Sunday, September 25, 2011

Systemic Simulation of Smart Grids

This blog has been extremely quiet for two years, mostly because I was busy with other topics, including Lean and Enterprise 2.0. In my previous post, I mentioned that I was looking at “Smart Distributed Things” through two instances, Smart Grids and Smart Home Networks. I will not talk about the second in this blog, since it is work-related (we’ve come up with the acronym BAHN : Bouygues Autonomous Home Network).
Smart Grids make an interesting instance of the “smart distributed network” because of the extraordinary amount of interest/excitement/hype that exists around this topic. There is a range of conflicting opinions, ranging from “this is a straightforward and marginal improvement of existing networks which are already quite smart” to “smart grids are the backbone of a new sustainable society, based on communities, subsidiarity (organic, multi-scale, resilient organization) and self-aware optimal management of resources”.
I am not an expert with any of these topics: electricity, power grids, energy, storage … but like any citizen, I would like to build my own opinion about the future of our country and our planet, as far as energy and global warming are concerned. Hence the idea of a small systemic simulation has emerged during my vacation month (last month). I tried to assemble a crude model of all the different aspects of the “smart grid ecosystem” as we may understand it, without too much detail, just the broad principles. Each aspect is actually quite simple to explain, if taken in isolation (e.g., anyone may understand why it is smart to couple a solar panel with local storage). It is the combination of all viewpoints, together with the huge amount of uncertainty (about the economy, the speed at which technology will get cheaper, the speed at which behaviors will change, etc.), which makes this a hard topic.
This is where I got this insight: I actually have a method for complex embedded models where half is unknown and the other half is unclear: GTES (Game-Theoretical Evolutionary Simulation). GTES is the perfect platform to assemble conflicting views of what a smartgrid should be, conflicting views about how the actors should behave, and try to generate some sense. In a word, I am planning to build a “serious game” to have a closer look at smart grids.
Let me first clarify what I said about the range of opinions and introduce three views of the smart grid, which I could label: the “Utility view”, the “Google view” and the “Japanese view”:

  1. The “Utility view” defines a smart grid as adapting the power network to local sources (as opposed to a one-way distribution network that goes from few large GW production units towards millions of consumers), adapting to intermittent production sources (though storage and favoring flexible production units that can adapt to the power surges of intermittent sources like solar or wind) and using price incentives to “shave” demand peaks.  This is a “no-brainer” program (“what to do” is clear), where the major issue is price: most techniques show a cost/benefit ratio that is worse than current practice. To believe in this approach, you must believe that new technology prices will go down (e.g., solar, storage),   or that electricity prices will go “through the roof” in the next 20 years, or that global warming fears will drive a significant price for CO2.
  2. The “Google view” defines a smart grid as a change from a tree structure to a network structure (centralized to de-centralized), the use of market forces to create a dynamic and more efficient equilibrium between supply and demand, and the use of IT to provide information to all actors, including end consumers. The importance of signals (pricing and power grid control) is so important in this view that it is often said that telecom, IT and energy network will merge (something which I don’t believe for a second – but it shows the spirit of the importance of “smart” in “smart network”). Calling this the “Google view” is a friendly reference to “What Would Google DoJ  The core of this approach is the principle that a significant amount of efficiency would be obtained with a “hyper fluid market”, made possible through IT technology.
  3. The “Japanese view” is human-centered instead of being techno-centered. The goal is to change human behavior to adapt to new challenges (lack of resources, global warming, …). Smart grids are the backbone of a multi-scale architecture (smart home, neighborhood, city, region, country) where each level has its own resources and autonomy, resulting in a system that is more resilient and with more engagement as a consequence of more responsibilities. Smart grids support the necessary behavioral transformation through communities and constant feedback. I call this a “Japanese vision” because I have heard it beautifully explained in Tokyo, but the systemic approach is common to Asia as a whole. Because active communities are “engaging”, Smart Grids help get rid of waste (muda in the lean sense) such as useless transportation, un-necessary usage, etc.

These views do not necessarily conflict; it is possible to envision the union of all these ideas. However, as soon as one tries to imagine a convincing deployment scenario, there are a number of questions that pop to mind. Here are a few examples:
  • What part does local storage play? Can there be a smart grid without distributed storage? What price hypotheses are necessary to make this realistic, considering that current energy storage price are too high to justify large-scale deployment? Even if solar or wind becomes free, having to store the energy with today’s techniques make this approach uncompetitive (with today’s parameters, obviously)
  • What CO2 price would change significantly the cost/benefits analysis? Actually, this extends more generally to the pair energy prices + CO2 price, but CO2 price is especially significant. Because of the abundance of coal, and because of the increasing availability of new forms of gaz, CO2 price is, from a naïve point of view, the key factor that could change the economic analysis of introducing alternative intermittent sources of energy.
  • What is the systemic benefit of local management, that is, giving autonomy to local community to handle a part of their energy decisions, at different scales? This is a “system dynamic” issue, related to the handling of peaks, shortages and crisis. In a regular mode, there are obvious benefits to the centralized approach, from economies of scale to averaging pseudo-independent demand. The “pseudo” is a tiny word but full of consequences: the absence of independence is what produces complex systems and disasters, from the financial crisis to industrial accidents. It is the study of bursts and dynamic scenarios, with feedback loops, that may show the benefit of a “smart system” with faster counter-measures and learning abilities.
  • What could be the large-scale effect of dynamic pricing on self-optimization of customer demand?  The “marginal story” of “peak demand shaving” is beautiful: to remove the few hours of peak-production with gaz/oil turbines which produce CO2 at a high marginal cost, by returning some of the value to the consumer, to convince her/him to postpone parts of her usage. The most common example being heating (house or water) since inertia makes postponing a viable alternative. However the story does not necessarily scale so well, nor does it necessarily address the “resilience issue”. If additional capacity is needed no matter what to cope with some kinds of peaks, its marginal cost for dealing with the “other types” become quite small. We are back to a “system dynamic issue” that cannot be resolved with a “back-of-the-envelope” ROI computation, but requires a large-scale simulation.

My goal is to get a first simple set of answers to these questions. Obviously, using GTES is not going to give me a price or a definite answer, but rather a “sense of how things are interrelated and react as a whole (system)”. Here is a simplified description of the model that I have built last month:

      This is a “game theory model” with four actors:

(1)    The regulator (government) which controls the price of CO2 and may both favor renewable energy (investment incentive through tax breaks) or regulate them (impose joint storage with new intermittent sources). The long term goal (what we call a strategy in GTES) of the regulator is to reduce CO2 while maintaining the economic output of the country.
(2)    The utility (national energy supplier) which runs its production assets, distribute electricity and sets its price dynamically according to demand and primary energy (oil / gaz) price variations. One will notice that I implement an ideal world where price can be set up freely and change constantly, which is very far from the truth, but I want to address question #4. The long term goal of the utility is to make money, deliver a proper return on investment for its new acquisition (if any) and ensure resilience (the ability to serve the necessary amount of energy in the future).
(3)    The local operator who operates a smart grid associated to a city or a county. The operator manages all local production and storage capacity that is linked to the grid (wind turbines, solar panels, storage, etc.). It also operates a fossil fuel small-scale plant to provide additional electricity when required, although it may also buy it at wholesale prices from the utility. The long term goal of the operator is simply to make money :)
(4)    The end consumer who tries to reduce her electricity bill (both its average value and its expected maximum value) while preserving her comfort. Optionally, this may mean to reduce her CO2 emissions :)
    The smart grid architecture is pretty naïve. I simulate a country that could be France or another European country, with one electricity utility, one thousand smart cities/ smart communities (with their own local operator), and twenty millions households. The national supplier produces most of the electricity when the game starts, using a mix of nuclear and fossil plants. The electricity is either sold to the local operators, or sold directly to the consumers (hence each operator has a given market share, that is the percentage of households that get their energy from this alternative supplier).

-          The heart of the model is the demand generation. Running the model once demand is established is not difficult, although the operational mode of the operator requires a careful description, since many choices need to be made (local production vs. wholesale buying, using energy from storage or storing energy for future use, etc.). The demand generator is actually crude and starts from a yearly and a daily pattern, to which a lot of random noise is added. The model allows both for independent noise (each consumer is different) and dependent variation (weather variations are shared by everyone in the same city).

-          Each actor can play his game through a few decisions (what we call its tactic in GTES). The utility most important decision is its pricing tactic. Prices are defined through a bunch of linear formulas, the coefficient of which are GTES tactical parameters. For those who are not familiar with GTES, an evolutionary algorithm (local optimization) is run to optimize (find the best value) these tactical parameters. Other decisions from the utility involve further investments in its production plant.  The local operator has a similar range of choices to make. It needs to define its operational production mode; it also needs to set up its pricing scheme. Once a year, it needs to decide about new investments, whether they are additional fossil fuel production capacities, renewable energy investment or additional storage. The end consumer can decide to reduce her demand when the price gets too high, at the expense of comfort (the tradeoff between the two being a design parameter of the model). The consumer may also switch from national to local providers and back. Last, the consumer may invest in “negawatt equipment” (such as house insulation or more energy-efficient equipment).

This whole model defines a “game”, which could actually be turned into a real game, SIM-style. Each actor is trying to maximize its long-term goal while making the proper “tactical choices”.
What are the next steps ?
  1. The code was written last month but I still need to run “20 years simulations” and make sure that the model is credible (the story told by one simulation run makes sense)
  2. I then need to “explore the tactics”, which means that when one of the actor make a decision, the impact on the game outcome is credible. This is the most time-consuming part, even with a simple model like this. This ensures that the game is “realistic”, even if it is obviously naïve.
  3. Apply game theory to find (Nash) equilibriums –  This is the fun part, since I have nothing to do and will leverage code that I have written for other problems. This is what GTES is designed for: looking at the conflicting strategies of the different actors.
  4. The last step of GTES is to randomize the “design parameters”. The model relies on a number of design parameters such as the demand-generation curve, the sensitivity to price or the efficiency of peak shaving, to name a few. I have no way to calibrate the S-curves that I am using, so I randomize the choice of these design parameters (Monte-Carlo simulation) to see if their value changes the conclusion that I would like to draw from these repeated simulations.
I’ll post a summary of my results if and when the computational experiments are successful. Today’s goal was just to share my overall analysis of the “smart grids” domain.


nyamurray said...

Hi Yves. I like your analysis, and am interested in your game theory results.

I think the 'regulator' actor and the CO2 price is going to be heavily influenced by the 'utility' actor - as currently - encouragement for renewables, penalties for coal-fired, probably a feedback loop there.

Energy efficiency and 'peak shaving' is good, but behavioural changes are a lag factor. Eg the 'local operator' actor is likely to cheat, and fail to pass on cost savings to consumers.

I think the best way to advance the game is to invest heavily in energy storage technologies by consumers, who then have a point of leverage with both 'local operator' and 'utility'. This is going to happen with industrial consumers, so the trickle down to ordinary consumer is again going to be slow. In fact, industrial consumers with energy storage technology may turn into 'local operators'.

All in all, I think that a smart grid is not only a functional network, but also an intelligent network where all the information is in the hands of all interested parties, rather than vested interests only.

So relevant cross-grid data has to be accessed by 'regulator', 'utility', 'local operator' and 'consumer', so that the rules of the game are subject to political pressure :) e.g. price fixing, collusion between regulator and utility, uncompetitive practice by local operators is discouraged, and innovation by all actors is encouraged.

Change is going to be accelerated by publishing the rules, the actors positions, and the technology innovation.

So a smart grid has to be data led, and the interfaces have to be published in a simple, easy to understand common protocols - network protocols, market interfaces, consumer information, etc - for the end result to be dramatic net growth in energy efficiency.

Otherwise, as you identify, the game may end in a gridlock. :)


Nya Murray

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