Solar photovoltaic and wind power are rapidly getting cheaper and more abundant – so much so that they are on track to entirely supplant fossil fuels worldwide within two decades, with the time frame depending mostly on politics. The protestation from some politicians that we need to build new coal stations sounds rather quaint.
The reality is that the rising tide of solar photovoltaics (PV) and wind energy offers our only realistic chance of avoiding dangerous climate change.
No other greenhouse solution comes close, and it is very hard to envision any timely response to climate change that does not involve PV and wind doing most of the heavy lifting.
About 80% of Australia’s greenhouse gas emissions are due to the use of coal, oil and gas, which is typical for industrialised countries. The land sector accounts for most of the rest.
Sadly, attempts to capture and store the carbon dioxide emissions from fossil fuels have come to naught due to technical difficulties and high cost. Thus, to curtail global warming we need to replace fossil fuel use entirely, with energy sources that meet these criteria:
- very large and preferably ubiquitous resource base
- low or zero greenhouse gas emissions and other environmental impacts
- abundant or unlimited raw materials
- minimal security concerns in respect of warfare, terrorism and accidents
- low cost
- already available in mass production.
Solar PV meets all of these criteria, while wind energy also meets many of them, although wind is not as globally ubiquitous as sunshine. We will have sunshine and wind for billions of years to come. It is very hard to imagine humanity going to war over sunlight.
Most of the world’s population lives at low latitudes (less than 35°), where sunlight is abundant and varies little between seasons. Wind energy is also widely available, particularly at higher latitudes.
PV and wind have minimal environmental impacts and water requirements. The raw materials for PV – silicon, oxygen, hydrogen, carbon, aluminium, glass, steel and small amounts of other materials – are effectively in unlimited supply.
Wind energy is an important complement to PV because it often produces at different times and places, allowing a smoother combined energy output. In terms of worldwide annual electricity production wind is still ahead of PV but is growing more slowly. The wind energy resource is much smaller than the solar resource, and so PV will likely dominate in the end.
Complete replacement of all fossil fuels requires solar and wind collectors covering much less than 1% of the world’s land surface area. A large proportion of the collectors are installed on rooftops and in remote and arid regions, thus minimising competition with food production and ecosystems.
The more widely PV and wind generation are distributed across the world, the less the risk of wide-scale disruption from natural disasters, war and terrorism.