For years, David Mills, the eminent solar energy technology developer, has dreamed of creating a new model for an energy system that does away with the conventional design of massive baseload infrastructure.
Next week the newly-retired founder of solar thermal technology company Ausra (now owned by French nuclear giant Areva), and a former leading researcher at UNSW, will present that model.
Using hourly data for energy use of the entire United States economy in 2006, Mills will demonstrate how it could have been powered almost exclusively by wind and solar (with storage and the help of biofuels for aircraft and some biomass capacity for certain smelting operations).
The details of his findings, including capacity and costing estimations, will be released when he addresses the Australian Solar Energy Society's annual conference in Canberra next week. But in an exclusive interview with Climate Spectator, Mills gave a broad outline of his conclusions and suggested there was a surprisingly small difference in costs.
“Everyone says that you need flatline baseload capacity (such as coal or nuclear, or in some countries hydro) and build on that platform, and use load-following gas turbines,” Mills said.
“They assume that being baseload makes it cheaper, and all other things are more expensive.”
“What we are suggesting is a new paradigm. The traditional paradigm of flatline baseload does not exist in this scenario, but you need to understand that the replacement for baseload power is not another baseload, it’s a system of flexible and inflexible energy mechanisms based around wind and solar and other sources.”
The study is an extension of an idea that Mills has held dear for some time. In 2005 he presented a talk in Canberra suggesting that solar plans with a “primitive” storage model could run the electricity grid in eastern Australia.
Two years later, he did a similar study for California concluding that, based on hourly data for energy usage in 2006, solar could have carried well over 90 per cent of the electricity load.
The latest study – completed with a former R&D specialist at Ausra, Wei Li Cheng, and a US Department of Energy analyst Phil Larochelle – looks at how solar and wind could handle the entire electricity needs for the US in the same year, and also looks at whether it could handle the entire energy needs for the country, including transport.
Interestingly, wind and solar account for around 50 per cent each of the electricity supplies to handle summer demand and peaks, while more wind was used in winter. Such a system would require a capacity redundancy above peak demand, but would in fact be less than current systems.
Mills says the study looked to test a number of different premises. The first premise was that there was enough solar and wind that, in combination, could run the US economy. There was.
The second was that solar and wind would be connected with a new electricity transmission system, using high voltage direct current lines for the spine of the network, which will allow more flows and result in considerably reduced transmission losses.
These are the sort of networks being contemplated by the Desertec consortium founded by a group of large European industrial giants that are looking to source solar power from north Africa to provide some of Europe’s energy needs.
Mills says China is installing more HVDC lines than any other country in the world – looking to link coal plants with the Three Gorges dam and wind and solar from the north and west of the country. “It very clear to see what they are doing and that it is a very good thing to do,” he said.
Mills says the data used for his study came from 2006, and was based around technology that might be used in 2050, but exists now – even though its lack of scale makes current deployment expensive. "Its not technology that we don’t have now. I didn't want people saying that it's future technology."
He says the model would need to be refined to be implemented, but it provides food for thought. He says it could easily apply to the Chinese and Australian economies, which also benefit from a population largely based on the eastern seaboard, western deserts (which can provide power later into the evening to the eastern consumers), and strong wind resources.
The Mills model will add to the considerable debate about the role of renewables – whether they are a “worthy” but annoying addition to the current network systems, or if they can assume a prominent role in powering economies.
Mills notes the work of the Beyond Zero Emissions group, which outlined a highly contentious study into how Australia could go 100 per cent renewable by 2020 – not so much to suggest it should be done, but that it could be done.
The German industrial giant Siemens has also produced a report entitled “Picture the Future”, which suggested renewable energy could, by 2030, provide 70 per cent of Australia’s electricity needs, with half coming from solar – augmented by storage and a suite of installation across different time zones – and the rest made up of an equal share of wind and geothermal.