Published on 08 Dec 2011
"If we could hold power in reserve to be tapped on demand, it would be possible to make much more extensive use of wind energy." - Kim Behnke
Energy & Utilities
Smarter Energy, Smarter Infrastructure
As the world works to move away from dependence on fossil fuels, renewable energies— such as wind, solar and biomass—have become the most attractive candidates as alternatives, especially in Europe. And because of its access to copious natural wind resources, Denmark has become a leader in developing wind energy
But wind energy is not without its challenges, the most important of which is simply that the wind does not blow constantly. It’s impossible to accurately predict when power will be plentiful and when it will not, complicating grid management and making it difficult to make wind energy a primary source of electricity.
Energinet.dk and the Danish Energy Association (Dansk Energi) created EDISON, an R&D consortium that is part of the Danish ecosystem to provide the necessary underpinnings to realize Denmark’s aggressive vision to increase its production of renewable energy to 50 percent of total generation by 2020.
- Reduction of load balancing costs due to increased demand-response - Increased use of wind energy relative to fossil fuels - Reduction of load on the grid by proactive time-shifting - Increase of battery and grid useful life
As the world works to move away from dependence on fossil fuels, renewable energies— such as wind, solar and biomass—have become the most attractive candidates as alternatives, especially in Europe. And because of its access to copious natural wind resources, Denmark has become a leader in developing wind energy. But wind energy is not without its challenges, the most important of which is simply that the wind does not blow constantly. It’s impossible to accurately predict when power will be plentiful and when it will not, complicating grid management and making it difficult to make wind energy a primary source of electricity.
“If we could shape consumption according to the available generation and hold extra power in reserve to be tapped on demand, it would be possible to make much more extensive use of wind energy,” says Kim Behnke, coordinator at Energinet.dk of the ForskEL funding program and main initiator of the EDISON project. “We could reduce our reliance on expensive short-term regulation power for load balancing, lowering both cost and carbon emissions.”
A number of utilities have created energy “buffers,” or ways to generate and store excess energy when it is plentiful and cheap, retrieving it later on when needed. One example is pumped hydro, which is how Norway provides Denmark with rapid balancing power today. In Norway, water in a lower reservoir is pumped uphill to a higher reservoir using inexpensive wind energy from Denmark at night when demand is low. The water is then released during the day to power generators which produce electricity at peak rates when the wind isn’t blowing in Denmark.
Electric cars store energy for grid
The Danish bet for a more self-sufficient emerging buffer on the power grid is electric vehicles. Totally electric cars will contain large batteries, and when the car is not being driven, it can be plugged into the grid. So why not use those batteries to store extra energy and even provide regulation power anytime they are connected? This is a promising idea, but it first requires sufficient R&D before being put into production nationally.
To explore this intriguing concept, Energinet.dk and the Danish Energy Association (Dansk Energi) created EDISON, an R&D consortium that is part of the Danish ecosystem to provide the necessary underpinnings to realize Denmark’s aggressive vision to increase its production of renewable energy to 50 percent of total generation by 2020. The initial phases of the project are based on a detailed simulation of electric vehicle use and wind energy generation on the Danish island of Bornholm, home to 40,000 citizens.
The goal of EDISON is to develop workable approaches to integrating electric vehicles into daily life, addressing not only the battery storage concept but also practical issues of usage, market influences and interaction with the existing grid. Along the way, it will produce valuable insight and experience for the consortium’s commercial partners.
Striking the right balance
Electric vehicles pose some daunting and unique challenges aside from their current high cost and limited range. One is that widespread use will significantly increase the demand for electricity, at a time when building new power plants on a vast scale is neither economically nor environmentally responsible. A second is an often overlooked issue: What happens when a million commuters in a large metropolitan area get home at the end of the day and all plug their cars in at almost the same time?
The addition of so much load on an already-stretched grid infrastructure highlights a critical fact of life for utilities: the grid must always remain in balance, with usage equal to generation. Too much demand and the result is brownouts or outages. Too much generation relative to usage, and again this could cause the grid to collapse.
“It’s like a leaky bucket,” says Per Noergaard, senior engineer in the Wind Energy Department at Risø National Laboratory of Danmarks Tekniske Universitet, (DTU, Technical University of Denmark). “Increase the size of the leak, and more water must be added to keep the level constant and vice versa. However, this is a great challenge, because ramp up can barely keep up with the often aggressively fluctuating renewables.” Indeed, Michael K. Espersen, senior power-system control operator at Oestkraft, the regional energy company for Bornholm, explains that in islanding mode (island detached from Nord European energy backbone), the Bornholm grid fails to be stable above 18 percent of wind, so additional available renewable energy cannot be used and fossil-fuel power plant units must be proactively brought up to stabilize today’s analog grid.
Needed: An intelligent grid
The opportunity for grid balancing and the issues surrounding it are at the core of EDISON. To make the idea of using electric vehicles to store energy practical, a number of considerations have to be addressed.
Driver needs and preferences must be accommodated, while giving each person an incentive to participate and make his or her vehicle available for use as a storage device. No driver, however altruistic or motivated by financial incentives, wants to turn on the ignition and find a vehicle without enough charge to complete the next trip. Likewise, no owner wants to entirely abdicate control of his or her personal vehicle to the power company and see the battery lifecycle severely degraded due to having provided inappropriate regulation power.
A way to intelligently charge and discharge each vehicle is necessary, and to determine when the grid should feed power to the vehicle (to minimize the impact from too many people trying to charge at the same time) and when it should even draw power from the battery. The control systems must be sophisticated enough to predict demand, grid capacity and also how much stored energy is available—how many cars are plugged in and their level of charge. Another important factor is that power systems will not be engineered from scratch. The proposed solution has to seamlessly extend the existing electrical grid control functions and the existing energy and regulation power marketplaces.
Power plant unlike any other
EDISON takes a holistic approach. It is centered on the idea of an electric vehicle virtual power plant (EV-VPP), in which vehicles attached to the grid are aggregated and treated as a single, large consumer/producer energy source to help balance the wind power when combined via market place. The EV-VPP concept is crucial, because from the point of view of the larger grid and the energy marketplace, it can be treated like any other generation source. That means it can complement existing means to provide regulation power, integrating seamlessly with existing infrastructures and enabling higher levels of renewables in the system.
“The containedness of the island is one of the reasons why we use Bornholm as the test environment,” says Behnke. “We can efficiently model the energy infrastructure, usage and market interaction in a defined way, isolating the environment from the larger European grid to effectively contain the scope of the experiment.”
At the heart of the EV-VPP is pilot software hosted on an IBM® BladeCenter® server cloud, created by researchers and developers at the Centre for Electric Technology (CET) of DTU in Copenhagen and the IBM Research – Zurich. The EV-VPP takes in a broad range of information, including price signals from the market, the state of the local grid in terms of load and the status of the vehicle fleet, respecting individual driver needs and preferences. “Using the IBM ILOG® CPLEX® Optimization Studio libraries, the EV-VPP automatically determines how to govern the fleet in real time, to benefit from day-ahead spot-market and dynamic regulation prices, avoid distribution grid congestion, optimize battery lifetime and adjust to individual driver requirements,” says Dieter Gantenbein, IBM leader in the EDISON consortium.
|The inside story|
|The multiyear EDISON project is unfolding in seven conceptual stages, starting with initial assessment of electric vehicle technology and concluding with field deployment of the actual system following laboratory tests. Along the way, all of the necessary design and development is being conducted, such as building charging stations, contributing to the standardization of communications between EV, CS and backend EV-VPP server software development and the validation of the security, stability and validity of the proposed approach.|
|IBM – Zurich is responsible for the development of the EV-VPP software that provides management of the entire system, including market and grid interfaces and charging logic.|
|EDISON organizers showed great foresight in assembling the consortium. “From the very beginning, we believed that the best way to approach this challenge was through teamwork,” says Kim Behnke. “By involving the best minds from all parts of the industry, we are going to emerge at the end of the project with better answers and results that benefit all. The nation will advance its goals, the citizens will see a cleaner environment and lower costs, and our development partners will come away with valuable knowledge that can further their own success. That’s true synergy: everybody wins.”|
Driving the driver
The key to making the transformation initiative work is recognizing the real-world needs and preferences of vehicle owners. “These batteries are not ours to govern,” says Anders Foosnæs, Power Systems consultant at the Danish Energy Association. “Their primary purpose is transportation, not smart grid management. So the drivers are king and always have the ability to override the system.” Car owners set their default preferences, either “eco” mode that lets the system determine when and how much to charge the car, or “VIP” mode that delivers full charging immediately. To provide an incentive to use eco mode, drivers are compensated in the form of reduced charging costs—but they have the ability to switch to VIP mode at any time, using a smartphone or web interface.
A driver must always have enough charge to go about his or her business, so the system includes sophisticated algorithms that build a predictive profile for each car based on past usage and are instructed to always provide adequate charge in the battery for the next trip. The profiles are remarkably detailed, accounting for day of the week and time of day.
The car can get charged anywhere in the system, since each individual vehicle is tracked. Latest when the owner’s card is swiped at the charge spot, the EV-VPP knows which car is connected. Knowing which station it’s plugged into, it can manage that battery properly while optimizing for the local grid state.
With its awareness of grid status and battery condition, the system can shift charging to times when the load on the grid is light, like the middle of the night. It can also adjust how quickly the batteries are charged, as well as manage the level of charge in each one.
This reduces the overall load on the grid, reducing the chance of failure or outage and extending the lifespan of existing grid assets. The active management of battery charging also produces a benefit for vehicle owners: by making charge-discharge cycles more even, the life of the battery pack is increased.
Electric vehicles in the real world
What gives the EDISON project a good chance of ultimately resulting in usable technologies and management approaches is its clear vision of actual needs and constraints.
The EDISON approach does not require wholesale changes to human behavior, the market place or existing infrastructures. It fits in seamlessly, while solving a critical challenge to the greater adoption of renewable energy. “That’s where EDISON shows such great promise,” concludes Gantenbein. “It’s a realistic win-win for the nation, the grid and the user.”
For more information
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© Copyright IBM Corporation 2011 IBM Corporation 1 New Orchard Road Armonk, NY 10504 U.S.A. Produced in the United States of America December 2011 All Rights Reserved IBM, the IBM logo, ibm.com, Let's Build A Smarter Planet, Smarter Planet, the planet icons, BladeCenter, CPLEX and ILOG are trademarks of International Business Machines Corporation, registered in many jurisdictions worldwide. Other product and service names might be trademarks of IBM or other companies. A current list of IBM trademarks is available on the web at ibm.com/copytrade.shtml This case study illustrates how one IBM customer uses IBM products. There is no guarantee of comparable results. References in this publication to IBM products or services do not imply that IBM intends to make them available in all countries in which IBM operates. 1 EDISON is an acronym for “Electric vehicles in a distributed and integrated market using sustainable energy and open networks.”