Energy Cannibalism
Encyclopedia
Energy cannibalism refers to an effect where rapid growth of an entire energy producing industry creates a need for energy
that uses (or cannibalizes) the energy of existing power plants. Thus during rapid growth the industry as a whole produces no energy because new energy is used to fuel the embodied energy
of future power plants.
to offset greenhouse gas emissions and thus to mitigate climate change
by replacing fossil fuel
plants with nuclear plants.
Energy cannibalism in this context is also true of any other energy source such as wind power
, solar power
, etc.
it must do two things:
This can become challenging in view of very rapid growth because the construction of additional power plants to enable the rapid growth rate create emissions that cannibalize the greenhouse gas emissions mitigation potential of all the power plants viewed as a group or ensemble.
(in GW) produces:
of electricity, where
(in hours per year) is the fraction of time the plant is running at full capacity, 
is the capacity of individual power plants and 
is the total number of plants. If we assume that the energy industry grows at a rate, 
, (in units of 1/year, e.g. 10% growth = 0.1/year) it will produce additional capacity at a rate (in GW/year) of
After one year, the electricity produced would be
The time that the individual power plant takes to pay for itself in terms of energy it needs over its life cycle
, or the energy payback time, is given by the principal energy invested (over the entire life cycle),
, divided by energy produced (or fossil fuel energy saved) per year, 
. Thus if the energy payback time of a plant type is 
, (in years,) the energy investment rate needed for the sustained growth of the entire power plant ensemble is given by the cannibalistic energy, 
:
The power plant ensemble will not produce any net energy if the cannibalistic energy is equivalent to the total energy produced. So by setting equation equal to the following results:
and by doing some simple algebra it simplifies to:
So if one over the growth rate is equal to the energy payback time, the aggregate type of energy plant produces no net energy until growth slows down.
but the same analysis is true for greenhouse gas emissions. The principle greenhouse gas emissions emitted in order to provide for the power plant divided by the emissions offset every year must be equal to one over the growth rate of type of power to break even.
Recent work expands earlier work to generalize the GHG emission neutral growth rate limitation imposed by energy cannibalism to any renewable energy technology or any energy efficiency technology.
These results indicate that any energy policies with the intention of driving down greenhouse gas emissions with deployment of additional nuclear reactors will not be effective unless the nuclear energy industry in the U.S. improves its efficiency
.
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
that uses (or cannibalizes) the energy of existing power plants. Thus during rapid growth the industry as a whole produces no energy because new energy is used to fuel the embodied energy
Embodied energy
Embodied energy is defined as the sum of energy inputs that was used in the work to make any product, from the point of extraction and refining materials, bringing it to market, and disposal / re-purposing of it...
of future power plants.
History
This term was first developed by J.M. Pearce in a paper discussing the potential for nuclear energyNuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...
to offset greenhouse gas emissions and thus to mitigate climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
by replacing fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
plants with nuclear plants.
Energy cannibalism in this context is also true of any other energy source such as wind power
Wind power
Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships....
, solar power
Solar power
Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available...
, etc.
Theoretical underpinnings
In order for an “emission free” power plant to have a net negative impact on greenhouse gas emissions of the energy supplyEnergy supply
Energy supply is the delivery of fuels or transformed fuels to point of consumption. It potentially encompasses the extraction, transmission, generation, distribution and storage of fuels...
it must do two things:
- produce enough emission-less electricityElectricityElectricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
to offset the greenhouse gas emissions that it is responsible for - continue to produce electricity to offset emissions from existing or potential fossil fuelFossil fuelFossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
plants.
This can become challenging in view of very rapid growth because the construction of additional power plants to enable the rapid growth rate create emissions that cannibalize the greenhouse gas emissions mitigation potential of all the power plants viewed as a group or ensemble.
Derivation
First, all the individual power plants of a specific type (Pearce used nuclear plants in the initial derivation) can be viewed as a single aggregate plant or ensemble and can be observed for its ability to mitigate emissions as it grows. This ability is first dependent on the energy payback time of the plant. Aggregate plants with a total installed capacity of (in GW) produces:of electricity, where
(in hours per year) is the fraction of time the plant is running at full capacity, is the capacity of individual power plants and is the total number of plants. If we assume that the energy industry grows at a rate, , (in units of 1/year, e.g. 10% growth = 0.1/year) it will produce additional capacity at a rate (in GW/year) ofAfter one year, the electricity produced would be
The time that the individual power plant takes to pay for itself in terms of energy it needs over its life cycle
Enterprise Life Cycle
Enterprise Life Cycle in enterprise architecture is the dynamic, iterative process of changing the enterprise over time by incorporating new business processes, new technology, and new capabilities, as well as maintenance, disposition and disposal of existing elements of the enterprise.- Overview...
, or the energy payback time, is given by the principal energy invested (over the entire life cycle),
, divided by energy produced (or fossil fuel energy saved) per year, . Thus if the energy payback time of a plant type is , (in years,) the energy investment rate needed for the sustained growth of the entire power plant ensemble is given by the cannibalistic energy, :The power plant ensemble will not produce any net energy if the cannibalistic energy is equivalent to the total energy produced. So by setting equation equal to the following results:
and by doing some simple algebra it simplifies to:
So if one over the growth rate is equal to the energy payback time, the aggregate type of energy plant produces no net energy until growth slows down.
Greenhouse gas emissions
This analysis was for energyEnergy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
but the same analysis is true for greenhouse gas emissions. The principle greenhouse gas emissions emitted in order to provide for the power plant divided by the emissions offset every year must be equal to one over the growth rate of type of power to break even.
Recent work expands earlier work to generalize the GHG emission neutral growth rate limitation imposed by energy cannibalism to any renewable energy technology or any energy efficiency technology.
Example
For example, if the energy payback is 5 years and the capacity growth is 20%, no net energy is produced and no greenhouse gas emissions are offset.Applications to the nuclear industry
In the article “Thermodynamic Limitations to Nuclear Energy Deployment as a Greenhouse Gas Mitigation Technology” the necessary growth rate, r, of the nuclear power industry was calculated to be 10.5%. This growth rate is very similar to the 10% limit due to energy payback example for the nuclear power industry in the United States calculated in the same article from a life cycle analysis for energy.These results indicate that any energy policies with the intention of driving down greenhouse gas emissions with deployment of additional nuclear reactors will not be effective unless the nuclear energy industry in the U.S. improves its efficiency
Efficient energy use
Efficient energy use, sometimes simply called energy efficiency, is the goal of efforts to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature...
.