ASHRAE Journal - July 2021 - 25

ROUNDTABLE
Lynn Mueller, president and
CEO of Sharc Energy in
Vancouver, Canada.
energy-which is often an intermittent
energy source.
Ram Narayanamurthy: From
my viewpoint, energy storage is
the whole spectrum, whether
it's behind the electric meter,
or in front of the meter, or even
in terms of gas storage. And the
whole world of energy storage is
any method by which we can create
a disconnect between when
energy is generated and when
energy is used. So storage could
be in different areas. I think in this case, we are focusing
on energy storage that's within the building envelope,
which could be thermal storage, active thermal storage,
passive thermal storage or battery storage.
Michael Deru: As building engineers, we need to think
about how buildings interact with the storage system,
how to best control the charging and discharging of the
storage. Storage is very important to the future of our
energy systems-its value will be maximized based on
where it is located and how it is used.
MacCracken: It is important to remember that fossil
fuels are a type of stored energy and are dispatchable
when you need them. For renewables to be dispatchable,
vast amounts of energy storage must be added to both
sides of the electric meter.
Torcellini: Going back to what Ram said about storage
on the building side of the meter versus on the utility
side of the meter: do you think there's a benefi t one way
or the other?
Benjamin Lowe: Taking advantage of scale economies,
utility scale storage is cheaper and has the potential to
apply a great amount of benefi t to many customers. At
the building level though, individual control can matter.
That is a benefi t that shouldn't be dismissed. The
benefi ts of having storage at the building, or utility scale
level, comes down to kind of cost-benefi t versus a desire
for control.
MacCracken: Storage at the building, or on the building
side of the meter, affords a couple of things. The
energy has already been distributed to where the load
will eventually be, which lowers the load on transmission
and distribution lines.
Buildings basically need two things. They need thermal
energy, and they need electrical energy. Therefore,
you can take advantage of the need for thermal energy
at the building with thermal storage and address electric
loads atnd electric storage on either side. You can't really
have thermal storage on the grid scale and distribute
it. So that's an advantage to having it at the building for
thermal-and thermal storage is very economical.
Deru: I think one of the advantages of having storage at
the building is that if energy is generated at the building,
either renewable or waste energy that you're recovering,
then you can recover it and store it locally. You can
access it when the building needs it. If it is integrated
properly with systems, you can increase the effi ciency
of systems. You can take advantage of system operation
dynamics and operate those systems when they're most
effi cient.
Lynn Mueller: As a manufacturer, we deal with the
hot water load predominantly on apartment buildings.
So that load becomes very easy to store for us, because
we've developed the intelligence to really know when
the demand is. We can also look for waste energy opportunities.
Storing sewage that's leaving the building is an
energy source. So with recovering the waste, heat energy
is pretty easy to store as well as hot water. The benefi t
of storage at the building level is reduction of delivery
losses and increased adaptability of supply; smaller,
more effi cient equipment; time-of-day peak avoidance;
and fl exibility.
Torcellini: Taking a comment that Mark made that
today's utility grids and energy systems have storage in
them. Whether it's the coal pile or the gas well, that storage
is inherent to those systems bringing reliability. That
reliability is only as good as the weakest link between the
storage and the end use. So if a power line goes down,
and if the storage is on the other side of the break from
the building, the building won't get power. Moving the
storage to the building and closest to the end use makes
your building more resilient. And in some ways, you are
moving storage. How does moving storage to the building
help with decarbonization and moving toward a
renewable future?
Narayanamurthy: The value proposition for storage
today comes from the cost of operating the energy
system, but the cost doesn't directly map to carbon benefi
ts. So for example, if I put batteries behind a meter in
California and run it for optimizing time-of-use rates,
you end up with a 15% increase in carbon content on the
building. And that's mainly because when you're in a
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