Nobel winning scientist Steven Chu says nuclear energy is needed

Nobel prize winner and Obama energy secretary Steven Chu believes all energy options, including nuclear, need to be used to beat climate change.

Physics Nobel prize winner Steven Chu chats with young scientists at this year’s Lindau Nobel Laureate Meetings at Lake Constance in Germany.

Steven Chu is emphatic as well as realistic. It is currently “impossible”, his word, for the world to get to the Paris Agreement goal of net-zero carbon emissions by 2050.

Chu, a scientist who won the Nobel prize for physics in 1997 and served four years as US energy secretary under Barack Obama, says the problem is that we don’t yet have the solutions ready – at the right price – which are needed reduce carbon emissions while providing reliable energy supplies.

He strongly believes that science and economics will come up with the answers. But the time lag means that everything must be thrown into the pot – nuclear and carbon capture, as well as renewables such as wind and solar – to speed the energy transition.

Chu gathered with 37 other physics and chemistry Nobel winners at the annual Lindau Nobel Laureate Meetings on Germany’s Lake Constance this month where he and other laureates discussed their work with over 600 young scientists from around the world. He told the opening session that shifting to a carbon-free economy was one of the defining challenges for science in the next few decades, or even centuries.

The Paris agreement commits the world to trying to limit warming to 1.5C above pre-industrial times, with a goal of holding the increase to well under 2C.

“Forget about 1.5 degrees, we’re over it,” Chu told the meeting.

“We passed 1.5 degrees this year and it is almost a certainty we will pass 2 and 2.5 degrees in the coming decades.”

Chu is optimistic that research and investment will bring about carbon-free energy, but not before atmospheric carbon levels rise to 550 or even 600 parts per million, well above the 450 ppm level believed to give a fair chance of restricting temperature rise to 2C. The level is now 225 ppm.

Australia has the advantage, he says, of being “blessed with incredible solar and inexpensive land”. But solar and wind are decentralised energy sources and need expensive new transmission networks, as well as high-capacity storage. Australia is similar to the US, which is suited to renewable energy because of many time zones and differing weather patterns that offer redundancy when the sun isn’t shining or the wind blowing in one place.

But in the US “utility scale batteries” that smooth out the bumps in renewable energy generation are still 10 times too expensive – currently about $US200 ($300) a kilowatt hour – for renewables to compete with gas as an energy source, Chu says.

Unfortunately big “utility scale” batteries are more expensive per kilowatt hour of capacity than electric vehicle batteries. “They have to be much better. They have to work for a longer period of time. They have to be much more reliable, and the chance of fire has to be zero because these huge battery farms will be fairly close to cities,” Chu says.

He’s confident the price will come down, but it relies on new battery technologies yet to be commercially available.

Not speaking specifically of Australia, Chu says the nuclear energy alternative is widely misunderstood. He believes it can be safe and, even with its record of accidents such as Chernobyl and Fukushima, is safer than coal – “the most dangerous source of energy” – by orders of magnitude. Aside from pumping out carbon dioxide at a great rate, coal also produces tiny airborne particles that damage health. “If you look at the anticipated or recorded deaths due to heart disease, to stroke, to lung cancer, to chronic obstructive pulmonary disease, it’s maybe 5000 times more dangerous than nuclear,” Chu says.

Nuclear has got safer because past accidents have boosted reactor safety standards. But the industry has to relearn how to design and construct them, Chu says. “You have to be able to build them on time and on budget.” He sees real advantages in modular reactors – some small enough to be carried on a truck – that are being developed by many companies, because they have the advantage of being mass-produced.

Unlike a large, one-off nuclear power station, where many things are being done for the first time, manufacture of modular reactors benefits from a learning curve.

“You end up building thousands and tens of thousands over decades. The cost will come down dramatically,” he says. “The safety will be higher because you’re building them under very much more stringent factory control.”

However, used nuclear fuel, which is compact but highly radioactive for tens of thousands of years, needs to be stored safely. The ideal place is way underground in geologically stable rock.

Australia is a good place for such waste and is sitting on a commercial opportunity, Chu says. Other countries will pay for safe storage. “Is it possible that Australia can say, ‘We’ll take your nuclear waste and we’ll charge you billions of dollars,’ ” he asks.

But currently most of the world’s electricity is generated using fossil fuel and, as long as that continues, Chu believes it’s urgent to capture the carbon dioxide and bury it. The problem is that carbon capture is very expensive with existing technology. “The cost needs to be cut at least in half to make it viable. But I think that’s possible and that’s one of my research areas. I’m hoping that we can reduce it fourfold,” Chu says.

To completely offset the impact of electricity generation using fossil fuels, which currently accounts from a quarter to a third of carbon emissions, this means sequestering between 10 billion and 15 billion tonnes of carbon dioxide in the ground each year, pumping it at high pressure into porous rock.

This is a massive task. In volume, says Chu, it’s five times as much as the rubbish now buried around the globe in landfill each year, except much deeper, using oil-drilling technology to reach suitable reservoirs.

Chu fervently believes doing nothing about energy generation and energy usage is not an option. But it’s difficult. “People say I don’t want this, I don’t like this, I don’t want that. I don’t like nuclear, I don’t like carbon emissions, I don’t like transmission lines, I don’t like coal.”

His reply? “You do like energy, you do like lighting at night, you do like airconditioning when it’s really hot, you do like transportation.

“OK, then we’ve got to figure it out, we have to make choices. Because if you only half believe the climate models, only half, we’re in real danger – real, real danger.”

Tim Dodd travelled to Lindau, Germany, with a travel grant from the Lindau Nobel Laureate Meetings.