June '05 Newsletter

As the days grow longer and hotter, Californians will start reaching for the air conditioner controls, putting a squeeze on the state's power supply and forcing utilities to pay higher prices for electricity. On scorching afternoons, high demand can lead to brownouts and blackouts. But relief is coming in the form of new technology being developed by a multidisciplinary group of CITRIS-affiliated researchers. Through a project called Demand-Response Enabling Technology, this group aims to provide California's 10 million residential power consumers with the ability to automatically respond to shortages in the state's electrical supply grid by reducing their electricity use at such times.

How will it work? California is making plans to charge more for energy used during peak hours. Demand-response technology relays this price information to homes, notifying residents when prices are high so they can reduce their energy consumption. Utility customers could, for example, pre-program their thermostat to turn off air conditioning and the hot water heater when prices peak. They could also check the current electricity price status via a small display in the laundry room before starting a load, not unlike someone waiting to make long-distance calls until Sunday when the rates are lower. The system receives information, shares it with the other sensors, and communicates it to the user via a network of small wireless devices that are very easy to install.

“Demand-Response is all about spreading the load and flattening the peaks of energy use,” says mechanical engineering professor Paul Wright, a principal investigator on the project.

The project has brought together a diverse group of CITRIS-affiliated researchers, each focusing on a specific aspect of the technology. Professor Jan Rabaey and his group in the Berkeley Wireless Research Center are working on the miniscule Pico Radios which will receive and transmit information between the meter, the thermostat, and the nodes, while Berkeley computer science professor David Culler, with the Intel Research Berkeley laboratory, is heading up work on the network that will enable all the parts to talk to one another. Professor Richard White and students at the Berkeley Sensor and Actuator Center are perfecting the assorted sensors inside the nodes. And to keep battery consumption down, Wright and his team are focused on incorporating “energy scavenging” technology, which converts things like the wall vibrations which occur when a person walks from one room to another into electric power to fuel the nodes.

Of course all the best technology in the world won’t change people’s ways if the controls are frustrating to use, as architecture professor Edward Arens, director of UC Berkeley's Center for the Built Environment and a principal investigator on the project, points out. Arens and mechanical engineering professor David Auslander have a team of architects and engineers designing the system’s intuitive, self-learning user interface. “We want to keep it very simple so that people don’t look at it, become confused, and get turned off. Part of what makes this a CITRIS project is making sure that society accepts and actually benefits from these ideas,” says Arens.

Noting that modern thermostats are so confusing that close to 80 percent of their owners override them, Arens says the interface his group is designing on will be as simple as a traffic light--a small green light for regular rates, yellow meaning an increase could be ahead, and red alert for high prices. A blue light could be added to indicate when there’s a particularly dire problem, say a power plant down. With the latter, says Arens, “people may choose to behave well not on a pricing basis, but out of a sense of goodwill, which studies have found to be very effective. A lot of people will turn things down if they know there’s a societal problem.” Easy PDA-style controls would enable energy-conscious Californians to shut things off even when they’re not at home.

After more than two years of collaborative work funded by the California Energy Commission’s Public Interest Energy Research program, the system will be put to the test this summer in three modern California homes as well as in a built-to-scale model located on campus. In addition to perfecting the interface and technology, Wright anticipates that the team will spend the next couple of years making the technology small and cheap enough to put into homes throughout the state. Demand-Response Enabling Technology and California’s dynamic electricity pricing are expected to become a reality within five years.

“Californians are ahead of the curve when it comes to energy conservation. These coming changes are a continuation of California’s cutting-edge energy policies over the past three decades,” says Arens.

For more information:

Demand Response Enabling Technology Developing Project

California Institute for Energy and the Environment

The California Energy Commission's Public Interest Energy Research program

On Electric-rate Regulation Peak pricing is critical for an energy-efficient future by Julie A Fitch (San Francisco Chronicle, March 15, 2005)

On Electric-rate Regulation Mandatory peak pricing is a misguided fine on energy-conscious consumers by Steve Colvin (San Francisco Chronicle, March 15, 2005)

"Cooling Off California's Energy Crisis" by David Pescovitz (Lab Notes, August 2003)

Water is one of the California’s most precious resources. Not because there isn’t enough of it--supply ebbs and flows with droughts and wet seasons--but because we need so very much of it for everything from washing dishes and taking showers to watering crops and making sure salmon have fresh water to spawn in. Unfortunately, keeping tabs on our water’s quality hasn’t proved easy. Years of fertilizing crops, building homes near watersheds, and other activities have led to a noticeable decline in water purity, something environmental engineers are working to reverse. But first, they have to understand what’s causing it.

“In California, we know where most of the flow is going because we need it all. But once we start getting into finer issues like the quality of the water and individual chemicals in the water, then we don’t track it as well,” explains Tom Harmon, an associate professor of environmental engineering at UC Merced whose research focuses on monitoring watersheds, areas of land that capture precipitation, draining it into marshes, streams, rivers, lakes, and groundwater.

Harmon and another CITRIS-affiliated researcher, UC Davis Civil and Environmental Engineering professor Geoff Schladow, are independently developing sensor networks that would enable them to conduct real-time monitoring of water quality--Harmon in the farming communities of the Central Valley and Schladow in the Lake Tahoe Basin. Improved scrutiny, they believe, would not only deepen researchers’ understanding of the causes behind water pollution, but also show how to reverse it.

Nowhere is situation’s seriousness clearer than on Lake Tahoe. Thirty years ago, visitors to the lake could gaze nearly 100 feet into its famous crystalline blue waters. Today, visitors can see only 60 feet down. For a long time, Schladow and other Tahoe researchers believed all the blame lay with phytoplankton, microscopic plants that blossom when fed nitrogen and phosphorous from excess application of fertilizer.

“In the last four or five years we’ve started to realize that the phytoplankton aren’t so important. Most of the damage is being done by extremely fine particles, just 1 or 2 microns, that have washed in from sources such as driveways or from stream erosion; some are even brought in by air currents which deposit them on the lake. It’s particles that seem to have increased and particles that have accounted for most of the loss of clarity,” says Schladow, who is director of UC Davis’ Tahoe Environmental Research Center (TERC).

Currently, a network of six meteorological stations (the kind used for weather reports) on floating rafts (four are operated jointly with NASA), eight additional stations along the lake’s shore, and several NASA satellites records the lake’s temperature, wind speed, infrared radiation, and clarity, uploading the data at regular intervals to a Web site available to anyone. However, in order to study the actual contaminants, Schladow and his team still have to paddle out onto the lake and collect samples by hand every ten days. Automating this process, says Schladow, is the obvious next step. To that end, he and his team of investigators are planning for the installation of a suite of new, automated samplers and sensors that may do just that. Additionally, they have a proposal in to the National Science Foundation (NSF) to build a network of smaller sensors along a set of nearby streams to study the interaction between the annual snow pack, the groundwater and the water quality in the streams.

Sensor networks along stream beds also play a key role in the work Harmon is doing. While it’s known that chemicals are trickling through California’s watersheds and into rivers, tracing their paths has been difficult because the sensors needed to detect these substances either don’t exist or aren’t hardy enough to survive long in nature. Among Harmon’s many research projects is one to modify fragile laboratory chemical sensors for just that purpose. Ultimately, he hopes that data from physical, chemical and biological sensor networks along rivers that drain from the snow pack through agricultural land could be combined with information on stream flow, temperature, and salinity from existing watershed gauging stations and satellite imagery to produce a big-picture view of the state’s water quality.

“If all the data was on the table in an easily accessible way and integrated with some forecasting model so that, just as we forecast the weather, we’d be able to forecast stream quality over certain branches of the stream based on presumed practices, we might be able to adaptively manage those practices. For example, we someday might be able to forecast optimal conditions for applying fertilizer or pesticides in a particular region of the valley, so that the farmer reaps the necessary benefits while the impact on local groundwater and rivers is minimal,” Harmon says.

While building a real-time map of the state’s water supply is going to take a lot of time and effort, Schladow points out that in the meantime “Lake Tahoe is a really great place to study these watershed processes because it’s relatively confined.” For that reason, students and researchers from around the world have flocked to this natural laboratory to learn and, in many cases, apply it to bodies of water half a world away. But learning isn’t the only reason Schladow believes his work there is important. He says: “It is a bellwether for our societal commitment to environmental restoration. These things take effort by a lot of people and that effort needs to be funded. If we can’t understand how to improve Tahoe and we can’t find the resources to do it, what are the chances of finding it for places that aren’t so unique and special?”

For more information:

S. Geoffrey Schladow's Web site

Tom Harmon's Web site

UC Davis Environmental Dynamics Laboratory

Tahoe Clarity Model

Tahoe Environmental Research Center

California CLEANER Planning Web site

Lake Tahoe REMOTE: Real-Time Monitoring of the Environment

CENS Research Project: Developing Error Resilient Sensor Networks to Protect Water Quality

CENS Research Project: Micromachined Potentiometric Nitrate Sensor

California Environmental Protection Agency State Water Resources Control Board

A Web of Sensors, Taking Earth's Pulse, by William J. Broad (New York Times, May 10, 2005) [Registration and payment required.]