electricity production, hydro, reservoir, non-alpine region, UPR, ecoinvent 3.6, Undefined
Location: TRE - Texas Regional Entity
This dataset represents the production of high voltage electricity at grid-connected reservoir hydropower plants in US - Texas Regional Entity in 2012. Here, the reservoir hydropower plants are modelled with non-alpine region plants extrapolated from data on Swiss hydropower plants. A representative sample of various types of dams in Switzerland is taken into account, i.e. 52 reservoir power plants with a height of mor than 30 metres, an annual gross production output of 17.8 TWh and an installed capacity of 9130 MW. As far as the construction is concerned, reservoir power plants and pumped storage power plants are dealt with together due to the fact that the construction efforts are related. Lifetime is assumed to be 150 years for the dam and 80 years for the rest of materials. The data refers to plant construction of a mix of types of dams built between 1945 and 1970; therefore they might not be representative for more modern construction, for an individual type and for small-scale and smallest-scale plants.
[This dataset is meant to replace the following datasets:]
Undefined unit processes (UPRs) are the unlinked, multi-product activity datasets that form the basis for all of the system models available in the ecoinvent database. This is the way the datasets are obtained and entered into the database by the data providers. These activity datasets are useful for investigating the environmental impacts of a specific activity (gate-to-gate), without regard to its upstream or downstream impacts.
Storage power plants have an appendant reservoir. The size of the reservoir can range from daily, monthly to annual storage reservoirs. According to the net head high-pressure, medium-pressure and low-pressure systems can be distinguished. High- and medium-pressure systems are constructed as dams. High-pressure storage power plants with a head of over 50 meters are very common in Switzerland. For this dataset concrete dams (arch dams and gravity dams) with a height of more then 30 meters are taken into account. Also pumped storage power plants are included because in most cases the data is only available for the overall generation system. The same counts for high- and medium-pressure and alpine run-of-river power plants which are also included in the storage power plant dataset. Due to the fact that the efforts for the plant construction are similar to storage power plants and that the estimated production is comparatively low, high- and medium-pressure run-of-river power plants are covered by the reservoir power station dataset.
The technology used in the dataset has an overall efficiency of 82%, more modern technologies show an overall efficiency of about 88%. The overall efficiency is composed of the efficiency of the works water channel, the turbine, the generator and the transformer and are listed below:
Efficiency of power plant current modern
Works water channel 0.95 0.95
Turbine 0.87 0.91
Generator 0.96 0.98
Transformer 0.98 0.99
Reservoir power plant total
without works water channel 0.82 0.88
with works water channel 0.78 0.84
Pumped storage power plant 0.70 0.74
The losses along the works water channel are primarily caused by friction and are calculated from the difference between gross and net head. Based on this calculation the efficiency of the works water channel amounts to 95%. The losses depend on the flow rate and have its maximum at full load. The smaller the cross section of adits and pressure pipelines, the higher the flow velocity and thus the friction losses. In older plants according to Bischof (1992) the efficiency of works water channels could be increased generally more than by replacing turbines and generators.
The efficiency losses in turbines depend on the turbine type (Kaplan, Francis, Pelton, etc.), the turbine output and on the ratio between turbined water amount and the rated water amount. In König (1997) examples for curve progressions of the relationship between these variables are shown. For current power plants an efficiency of 87% is assumed, more modern turbines show an efficiency of about 91%.
The efficiency of generators depends on the output, the rotation speed of the generator and the cooling system. Some relevant data can be found in König (1997). For today’s power plants an efficiency of approximately 96% is assumed, modern generators show an efficiency of about 98%. The efficiency of transformers amounts to 98%, respectively 99%.
Bischof, R. (1992) Modernisierungspotential bei bestehenden Wasserkraftwerken. Vortrag beim Schweizerischen Technischen Verband, Sektion Graubünden, 21. Oktober 1992. Churwalden, Schweiz [unpublished].
König F., von (1985) Bau von Wasserkraftanlagen. C.F. Müller, Karlsruhe.