Definition Of Renewable Energy
The phrase "renewable energy" is not a well defined one.
It can mean different levels of the same idea to different groups.
First, the definition of a source of energy. This means the most primary resource in the chain.
It is also that which depletes going forward.
For oil, we use many things in the supply chain (steel for equipment and vehicles, glass, rubber, concrete, etc.) but the one we most concern ourselves with is the oil we're burning in the end.
It is also that which depletes going forward.
For oil, we use many things in the supply chain (steel for equipment and vehicles, glass, rubber, concrete, etc.) but the one we most concern ourselves with is the oil we're burning in the end.
Even a solar CSP (the mirrors in the desert sending sunlight to a tower) uses steel and glass but it's the sun that's the 'depletable' source of primary fuel.
The most common definition of renewable energy is that these types of energy sources (the most primary of each) is something which is either unlimited or replenish-able.
Solar is the most easily identifiable because it is endless (in human civilization's context).
Solar is the most easily identifiable because it is endless (in human civilization's context).
Wind comes from solar so that's basically equivalent.
The same applies to wave, tidal and some would argue dams.
Geothermal comes from the internal heat of the planet which is also contextually inexhaustible.
Nuclear is not technically inexhaustible but it might as well be.
The same applies to wave, tidal and some would argue dams.
Geothermal comes from the internal heat of the planet which is also contextually inexhaustible.
Nuclear is not technically inexhaustible but it might as well be.
Then we have hydrogen. It's an element that's inexhaustible, sure, but we can't tap into that.
We must 'refine' it from other primary sources.
Either we use electricity to crack water into separate hydrogen and oxygen (a process which uses more electricity than we get from the hydrogen in the end) or, more often, we refine natural gas into hydrogen gas and some other stuff.
We must 'refine' it from other primary sources.
Either we use electricity to crack water into separate hydrogen and oxygen (a process which uses more electricity than we get from the hydrogen in the end) or, more often, we refine natural gas into hydrogen gas and some other stuff.
Either way, the hydrogen ends up being a method of transport and storage for the more depleting energy source of that refining.
This confusion leads to the arguments that hydrogen is not a source but a battery. This is mostly true in the real world.
Only using direct solar heat to crack water at extreme temperatures (over 2500 degrees F) would it move into the categories like wind and wave where it's derived from a truly renewable source like the sun.
Only using direct solar heat to crack water at extreme temperatures (over 2500 degrees F) would it move into the categories like wind and wave where it's derived from a truly renewable source like the sun.
Another definition of renewable includes environmental harm.
We all know that while damming up a river results in providing endless energy but also harms the local ecosystem to a great extent.
It floods land that formerly had wildlife and flora/fauna as well as people's homes.
We all know that while damming up a river results in providing endless energy but also harms the local ecosystem to a great extent.
It floods land that formerly had wildlife and flora/fauna as well as people's homes.
Placing all this underwater causes it to rot and become a large source of methane and that's more harmful than CO2 with respect to global warming.
It also creates a barrier for many species to live their lives normally.
It also creates a barrier for many species to live their lives normally.
For example, fish can no longer swim up or downstream past the dam and herds can no longer cross the river there because it's much wider and deeper.
It also causes erosion which changes the river faster than it otherwise would have.
So, basically in this definition, every source of energy is not fully renewable.
It also causes erosion which changes the river faster than it otherwise would have.
So, basically in this definition, every source of energy is not fully renewable.
From dams to nuclear to clean coal, methane hydrates, 'burning' boron or aluminum, ocean thermal, wave and even wind, all of these are respectively argued to harm the environment in decreasing amounts.
Only solar escapes all criticisms of depleting it's primary source and harming the environment in some way.
This is because in the end and since it's only delaying the sun from heating the planet (all energy except light that leaves the planet eventually turns to heat) so there's no net change.
This is because in the end and since it's only delaying the sun from heating the planet (all energy except light that leaves the planet eventually turns to heat) so there's no net change.
The last major difference between definitions of renewables is in the economics. Some suggest that to be renewable, an energy source must be 'free'.
The term free is always assumed to refer to the marginal cost after purchasing and installing the system but that's a minor point.
The term free is always assumed to refer to the marginal cost after purchasing and installing the system but that's a minor point.
Ongoing cost is relevant here.
See, if one installs solar panels, they are getting free energy but if one buys power monthly from a utility company that sourced it from solar panels, it's no longer 'renewable'.
See, if one installs solar panels, they are getting free energy but if one buys power monthly from a utility company that sourced it from solar panels, it's no longer 'renewable'.
This is often used as an argument against any source that's centrally sold, influenced anywhere in it's supply chain or controlled through the market or regulation.
In short, moving from utility coal power to utility nuclear or solar... it makes zero direct difference to the customer because they're never going to eliminate their bill.
The "controlled" aspect of centralized power is also a point of contention.
Since a homeowner with solar PV on their house and still connected to the grid is still under the control of the grid market, they are still subject to price changes (as well as where that utility sources their power) without their control.
Since a homeowner with solar PV on their house and still connected to the grid is still under the control of the grid market, they are still subject to price changes (as well as where that utility sources their power) without their control.
Many people go off-grid because of this future uncertainty and many of them cite that 'grid-tie' is no longer renewable because of this factor as well as that of grid imbalance (another topic).
Overall, when questioning the definition of renewables, one must make an assumption on which of these levels of the definition applies.
Generally, it's always the source only but that frequently gives rise to arguments from the other definitions. So, read clearly and debate with predefined definitions.
