17 May 2023
In Australia, great reliance is being placed on electricity generation from solar panels, both roof-mounted and solar farms. The aim is to replace generation from coal and gas to reduce carbon dioxide emissions. Researchers recognise that, for this to succeed, the electricity generated and used must be greater than the electricity expended in making and installing the panels (embodied energy). The number of years it takes for this energy recovery is called Energy Pay-Back Time (EPBT). It is clear that pay-back times should be short because, until the embodied energy is replaced, there cannot be any positive output.
Numerous studies have determined that the pay-back time is between one and five years for rooftop solar and longer for solar farms. This is all very well, but solar panels alone are not a practical, generating system. Nothing is generated from late afternoon through the night to the next morning. No electricity every night… Clearly, a battery has to be added for continuous supply and the embodied energy from the manufacture of the battery has to be included in the analysis. Electricity consumed overnight is replaced when the battery is recharged by the solar panel during the next day.
What happens if the next day is cloudy? Clearly, a bigger battery and a bigger solar panel would be needed. The embodied energy of the bigger battery and panel must be included in assessing pay-back time and the viability of the system. What if the day after that is also cloudy? An even bigger battery and panel than needed. How many cloudy days need to be accounted for?
Any electricity generation system that cannot recover the energy embodied in its manufacture, in a short time or not at all in its lifetime, cannot be considered viable for electricity supply or for emissions reduction.
Yooko Tsuchiya et al reported on two cases of PV electricity generation systems in sub-Saharan rural Tanzania, concluding that EPBT analyses showed unsatisfactory performance. They reported that: ‘At one site, the EPBT even exceeded the lifespan of the PV panel, indicating that energy recovery was impossible.’
The question arises as to whether PV electricity generation can replace coal/gas generation in Australia. This study examines the energy recovery potential of rooftop solar for three cities in Australia representing the extremes of climate, viz. Melbourne, (worst case state capital for sunny days, excepting Hobart), Perth, (best case state capital for sunny days), and Alice Springs (central Australia).
The Australian Bureau of Meteorology (BOM) has records of solar radiation day-by-day for years 1990 to 2022. These data sets show that, of these 33 years, 16 have radiation below average and that May, June, and July are the months most likely to risk electricity shortages, ie. blackouts.
Using these data, a new study has calculated the sizes of solar panel and battery which give the least, combined, embodied energy, then calculated the Energy Pay-Back time for Melbourne, (least sunny days capital excepting Hobart), Perth (most sunny days capital), and Alice Springs (central Australia). Full details of the study are available on request.
The results show that:
- The Energy Pay-Back time for roof-top solar generation of electricity is 22 to 24 years for Melbourne, 14 to 15 years for Perth, and 14 years for Alice Springs.
- For Melbourne, Perth, and Alice Springs, EPBT’s exceed the lifetime of the battery, therefore, batteries have to be replaced twice in the 30-year lifetime of the solar panel. Accounting for this, the energy embodied in the manufacture and installation of the system is not recovered in the lifetime of the system.
- Storage of excess summer generation for practical use requires very large batteries, resulting in unfavourable EPBT.
The following conclusions can be drawn:
- Since prior research indicates that solar farms are worse than rooftop solar, solar farms are not a feasible replacement for traditional coal/gas-based electricity generation.
- Given equal dollar value eg dollars per kWh, assigned to both input and output electricity, the cost results will echo the energy results, that is to say that the cost incurred in manufacture etc. will not be recovered in the lifetime of the system. Given that, within that lifetime, the batteries would be replaced at additional cost, it follows that electricity generated by the solar system will always be more expensive than the input coal/gas electricity which established the system. Statements by politicians such as, ‘the reason electricity is more expensive now is because we do not have enough renewable energy’ is the reverse of the facts. The more solar generation we have, the more expensive electricity will become.
- Subsidies to adjust input and/or output dollar charges do not change the costs. They transfer costs to another element of production, for zero added value. Such subsidies are therefore inherently inflationary.
- Continued purchase of solar panels and batteries from low-cost, coal/gas-based producers while, at the same time, inhibiting and closing domestic coal/gas-based electricity, presents national security issues, for no economic or environmental benefit.
- Persistence with the widespread installation of PV panels and batteries and closure of coal or gas-fired power stations, will result in greater not lesser emissions of carbon dioxide, higher electricity charges, and higher inflation.
Put simply, Australia mines coal and exports it to China where coal-fired power stations generate electricity, which is used to manufacture PV panels and batteries, which Australia buys and uses to generate electricity from the rays of the sun. In their lifetimes, the solar panels never generate enough usable electricity to replace the coal/gas electricity they originated from.
Reliance on solar combined with closing down coal and gas generation is definitely premature and will lead to power shortages, inflated energy costs, compromised national security, and increased carbon dioxide emissions. Australia would be better off for supply reliability, emissions, costs, and sovereign security, to use coal and gas domestically for electricity generation.
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Comment by Nelle-bloody ridiculous- nowhere to grow food -people have to wake up to woke or risk starving