There needs to be an easy to understand number that all of humanity is aware of, reflecting the amount of avaiable energy that people currently use compared to what is physically available. In fact, this number is so important that it should be put on the OSE Dashboard.
We call this the Solar Fraction.
It is the fraction of power that humans currently use - compared to the total available power impinging on the surface of the earth from the sun. Because all of the power that humans use, outside of nuclear, comes or came from the sun.
This starts with understanding the distinction between power and energy as well.
That number is 5000.
This number is calculated at Fraction of Available Solar Energy That Humans Currently Use
The implications of this number are profound. This number defines the limits of human carrying capacity - based on the assumption that energy enables human life. Access to energy enables the entire civilization to run. For example, we convert rocks into steel and computer chips by using energy.
The implications are both sobering and encouraging. 5000 means that there is ample available energy - if for example used by PV panels or windmills - to provide all of humanity's energy 5000 times over. That is even if we consider all the wasteful human activity on earth - such as the enormous amounts of energy to ship parts and products around the world several times before they reach a customer.
5000 is not realistic, as solar cells are 10% efficient, and run 1/4 the time, so we reduce that to only about 100x the available energy if we run the entire civilization on photovoltaics. Is there space? Currently, we would need only 1/2% of the earth's surface (accounting for the other half of the globe which is at night). Yes, plenty in the deserts, and plenty on rooftops of the Walmarts of the world, or on the ocean if we like. It would be roughly the area of Spain - see excellent infographic at - . Or similar for wind alone.
The considerations of 'is there enough space if we did X' is somewhat ill-framed. This is because such discussions carry with them the idea of fitting new structures into old infrastructures, without changing infrastructures in a systematic way. In other words, if we change the entire infrastructure, we could achieve better systems design. So stating that 'retrofitting would never work because it would interfere with existing feature X' does not consider a systems approach and should typically not be considered a fundamental barrier, if a deep solution is sought.
One important side point: each human would need a 9x9 meter array to power all of their energy needs if balanced amongst the human population. This is also why Distributed Production is the future.
The energy available compared to that required is still vastly huge. If we could do 1/2% of the earth's area in PV alone - that implies that we comfortably have enough room for 10x more people (think 70B human population) - and perhaps 100x more (think 700B human population).
The point is - humanity has to make long-term decisions on population and resource allocation. Do we want to spam the world with more people, or leave more room for other species? Because space is finite, and the current trend is ecocide.
The OSE solution is to distribute production and localize economies in order to achieve a balance between human populations, wild populations, and natural life support systems. This is based on OSE's notions of responsible earthly denizenship. Read more about How Economic Localization Can Be the Greatest Measure for Safeguarding the Environment