Prof Steven Chu gives Romanes Lecture on energy and climate change

Professor Chu shared the Nobel Physics Prize in 1997 for the development of methods using lasers to cool and trap atoms, before serving as Secretary for Energy from 2009 to 2013. He is currently Professor of Physics and Molecular and Cellular Physiology at Stanford University.

His overall message to his audience was that better solutions to the energy and climate challenge mean two things: that solutions need to be environmentally better but at the same time make economic sense.

He said science and technology will play a crucial role in this, finding solutions that include energy efficiency and clean energy sources, although policy nudges are essential to help accelerate the process.

Professor Chu explained what has happened in recent trends in fossil fuels, particularly in oil and natural gas, and gave an 'epidemiological' view of climate change. He outlined what is happening now and how we can mitigate the risks with science, technology and policy so that sustainable energy becomes the low cost option.

His starting point was the epidemiological evidence that established the link between smoking and lung cancer and other diseases. He said while there is enough evidence on climate change to persuade most reasonable people that the climate appears to be changing, the big issue is the risk of our behaviour will affect future generations.

'In smoking, if you smoke you incur the risk of getting lung cancer. We as adults can emit carbon dioxide but hey, it’s the children and grandchildren and their grandchildren who run the risk. "So I don’t see the problem": This is what society has so far been saying. "Do we want to take a one per cent hit in my style of living because of my children and grandchildren in 20 years, 50 years, 100 years from today and for the next 1,000 years? No problem. That’s not my problem." I think it is, but so far society has not embraced this as a problem.'

Professor Chu explained that research will reshape energy's future, enabling grids that run on renewable energy and creating batteries and vehicles that are both more efficient and powerful.

He said that in the United States, natural gas is the cheapest form of energy, but wind turbines are getting better, more reliable and efficient. In five to ten years, he forecast that it will become cheaper to generate electricity with onshore wind than natural gas.

'It is two and a half times less than Europe because we have good wind even if we have incredibly inexpensive natural gas. Solar is going to become comparable. Nuclear is expensive. It’s expensive because we still haven’t figured out how to build power plants on time on budget…Coal in the US is out of the picture. It’s supplanted by natural gas.'

Turning to Britain, Professor Chu said that offshore wind is three times more expensive than onshore and that breakdowns of wind turbines presented particular problems, such as the corrosive qualities of salt water. He also suggested erecting cranes alongside turbines so they can be serviced more easily.

'When we can solve those problems it becomes cheap, very cheap because wind off the ocean is much more reliable than on land.'

Professor Chu went on to talk about the cost of solar energy, which he said was also going in the right direction. However, he gave Hawaii, where there was an ‘inertia issue’ rather than an engineering issue, as an example of why some sunny places still prefer to burn diesel fuel rather than rely on using more solar power.

He pointed out that the cost of renewables depends on where you live and that there will always be a need for back up on demand power. He said that over the next 20 years, the United States could not rely on an energy mix of 80-100% renewables because there are still days when the wind just stops blowing or the sun is not shining.

He asked: 'Why aren’t utility companies getting all excited about the new low-cost option of renewable energy?’ He explained: 'The reason is energy on demand systems are much easier to engineer… We can go to 50-60% of renewables by mid-century but you still need that back-up power. Because of this, utility companies are not really pushing technical innovation. They’re a regulated company. They get yelled at if there’s a blackout so they don’t want to make change.

'We need a new business model in the US and probably the rest of the world. The technology is going to demand it anyway. Why don’t we have it? We don’t have summer/ winter storage and Europe definitely needs summer/winter storage.

'Renewable energy is going to get cheaper than any other form of energy. You can make excess energy and night-time energy and if you can take this and split water into hydrogen and oxygen and you can take carbon dioxide from a fossil fuel plant, which we will need for back-up power, and combine it to form a liquid hydrocarbon, then you can put that on a big tanker and store that anywhere. You can get a 90-day supply of electricity and also an alternative to transportation fuel. We don’t have this technology. We need some good chemists and physicists to figure this out.'