Facts on Australia’s Electricity Dilemma
- It is unwise for Australia to rely on weather dependent wind, solar and hydro for electricity generation as the continent is noted for having the world’s most variable and unpredictable weather ill matched to electricity demand which is characterised by reliability and predictability.
- Unlike many countries Australia will never have much conventional hydro electricity. As the flattest and driest continent Australia’s renewable electricity must mainly come from wind and solar generation.
- Batteries and pumped hydro systems do not make electricity. All they can do is give back previously generated electricity less a discount of about 20%.
- Depending on weather conditions, combined wind farm capacity across Australia can produce as little as 2% or more than 70% of design capacity. Solar varies from 0% to about 80%. The proportion of a generator’s design capacity actually generated is known as “capacity factor”.
- The electricity grid is not a storage system. Daily, weekly or monthly averages are meaningless. Generators of all types have to meet instantaneous demand every second of every day.
- With average capacity factors of between 20% and 30%, approximately three times more wind and solar capacity is required to replace a given thermal generator’s capacity. And that assumes sufficient storage is associated with the renewables to cover their inevitable wide swings in output.
- Weather systems can dominate the entire country meaning that geographic diversity is no solution to the problem of “wind drought”.
- Solar panels produce electricity almost entirely between the morning and evening peaks of the typical demand curve so they do not reduce peak demand. And they produce nothing at night.
- The $6bn Snowy 2 project will not produce any extra water or generate any new electricity. Its sole purpose is to make intermittent renewable energy reliable to match the thermal generators deemed no longer needed. When the capital and operating costs of such storage systems is added as it must be, renewable electricity can never be considered cheap.
- In a global emissions context Australia is inconsequential. Nothing Australia does can possibly make any measurable difference to world emissions.
- With current technologies batteries and pumped hydro storages will be hopelessly inadequate to compensate for inevitable wind droughts or even to cover the 16 hours per day that solar systems don’t work.
- In a future of thermal generator shut downs and therefore limited dispatchable thermal power, surplus night time off-peak electricity will not exist. Then opportunities to recharge pumped hydro storages and batteries will be limited to unpredictable high capacity factor wind and solar episodes.
- If the sun isn’t shining, the wind isn’t blowing and the storages are empty electricity is not available at any price.
- Design capacity comparisons between dispatchable generators and wind and solar generators are meaningless because of the unpredictability of “capacity factors”. To say that a wind or solar farm will power X number of households is nonsense.
Alex Campbell BE Revised 27th March 2018