Despite the end-of-school-year mania, I managed to get away to the 2017 IEEE Innovative Smart Grid Technologies conference in Washington, DC, in late April, to talk about the Smart Grid grad course that I was wrapping up at UT. I participated in a panel, “Innovations in Smart Grid Education,” chaired by Dr. Kenneth Lutz of the University of Delaware, with participants from MIT, the University of Illinois at Urbana-Champain, Wichita State University, and Clemson University.
I talked about the Smart Grid grad course I taught at UT this semester, making the point that “smart grid” discussions in practice are often focused on the distribution system and end-use, despite typical definitions in the literature being more general. I took an expansive definition in this class, including transmission and generation, for example, which also allowed me to invite colleagues from ERCOT and Oncor to participate.
Why do I use an expansive definition in my pedagogy?
Because the phrase “smart grid” implies that the existing grid is stupid. In fact, for many years in North America and elsewhere, operation of the transmission grid has been incredibly sophisticated — far more sophisticated than any other infrastructure system I’m aware of.
When we focus only on making the distribution grid smart, we risk throwing the baby out with the bathwater, by not building on the existing smarts in the transmission system.
In terms of pedagogy, this means students need to be aware of the entire grid, both smart and not-so-smart, in order to avoid a skewed perspective on the electricity system. As we look toward solving problems such as integrating high levels of distributed solar PV, we need to remember that the existing transmission and generation system provides the foundational infrastructure.
Highlights of the course include an overview of architecture of the smart grid, the generation and transmission system, distribution systems, and end-use. The strongest common theme: we are all searching for a good textbook!
Jaime Luengo shows UT professor Gary Hallock how the solar-powered water pump works.
It’s been my pleasure for the past several years to supervise a senior design project in my Electrical and Computer Engineering department at The University of Texas at Austin. The project is aimed at avoiding battery storage in off-grid solar applications by taking advantage of the storability of the final product or service provided by an electric motor.
Think of an electrically-driven water pump that is filling a raised tank, with the water then being used for domestic or agricultural use by letting it flow downhill. If the pump and tank are sized appropriately, then the pump could operate when power is available and still pump enough each day to cover the needs.
Our team’s approach to powering this system from the sun without battery storage has been to use a variable-speed drive for an electric motor and vary the drive frequency to match the power output from a solar panel. When the sun is shining brightly and more power is available from the solar panel, we adjust the drive frequency up so that the motor can use all the power. When it is cloudy and the solar panel produces less power, we adjust the drive frequency down so that the motor is still pumping, but at a lower rate, and using the available power. By adjusting the drive frequency this way, we can utilize whatever power is available from the panel without battery storage. We are storing the energy by pumping water uphill.
This year’s senior design team included (left to right): Carly Stalder, Ankit Sharma, Ji Hoon Seon, and Max Granat. Not pictured: Jaime Luengo, Cody Scarborough, Schuyler Christensen.
(There are other potential applications, such as-available air conditioning or other mechanical loads where there is inherent storage in the end-use product or service.)
Several senior design groups have been working toward this goal over the last few years. This year the students really came together and were able to build on previous groups’ efforts to build a working prototype that could harness variable light levels.
These photos show you the results: a working prototype that pumps more when the sun is bright.
Brad Jones (left) and Ross Baldick at the Austin Electricity Conference.
Decarbonization was the theme of the seventh annual Austin Electricity Conference, held April 20 and 21 by the UT McCombs School of Business, Cockrell School of Engineering, LBJ School of Public Policy, and School of Law.
As the name implies, decarbonization entails shifting the fossil fuel mix toward less intense producers of carbon dioxide together with reduced reliance on fossil fuels for electric generation over time. Our questions: How to implement a zero-carbon grid from a legal and policy perspective? How to achieve it from a technical perspective?
It was my pleasure to introduce keynote speaker Brad Jones, who has been an electricity industry executive for more than three decades. I first began to know Brad closely when he was Vice President for Generation Development at TXU. We disagreed on whether to implement the nodal market, and I remember his graciousness and intelligence during that debate. He then became Vice President for Government Affairs at Luminant, the successor generation firm of TXU. He joined ERCOT as COO in 2013 and in 2015 became President and CEO of the New York ISO (NYISO), which operates the state’s wholesale electricity market and is responsible for its bulk electric system reliability.
Lower carbon dioxide emissions, green technology, and renewables, Jones said, have become front and center in New York, even making it into the headlines of TheNew York Times. At the NYISO, priorities include decarbonization, integration of high levels of renewables, and creating a two-way grid. The state is introducing a requirement for electrical load-serving entities to purchase zero emissions credits (ZECs) in proportion to their statewide load, with proceeds going to eligible nuclear power plants. This provides market-compatible support for nuclear generators that values their zero carbon emissions, complementing analogous schemes for renewable resources. He emphasized that ZECs are designed to be a bridge to the future, and that New York is not expecting that ZECs will be needed forever. The state, in other words, is acknowledging the social cost of carbon.
Jones also discussed distributed energy resources (DERs). We need, he said, to value the contributions of DERs, by: 1) facilitating compensation through transparent pricing and metering, and 2) offering financial credit for reducing the load on distribution systems.
Jones concluded by emphasizing the need to internalize a carbon price into the wholesale market. That price will help to do two things. First, to guide operational decisions toward existing low-carbon resources. Second, to guide capital decisions — such as building more low-carbon generation in New York and building new transmission to bring Canadian hydro power to the state.
Brad Jones (left) and Ross Baldick at the Austin Electricity Conference.
On my panel, “Managing the Decarbonized Grid,” we discussed the technical challenges of operating an electricity grid with low or zero emissions. I emphasized that these challenges depend on the mix of resources used. (Click here to download my introduction and the panelists’ introductory remarks.)
For example, our main path to decarbonization in recent years has involved renewable resources such as wind and solar, which are generally connected to the grid via power electronic converters. Power electronics interfaces have a crucial difference with traditional grid-connected rotating machinery in that they do not “natively” provide inertia. Inertia has been essential in the control of the electricity system since its inception, because it enables stable synchronization of the electric waveforms in the grid and serves to limit the rapidity of changes after a disturbance. In order to decarbonize with renewables, we need to deal with this reduction or elimination of inertia.
One solution is to utilize the renewable resources to “synthesize” inertia using the flexibility of their power electronic converters; however, the drawback here is that some of the renewable production is sacrificed. A second solution, being developed and tested by panelist Brian Johnson of the National Renewable Energy Laboratory in Golden, Colorado, explores controls for power electronic converters that do not rely on inertia to provide synchronization.
My wife and I often enjoy BBC documentaries, and historian Dan Snow is a favorite host. In his series about the history of railways in England, he observed that, as the industrial revolution increased manufacturing in England, there was a need to move product around more cheaply, which in turn encouraged transportation innovations such as the steam train.
In a previous post, I’ve talked about the fraught nature of technical predictions. The same applies to predictions about costs, but the history of railways suggests that invention will be applied to reduce the costs of parts of the supply chain that are growing relatively more significant. For example, as relative costs reduce for any one particular contributor to electricity production, attention turns to bringing down the costs of other components.
In the context of renewables, we have seen ongoing reduction in the cost of wind and solar. To support the utilization of that energy, various ancillary services are required, including “regulation ancillary service.” If you had asked me a decade ago about renewable integration, I would have predicted that regulation ancillary service would become an increasingly significant part of the cost of renewable integration. However, in recent work with Juan Andrade and Yingzhang Dong, we investigated why, in fact, the amounts (and costs) of regulation ancillary service have not increased in the Electric Reliability Council of Texas (ERCOT), despite a huge increase in renewable penetration.
The fundamental answer is that there have been a multitude of changes to the ERCOT market design that has allowed the generation capacity for regulation to be utilized more effectively. The biggest change was the move from the zonal to the nodal market, but other changes have also contributed. These changes have enabled significantly more wind power to be utilized without increasing the cost of regulation ancillary service needed.
As with locomotives and manufacturing, as the need and costs of ancillary services seemed to be looming larger, imagination and innovation have resulted in better ways to utilize ancillary services to complement the production of renewable energy.
As many of the contributors to costs of renewables decrease, the issue of intermittency and the need for storage becomes more significant. Battery storage is currently too high-cost for bulk storage. But John Goodenough, inventor of the lithium-ion battery and my colleague in mechanical engineering, has recently published a paper describing a solid-state lithium-ion battery that may significantly improve the economics of battery storage. Lower cost batteries may be the new locomotive of renewable development.
Ross Baldick PhD provides strategic consulting to the electricity industry. Emeritus Professor of Electrical and Computer Engineering at The University of Texas, he is the author of "Applied Optimization: Formulation and Algorithms for Engineering Systems."