Hydro Power and Water Management: Balancing Energy Production and Conservation
Water provides an abundant, renewable, and low-cost energy source. Power plants utilize this resource by storing it in a reservoir before turning turbines and generators that generate electricity.
Hydropower offers many advantages, but also presents some challenges. These include balancing energy production and conservation at various scales and times, as well as potential adverse impacts on river organisms.
Precipitation occurs when water vapor in clouds condenses to liquid (rain) or solid (snow, hail). The temperature of both the cloud and Earth’s surface determines which kind of precipitation forms.
Raindrops form when water vapor in the air comes into contact with a particle of dust, smoke or other pollutants called “condensation nuclei.” These particles provide the surface for water vapor to condense onto.
When temperatures on Earth’s surface and in the atmosphere drop, ice crystals may form on condensation nuclei. These crystals then fall to Earth as snow or sleet.
Storms can enlarge these ice crystals as they absorb more moisture as they fall. In dry or hardened soil areas, this may lead to flooding.
Hydropower facilities use the force of water to generate electricity. They can range in size from large installations like Hoover Dam to smaller ones that take advantage of water flows in irrigation ditches or municipal water systems.
Hydropower facilities generate energy based on how much water is stored in reservoirs. Seasonal and long-term changes in precipitation patterns can significantly influence available water for production.
Hydropower facilities, also referred to as pumped storage plants, act like batteries by storing energy generated from other renewable sources for later use. This type of power plant offers an efficient and flexible way to store energy that helps balance fossil and renewable fuel usage.
Hydropower generation does not emit air pollution or greenhouse gas emissions, but dams can have negative environmental and societal effects which should be taken into account before construction. For instance, dams may degrade aquatic and riparian habitat, hinder migratory fish passage, and displace local communities.
Energy storage is essential to maintain grid stability when dealing with variable sources of renewable power, like wind and solar. Batteries installed in homes, electric vehicles and power stations provide short-term capacity up to several hours, but more capacity is necessary in order to meet the demands from wind and solar – something pumped storage hydropower can do cost effectively and at scale.
Pumped storage plants store energy by using two interconnected reservoirs, one at a higher elevation than the other. When there is excess capacity in the upper reservoir, water is pumped to it while during times of high demand it’s released back into the lower one through a turbine.
Power is generated as the water passes through reversible Francis turbines on its way to a lower reservoir, creating electricity in the process. Variable speed technology – which permits precise power regulation at specific ranges during both pumping and generating – further enhances round trip efficiency.
Turbines convert the kinetic energy of moving fluids into usable mechanical or electrical energy. They’re often employed in water management to regulate water flow from reservoirs or pumped storage facilities.
Welsh Water’s Bryn Cowlyd Energy Recovery Project in north Wales uses a turbine to generate renewable energy and regulate water flow from Llyn Cowlyd – Wales’ deepest lake – while providing it with water for its treatment plant and headworks. This dual purpose allows them to supply their customers with clean drinking water while simultaneously producing electricity.
Hydroelectric power plants utilize several types of turbines, depending on the working fluid and required head. Impulse turbines (or Pelton wheels) are the most efficient option and can be found in many large power plants. They operate best at high heads with stable flows, providing several hundreds of megawatts of capacity.