27 Jan 2016

The growth of solar energy and what's leading cutting edge technology

From Nine To Noon, 9:40 am on 27 January 2016

A leading New Zealand researcher believes solar energy will be the preferred choice of the average electricity consumer by the middle of the century.

solar panels

Photo: 123RF

Harnessing energy from the sun and turning it into electricity has never been more efficient - nor cheaper.

The world is embracing solar energy on a massive scale - with the latest figures showing that in 2014 photovoltaics (or PV, the method of converting solar energy into direct current electricity) are supplying 178 gigawatts of energy.

The International Energy Agency predicts that by 2050, solar PV will provide about 16 percent of global electricity, as manufacturer are scaling up, bringing prices down.

Justin Hodgkiss is a senior lecturer in Physical Chemistry at Victoria University of Wellington, and a Rutherford Discovery Fellow.

He is investigating how to capture solar energy into ultra thin materials for electricity generation and told Nine to Noon price was the biggest factor in people's willingness to go down the solar track.

He said the rate at which PV had been taken up was growing exponentially.

"I looked back and it's actually quite simple, it doubles every two years and it has been for about 30 years since the technology has existed ... that's exactly what would be predicted for any technology."

He said many predictions about what proportion of global electricity would be sourced from solar in the future had been too conservative and way off the mark.

Justin Hodgkiss, on the right, leads a team at Victoria University that focuses on polymer-based solar cells. Joe Gallagher, left, is currently completing his PhD.

Justin Hodgkiss, on the right, leads a team that focuses on polymer-based solar cells. Joe Gallagher, left, is currently completing his PhD. Photo: Veronika Meduna / RNZ

He believed solar would dominate by the middle of the century.

"I think it's going to be purely economic and financial. The cost of solar PV is only going in one direction, down, so the growth is inevitable.

"I would listen to people like Warren Buffet, the most successful investor in the world and he's an infrastructure investor and he's putting all of his money on solar."

He said aside from price, the other issue at play in New Zealand for instance was the nexus between existing supply through a national transmission grid and those who wanted to source off the grid.

"There's a big tension because we can't do without the grid right now and the grid costs money and the people who own the grid want users to pay for that.

"The solution if you want to be entirely PV is to completely remove yourself from the grid, and the sun only shines during the day if you're lucky in Wellington."

He said being able to rely fully on solar, without having to flick between it and the grid, was in many ways the final frontier in making solar popular.

That meant for instance being able to store enough of your own solar to get you through a 24 hour cycle.

He said batteries were probably the leading way to do that currently and there had been some exciting research in that area in the last few years but there were some limitations with battery production.

He is also a principal investigator in the MacDiarmid Institute for Advanced Materials and Nanotechnology where he is looking into another option - polymers, which are long chains of molecules.

"The central part of that chain absorbs light and conducts electricity. The benefit of these materials is that polymers are essentially plastic, they can be made cheaply and they can be manufactured cheaply so you can just print them."

"Their efficiencies have gone up by more than one and a half times, that's the effectiveness of converting light to electricity. That actually is starting to make them viable."

He said there was no doubt PV was becoming more feasible for use on a larger scale.

"The efficiency is now around 12 percent and that doesn't sound a lot but the thermodynamic limit is 30 percent, the cells you have on your roof are probably about 15 percent so we're actually in that ball park and that's where they need to be in order to start manufacturing and people are really getting into the engineering side of it now."

"I suspect that the weight of research is going to be more towards engineering than basic science and I suspect you'll actually see products in the next five years made from these materials."

Listen to Justin Hodgkiss talking to Kathryn Ryan on Nine to Noon