Hydro · Analysis
I.How the river made power, and why the drop matters
These dams were not built to make electricity. Most of them predate the grid. The Schuylkill Navigation Company strung a system of dams, canals, and locks along the river in the 1820s and 1830s to float anthracite coal down from the mountains, and mill towns like Manayunk grew up around the water power those dams made available. A mill did not ask for much. A waterwheel turning a few stones was plenty.
Electricity is greedier. The power you can pull from moving water is roughly the height the water falls (engineers call it head) times how much water is flowing. The Schuylkill's dams are low, on the order of ten to twenty feet at most, so the head is small, and the flow swings hard between an August trickle and a February flood. Low head plus variable flow is the hardest case for a turbine: modest power in the best weeks, and almost nothing in a dry stretch.
II.What a revival actually requires
Say you own an old dam and want to put a turbine in it. The first stop is the Federal Energy Regulatory Commission (FERC, the agency that licenses non-federal hydropower). Even a small project usually needs a federal license or an exemption, and the review looks at fish, recreation, water quality, and historic structures. FERC offers streamlined paths for small and low-impact projects, but streamlined still means studies, comment windows, and years, not months.
Then there is the fish. The Schuylkill is in the middle of a decades-long effort to bring American shad back upriver to spawn, and the Fairmount Dam has carried a fish ladder since the late 1970s to help them climb past it. Any new turbine has to prove it will not chop up migrating fish or block their path, which usually means screens, a bypass, and a fish passage plan blessed by the Pennsylvania Fish and Boat Commission. Behind many of these dams sits a second problem: decades of sediment, some of it laced with coal silt from the old anthracite trade, that nobody wants to stir up.
III.Which sites might, and which won't
Ironically, the most famous dam on the river is the least likely to spin a turbine. Fairmount Dam feeds the historic Fairmount Water Works, a National Historic Landmark that pumped the city's drinking water using water power in the 1800s and now serves as a museum and a fish ladder. Its value is history and habitat, not megawatts, and that is unlikely to change. The same logic covers most of the visible dams: small, old, and worth more as parks and fish passage than as power plants.
Better bets are quieter. Low-head turbines have improved, and a dam with steady flow, a clear owner, and no fish-passage fight can pencil out, especially if the power feeds a nearby load and skips the grid. Water utilities sometimes place small turbines inside their own pipes and treatment plants (a conduit project, which faces a lighter federal review because it uses infrastructure that already exists). That kind of hidden hydro, not a restored mill dam, is where the Delaware Valley is likelier to see new water power.
IV.Worth watching this month
1. Watch whether FERC posts any new small-hydro or conduit exemption filings for Pennsylvania sites in its public eLibrary docket, which is open but usually quiet.
2. The Pennsylvania Fish and Boat Commission's shad counts at the Fairmount Dam fish ladder should surface after the spring migration, a routine figure that signals how the restoration is going.
3. Any Schuylkill dam that lands on PA DEP's dam safety inspection or repair lists is worth noting, since a dam facing costly repairs is one whose owner may weigh removal against reuse.
4. PJM's interconnection queue for small generators in the Philadelphia zone is where a new hydro project would first have to appear before it could sell power to the grid.
5. Dam-removal proposals from local watershed groups are more common than revival proposals and often settle a site's future first.
Frequently asked questions
- Could the Schuylkill ever power a lot of homes?
- No. The river's dams are low and its flow is seasonal, so even all of them together would make a small amount of power. Small hydro here is measured in enough for a building or a block, not a neighborhood.
- Why keep the dams if they don't make power?
- They hold water levels for recreation and rowing, and in Fairmount's case carry a fish ladder and a landmark. Some are also just expensive to remove.
- What is the hardest part of reviving a dam for power?
- Usually the combination of a small height drop, seasonal flow, federal licensing, and fish passage. Any one is manageable, but together they often make the math fail.
- Is anyone doing small hydro in the region?
- The likelier path is conduit hydro inside existing water and wastewater systems, which faces a lighter federal review. Restored mill dams are rare.
- Who decides whether a dam gets a turbine?
- FERC licenses the project, PA DEP oversees dam safety and water quality, and the Pennsylvania Fish and Boat Commission weighs in on fish passage.
Sources on the bench
FERC, Hydropower Licensing Federal agency page explaining how non-federal hydropower is licensed and exempted, including small and conduit projects. · www.ferc.gov/licensing
Pennsylvania DEP, Division of Dam Safety State program that inspects and regulates Pennsylvania dams, the office that governs any repair, removal, or reuse. · www.dep.pa.gov/Business/Water/Waterways/DamSafety
Pennsylvania Fish and Boat Commission State agency behind American shad restoration and fish passage decisions on the Schuylkill. · www.fishandboat.com
PJM Interconnection The regional grid operator whose interconnection queue a new generator must enter before selling power. · www.pjm.com
Fairmount Water Works Interpretive Center Run by Philadelphia Water, this covers the history of water power at the Fairmount Dam. · fairmountwaterworks.org
U.S. Department of Energy, Hydropower Basics Plain federal explanation of head, flow, and low-head hydropower. · www.energy.gov/eere/water/hydropower-basics