As electricity costs continue to rise, water and wastewater treatment
facilities are faced with the challenge of providing high-quality, reliable
water services while reducing operating costs
Introducing the power network
After looking at potential solutions to this challenge, the water and
wastewater treatment utility Pennsylvania American Water (Hershey, Pa.) decided
to join the ENBALA Power Network® (Toronto). The network connects
various facilities with flexible electricity demands to the smart grid to help
achieve electrical Grid Balance™, said Ron Dizy, president and CEO of ENBALA
Grid Balance is an ancillary service where electricity system operators
rely on generators to increase and decrease power generation to match real-time
demand. These operators, the independent system operators (ISOs) and regional
transmission organizations (RTOs), must maintain a continuous balance between
demand and supply to ensure all consumers (commercial, industrial, and
residential) have a reliable supply of electricity.
But operators face challenges of maintaining this balance as an increasing
amount of energy comes from intermittent renewable energy sources such as wind
and solar, Dizy said.
"With the evolution of the grid and the increased amount of renewable
sources being added, grid operators require innovative solutions,” Dizy said.
The network balances the electric power system on the demand side,
providing electricity system operators an innovative way to integrate more
renewable energy to the grid, Dizy explained. ISOs and RTOs pay ENBALA for its
service, the company then shares those funds with large-scale electricity users
(commercial, industrial, and institutional organizations) connected to the
network. These electricity users are paid based on the amount of electricity
flexibility they provide to the network.
Water and wastewater treatment facilities use a large amount of energy, but
treatment processes are inherently flexible. “Grid Balance generates an extra
revenue stream for the plant and helps offset high electricity costs,” Dizy
said. “When a pump is slowed down for a period of time, it decreases its flow,
which also represents a decrease in electricity consumption and drop in power.
At another time, the pump will be sped up for the same period of time,
balancing out the required pump demand. Within a given day, energy consumption
Other processes where electricity use can be adjusted throughout the day
while maintaining necessary treatment levels include aeration blowers and water
treatment reservoirs, Dizy said.
Real results of connecting
Pennsylvania American Water decided to start by connecting one pump at its
Shire Oaks Pump Station to the network. The station has an average demand of
1.1 million kWh per month and peak demand of 1650 kW.
The utility worked with ENBALA engineers to connect the pump and meet all
security requirements. The connection required no additional infrastructure
other than the local communications panel installed by ENBALA.
Once connected, the utility specified constraints on the flexibility and
availability of its pump’s electricity use so it would not interfere with the
quality of the water supply, other equipment, or processes.
“Each asset in the network has a set of constraints and responds to the
Grid Balance requests when available. It is the network effect that makes
responding to Grid Balance requests possible without impacting the operating
processes of any of the assets in the network,” Dizy said.
If an asset is not available, it does not receive an operational adjustment
request, leaving only available assets to deliver Grid Balance, and asset owners
are not penalized for not being able to respond to requests.
“The great thing about ENBALA is, with the system turned on and lowering
our net cost of energy, we don’t even know it is there. It is invisible to our
operations,” said Dan J. Hufton, Pennsylvania American Water senior director of
The Shire Oaks pump receives real-time requests from the network that are
passed along by PJM Interconnection (Valley Forge, Pa.), the region’s
electricity system operator. Shire Oaks’ potential is to provide a consistent
average of 400-kW Grid Balance to PJM. This can offset 2% to 3% of the
station’s total energy bill, according to Dizy.
Pennsylvania American Water found that the project did not compromise
operations. Samples of storage tank water levels while the pump was
participating in the network showed that water level was consistently within
the utility’s specified predetermined set points. And the station did not
experience any abrupt or undesirable changes in water levels, pressures, or
flow rates, allowing employees to predict and control station operation.
Also, the utility’s tests concluded that network equipment did not create a
security risk because it conformed to industry best practices and
recommendations for securing industrial control systems, according to Dizy.
Based on Pennsylvania
American Water’s results, the utility noted that constraints on pump operations
could be loosened by increasing the pump’s variable-frequency drive speed
balance. These actions would increase the range and revenue potential of the
service, Dizy said.