# Question: hydropower the current demand load for electricity in the us...

###### Question details

**Hydropower**

The current demand load for
electricity in the US is ~ 600 GW_{e}. Of that, we get
about 70 GWe from hydropower. If we were to increase our use of
hydropower using 90% efficient hydro-turbines by seven-fold to 490
GWe:

- How many metric tons of CO
_{2}emissions would this avoid annually? (Assume it replaces coal; assume coal is 90% carbon by mass; assume the replaced coal fired plants are 35% efficient). You will need to have some idea of how much energy is released per kg of coal burned! You can ‘guesstimate’ the embedded greenhouse gas emissions associated with building the dams and hydro infrastructure at ~ 10 g CO_{2}/kW-hr of hydropower energy - What volume of water would be needed to be stored?
- assuming-We could build 50 ft deep reservoirs on average and with 250 feet of head, on average

- How much land area in square kilometers would be needed for these reservoirs?
- Given an annual average rainfall rate of 20 inches per year, what size watersheds would be needed to fill these reservoirs?
- What sustainability issues other than energy and GHG emissions would have to be faced if you were to attempt this transition?

Remember that Power = (Q)(H)(γ)
modified by efficiency (Q is flow rate, H is total head, gamma is
specific weight (~62.4 lb/ft^{3} or 9.8
kN/m^{3}))