Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?
Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?

To maintain economic wealth (roads, hospitals, power
lines, etc.) power needs to be consumed. The same applies to economic activity,
since any activity requires the consumption of energy. According to the Environmental Protection Agency, the burning
of fossil fuels was responsible for 79 percent of
To maintain economic wealth (roads, hospitals, power lines, etc.) power needs to be consumed. The same applies to economic activity, since any activity requires the consumption of energy. According to the Environmental Protection Agency, the burning of fossil fuels was responsible for 79 percent of U.S. greenhouse gas emissions in 2010. So whilst economic activity takes place fossil fuels will be burned and CO2 emissions are unavoidable - unless we use exclusively renewable energy resources, which is not likely to occur very soon. However, the increasing CO2 concentrations in the atmosphere will have negative consequences, such droughts, floods, crop failures, etc. These effects represent limits to economic growth. The CLD illustrates some of the more prominent negative feedback loops that act as a break on economic growth and wealth.  As the negative feedback loops (B1-B4) get stronger, an interesting question is, 'will a sharp reduction in economic wealth and unavoidable recession lead to wide-spread food riots and disturbances?'

Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?
Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?

Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?
Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?

Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?
Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?

This model prototypes the working of an Smart Grid with Electric Vehicles   The
 objective is testing the theoretical advantages of batteries (also 
batteries in Electric Vehicles) in combination with renewable energies. 
The model considers two houses, that store energy both in Electric 
Vehicles (
This model prototypes the working of an Smart Grid with Electric Vehicles

The objective is testing the theoretical advantages of batteries (also batteries in Electric Vehicles) in combination with renewable energies. The model considers two houses, that store energy both in Electric Vehicles (Vehicle to Grid), and in a communal battery.

Except when specified otherwise, the units of all variables are expressed in W/h.

Press "Story" in the lower bar for a guided tour over the model. Better seen at 50% zoom.

by Carlos Varela (cvarela@gmx.at)
 This is the original model version (v1.0) with default "standard run" parameter set: see detailed commentary  here  and  here . As of 2 September 2015, ongoing development has now shifted to  this version  of the model.   The significance of reduced energy return on energy invested (EROI) in the tr
This is the original model version (v1.0) with default "standard run" parameter set: see detailed commentary here and here. As of 2 September 2015, ongoing development has now shifted to this version of the model.

The significance of reduced energy return on energy invested (EROI) in the transition from fossil fuel to renewable primary energy sources is often disputed by both renewable energy proponents and mainstream economists.​ This model illustrates the impact of EROI in large-scale energy transition using a system dynamics approach. The variables of primary interest here are: 1) net energy available to "the rest of the economy" as renewable penetration increases [Total final energy services out to the economy]; and 2) the size of the energy sector as a proportion of overall economic activity, treating energy use as a very rough proxy for size [Energy services ratio].
This model aggregates energy supply in the form of fuels and electricity as a single variable, total final energy services, and treats the global economy as a single closed system.
The model includes all major incumbent energy sources, and assumes a transition to wind, PV, hydro and nuclear generated electricity, plus biomass electricity and fuels. Hydro, biomass and nuclear growth rates are built into the model from the outset, and wind and PV emplacement rates respond to the built-in retirement rates for fossil energy sources, by attempting to make up the difference between the historical maximum total energy services out to the global economy, and the current total energy services out. Intermittency of PV and wind are compensated via Li-ion battery storage. Note, however, that seasonal variation of PV is not fully addressed i.e. PV is modeled using annual and global average parameters. For this to have anything close to real world validity, this would require that all PV capacity is located in highly favourable locations in terms of annual average insolation, and that energy is distributed from these regions to points of end use. The necessary distribution infrastructure is not included in the model at this stage.
It is possible to explore the effect of seasonal variation with PV assumed to be distributed more widely by de-rating capacity factor and increasing the autonomy period for storage.

This version of the model takes values for emplaced capacities of conventional sources (i.e. all energy sources except wind and PV) as exogenous inputs, based on data generated from earlier endogenously-generated emplaced capacities (for which emplacement rates as a proportion of existing installed capacity were the primary exogenous input).
Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?
Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?

The significance of reduced energy return on energy invested (EROI) in the transition from fossil fuel to renewable primary energy sources is often disputed by both renewable energy proponents and mainstream economists.​ This model is a first attempt to illustrate the impact of EROI in large-scale e
The significance of reduced energy return on energy invested (EROI) in the transition from fossil fuel to renewable primary energy sources is often disputed by both renewable energy proponents and mainstream economists.​ This model is a first attempt to illustrate the impact of EROI in large-scale energy transition using a system dynamics approach. The variables of primary interest here are: 1) net energy available to "the rest of the economy" as renewable penetration increases [Total final energy services out to the economy]; and 2) the size of the energy sector as a proportion of overall economic activity, treating energy use as a very rough proxy for size [Energy services ratio].
This model aggregates energy use in the form of fuels and electricity as a single variable, total final energy services, and treats the global economy as a single closed system.
The model includes all major incumbent energy sources, and assumes a transition to wind, PV, hydro and nuclear generated electricity, plus biomass electricity and fuels. Hydro, biomass and nuclear growth rates are built into the model from the outset, and wind and PV emplacement rates respond to the built-in retirement rates for fossil energy sources, by attempting to make up the difference between the historical maximum total energy services out to the global economy, and the current total energy services out. Intermittency of PV and wind are dealt with via Li-ion battery storage. Note, however, that seasonal variation of PV is not addressed i.e. PV is modeled using annual and global average parameters. For this to have anything close to real world validity, this would require that all PV capacity is located in highly favourable locations in terms of annual average insolation, and that energy is distributed from these regions to points of end use. The necessary distribution infrastructure is not included in the model at this stage.
It is possible to explore the effect of seasonal variation with PV assumed to be distributed more widely by de-rating capacity factor and increasing the autonomy period for storage.

This version of the model takes values for emplaced capacities of conventional sources (i.e. all energy sources except wind and PV) as exogenous inputs, based on data generated from earlier endogenously-generated emplaced capacities (for which emplacement rates as a proportion of existing installed capacity were the primary exogenous input).
Afirmația că nu poate exista activitate economică fără energie și că combustibilii fosili sunt finiți contrastează cu faptul că banii nu sunt finiți și pot fi creați de guverne prin intermediul băncilor lor centrale la costuri marginale zero ori de câte ori este nevoie.
         Un fapt important de
Afirmația că nu poate exista activitate economică fără energie și că combustibilii fosili sunt finiți contrastează cu faptul că banii nu sunt finiți și pot fi creați de guverne prin intermediul băncilor lor centrale la costuri marginale zero ori de câte ori este nevoie.
Un fapt important despre cărbunele, gazul și petrolul (mai ales atunci când sunt produse prin fracking) este că raporturile lor energetice nete scad rapid. Cu alte cuvinte, energia necesară pentru a extrage o anumită cantitate de combustibili fosili este în continuă creștere. Raportul în scădere „EROI” (Returul Energiei asupra Energiei Investite) oferă încă un avertisment că nu ne mai putem baza pe combustibilii fosili pentru a ne alimenta economiile. În 1940 a fost nevoie de energia unui singur baril de petrol pentru a extrage 100. Astăzi, energia unui baril de petrol va da doar 15. Nu putem aștepta până când raportul scade la 1/1 înainte de a investi serios în surse alternative de energie, pentru că până atunci societatea industrială așa cum o cunoaștem în prezent va fi încetat să mai existe. Un EROI de 1:1 înseamnă că este nevoie de energia unui baril de petrol pentru a extrage un baril de petrol - producția de petrol s-ar opri pur și simplu!

The statement that there can be no economic activity
without  energy and that fossil fuels are
finite contrasts with the fact that money is not finite and can be created by governments
via their central banks at zero marginal cost whenever needed.

 An important fact about COAL, GAS and OIL (even
wh
The statement that there can be no economic activity without  energy and that fossil fuels are finite contrasts with the fact that money is not finite and can be created by governments via their central banks at zero marginal cost whenever needed.

An important fact about COAL, GAS and OIL (even when produced via fracking) is that their net energy ratios are falling rapidly. In other words the energy needed to extract a given quantity of fossil fuels is constantly increasing. This ratio (Energy Invested on Energy Returned - EIOER) provides yet another warning that we can no longer rely on fossil fuels to power our economies. We cannot wait until the ratio falls to 1/1 before we invest seriously in alternative sources of energy, because by then industrial society as we know it doday will have ceased to exist. 

PS: A link between growth in energy consumption and GDP growth is clearly illustrated on slide 13 of Gail Tverberg's presentaion entitled ''Ooop! The world economy depends on an energy-related bubble''. In fact, the slide shows that growth in energy consumption usually precedes GDP growth.

https://gailtheactuary.files.wordpress.com/2015/10/oops-debt-bubble-10_30_15.pdf

Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?
Buying and storing electricity when it is cheap, and selling it when it is expensive. What are the benefits, both public and private?

  Colombia has the opportunity to implement the Autoswitch, but there are no guarantees of its impact on the market, given its complexity. This model implements two policies: Price Control through Demand Response - RD and Autoswitch. In this model we explore de impact of the AMI cost.
Colombia has the opportunity to implement the Autoswitch, but there are no guarantees of its impact on the market, given its complexity. This model implements two policies: Price Control through Demand Response - RD and Autoswitch. In this model we explore de impact of the AMI cost.
To maintain economic wealth (roads, hospitals, power
lines, etc.) power needs to be consumed. The same applies to economic activity,
since any activity requires the consumption of energy. According to the Environmental Protection Agency, the burning
of fossil fuels was responsible for 79 percent of
To maintain economic wealth (roads, hospitals, power lines, etc.) power needs to be consumed. The same applies to economic activity, since any activity requires the consumption of energy. According to the Environmental Protection Agency, the burning of fossil fuels was responsible for 79 percent of U.S. greenhouse gas emissions in 2010. So whilst economic activity takes place fossil fuels will be burned and CO2 emissions are unavoidable - unless we use exclusively renewable energy resources, which is not likely to occur very soon. However, the increasing CO2 concentrations in the atmosphere will have negative consequences, such droughts, floods, crop failures, etc. These effects represent limits to economic growth. The CLD illustrates some of the more prominent negative feedback loops that act as a break on economic growth and wealth.  As the negative feedback loops (B1-B4) get stronger, an interesting question is, 'will a sharp reduction in economic wealth and unavoidable recession lead to wide-spread food riots and disturbances?'

Two households with PV systems and Electric Vehicles, sharing a battery and connected to the grid. What are the advantages?
Two households with PV systems and Electric Vehicles, sharing a battery and connected to the grid. What are the advantages?


A detailed description of all model input parameters is available  here . These are discussed further  here  and  here .   Update 6 August 2018 (v2.8): Updated historical wind and PV deployment
 data for 2016-2017, adding projected PV deployment for 2018. Data via 
https://en.wikipedia.org/wiki/Grow
A detailed description of all model input parameters is available here. These are discussed further here and here.

Update 6 August 2018 (v2.8): Updated historical wind and PV deployment data for 2016-2017, adding projected PV deployment for 2018. Data via https://en.wikipedia.org/wiki/Growth_of_photovoltaics and https://en.wikipedia.org/wiki/Wind_power_by_country.

Update 26 October 2017 (v2.7): Updated historical wind and PV deployment data for 2015-2016, adding projected PV deployment for 2017. Data via https://en.wikipedia.org/wiki/Growth_of_photovoltaics and https://en.wikipedia.org/wiki/Wind_power_by_country.

Update 18 December 2016 (v2.7): Added feature to calculate a global EROI index for all energy sources plus intermittency buffering (currently batteries only, but this could be diversified). The index is calculated specifically in terms of energy services in the form of work and heat. That is, it takes the aggregated energy services made available by all sources as the energy output term, and the energy services required to provided the buffered output as the energy input term.

Update 29 June 2016 (v2.6): Added historical emplacement for wind and PV capacity. The maximum historical emplacement rates are then maintained from year 114/115 until the end of the model period. This acts as a base emplacement rate that is then augmented with the contribution made via the feedback control mechanism. Note that battery buffering commences only once the additional emplacement via the feedback controller kicks in. This means that there is a base capacity for both wind and PV for which no buffering is provided, slightly reducing the energy services required for wind and PV supplies, as well as associated costs. Contributions from biomass and nuclear have also been increased slightly, in line with the earlier intention that these should approximately double during the transition period. This leads to a modest reduction in the contributions required from wind and PV.

Added calculation of global mean conversion efficiency energy to services on primary energy basis. This involves making an adjustment to the gross energy outputs for all thermal electricity generation sources. The reason for this is that standard EROI analysis methodology involves inclusion of energy inputs on a primary energy equivalent basis. In order to convert correctly between energy inputs and energy service inputs, the reference conversion efficiency must therefore be defined on a primary energy basis. Previously, this conversion was made on the basis of the mean conversion efficiency from final energy to energy services.

Update 14 December 2015 (v2.5): correction to net output basis LCOE calculation, to include actual self power demand for wind, PV and batteries in place of "2015 reference" values.

Update 20 November 2015 (v2.4): levelised O&M costs now added for wind & PV, so that complete (less transmission-related investments) LCOE for wind and PV is calculated, for both gross and net output.

Update 18 November 2015 (v2.3: development of capital cost estimates for wind, PV and battery buffering, adding levelised capital cost per unit net output, for comparison with levelised capital cost per unit gross output. Levelised capital cost estimate has been substantially refined, bringing this into line with standard practice for capital recovery calculation. Discount rate is user adjustable.

Default maximum autonomy periods reduced to 48 hours for wind and 72 hours for PV.

Update 22 October 2015 (v2.2): added ramped introduction of wind and PV buffering capacity. Wind and PV buffering ramps from zero to the maximum autonomy period as wind and PV generated electricity increases as a proportion of overall electricity supply. The threshold proportion for maximum autonomy period is user adjustable. Ramping uses interpolation based on an elliptical curve between zero and the threshold proportion, to avoid discontinuities that produce poor response shape in key variables.

Update 23 September 2015 (v2.1): added capital investment calculation and associated LCOE contribution for wind generation plant, PV generation plant and storage batteries.

**This version (v2.0) includes refined energy conversion efficiency estimates, increasing the global mean efficiency, but also reducing the aggressiveness of the self-demand learning curves for all sources. The basis for the conversion efficiencies, including all assumptions relating to specific types of work & heat used by the economy, is provided in this Excel spreadsheet.

Conversion of self power demand to energy services demand for each source is carried out via a reference global mean conversion efficiency, set as a user input using the global mean conversion efficiency calculated in the model at the time of transition commencement (taken to be the time for which all EROI parameter values are defined. A learning curve is applied to this value to account for future improvement in self power demand to services conversion efficiency.**

The original "standard run" version of the model is available here.
Physiology based insight to compare the energy balance and carbohydrate insulin models described in Nature Metabolism Obesity Causal Model Differences 2024  article  See also Speakman and Hall's 2021  science article  and  insight  and Stock flow Comparisons  insight
Physiology based insight to compare the energy balance and carbohydrate insulin models described in Nature Metabolism Obesity Causal Model Differences 2024 article See also Speakman and Hall's 2021 science article and insight and Stock flow Comparisons insight
A simple simulation​ of a house losing heat at a rate based on indoor vs. outdoor temperature difference, and turning a heating system on and off to maintain indoor temperature.
A simple simulation​ of a house losing heat at a rate based on indoor vs. outdoor temperature difference, and turning a heating system on and off to maintain indoor temperature.