Wind and solar power have gained in popularity amongst Australian politicians in recent years, with a number of announcements being made by leaders intending to massively increase the amount of wind and solar power generated.
This is an article analysing the planning and land use implications of a greater share of solar and wind electrical power generation. It is not an article about climate change or the economics of energy and I would leave it to those with expertise and experience in these areas to comment on these aspects.
Energy is fundamental to how we got here, the layout of our cities and countryside. Early civilizations obtained energy from more primitive and less dense sources of energy such as burning wood, human physical labour, the work of animals and the sun/wind. In the article "When Britain Ran Out of Wood", John U Nef describes how Great Britain shifted it's primary source of energy from wood to coal largely out of necessity, as an expanding population in Great Britain led to almost all of the forests in the country being cut down for agriculture, heating and construction.
While there was some limited burning of coal in other parts of Europe and China earlier, Great Britain was the first country to start producing and burning coal on a large scale and to become an economy based on coal.
In terms of energy density, while it may have been a transition out of necessity, the shift to coal made a lot of sense. The list below shows the energy density of various fuels:
Wood - 18MJ/KG
Coal (bituminous) - 24-35MJ/KG
Crude oil - 41.87 MJ/KG
Natural gas - 53.6 MJ/KG
Lithium ion battery - 0.36–0.875 MJ/KG
Uranium 235 - 3,900,000 MJ/KG
Great Britain's shift to coal allowed it in the 18th and 19th centuries to dominate the world by shifting to an energy source far more dense than other civilizations that were still operating on wood at the time, including the takeover of the Australian continent.
Early empires rose by enslaving conquered populations and capturing their work, and by taking their gold—a claim on work. World War I was fought initially over coal. Germany challenged Great Britain's energy dominance by sinking ships like the Lusitania that was carrying coal. World War II was fought largely over oil. Germany’s first attacked Poland because it produced oil. Japan took Indonesia for its oil and then attacked the United States for denying it oil exports.
The United States rose initially on the backs of negro slaves. It became a major power first on the back of coal and then petroleum - the most productive slave in human history.
As can be seen above, humans have gradually transitioned to more productive sources of energy over the past five hundred years. First from wood to coal, then to oil/natural gas and certain countries have also recently adopted nuclear energy. There has not to date, been a voluntary shift from more dense sources of energy to less dense sources as is now being advocated with solar and wind.
The shift towards more dense forms of energy, while improving our standards of living has in many respects allowed us to become much more wasteful. Suburbs completely designed around the car have only become possible during the oil age. The coal powered stream train did open up large inland areas away from waterways for human settlement, although housing was required to be located much closer together due to limitations in energy availability. A large inland city away from a river such as Canberra - almost completely dependent on trucking goods inland long distances and on car use, would not have been viable until very recently in human history.
Since wind and solar power are not burned, it is harder to calculate their energy density directly. Energy expert and geologist Art Berman calculates that natural gas is 1100 times more dense than wind power and 169 times more dense than solar power.
Perhaps unsurprisingly, Australia currently uses mainly dense sources of energy. Based on Australian government statistics, oil accounts for 37.3%, coal 28.4% and gas 27.4%. Renewables currently only account for only 7%, with solar and wind 35.6% of that 7% figure.
If we were to look at electricity only (just 25.7% of total energy use), what would be the land use implications of switching from coal and gas to solar and wind?
Below shows an aerial image of Bayswater Power station (NSW Government SIX Maps). Despite having many environmental drawbacks including emissions, it is actually very space-efficient, with the capacity to generate 2640 MW of electricity over no more than a few kilometres. Mining the coal to feed the power station does also occupy land area, although this would be a separate topic (as would the mining of raw materials for solar and wind installations).
A 1MW solar farm would occupy approximately 2-3 hectares, so an equivalent solar farm would look at an area of approximately 6600 hectares (before one even started looking at the need for redundant capacity, backup etc. to address intermittency issues).
What about wind power? A search reveals that the Siemens SWT-2.3-108 is currently the most popular type of wind turbine. It has a rotor diameter of 108m, tower height of 80m and capacity of 2.3 MW. If we were again to ignore intermittency issues etc. then we would be looking at over 1147 of these to replace one Bayswater power station. Each one of these turbines requires an access road for for installation, oil changes etc.
Installation of more diffuse forms of electrical power generation will also require an exponential increase in the number of power lines to connect them. Power line developments are often controversial and most people do not like living near them due to visual impacts, perceived electro-magnetic impacts, loss of vegetation and lack of ability to build under/near them.
In terms of solar, locating as much of it as possible on existing buildings would make sense, as it would reduce pressure on land clearing, competition with agriculture, the natural environment and other land uses. Nevertheless, the sheer scale of additions to capacity talked about makes even this a challenge.
The scale and height of modern wind turbine developments makes them unlikely to ever be palatable within urban areas, meaning it is likely that rural and regional areas will be expected to accommodate them. This is increasingly controversial in many parts of the world. A Victorian Wind farm was ordered by a court to stop emitting noise at night earlier in the year. The UK government imposed an effective ban on onshore wind power development in 2013 due to similar controversies.
Local residents are often happy to accept the negative impacts of something if they see positive impacts in their area eg. employment. This is critical for anything to have a social licence to operate in a particular area. For example the Mayor of Lake Macquarie City Council has expressed concern about the closure of a coal fired power station in her area due to loss of hundreds of jobs, despite it's pollution impacts.
The actual employment impacts of mass rollout of wind and solar power appear limited at best in rural and regional Australia. With most manufacturing of the machines currently occuring offshore eg. in China, employment is largely limited to assembly/installation and some limited maintenance roles. The lack of employment generation in regional areas is likely to accelerate controversy over their rollout.
As can be seen above, while solar and wind power do not burn any fossil fuels directly, they are not necessarily "green", due to exponential increases in the land area required to accommodate them and they have the potential to drive political divisions between residents of the cities and regional areas to breaking point over coming decades.
The best way that we can protect nature as humans is to leave as much of it alone as possible. To achieve this, the best thing we can do is reduce the footprint of our activities. Some practical measures would be ending the wasteful practice of suburban sprawl and finding ways to reduce the total area of land that is dedicated to agriculture, mining, roads, logging etc.
Stop wasting 34% of our food? People being satisfied with smaller vehicles and houses, walking and public transport? People being satisfied with using less energy? All of these things would actually require us to change our behaviour, which might be better for us and the environment.