Steven Chu in a laboratory at Stanford University in 1997
In 1997 Steven Chu won the Nobel Prize for his work with lasers at Stanford University. Image: Linda A. Cicero/Stanford News Service

How would you describe the challenge facing the world?

The Industrial Revolution and all that followed has been fuelled by our ability to find, extract and use abundant sources of fossil energy with increasing ingenuity.

For an increasingly larger fraction of humanity, our homes are lit at night, warmed in winter and cooled in summer.

We ride in vehicles that have the power of hundreds of horses and in planes with horsepower in the tens of thousands.

But there is a catch. The cost of keeping the equivalent of billions of horses working for humanity has a modern-day equivalent of keeping the stables clean.

Our modern-day waste products are the sulphur and nitrogen oxides, particulate matter, mercury and other pollutants that are emitted when we use fossil fuels.

In addition, the atmospheric concentration of greenhouse gases (GHGs) such as carbon dioxide (CO2), methane and nitrous oxide has risen sharply in the last 65 years.

The average global land and ocean surface temperature has risen by around 1.1° Celsius since 1880.

More worryingly, 80% of that temperature rise has been in just the last 38 years.

So, the world needs to clean up its stable urgently if it is to stay healthy. But what about the 1.1 billion people with no access to electricity? How can they be helped?

For people in the developing world, improved access to energy would help raise their standards of living.

And, just as cell phones leap-frogged past landline use in the developing world, new technologies can give people in those countries access to energy.

Small local solar power grids in isolated rural areas in developing countries can be used to charge cell phones, to pump and purify water, and charge LED lanterns to read at night without poisoning the air in their homes with kerosene lamps.

Even when backed by batteries, solar power is a cheaper and cleaner alternative to diesel-fuelled power generators.

I’m optimistic that they can bring energy to a lot of rural areas which would not have been connected to countries’ national grid systems for a long time.

What about generating cleaner electricity in the developed world, in Europe for example?

The price of solar has fallen dramatically around the world, but I don’t see much potential in northern Europe.

Most of the future growth in renewable energy will be in wind power. But when there’s no wind you need to be able to call on other sources of energy.

You need back-up, or on-demand, energy sources that you can control, energy storage and electricity transmission links that are hundreds or even thousands of kilometres long to reach better wind power sites.

For on-demand electricity you only have two choices – fossil fuels or nuclear. Virtually all technologies have learning curves whereby the more you produce the better you get at it and the cheaper it gets.

Nuclear is one of the very few technologies to have inverse cost curves; the more plants we have built the more expensive it has become, largely because of rising concerns about safety and public fears.

I don’t think nuclear plants are going to play a major long-term role in many countries until we relearn how to build them on time and on budget.

Gas is the least polluting of the fossil fuels. Hopefully, within 10-15 years we will have piloted technologies that can capture and compress CO2 at a cost of around $35/tonne of CO2. The question is what do we do with the CO2 after capture?

Steven Chu

Steven Chu

Steven Chu is Professor of Physics and Molecular & Cellular Physiology at Stanford University in California.

He was awarded the Nobel Prize in Physics in 1997 for the development of methods to cool and trap atoms with laser light.

President Barack Obama appointed Chu as his Secretary of Energy in 2009, a position he served until 2013.

As Secretary of Energy he began several key technology development initiatives including the Advanced Research Projects Agency, and the government’s energy innovation hubs, which aim to accelerate scientific progress through integrated research and engineering centres.

Storing it safely underground is one approach. What else could be done?

Total global CO2 emissions are currently more than 32 gigatonnes a year. For carbon capture technologies to play a meaningful role in the fight against climate change you need to capture and store, or find innovative ways to use, at least a few gigatonnes each year.

Captured carbon needs to be economically recycled into commercially viable products – such as calcium carbonate for making cement – as an alternative to carbon storage.

The cost of electricity is already 3 cents/kilowatt hour (kWh) in regions with good sun and wind resources, and many people believe costs could fall to 2/kWh in 10-years’ time.

Such cheap electricity opens the possibility of using electrochemistry to recycle the products of fossil fuel combustion – reducing the CO2 into carbon monoxide and hydrogen and splitting the water into hydrogen and oxygen.

Could chemical batteries play a bigger role, such as for storing excess renewable power?

Chemical batteries are still expensive. Prices are coming down dramatically because of mass production, but I don’t see the price of battery storage going significantly below $100/kWh within the next decade, or even longer.

You probably would need something like $10/kWh to make batteries a widespread solution for seasonal storage. Tesla’s new lithium-ion battery in Australia has roughly 100 megawatts (MW) of capacity, making it by far the largest in the world.

But it’s still only a very small fraction of what is needed. For example, in Texas, electricity demand on hot summer days can reach 80,000 MW.

What role could carbon pricing play in reducing emissions? How could governments approach it?

I used to be agnostic on whether we should take the emissions cap-and-trade approach or the carbon tax route, but now I’m more in favour of a carbon tax.

The reason is Europe started and operates a cap-and-trade system but the emissions price collapsed before long, in large part because there were too many credits given out.

Policy makers need great courage to reduce the number of allowances, year by year, because there’s so much pressure from various interested parties.

For carbon-pricing mechanisms to have a significant impact on emissions, governments need some way of arriving at a meaningful cost on carbon. By meaningful, I mean about $60-70/tonne of CO2 within the next couple of decades.

You can’t suddenly do that, but over two decades getting to $70/tonne will give industry plenty of time to prepare.

A carbon tax that rises in a predictable way would give certainty, and businesses always say they want certainty.

Can an effective global mechanism for pricing emissions be developed without US involvement?

I had been hoping that the governments of the USA, China and Europe could work together to co-ordinate their carbon pricing systems.

Carbon pricing is not something that you can negotiate in the United Nations.

It’s something where a bunch of sincere partners get together and the rest of the countries either join in or face carbon-price adjustments at trade borders.

That would prevent the countries who are moving forward on this from being economically penalised.

But now one of the major players, the USA, doesn’t appear to want to do this, certainly for the next few years.

It’s now a question of whether Europe and China can develop effective carbon-pricing mechanisms without the USA.

Shell Science Council

Steven Chu is a member of the Shell Science Council.

The council was set up by Shell in 2013 as a forum for its chief scientists to work with external peers to help keep the company at the forefront of energy technology innovation.

Around 10 external science and technology experts, including from many of the world’s top universities, regularly meet with a similar number of Shell Chief Scientists to help develop effective, innovative solutions to some of the world’s most important energy challenges.

Steven Chu spoke to Daniel Fineren

More In Inside Energy

Adair Turner: we need action on climate change

The former financial regulator Adair Turner on why he is chairing the Energy Transition Commission.

Harnessing human ingenuity

The world needs urgent investment in innovation, says Robert Armstrong, Director of the Massachusetts Institute of Technology Energy Initiative.

You May Also Be Interested In

Climate change and energy transitions

A key role for society – and for Shell – is to find ways to provide much more energy with less carbon dioxide.

Renewables and Energy Solutions

The global energy system is changing. A planet destined for more people and rising living standards will need more energy. But the world must also find ways to reduce carbon emissions and tackle climate change. Shell’s New Energies business focuses on new fuels and power.

The energy future

How will the world produce more, cleaner energy to power our homes and cities, and fuel our vehicles in decades to come?