Renewable electricity is affordable

Our latest peer-reviewed paper, currently in press in Energy Policy journal, compares the economics of two new alternative hypothetical generation systems for 2030: 100% renewable electricity versus an “efficient” fossil-fuelled system. Both systems have commercially available technologies and both satisfy the NEM reliability criterion. However, the renewable energy system has zero greenhouse gas emissions while the efficient fossil scenario has high emissions and water use and so would be unacceptable in environmental terms.

We used the technology costs projected to 2030 in the conservative 2012 study by the Bureau of Resources and Energy Economics (BREE). (In my personal view, future solar PV and wind costs are likely to be lower than the BREE projections, and future fossil fuel and nuclear costs are likely to be higher.) Then, we did thousands of hourly simulations of supply and demand over 2010, until we found the mix of renewable energy sources that gave the minimum annual cost.

Under transparent assumptions, we found that the total annualised cost (including capital, operation, maintenance and fuel where relevant) of the least-cost renewable energy system is $7-10 billion per year higher than that of the “efficient” fossil scenario. For comparison, the subsidies to the production and use of all fossil fuels in Australia are at least $10 billion per year. So, if governments shifted the fossil subsidies to renewable electricity, we could easily pay for the latter’s additional costs.

Thus 100% renewable electricity would be affordable under sensible government policy, busting another myth. All we need are effective policies to drive the transition.

Renewable electricity is reliable

In a previous article for The Conversation I reported on the initial results of computer simulations by a research team at the University of New South Wales that busted the myth that renewable energy cannot supply base-load demand. However at the time of the article I was still under the misconception that some base-load renewable energy supply may be needed to be part of the renewable energy mix.

Since then Ben Elliston, Iain MacGill and I have performed thousands of computer simulations of 100% renewable electricity in the National Electricity Market (NEM), using actual hourly data on electricity demand, wind and solar power for 2010. Our latest research, available here and reported here, finds that generating systems comprising a mix of different commercially available renewable energy technologies, located on geographically dispersed sites, do not need base-load power stations to achieve the same reliability as fossil-fuelled systems.

The old myth was based on the incorrect assumption that base-load demand can only be supplied by base-load power stations; for example, coal in Australia and nuclear in France. However, the mix of renewable energy technologies in our computer model, which has no base-load power stations, easily supplies base-load demand. Our optimal mix comprises wind 50-60%; solar PV 15-20%; concentrated solar thermal with 15 hours of thermal storage 15-20%; and the small remainder supplied by existing hydro and gas turbines burning renewable gases or liquids. (Contrary to some claims, concentrated solar with thermal storage does not behave as base-load in winter; however, that doesn’t matter.)

After Greg Rutherford's annus horribilis

After Greg Rutherford's annus horribilis – which culminated in failure to qualify for the world championships long jump – the Olympic gold medallist again defended himself after criticism from his irritabilis rivalisChris Tomlinson.

Rutherford, who has been straining to get fit after rupturing a hamstring in early July, claimed he had "defied the laws of science" to make it to Moscow. Unfortunately he could not defy the laws of gravity, or those of the IAAF. His leap of 7.87m, nearly half a metre below his personal best, was good enough only to finish 14th in qualifying. Only the top 12 made it to Friday's final.

Tomlinson, who lost out in selection to Rutherford after both failed to jump the 'A' standard of 8.25m, made his feelings clear. "Words can't describe my anger. Season ruined on media profile and not current athletic form, thanks for the support from the athletics community," he wrote in a tweet later deleted.

But Rutherford, not unreasonably, pointed out that he has the much better head-to-head record in 2013 – and as the Olympic champion deserved his shot. "Ultimately I'm still British No1 and still jumped further multiple times than him this year," he said. "I've beaten him every time apart from when I got hurt. It's a no brainer. Surely, you'd pick anyone in any event in the same scenario?

"Again, Chris is obviously going to be upset but there's nothing I can do about that. We both put ourselves in a not-great position by not jumping an 'A' qualifier so that's what it comes down to. I'm not too concerned about tweets and whatever else."

Even so Rutherford, who has lost his sponsors and his American coach Dan Pfaff this year, will perhaps cringe when reminded of his words when named in the Great Britain team: "It would be awful for me to tarnish what happened at London 2012 by turning up to a world championships, telling everyone I'm fit and then go out in qualification because my hamstring is sore and I can't jump. That just makes you look like a mug."

He did not look like a mug in Moscow. He just was not the fearless, attack-the-board-at-all-costs jumper seen in London. Rutherford insisted he was fit but just a little fearful of suffering pain when he jumped.

"I defied the laws of science being able to compete after five weeks," he said. "I literally ruptured one of my hamstrings. I didn't just tear it: I ruptured it. I have half of a hamstring. But I'm still good enough to jump."

Rutherford will now base himself permanently in the UK after deciding that training in America with Pfaff, the mentor who guided him to the Olympic title, was not working. Unsurprisingly moving to Middlesbrough to work with Tomlinson is not part of his plans.

The day after her fifth-place finish in the heptathlon, Katarina Johnson-Thompson was rolling her eyes at comparisons with Jessica Ennis-Hill and struggling to breathe after the exertions of competition. "My throat's killing. I can talk but I can't breathe. If I talk it's like one of those old smoker's coughs. It's not a virus — it's because I worked my lungs so hard in the 800m."

Her coach Mike Holmes believes she can make the improvements in her shot put and javelin needed to win medals at global championships. "We are beginning to make some progress," he said. "We have focused really hard on strength this winter and I have pictures of her with 300 kilos on her back, half squats. They are terrifying, but they have not translated through. Her body doesn't quite get what the shot put requires but it's up to me to use my initiative. We are trying, believe me."

Britain's best hope of a medal on Thursday sit firmly on the shoulders of Perri Shakes-Drayton, who is seeking to become Britain's first women 400m hurdle champion since Sally Gunnell in 1992. She is unlikely to defeat the Czech favourite Zuzanna Hejnova, who has run five of the sixth fastest times in the world this year, but Shakes-Drayton insists that she is feeling no pressure. "This is nothing like the Olympics, it's not in my backyard," she said.