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Caltech research on ‘smart grid’ explores how 100% green energy can meet growing demand

The transition to renewable energy creates a host of challenges, from keeping the grid stable, to storing electricity, to interactive management of demand.

LOS ANGELES (CN) — The record heatwave that pummeled California this month put unprecedented demand on the state's electric grid. The balancing act to keep the lights and air conditioning on during the triple-digit temperatures also gave a glimpse of what the future holds as climate change and a shift to renewable energy sources will require consumers to become more flexible when it comes to using electricity.

Researchers at the California Institute of Technology in Pasadena are at the forefront in trying to solve this conundrum: How can an electric grid fed by unpredictable solar and wind power meet the future requirements of the state when more extreme heatwaves and a simultaneous transition to zero-emission vehicles will only mean greater demand for electricity? The solution they're working on is a decentralized "smart grid" where mathematical models will be used to optimize power distribution and consumption based on when and where it's available and most needed.

"The transition to clean and sustainable energy is massive and involves many different aspects," said Steven Low, professor of computing and mathematical sciences and electrical engineering at Caltech, whose research involves electric-vehicle charging and smart-grid infrastructure. "These extreme weather events will add to challenges during this transition."

California is spending billions of dollars to make sure the state's grid can withstand the increased demand caused by heatwaves in the coming years as well as diversifying the state’s clean energy portfolio with long duration storage and offshore wind in particular.

"These technologies complement our abundant solar resources by providing generation at the end of the day and into the evening as the sun sets," a spokesperson for the California Energy Commission said in an email.

Renewables supplied 56% of California's power at noon on Sept. 22, 2022 (Source: ISO).

The idea of a smart grid has been around at least since the 2007 U.S. Energy Independence and Security Act, which called for an "increased use of digital information and controls technology to improve reliability, security, and efficiency of the electric grid." But California's goal to have 100% renewable energy by 2045 is adding urgency to the need to implement new technology to keep the grid stable and demand and supply balanced when it's fueled by solar and wind power.

The research at Caltech focuses on numerous aspect of sustainable energy. Chemical engineers are working on fuel cell and energy storage — new kinds of batteries and new kinds of materials to produce batteries with drastically longer life and also higher capacity.

As the sun goes down and people come home, there's a rapid discrepancy between the available renewable energy and consumer demand. During the recent heat wave, Californians were urged to set the thermostat on their air conditioner higher in the evening and avoid using large appliances to prevent outages. Stored energy can fill some of that gap and the California Independent System Operator, which oversees the power grid, cited the more than 3,000 megawatt in battery storage that have come online in the past two years as one of the reason outages were avoided during the recent heatwave.

"In Southern California we have plenty of solar and wind," said Marvin Moon, assistant general manager for power delivery with the Pasadena Department of Water and Power, which is working with Caltech on implementing new technology. "The challenge is energy storage, which is 15 years behind solar technology."

Solar power makes up the vast majority of renewable energy on the California grid on Sept. 22, 2022, at 2:15 p.m. (Source: ISO)

California will need a lot more battery storage and it's unclear whether the stationary lithium-ion batteries that are used now will be sufficient, particularly on a systemwide level according to Low, and therefore some new long-term storage solution will have to be found.

A second, maybe more esoteric question is how to stabilize the grid when it's powered by inherently unstable sources such as wind and sunshine.

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With traditional electricity generation, the huge rotating turbines at natural gas or nuclear power plants provide the bedrock of stability for the entire power grid, such as keeping the voltage within certain parameters, from the transmission network to the distribution network. And it's on the generation side that the power grid traditionally has been controlled so that it can meet the anticipated demand.

As these traditional power plants are retired and replaced by wind and solar farms, the problem is how to keep voltage magnitudes within their parameters and maintain safety and integrity across the network with a fluctuating supply.

"How do you think about maintaining stability without this inertia?" Low said. "That is one of the biggest stability challenges that people are working on actively in research."

And as the grid will become less certain and controllable on the generation side, control will have to shift to other points within the transmission and distribution side, such as at transformers and substations where new monitoring and control devices can be installed to keep the grid stable.

"These are all control and optimization opportunities inside the network where new hardware, software and algorithms can be developed to achieve a much more active, realtime and dynamic control of the system," Low said. "This will allow us to integrate more renewables."

Peter Klauer, senior adviser on smart grid technology with the California Independent System Operator, agrees that better information is key to the reliability of the network as it moves away from traditional power sources.

"We need more, faster and accurate information of what's happening on the grid," Klauer said. "It's becoming more dynamic and more challenging to forecast."

One of the new challenges for the ISO is that many households have started to use their own solar panels to generate electricity and the real-time data the grid operator gets from the utilities, for instance on the impact of these rooftop panels on demand, is still imperfect, according to Klauer.

Another major change with the switch to clean energy is that demand will need to be more flexible, responsive and actively managed through interactive technology. This can be through smart appliances that can communicate with the grid to determine when it's optimal to run the dishwasher or when to adjust the thermostat. It can also extend to commercial and industrial users, such as data centers, to determine when it's optimal to perform certain tasks that require a lot of electrical power.

One specific challenge for California will be that the state will only allow zero-emission cars to be sold starting in 2035, which will mean that millions more EVs will need to be charged, adding further strain on the power grid.

To address this problem, Low and a group of researchers at Caltech have developed an adaptive charging network, whereby EV owners can use a mobile app to tell a garage that's part of the network how much power they need and how long they plan on parking. The garage will use an algorithm to decide when each EV will be charged in a way that is optimal for the entire system, thereby minimizing the cost to the network.

Large scale adaptation of such smart charging systems, particularly at workplace parking facilities, will enable California to accommodate 10 million EVs using the abundance of solar power during the day, according to Low.

Other researchers around the world are also looking at the future of the electric grid and at the challenges involved in the transition from fossil fuels to renewables and the need to accommodate the growing number of EVs.

Rajit Gadh, the director of UCLA’s Smart Grid Energy Research Center, for example, said in an interview this month with a university publication that some of the newer EVs on the market have the ability to discharge power into the grid and that, if all of the current 1 million EVs on the road in California were outfitted with this capability and appropriate financial incentives existed, the battery resources of these EVs combined would be able to provide a reserve support for the grid during peak hours on extreme heat days when energy is most needed.

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