Introduction

Electricity is an essential resource in the modern world. Even more important is the production and transmission of electricity to end users. As of now, the US power grid does not store any electricity, so the amount demanded must equal the amount produced.

Currently, in the US, the vast majority of the electricity produced comes from non-renewable sources like coal, natural gas, and oil. The rest is produced from renewable and nuclear sources.

The Issue

As the world transitions to more renewable sources of electricity, there is a big problem we will need to overcome: the environment produces electricity at a rate different from the rate at which people consume it.

This is true with all renewable sources: hydropower works best during the rainy season, wind farms work best when it is windy, and solar farms work best when it is sunny. Unfortunately, these peaks in renewable energy production do not align with the demand.

So, when these renewable sources can’t make enough power, the fossil fuel generators are fired up, or the nuclear power plants are turned up to produce additional electricity to meet the demand. This is especially true during the peak hours in the AM and PM.

A Proposed Solution

To address this problem, I, Dylan Ulshafer (a fellow Howell Engineer) and another gentleman at Drexel University worked up a solution for our Senior Design Project. Using a local example we could observe and study, we proposed converting the Marsh Creek Dam to generate electricity during peak demand in the AM and PM.

The Marsh Creek Dam is located in Downingtown, PA, and currently has three existing uses: flood control, water supply, and recreation. All uses that need to remain unaffected by our additional proposed use.

How We’d Proceed

The plan is to construct a basin with a volume of 360,000 cubic feet of storage (the equivalent of four Olympic-sized swimming pools), a building containing a 275 kW hydroelectric generator, and an aboveground penstock to siphon water from the reservoir to provide a consistent supply of water. The basin would function similarly to a typical Howell Engineering-designed basin. Water would flow into the basin at a very high rate and then be slowly released into the environment at a lower rate.

It has been calculated that the system could produce about 1 gigawatt of electricity in a typical year, which is the equivalent yearly demand for about 100 typical American homes. Below is an idealized profile view of how the system would operate.

How it Works

A typical and idealized day of this system would function as follows. At 6 AM (the beginning of the AM peak demand), the basin would be empty, and water would begin to flow through the generator until 9 AM, at which point the basin would be completely full, and the generator would be shut off.

Then, from 9 AM until 4 PM, the basin will drain into the stream, providing the stream with the same amount of flow it was originally intended to receive.

Then, at 4 PM (the beginning of the PM peak demand), the basin will be empty, and the generator will be turned on again, generating power from 4 PM to 8 PM.

At 8 PM, the basin will be full, the generator will be shut off, and the basin would drain overnight, feeding the stream at the rate required by the other uses.

Other Considerations

In reality, the workings of this system are more complicated. Many other factors come into play when determining how long the generator will run and how long the basin will drain, including the pool elevation of the reservoir, water supply volume demanded downstream, and stream flow rate required for wildlife located downstream.

We think this system will fit seamlessly within these requirements because no matter the stream flow rate desired, there is a combination of generator run time and basin drain time to accommodate any condition. This will allow the maximum amount of power to be generated as close to the time of peak energy demand as possible.

The Potential

The purpose of this project was to determine the technical feasibility of such an endeavor, and we are confident that it could be technically feasible.

With enough of these systems across the county controlled by the central power grid, it could be possible to lessen the need for fossil-fueled generators to offset the shortcomings of renewable energy sources.

We Welcome Comments and Insight 

We believe this proposal could usher in a new era of converting existing dams to produce peak-demand hydropower. Below is a link to the full report, and I welcome anyone who knows more about dams and hydropower than us to weigh in.

If you would like to discuss this further, please contact me at [email protected].

Marsh Creek Hydroelectric Project Final Report Spring 2022 (pdf)