ANNUAL SYMPOSIUM

Australia's science future 3-4 May 2000
Full listing of papers

Dr David Mills has been active in solar energy research since 1975 and has been at the University of Sydney Department of Applied Physics since 1980. He has worked on a number of original concepts since, and where appropriate has worked to commercialise these. They include the establishment of the upper limit of optical concentrating performance for asymmetrical solar concentrators, the first storage solar cookers, low emittance solar coatings, advanced solar water heaters and advanced solar thermal power plant design. His compact linear fresnel reflector power plant design was the recent winner of a $2 million Australian Greenhouse Office Showcase commercialisation grant; with 17,000 m² of reflector, it will be the largest solar plant in Australia. Also, 300,000 evacuated tubes are produced per annum in China based on proprietary selective coatings developed by his project, funded by the National Energy Research Development and Demonstration Committee. In 1995, he co-founded Solsearch Pty Ltd, a design company for solar collector technology, and he is the immediate past president of the International Solar Energy Society (ISES).

Symposium themes - Energy

Tackling global emissions with renewable energy technology
by David Mills
D.Mills@physics.usyd.edu.au

Abstract
The current set of carbon abatement scenarios, which appeared in 1997 on the International Panel on Climate Change website, are highly divergent from political actions currently planned by world leaders. To stabilise atmospheric emissions by 2050 would require global per capita emissions 8 or 9 times lower than current Australian per capita emissions. This almost certainly requires an energy economy run using renewable energy, and this is far from what is currently planned in most countries. Many have suggested that the problems associated with achieving stabilisation of global emissions are technical and economic. Dr Mills, however, advances the view that the main issue is not one of technical or economic viability, but political manipulation. He describes a number of technologies which together have the clear technical potential to fully replace existing generation, using both direct and indirect solar energy resources; discusses their technical potential, including integration of different renewable energy (RE) resources; and assesses where these might fit within a self-consistent energy economy.

It is often claimed that these technologies are uneconomic. Is it so? How would we know? Full societal economic evaluation of renewable energy sources is almost completely absent from market practice. This is startling in a modern economic paradigm that supposedly abhors cross subsidy. 'User pays' is a common economic catch-cry. 'Polluter pays' is green propaganda.

Some RE technologies are currently competitive even in today's biased marketplace. Others would need environmental and other costs to be addressed. For example, the recent World Bank analysis of solar thermal electricity suggests that this technology would be cost effective against coal-fired generation under possible future carbon trading rates of the order of $25 per tonne, without inclusion of (often quite large) local environmental and health costs. These technologies are societal bargains, not 'uneconomic'.

RE technology is still being improved and costs are still going down. These improvements are not prerequisites for public legislative action, but outcomes. The more accurately renewable energy is valued, the more it will attract investment and the faster it will develop. Society will be wealthier and healthier for it. Dr Mills will conclude by suggesting areas of policy response to hasten RE uptake.

An economist, John Byrne, has calculated that the sustainable level of greenhouse gas emissions for the world's population as at 1990 is 3.3 tonnes of carbon dioxide per head per year. Each Australian currently accounts for about 26 tonnes per annum. So an eight-fold decrease is required from today's emissions levels

But the world’s population is growing. As it grows, the per capita allocation decreases. This creates equity problems. Already the developing countries want to increase their allocations to allow industrial development.

Despite energy efficiency, global demand will still increase by about 50 per cent by 2050. Business as usual would be much worse.

And energy efficiency faces some problems. As the cost of electricity drops, the cost-effectiveness of energy conservation also decreases. Also, the money saved from energy efficiency can often be spent on more energy services, for example, a fuel-efficient car may be driven further, a low-power light bulb may be left on.

Energy generation from clean sources must be increased to displace old and newer fossil fuel technologies.

Solar energy is mostly used in water heaters. But as solar electricity it could provide around one-quarter of the energy market by 2050, and much more later

Despite rapid growth, photovoltaic power from semiconductors supplies a microscopic amount of energy. Because it is starting from such a low base it will not contribute extensively until after 2030, even assuming a fast growth rate that continues for decades.

Solar thermal electricity produces heat for use in a boiler/generator. There is only a little in California but this has the potential to be a very large source of energy. It can deliver 24-hour power. Another version is the Australian compact linear fresnel reflector array. This low-cost solar plant can be added to coal-fired plants in order to remove the need for additional turbines and electrical infrastructure. A pilot plant is to be built at Stanwell in Queensland.

Wind power is growing rapidly. It is about 15 years ahead of solar in market size.

Biomass mostly firewood at present can be used for electricity production but is limited by the amount of land required.

My energy scenario has direct solar electricity not being important before 2030, but after that it is essential to the replacement of fossil fuels. Wind, solar heat and biomass grow in the developed countries until 2050, then stabilise. Meanwhile fossil fuel usage grows in developing countries.

The direct costs of renewable energy have been falling. Wind and solar thermal electricity will cost US3 to 4 cents per kilowatt-hour. This is 50 per cent more than coal. Photovoltaic power costs about US30 cents per kilowatt-hour but is expected to drop.

If Australia spent 50 per cent more on its energy this would add 2.25 per cent to gross domestic product. But if demand dropped, this would compensate for the higher price. Before 2030 the effect of a shift to renewables will be small.

The costs need to be set against the societal benefits of avoiding local damage to health and the environment, and reducing global pollution. In effect, the rest of society subsidises the fossil fuel energy industry in health and environmental costs. If you include just some of the environmental costs, the cost of fossil fuel energy rises to around the cost of solar thermal electricity.

I would make the following policy suggestions:

• adopt full cost accounting for energy conservation and production technologies, including societal and environmental costs;
• set up a federal-state program to work out mechanisms for incorporating external costs in the energy market such as revenue-neutral ‘feebates’ for using clean technology;
• declare an emissions goal for 2050 of atmospheric sustainability; and
• establish milestones to meet this goal.

A cost-effective renewable energy economy is feasible at practical growth rates and should be pursued.

Session discussion

Does the cost of solar voltaic include the cost of the silicon and the pollution created during manufacture?

David Mills. We have to take that into account in full cost accounting. Biomass and hydroelectricity have social costs, mostly land. These should be in the costs. We need an energy technology-independent assessment.

Should nuclear power be considered as a means of reducing greenhouse gas emissions?

Karl Föger. That is a hotly debated issue. Politically it is not attractive. It is also not attractive on cost the capital and decommissioning costs, and storage of spent fuel, are large. Unless there are strong innovations, it won’t be viable. Germany, the USA and Sweden are phasing out nuclear power. France and Japan are still building.

John Wright. Nuclear is not an issue in Australia. The real problem is cost. Japan is putting in a large number of new plants. Their plans may not be achievable.

What is the ratio between domestic and industrial use of energy? Are there policies to encourage domestic users to be more efficient?

David Mills. There are Commonwealth programs to encourage consumers to lower emissions. There are also State programs.

Karl Föger. In some European countries there are incentives to make houses more energy efficient.

Are there incentives to use roofs to produce electricity?

David Mills. The Federal Government offers a subsidy for solar generation.

Is there any sustainable technology that can be applied to the aviation industry?

David Mills. Pollution is a major cost of travelling overseas; aviation is a bad polluter. There has been no effort to use ethanol as the basis for jet fuel.

What about the use of hydrogen as an energy source, for transport, cooking and so on?

John Wright. Thirty years ago we talked about the hydrogen economy. There is no longer the fear of running out of resources. But there will be a swing back towards the hydrogen economy. We will extract the carbon from hydrocarbons before their use as a fuel, using only the hydrogen. It could also be used in gas turbines. We will produce hydrogen from solar technology. There has been a lot of innovative research.

Karl Föger. Shell has recognised that hydrogen may be the way of the future and set up a subsidiary Shell Hydrogen.

David Mills. Hydrogen is an electricity carrier, not a source. The former uses of hydrogen might be able to be handled by the existing electricity system.

Hydroelectricity appears to have dropped off your list of options.

John Wright. Not at all. This country is limited in its water resources, or it would have more hydro schemes. Hydro has other environmental impacts. There will be no more large dam projects. However, a lot of mini-hydro systems are being set up without building dams or chainsawing land.

David Mills. People in the hydro field see a big increase in its use. However, there are severe restrictions on land.

We need scientists who can not only do research but also communicate and lead projects. Does the education system have a role to play in producing such scientists?

Karl Föger. Engineering courses include project management but very few science courses. Advanced problem solving teaches you how to solve problems most efficiently in minimum times and with minimum resources. Communication needs to become an important part of science courses.

Is the secondary science curriculum boring?

Karl Föger. My comments were geared more towards university education, but of course, interest in science is raised in primary and secondary school. An interesting and broad curriculum in secondary science education will play an important part in attracting able students to a science career.

How can we solve the aircraft fuels problem?

David Mills. From biological sources.

What about heat pumps and greenhouse gas emissions?

David Mills. There are three types of heat pumps: geothermal (using heat in the ground), air and solar. They can address only a fraction of the total thermal market.

Do geothermal energy sources include deep drilling?

David Mills. Yes. Deep drilling hot dry rocks and conventional drilling are different techniques, and one can also use geothermal heat pumps.