Welcome to the Vicinity Energy Grays Ferry facility
Tour stops
Safety is our top priority. All visitors should be dressed in the proper attire prior to entering the facility. This includes close-toed shoes, long pants, and personal protective equipment such as safety glasses, hard hats, and ear protection. Visitors should always be aware of their surroundings and do not touch any equipment, machinery, or tools.
Please remain with your group at all times. If you are separated, call your teammates that are on the tour, and we will send someone to retrieve you.
Safety is our top priority. All visitors should be dressed in the proper attire prior to entering the facility. This includes close-toed shoes, long pants, and personal protective equipment such as safety glasses, hard hats, and ear protection. Visitors should always be aware of their surroundings and do not touch any equipment, machinery, or tools.
Please remain with your group at all times. If you are separated, call your teammates that are on the tour, and we will send someone to retrieve you.
Installed in 1999, our combustion turbine uses a Siemens/Westinghouse D5A, or 501D5A, which has a 130MW rated capacity. Similar to a jet engine, it draws and compresses air, mixes it with fuel and ignites it in a combustion chamber, creating high-pressure gas. The expanding gas spins the turbine blades, which drives both the air compressor and a generator to produce electricity.
The turbine intakes 830 lbs. of air per second, heating the rotor inlet temperature to approximately 2,150 °F. The heat is used to generate electricity, and hot air is exhausted from the turbine at about 1,006 °F.
Did you know: The rotor inlet reaches temperatures as hot as molten lava.
The exhaust heat from the combustion turbine is funneled to the heat recovery steam generator (HRSG) where hot gases flow over finned boiler tubes, transferring heat to the water in the tubes. This produces high-pressure and low-pressure steam. Thousands of pounds of high-pressure steam travel to a steam turbine and creates electricity that we sell to PJM Interconnection. Or high-pressure steam is distributed to our steam customers via underground pipes. The low-pressure steam is mixed with leftover steam and exhausted into the atmosphere via a stack at 170 ° F.
Our steam and electricity production fluctuates depending on the season. During hotter months, we maximize our electricity production because energy demands are higher. At our full capacity, we can produce 163 million megawatts. In the winter, we focus on steam because it’s used in our customer buildings for heating. While steam production can vary, it can exceed 1 million pounds of steam per hour in the winter. Between seasons, we service our equipment, continuously improving to ensure we are operating as efficiently as possible.
Co-generation model
The combination of the combustion turbine with the heat recovery steam generator is what makes up the co-generation or “combined heat and power” model at Vicinity. The facility generates power for the regional electric market as well as steam for the city of Philadelphia. This helps commercial and residential buildings achieve organizational goals, lower carbon emissions, and support a healthier city and environment.
Pollution control
Combustion emissions pass through an oxidation catalyst which turns the carbon monoxide (CO) within the combustion emissions into carbon dioxide (CO₂). It also goes through selective catalytic reduction where small amounts of aqueous ammonia (NH₃) are injected into the combustion emissions converting its nitrogen oxides (NOx) into nitrogen gas (N₂) and water vapor.
Some of the electricity generated from the combustion turbine is sold to PJM Interconnection, the largest power grid in the United States. PJM serves electricity to businesses and residents in Pennsylvania, along with 12 other mid-Atlantic states. Vicinity Energy is one of several utility providers that participate in the wholesale power market with PJM.
Natural gas needs to go into the combustion turbine at a certain PSI. The equipment inside the gas compressor house ensures this PSI is correct at all times by building pressure in gas lines that run to the combustion turbine. It was more commonly used when the Philadelphia Refinery was in operation, as pressures would enter our lines generally at lower pressures. Since the refinery is no longer operating, we do not need to utilize it as often.
This tank was built in 1957 and can hold 2.5 million gallons of #6 fuel oil. In the 1950s, boilers 23, 24, and 26 ran on this oil. The City of Philadelphia has since passed an ordinance that prevents #6 fuel from being delivered to facilities within the city. The tank has been emptied and cleaned and now holds #2 ultra-low sulfur diesel fuel. Boilers 23 and 24 are retired, but boiler 26 still uses this tank and fuel as a backup to natural gas.
The demineralization plant uses a two-step process to remove dissolved minerals (ions) from our water. City water passes through a cation ion which exchanges positively charged ions like calcium and magnesium for hydrogen ions. Then, the water moves to an anion unit where negatively charged ions (chloride and sulfate) are exchanged for hydroxide ions.
The hydrogen and hydroxide ions combine to form pure water which is less corrosive for our boilers. Untreated city water would corrode the boilers tubes causing water leaks and lowering our efficiency.
The Grays Ferry facility was built in the early 1900s and predominately ran on coal until 1937. During that time, the Clearwell was used as a settling tank to filter out ash and sludge from incoming water.
The tank consists of an upper basin and a lower basin. Water enters through the upper basin and travels over a weir to the lower basin before exiting through the water discharge line. This allows solid material like ash to settle out of the water and collect in the basin.
Today, our plant no longer runs on coal, so the Clearwell now moves rainwater and condensate through the basins to the sewers.
When the plant was powered by coal, railcars would ship coal from the river into the building through Ash Alley. Coal would be lifted to the roof of the plant and fed through the top of the boiler for fuel. The residual dust from the coal is what gives this area the nickname, “Ash Alley.”
There are two sets of old boilers depending on where you are in the plant. If you’re headed to see the rapid start boilers, you will see rows of old coal-fired boilers. While these haven’t been used for several decades, the plant once had hundreds of employees shoveling coal into the boilers.
If you are headed to the RO plant, you might see Boilers 23 and 24 – which are retired #6 oil boilers.
Here in turbine hall A1, we plan to install an industrial-scale heat pump in the coming years. The heat pump will draw water from the river at ambient temperatures. Pipes will transfer the river water to the evaporator which will extract thermal energy from the water. This will be done using ammonia-based chemicals. The ammonia carries the extracted heat to a condenser, which creates low-pressure steam. The low-pressure steam then travels to the steam compressor where it’s converted into high pressure, carbon free eSteam™ that can be distributed. The cool water that had the heat extracted is returned to the river.
Fun Fact: Even the coldest water has some amount of heat, it’s just a matter of extracting it!
The water used at our facility needs to be very pure, so we process it using reverse osmosis.
Osmosis is a natural process where water moves from a low-concentration solution to a high-concentration one through a semi-permeable membrane. Reverse osmosis does the opposite: Water is forced (under pressure) from a high-concentration solution (like salty or polluted water) through a semi-permeable membrane to remove salts, bacteria, and contaminants, resulting in clean water.
At our Grays Ferry facility, we remove large particles from the water, adjust the pH, and add anti-sealants to protect the RO membranes. We use a high-pressure pump to push this water through the membrane where only water molecules are able to pass. Salts, bacteria, viruses, and other dissolved impurities are rejected.
This makes Vicinity more environmentally friendly and financially conscious. In fact, we were once the largest PWD customer, having a bill that exceeded millions. Water purchased by PWD had to be demineralized to get rid of impurities. This process was very costly, and the harsh chemicals were detrimental to the environment. Now, we have a much cleaner system that efficiently purifies water.
In 1997, the plant was upgraded to include a combined cycle setup featuring a gas turbine (118MW) and a steam turbine (45MW). This replaced older boilers and generators in the turbine hall and increased the plant’s production to 1.4 million pounds per hour of steam. The turbine hall is now built to be dispatchable, meaning it ramps up or down to support renewable energy integration.
The steam turbine is a key part of the turbine hall, working alongside the gas turbine to produce both electricity and steam. This helps our Grays Ferry plant support grid reliability and the district heating system in Philadelphia. We deliver steam through more than 41 miles of underground piping to serve hospitals, universities, and office buildings in Center City and West Philadelphia.
How does the turbine hall work?
First, the plant burns natural gas in a gas turbine, which produces electricity and a lot of hot exhaust gases. That hot exhaust is used to boil water in a special boiler called a Heat Recovery Steam Generator (HRSG). This is where the water turns into high-pressure steam.
The steam then flows into the steam turbine, which has blades like a fan. The pressure of the steam pushes the blades, causing the turbine to spin. The turbine is connected to a generator, and as it spins, the motion turns into electricity.
The steam that passed through the turbine still has heat. Instead of wasting it, the plant sends it to heat buildings in Center City and West Philadelphia through underground pipes.
The central hub is where operators monitor, control, and coordinate the major processes involved in generating electricity. It’s the brain of the power plant, allowing us to run operations more efficiently, and it’s monitored by one or two people, 24/7.
Inside the control room are live data displays, SCADA/DCS Systems (Supervisory Control and Data Acquisition / Distributed Control System), and visual interfaces showing plant processes in real-time. There’s also alarms and indicators that warn operators of abnormal conditions (e.g., overheating, overpressure) and communication systems that help them coordinate with field operators and other departments.
The control room can oversee boiler operations like fuel supply, combustion control, and manage steam temperature and pressure. It can access steam operations such as speed control, steam flow regulations, and load adjustments. The control room also manages our cooling systems, keeping operators informed on condenser water flow and cooling tower operations. Lastly, the control room can tap into our auxiliary systems (pumps, fans, feedwater systems, etc.) and optimize general operations like voltage regulation and synchronization with the power grid.
The rapid start boilers (RSBs) went into commission in 2014. These are special auxiliary boilers designed to fire up quickly (within minutes) so steam is available fast when grid or heating demand spikes. These boilers maintain steam supply when demand surges or when the main steam system needs to start up quickly without relying solely on the HRSG.
For example, if the steam system needs to ramp up (ex: early in the morning when buildings need heat), the plant gets a signal to produce steam quickly. Natural gas is sent into the rapid-start boiler’s combustion chamber where an igniter sparks, and the gas burns, creating intense heat.
Pre-treated water flows through tubes or coils inside the boiler. The hot gases from the flame pass over these tubes. Because the system is compact and optimized for speed, it can convert water into steam in just a few minutes, compared to traditional boilers. The steam can then go directly into the district heating system or spin the steam turbine to generate more electricity.
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