The Power Plant of the Future Is Right in Your Home
If we want more renewable
energy, our grids will have to manage themselves. A small experiment in
Colorado is lighting the way.
KATELA MORAN ESCOBAR has always dreamed
of being a homeowner, but she never imagined her first house would double as an
energy experiment. Last July, Escobar and her family moved into Basalt Vista, a
new affordable housing project in the small town of Basalt, Colorado, just
north of Aspen. The development is a bulwark against the skyrocketing housing
prices in Roaring Fork Valley, but it’s also a living laboratory to test
advanced power grid technologies that could turn every home into an appendage
of a decentralized power plant.
Basalt Vista is designed
to be an all-electric community that produces as much power as it uses. Each
home comes outfitted with an electric vehicle charger in the garage, a large
battery pack in the basement, and a roof covered with solar panels. The homes
are linked together as a microgrid, a self-contained
electricity distribution network that can operate independently of the regional
electric grid. Their energy systems work together to balance the energy load
across the neighborhood—the solar panels harvest energy, plugged in EVs can store
electricity as needed, and large battery packs can supply power when the sun
isn’t shining.
But what makes Basalt
Vista’s microgrid unique is that it autonomously allocates power. There’s an
internet-connected control box in the basement of each home running
experimental software that continuously optimizes electricity distribution
across the microgrid and the flow of energy to and from the larger regional
grid. When one home produces more energy than it needs, it can autonomously
make the decision to redistribute it to its neighbors or store it for later.
“We don’t have to deal with any of the machinery,” says Escobar. “The house works all by itself.”
Basalt Vista is a testbed
for a so-called “virtual power plant,” a network of self-optimizing energy
resources that unbundles the centralized utility and distributes it across the
grid. Like microgrids, virtual power plants consist of distributed energy
systems such as rooftop solar panels, EV chargers, and battery packs. The
difference is virtual power plants aren’t really designed to disconnect from
the greater grid. Instead, they aggregate and control distributed energy
sources so they can perform the functions of a large centralized power
plant—generating and storing electricity—for the wider grid.
This virtual power plant
could serve as an antidote to the inherent variability of renewable energy systems
by efficiently matching supply and demand across widely-distributed electricity
producers and consumers. For now, the technology exists in the basements of
Escobar and her neighbors at Basalt Vista. But if the experiment is successful,
it may one day control power for millions of other families.
“Traditionally, we’ve
delivered electric service over a one-way transmission and distribution grid
from centralized power plants to relatively passive consumers,” says Bryan
Hannegan, CEO of Holy Cross Energy, a small nonprofit utility that services
Basalt, Aspen, and other nearby communities in Colorado. “That architecture is
changing dramatically and consumers are now producing as well. Power plants are
no longer large and centralized; they’re numerous and distributed.”
Before he took the helm of
Holy Cross in 2018, Hannegan was the founding director of the Energy Systems
Integration Facility at the National Renewable Energy Laboratory outside of
Denver. The facility was conceived as a “grid-in-a-box” where researchers could
study how solar panels, electric cars, battery storage systems, and other so-called
“distributed energy resources” affect the way electricity moves around a grid.
As more homes and
businesses install their own renewable generation and storage systems, it makes
it more difficult for centralized utilities to manage electricity supply and
demand. Ensuring that electricity gets to the customers who need it, when they
need it, is simpler when you have a small number of large power plants that run
on predictable fuels like coal, natural gas, or nuclear. But the energy
produced by distributed energy systems tends to be renewable and therefore
highly variable—sometimes the sun is shining, sometimes it’s not. Moreover,
there are a lot of distributed systems. Instead of managing a
few large power plants, utilities would have to manage millions of small ones.
“Utilities are moving away
from just selling electricity to end users to managing the networks and
electricity flows,” says Haresh Kamath, a senior program manager for
distributed energy resources at the nonprofit Electric Power Research Institute.
“There’s a lot of advantages to having these energy systems close to the end
users, especially if the utilities have some way to orchestrate and coordinate
them.”
Generating and storing
renewable energy closer to where it’s used can increase the resiliency of a
grid by ensuring that the electricity keeps flowing to users even if the rest
of the grid is damaged by wildfires or other disasters.
But the price of resiliency is efficiency. The proliferation of distributed,
variable energy resources creates uncertainty for electricity demand; utilities
will either produce too much or not enough. For Hannegan and his colleagues at
NREL’s Energy Systems Integration Facility, it was clear that to create an
electricity supply that is clean, resilient, and efficient,
the grid of the future will have to largely manage itself.
In 2016, the Department of
Energy awarded the National Renewable Energy Laboratory a $4.2 million grant to
develop autonomous grid control software as part of its Network Optimized
Distributed Energy Systems or NODES program. The idea, says NODES project lead
Andrey Bernstein, was to create algorithms that optimized electricity
distribution both at the level of individual homes and at the level of the
entire grid.
“The problem is that the
current technology is not able to integrate very large amounts of distributed
energy resources,” says Bernstein. “What NODES produces is a plug-and-play
platform that enables the integration of millions of devices such as solar
panels, batteries, and electric vehicles that can be controlled at the edge of
the system.”
The algorithms developed
by Bernstein and his colleagues turn the grid into a two-way street. Instead of
the top-down approach in which a centralized utility dispatches electricity to
end users, the autonomous control software allows distributed energy systems to
push excess electricity back onto the larger grid in the most efficient way
possible. If it’s a sunny day and rooftop solar panels are producing way more
power than their owners need, there’s no reason for a utility to be burning as
much coal or natural gas. But without a network of autonomous controllers
keeping tabs on distributed generation, a utility has a blindspot and can’t
take advantage of the excess clean energy.
The autonomous grid
control software developed at NREL was designed for handling tens of thousands
of energy systems. But what works in the lab won’t necessarily be able to
handle the chaos of real life. So after three years of testing the algorithms
at NREL’s grid-in-a-box lab, the NODES team was ready to test it in the field.
The autonomous software was first tested on a microgrid at a small vineyard in
California and later was installed in small control boxes in the basements of
the first four houses built at Basalt Vista.
Holy Cross’ embrace of
autonomous grid control software shows that proliferation of distributed
renewable energy systems isn’t necessarily a mortal threat to electric
utilities. From a utility’s perspective, the growth of rooftop solar panels,
battery storage, and other distributed energy systems made it more challenging
to efficiently and reliably provide electric power. The Basalt Vista experiment
may be small, but it’s proving that it’s possible to autonomously control
distributed renewable energy systems so that they augment the grid’s
reliability.
“In most places, it’s
still a challenge for utilities to figure out how to use distributed resources
at scale,” says Chaz Teplin, an electricity practice manager at the Rocky
Mountain Institute, an independent sustainability research organization. “I
think what Holy Cross is doing is really great because they’re taking a
collaborative approach where everyone can benefit from what they’re bringing to
the table.”
Escobar says living in an
energy experiment has its perks. In addition to the environmental benefits of
living in a home that produces as much power as it uses, she says it's also
easy on her family’s bank account. During the summer, Escobar says her
electricity bills were just $12 per month. The bills were higher during the
winter because the house requires more electricity to run its heaters, but
Escobar says she expects to see significant savings on her electric bill
averaged over the course of a year. “Living in an affordable house with net
zero energy use is great for the environment and our finances,” Escobar says. “I hope this model is replicable in other places.”
Basalt Vista is pioneering
autonomous control of renewable energy systems, but it’s hardly the only
utility exploring virtual power plants. In Utah, a new 600-unit apartment
complex was outfitted with solar panels and battery storage that provides
backup power and demand response for the local utility, Rocky Mountain Power.
And Vermont’s Green Mountain Power has subsidized the installation of Tesla Powerwall battery systems in people’s homes to
help offset the peak power demand during the summer.
So far, the results from
virtual power plant trials have been promising. They help utilities and their
customers save money, increase the amount of renewable energy systems on the
grid, and bolster the resiliency of local power networks. Each of these trials
has been relatively small, but the advent of autonomous grid control
technologies points to a future where everyone’s house can also be a power
plant.
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