Hydro Power Electrical Power Systems
Pumped Electrical Power Systems Storage
One of the biggest challenges to renewable energy systems is storing power. Most of the types of renewable energy have challenges when it comes to having power on demand. Sun or wind is not reliable sources of power as compared to fossil fuels. The sun could be hidden for an extended period behind clouds. The wind might not be blowing all the time, at least at enough speed to power windmills.
Any excess power is typically wasted. Fossil fuels are stored energy, which are easier to store and use on demand. Whenever the user chooses to turn electrical power systems on, the power is there, waiting to be put to whatever purpose the user requires. The modern lifestyle has allowed people to become adjusted to just flipping a switch and getting power in response. In most developed countries, delivery of utilities such as gas, water, and electricity to homes is standard.
Technology has been improving enough in recent years to allow for some of these challenges to be overcome. Systems to store power generated by renewable energy sources either are in place, or are being developed, which will allow the energy to be stored until it is needed by users.
Hydropower is one of the oldest and most implemented renewable sources of energy. The first pumped hydro installation occurred in the late 1800’s. This system takes advantage of physics to store water in a containment area until there is a demand to generate electricity. Water is then introduced to the turbines to generate electricity. These turbines can also be used to help pump water into a storage pond. This has cost savings on equipment requirements.
Pumped storage electrical power systems work by pumping water from a low reservoir to a higher reservoir when demand is low and supply is high. The operator then, using the water accumulated in the higher storage pond, is able to generate electricity when demand rises.
Pumped hydro storage works around the problem of storing the converted electricity by only generating electricity when there is demand for electricity. It uses the potential for energy, rather than trying to use a battery type system.
When situated in a good geographic location and near a natural body of water, pumped storage facilities can be constructed without major capital expenditures. This can also eliminate the need for hazardous chemicals.
While these facilities can require little in the way of major capital investments to get running, they do require large amounts of land. This makes them ill-suited to have in close proximity to large urban centers. This means that they have to be able to access high-capacity electrical transmission lines. This also allows for easier storage of power generated by the turbines.
Bath County Pumped Storage Station, located in Bath County, Virginia, is the largest pumped storage facility. This facility has a capacity of up to three gigawatts. Most large power stations are able to generate up to several thousand megawatts per hour, for several hours.
Pumped storage facilities are able to begin generating power very quickly. Pumped storage facilities are more responsive to changes in power demand than their gas-powered plant competitors are. Hydro powered generators are also more environmentally friendly when compared with power plants that burn fossil fuels.
There are losses associated with the pumped storage system for hydropower due to evaporation, but there are also gains from run-off and rainfall. This system allows for quick, on demand alternative energy generation.
Pumped has the largest capacity of all the various grid energy storage systems that are in use today. These are also very efficient, with reported rates in the 70-80% range. This means that approximately 70-80% of the energy expended to pump the water through the turbines is recouped at the end of the process. Some operators have reported as high as 85% efficiency.
The overall efficiency and capability of pumped storage electrical power systems to respond to increased demand rapidly has led to their use to level the output of intermittent power sources, such as wind, tidal and solar power. This helps balance out the load in times of high demand, and low output. This extends the grid’s peak capacity.
Pumped storage systems can be combined with wind farms to achieve much better results than either could produce independently. Wind can be used to power the pumps directly. This increases the overall efficiency of pumped storage. Solar power also can be used in much the same way to power pumps. This makes such intermittent power sources much more reliable.
It is also possible to use seawater from the ocean to power hydro plants; however, the salt in the ocean creates a problem with corrosion that does not exist in fresh water pumped storage facilities. These types of pumped storage facilities work well when the storage pond can be located on a cliff, giving the advantage of greater force when the intake opens up and water flows through.
Tidal Barrages are able to take advantage of the power of the tides to generate energy. At high tide, water is allowed to flow through a tidal barrage. This water fills up a storage area such as a river or pond. The water is then released at low tide. This works to generate electricity each time the water passes through the tidal barrage.
One of the main barriers to widespread adoption of tidal barrages as an alternative energy source is the high capital cost and low energy generation. It takes a long time for a return on investment to occur with tidal barrages. Another disadvantage to this system is the ecological impact both on animals and on plant life in the area.
For regular pumped storage systems that are located near the sea, or another large body of water, a proposed system for alternative energy combines the power of the waves with pumped storage. It proposes to accomplish this by using a system of ocean buoys connected to pistons. These pistons are connected to pumps that pump in seawater from the ocean into the storage ponds.
