we in the developed world generally take for granted but which exists only as a consequence of our historical dependence on fossil fuels, and is grossly inefficient.

In a mixed-energy-source scenario, the traditional grid would be challenged by localized generation, the form of which would vary according to location: Saudi, sunshine. Greenland, geothermal.

The off-grid or localized grid scenario begs the question of how large amounts of energy will be transferred from one place to another, which will no doubt continue to be either required or an economically viable activity. The classic answer is hydrogen, but it is unfortunately a lousy way to transport energy, thanks largely to its volatility.

In theory, the development of cheap, high-load superconducting cables -- perhaps made of carbon nanotubes -- might keep the old-fashioned grid alive but it seems to me that an efficient means of converting whatever energy source happens to be available to you into a fuel that is liquid, or close to it, at room temperature -- e.g., methanol -- combined with a fuel cell technology to make good use of it, would be a hard system to beat when it comes to storage and transmission.

As I write, there are at least a few scientists around the world trying to figure out ways to outdo Mother Nature in turning sunlight into a compact, transportable energy source. All of which happens, of course, on the nanoscale.