New York broke temperature and energy-use records in late July, and expectations that heat waves might become a more common feature of Eastern Seaboard summers are raising pressing questions about power grid stability -- and how utilities can manage the load when demand peaks.
There are both supply- and demand-side solutions to managing rising energy demand in densely populated areas like the U.S. Northeast. But the long lead times and high costs of some supply-side solutions, such as construction of new generating capacity, may prove ill-equipped to meet near-term needs for load balancing.
“Options on the supply side include building or firing up peaker plants, building renewables capacity or buying electricity on the wholesale market,” according to Paul Carp, Honeywell Smart Grid Marketing Manager. “Typically there are -- and I’m thinking largely about the regulated, investor-owned utility world -- very long filing and regulatory processes involved,” Carp said. He added that it can take five to ten years, or more, to build a plant, and “obviously a ton of capital investment.”
On the demand side, utilities have multiple options, such as introducing new tariffs or new financial incentives linked to demand-management programs that encourage a temporary reduction in energy use or long-term efficiency. For demand response (DR), there are newer technologies -- such as Wi-Fi-enabled thermostats and other automated demand response devices -- that can help utilities get the most out of their investment.
“When you’re talking about the Eastern Seaboard and the massive [recent] heat wave, we’ve helped install and enable hundreds of thousands of load-control devices,” Carp said. “It could be a thermostat, it could be a switch, it could go on a hot-water heater or a furnace,” he said. “For the Eastern Seaboard, it’s more than 650,000 devices.”
A utility can communicate directly with a load control device, and when needed, reduce load through such measures as cycling a unit on or off every fifteen minutes, or by modifying temperature by a degree or two. “This was definitely used in the most recent heat wave,” Carp said.
The average U.S. home has a load of around 4 kilowatts, and air conditioning uses around a third of that, he said. Assuming DR can reduce the load of each home by about 1 kilowatt, “if you take 650,000 endpoints, that is a massive amount of load shed. Roughly 650 megawatts is equivalent to a medium-sized power plant.”
“It’s a significant amount of capacity that we’ve helped enable our utility customers to shed,” he said.
The proliferation of smart devices is also providing utilities with better data, allowing for more targeted -- and more effective -- DR events.
“On the commercial/industrial side, there’s a lot of meter feedback coming back from facilities to utilities,” said Carp. “That information is really valuable in terms of understanding how the facility is responding, and what needs to happen to get more or less shed from that customer.”
More targeted events could entail grouping customers that employ load-shifting -- for example, pushing back electricity-intensive production from 2 p.m. to 6 p.m. -- or calling an event that will apply to a specific geographic region to relieve congestion in a localized area, Carp said.
“Taking meter data, analyzing it, understanding what that means, and giving more analytics back to the utility can allow it to call a more effective DR event in the future,” Carp said.
Faster, Better, More Efficient
Looking forward, utilities may have access to a new application of DR called “fast DR.” While traditional DR events require day-ahead or hour-ahead notification, Honeywell is currently engaged in a pilot project in Hawaii that enables utilities and commercial and industrial consumers “to reduce demand within ten minutes of notification of a pending imbalance between supply and demand,” the company said in a statement.
This capability could prove particularly critical in Hawaii, which gets more than half of its power from fossil fuels, and has the highest electricity costs in the country. The state has set a target of producing 40% clean energy by 2030. “They’re looking to bring on a lot of wind and solar, which is going to cause significant challenges in balancing the grid,” said Carp.
The variability of power generation from wind and solar (often referred to as "the intermittency problem") complicates load management. Sometimes renewables produce too much, and sometimes too little.
What fast DR could enable utilities to do is employ near-real-time automated DR. This could be an invaluable tool for managing problems with unpredictable and variable energy supply, especially in the absence of viable large-scale energy storage solutions.
With fast DR, “they can essentially do it in seconds, and those facilities can begin responding to that signal immediately,” Carp said. “If the wind stops blowing or the sun stops shining, this can generate a positive or negative load as necessary.”