When running a power system to supply electrical energy to homes and businesses, engineers strive to satisfy three objectives:
Providing a reliable service
Minimizing the cost of providing this energy
Reducing the environmental impact of the system, in particular facilitating the use of renewable energy sources
Unfortunately, these objectives conflict: improving reliability increases costs and renewable energy sources affect reliability unless costly security measures are put in place. The main objective of our research is to develop techniques that achieve the optimal balance between these three essential goals. In particular, using advanced optimization techniques, we explore how flexibility resources (such as demand-side participation, energy storage and agile generating units) should be deployed and operated. This is the essence of what has recently been called the "smart grid." In this respect, we are also working with colleagues who are specialists in communications, sensors and control to explore how these rapidly evolving technologies can be harnessed to help meet the objectives mentioned above.
While integrating these objectives is an important part of our work, we also do research on each of these topics taken separately. For example, we have developed probabilistic techniques to assess the operational security of power systems. As part of this strand of work, we are exploring the complex mechanisms that lead to blackouts in large power systems. We also study electricity markets. The next challenge in this area is to develop mechanisms which will ensure that competitive electricity markets deliver sufficient investments to meet the evolving needs of the electricity supply system.
Current Research Projects
Energy Positioning: Control and Economics
Sponsor: Department of Energy, ARPA-E GENI program
Collaborators: Prof. Ian Hiskens, University of Michigan
- Prof. Daniel Kirschen
- Dr. Hrvoje Pandzic
- PhD student Ting Qiu
- PhD student Yishen Wang
Abstract: The University of Washington and the University of Michigan are developing an integrated system to match well-positioned energy storage facilities with precise control technologies so the electric grid can more easily include energy from renewable power sources like wind and solar. Because renewable energy sources provide intermittent power, it is difficult for the grid to efficiently allocate those resources without developing solutions to store their energy for later use. The two universities are working with utilities, regulators, and the private sector to position renewable energy storage facilities in locations that optimize their ability to provide and transmit electricity where and when it is needed most. Expanding the network of transmission lines is prohibitively expensive, so combining well-placed storage facilities with robust control systems to efficiently route their power will save consumers money and enable the widespread use of safe, renewable sources of power. Go to this project's web page.
For a project description, click here.
For the project fact sheet, click here.
Power System Flexibility
Sponsor: University of Washington
Abstract: Recent years have witnessed the integration of large amounts of stochastic renewable energy sources, such as wind and solar photovoltaic. This is likely to continue and will probably be accompanied by the deployment of a significant amount of demand response. While these developments are desirable, they are also likely to increase the uncertainty on the load/generation balance. The standard answer to this problem is to say that the system needs more "flexibility" to handle this uncertainty. However, installing and deploying flexibility costs money. On the other hand, if the system is not sufficiently flexible, operators may have to resort to load shedding or the curtailment of renewable generation to maintain the stability of the system. We are therefore investigating the following questions: How do we quantify flexibility on various timescales? How much flexibility do we actually need? How much physical flexibility (i.e. from generation, storage, and demand response) is needed and how much can be accomplished using virtual flexibility (i.e. improved operating procedures and market design)? What is the optimal portfolio of flexibility resources? Go to this project's web page.
Distributed Energy Resources Management System
Sponsors: Department of Energy, Alstom Grid
Abstract: Until recently, it was possible to operate distribution networks in a "build and forget" mode because the load evolved slowly and in a predictable way and because these networks did not involve any active components. A number of factors are converging to make this operating paradigm unsustainable:
- The integration of Distributed Energy Resources (DERs) such as wind generators, PV panels, and small scale Combined Heat and Power plants in the distribution network
- The large scale deployment of electric cars, which will not only increase the overall demand for energy but also change the profile and characteristics of the loads in the distribution network
- The implementation of Demand Response (DR) schemes that will link the load to price signals that may become increasingly local.
In this project we are exploring how we can leverage the various sources of data that are becoming available (e.g. smart meters, distribution automation) to make the operation of the distribution networks more efficient and more reliable and to facilitate the integration of distributed energy resources. Go to this project's web page.
Architectural and Algorithmic Solutions for Large-Scale PEV Integration into Power Grids
Sponsors: National Science Foundation
Abstract: Electric Vehicles (EVs) are now a reality; and it is expected that in the near future large volumes of these devices will be integrated to the existing power grid. If allowed to charge in an uncontrolled manner, these devices will charge their batteries when connected to the grid circuits, increasing the already high peak-demands that are served by expensive generation sources. Furthermore these additional demands could be translated into potential over-loadings and the need to invest into wires and power generation assets in order to be successfully accommodated. On the other hand, technical and economic benefit would be attained if the charging of these devices takes place when the system is lightly loaded, and being served by cheap generation.
The research conducted under this grant proposes algorithmic solutions to accommodate the EVs demand in an optimal manner, not only to minimize costs, but also to exploit their ability to charge and discharge on command, to provide services to the power system. At the same time, we also seek to exploit this inherent flexibility to minimize not only the electricity cost for the EV owners, but also the degradation of their batteries. Go to this project's web page.
Assessment and enhancement the smart building's flexibility and responsiveness
Abstract: Buildings represent a large share (about 40%) of the total energy consumed at national level. The majority of this energy consumption takes place when the building is being occupied during office hours. As expected, these are the periods in which the power system's generation fleet is being used most heavily, not only producing large amounts of power to meet the demand, but also greenhouse gaseous emissions. Therefore by harnessing the flexibility of the pliant appliances in the building as well as energy efficiency measures, the timing and amount of power consumption, and thus on pollution from the supply sector would be greatly reduced. This research proposes tools to optimally operate and retrofit buildings to minimize their power consumption and their carbon footprint. Go to this project's web page.