Can the world convert to total renewable energy by 2050?

In 2009, Stanford University engineering professor Mark Jacobson outlined a plan for the world to get all its energy – including transport and heating fuel and electricity – from wind, water and solar resources by 2050.

Considered radical at the time, the model has been fleshed out to provide details for 139 countries and is now seen as far less extreme than it once was. The conversion would not only eliminate most greenhouse gas emissions, Mr. Jacobson says; it would dramatically improve human health and create millions of new jobs. He spoke recently to The Globe and Mail's Richard Blackwell.

Many people would suggest your proposal is radical and impractical. Is it?

I think it is actually mainstream now. At the Paris conference, they were talking about 100-per-cent renewable energy. In the United States, presidential candidates on the Democratic side have embraced it.

Does that reflect a major change in attitude since you first proposed this in 2009?

It was definitely radical in 2009, and even through 2013 and partly in 2014. Most of this transformation has taken place in people's minds in the last year. The goal to get to 100-per-cent renewable energy has gathered a huge momentum.

Are you happy with the Paris agreement, which is fairly vague in how it will get to its goals?

It is certainly positive. It is not enough to really address the problem full on. But in terms of what is possible at an international level – trying to get 195 countries to agree – it's a good start. But each individual country can do a lot more than what that agreement would indicate. Not only can, but should, because it will be to their own benefit.

Is converting transport – cars, planes and other vehicles – the most difficult part?

I think it is easier to transform transportation than anything else, because the turnover time of a vehicle is usually around 15 years. The turnover time of a power plant is between 30 and 40 years. The technology is there for ground transportation right now … although less so for long-distance ships and planes. Aircraft are probably the hardest to change. Everything else we could transform within 15 to 20 years.

What technology would allow the conversion of aircraft to renewables?

We propose cryogenic hydrogen, which is just hydrogen at a low temperature. It was used to propel the space shuttle. It has been tested and it works.

Why do you not have any nuclear power in your models?

It has disadvantages compared to wind, water and solar, and it is not necessary. It might be better than gas or coal, but it still results in nine to 25 times more carbon emissions and air pollution than wind power, per unit of energy generated.

Also, 1.5 per cent of all nuclear reactors built have melted down seriously. And countries have secretly developed weapons under the guise of civilian programs. Then there are radioactive waste issues that are not resolved. And they cost three to four times more right now than wind power and two to three times more than utility-scale solar. There is really no advantage to using it.

Some people oppose hydro power because of the carbon footprint when large projects drown forests. Is that an issue?

We have zero new hydro. It is all existing hydro, so there is no new footprint of any kind.

Isn't there a physical and environmental footprint from building so much new wind and solar power?

Keep in mind that we are also subtracting all the footprint related to gas, coal, oil and nuclear. There are 2.3 million gas wells spotting the Great Plains of the U.S. and Canada. Well pads, roads and storage facilities take up an area the size of the state of Maine. We would be subtracting that, and all the coal mines, all the oil refineries and the oil wells.

The new physical footprint for everything, worldwide, would be about 0.3 per cent of the world's land area. The spacing [between wind turbines and solar panels] is another 0.6 per cent of the world. And most of that spacing can be used for agriculture.

What about concerns over materials used in solar panels and wind turbines?

There is an environmental impact for mining [those materials]. But it is a one-time [impact] for each device. With fossil fuels, you need to keep mining continuously. The solar panel footprint is trivial in comparison to the fossil-fuel footprint.

How do you convince countries with big oil and gas industries, like Canada, that this shift is a good idea?

It is [a matter of] information. If people realize that they are going to make and save a lot more money by converting, then the transition would go naturally. If the benefits are clearly laid out, versus the costs, it is a no-brainer for most people.

What about all the people employed in the oil and gas industries who may lose their jobs?

If you convert, you create an additional 22 million jobs worldwide. Sure, you would have to retrain some people, maybe a lot of people in oil and gas, but there are jobs that will be available, both in construction and permanent operation jobs.

Which countries did you find will have the most difficulty to shift to an all-renewable energy economy?

The ones that were the hardest were the smallest – such as Singapore and Gibraltar. They have pretty high populations but not much area, so it is hard for them to produce all their own energy and be energy independent. In Singapore, they will have to transfer some energy from Malaysia. Gibraltar will probably get it from Spain.

Most countries have either a lot of solar or a lot of wind, or a mixture of both. There weren't any countries that we couldn't do it in. In some countries, it is more of a political issue because they are war-torn.

Is energy storage going to be a key factor in making this work?

You do need a lot of storage, but it is low-cost storage: pumped hydroelectric storage, concentrated solar power with storage, and heat stored in water and rocks. Combining those with demand response and some hydrogen, which is also a form of storage, will solve the problem.

Is 2050 still a practical date to achieve that goal?

Our goal is to get to 80 per cent by 2030 and 100 per cent by 2050. It is certainly technically and economically practical. Whether it is politically tractable is a different question.

This interview has been edited and condensed.

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CANADA'S 100-PER-CENT RENEWABLES SCENARIO (2050)

Energy mix:

Solar: 21.2 per cent

Onshore wind: 37.5 per cent

Offshore wind: 21 per cent

Wave energy: 2 per cent

Geothermal: 1.9 per cent

Hydroelectric: 16.2 per cent

Tidal turbine: 0.2 per cent

Job creation impact: 293,000 construction jobs; 463,000 full-time operation jobs

Avoided health costs per year: $107.6-billion

Avoided pollution deaths per year: 9,598

Source: Stanford University