Research generates reliable energy source during outages

December 09, 2003

MADISON -- As utility companies search for ways to avoid blackouts, like the one that shut down the northeastern corner of the United States last summer, one idea comes from the University of Wisconsin-Madison.

Researchers from the College of Engineering have designed a system where a small network of local generators can reliably disconnect from the rest of the power supply, enabling locations where electricity is critical to stay in operation.

Most buildings receive their electrical power from transmission lines branching off a main power grid. With energy coming from a large network -- the one responsible for the August 2003 blackout stretched 157,000 miles -- any disruption could cause a cascade of powerlessness in cities near and far.

Because the new technology developed at UW-Madison receives its power locally, it can "leap frog" transmission lines, avoiding any failures within those lines, says lead inventor Robert Lasseter, professor emeritus of electrical and computer engineering.

The UW-Madison technology consists of a microgrid, a small network of several power generators located at a single site. These generators, integrated into the main energy distribution system, encompass a wide range of power sources, including micro-turbines, gas internal combustion engines, fuel cells and photovoltaic, which generates voltage from light exposure.

When problems occur within the transmission lines, the generators and their loads (the devices each one powers) can separate from the main distribution system to isolate particular areas - hospital rooms or factory floor, for example - from the disturbance.

Explains Lasseter: "The critical loads in a microgrid can ride through any event. That means they can stay alive when the grid fails." The ability to "island" generators and electrical loads together, he adds, has the potential to provide higher local power reliability than that provided by the distribution system as a whole.

But providing this reliability requires more than separating the microgrid from the main power system, says Lasseter. Drops in voltage, even from generators in a small network, can lead to fluctuations in power that shut down equipment or recalibrate machinery. These are the types of costly problems that businesses want to avoid during a blackout, Lasseter adds.

To dodge these fluctuations, the Wisconsin engineer and his graduate student, Paolo Piagi, have fit the generators in the migrogrid with voltage source inverters - a power electronic device that allows each generator to regulate voltage, thereby regulating electric current and the energy it produces.

Besides sidestepping possible power outages, the microgrid system is more energy efficient. All generators - whether part of a utility plant or small building - produce more waste heat than electricity.

However, smaller generators, such as those in Lasseter's microgrid network, can easily be placed in areas that need to be heated, says the Wisconsin engineer. This placement of the generators and the waste heat they produce, he adds, can bump up the amount of usable energy to nearly 90 percent, and can do so without the use of complex heat distribution systems, such as steam and chilled water pipes.

Lasseter and his UW-Madison colleagues are discussing a project to build a working microgrid with the California Department of Energy and the national laboratories of Sandia, Oak Ridge and Lawrence Livermore. The project would simulate the possible use of a microgrid at a small factory.

The microgrid design is patented by the Wisconsin Alumni Research Foundation, a non-profit organization that patents and licenses intellectual property for the university.
-end-
-Emily Carlson
608-262-9772
emilycarlson@wisc.edu

University of Wisconsin-Madison

Related Energy Articles from Brightsurf:

Energy System 2050: solutions for the energy transition
To contribute to global climate protection, Germany has to rapidly and comprehensively minimize the use of fossil energy sources and to transform the energy system accordingly.

Cellular energy audit reveals energy producers and consumers
Researchers at Gladstone Institutes have performed a massive and detailed cellular energy audit; they analyzed every gene in the human genome to identify those that drive energy production or energy consumption.

First measurement of electron energy distributions, could enable sustainable energy technologies
To answer a question crucial to technologies such as energy conversion, a team of researchers at the University of Michigan, Purdue University and the University of Liverpool in the UK have figured out a way to measure how many 'hot charge carriers' -- for example, electrons with extra energy -- are present in a metal nanostructure.

Mandatory building energy audits alone do not overcome barriers to energy efficiency
A pioneering law may be insufficient to incentivize significant energy use reductions in residential and office buildings, a new study finds.

Scientists: Estonia has the most energy efficient new nearly zero energy buildings
A recent study carried out by an international group of building scientists showed that Estonia is among the countries with the most energy efficient buildings in Europe.

Mapping the energy transport mechanism of chalcogenide perovskite for solar energy use
Researchers from Lehigh University have, for the first time, revealed first-hand knowledge about the fundamental energy carrier properties of chalcogenide perovskite CaZrSe3, important for potential solar energy use.

Harvesting energy from walking human body Lightweight smart materials-based energy harvester develop
A research team led by Professor Wei-Hsin Liao from the Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong (CUHK) has developed a lightweight smart materials-based energy harvester for scavenging energy from human motion, generating inexhaustible and sustainable power supply just from walking.

How much energy do we really need?
Two fundamental goals of humanity are to eradicate poverty and reduce climate change, and it is critical that the world knows whether achieving these goals will involve trade-offs.

New discipline proposed: Macro-energy systems -- the science of the energy transition
In a perspective published in Joule on Aug. 14, a group of researchers led by Stanford University propose a new academic discipline, 'macro-energy systems,' as the science of the energy transition.

How much energy storage costs must fall to reach renewable energy's full potential
The cost of energy storage will be critical in determining how much renewable energy can contribute to the decarbonization of electricity.

Read More: Energy News and Energy Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.