Feasibility Study Of Hydro Power Plant
A pre-feasibility study is carried out to determine whether the site is worth further investigation. This study could involve visiting a site to measure head and flow rate, or it could simply be a map study.
If the site looks promising, the next step is to carry out a full-scale, detailed feasibility study. Information collected by this study should be of the highest quality and should be accurate enough to permit a full technical design of the project without a further visit.
A feasibility study includes a site survey and investigation, a hydrological assessment, an environmental assessment, the project design, a detailed cost estimate and the final report. The depth of study will depend largely on the size and complexity of the system.
For a small system such as a battery-based system, the feasibility study can be less rigorous than for a larger system. Carrying out a feasibility study is highly technical.
Unless you have a strong background and experience in the area, it is best left to professional consultants or energy experts. Such expertise may be expensive, but the project could become much more expensive without professional help.
If a consultant prevents only one serious mistake in the project, that person will have earned his or
her fee many times over. If you are going to call a consultant or manufacturer, make sure that you
have at least a rough estimate of the head (vertical drop), length of pipe needed for the head and an
approximate flow rate of your micro-hydropower site.
These are the first things that you will be asked. The feasibility study should answer as many of the following questions as possible:
• How much head is available?
• How long does the canal/pipeline have to be in order to reach the head?
• What are the minimum and maximum flow rates, and when do these occur?
• How much power can be generated with the available flow rates?
• Who owns the land?
• Where are the nearest electricity power lines?
• What would the environmental effects of installing a micro-hydropower system be?
• What is the approval process to install the micro-hydropower system?
• What financial incentives are available that encourage renewable energy, and how can you apply for them?
• How much will it cost to develop the microhydropower system?
Finding answers to as many questions as possible will enable you to identify any major problems before you invest a lot of time and money in the project.
During the feasibility study, all relevant technical and non-technical information needs to be collected. This includes the location of the intake, forebay tank and powerhouse; the length of the diversion canal/pipeline; the penstock; and the transmission/distribution network.
The feasibility report should contain detailed technical information.
Design of the system includes civil works, the penstock, generating equipment and an estimate for the total cost of the system. It is helpful to keep in mind that the cost per kilowatt increases for low-head systems, low-flow systems and for systems where a great deal of civil works components need to be constructed.
Wednesday, April 12, 2017
FLOW DURATION CURVES OF HYDRO POWER PLANT BASIC INFORMATION AND TUTORIALS
Flow Duration Curve and Energy Calculations
As an owner/developer of a potential hydro site, you may wonder how much power your site will produce. A more exact question is how much energy it will produce – it is energy in kilowatt hours (kWh) that we buy from or sell to the electricity supplier.
Energy is a measure of the length of time we have used or produced a given amount of power. For example, if you use 1 kW (1000 W) of electricity for one hour, you have used 1 kWh of electrical energy.
A site on a stream or river that has a highly variable flow (i.e., a wide range of flows with many highs and lows) may not produce as much energy as a river that has a smaller range of flows but that is more consistent on average.
A hydrologist or professional consultant can produce a flow duration curve (FDC) for a river or stream by ordering the recorded water flows from maximum to minimum flow.
This is a way to show the probability in graph form of how many days in a year a particular flow will be exceeded. (The area below the curve is a measure of the energy potential of the river or stream.)
The FDC is used to assess the expected availability of flow over time and the power and energy at a
site and to decide on the “design flow” in order to select the turbine. Decisions can also be made on how large a generating unit should be.
If a system is to be independent of any other energy or utility backup, the design flow should be the flow that is available 95 percent of the time or more. Therefore, a stand-alone system such as a micro-hydropower system should be designed according to the flow that is available year-round; this is usually the flow during the dry season.
It is possible that some streams could dry up completely at that time. Remember that for any water source, be it a river, stream or creek, there will be a difference in flow between winter and summer, and this will affect the power output produced by a micro-hydropower system.
Flow in the stream changes continually (sometimes daily) if precipitation has occurred; however, some generalizations can be made. In southern Ontario, rivers and streams are at their highest levels in early spring and are at their lowest levels in late summer. In northern Ontario and Quebec, smaller rivers and streams are usually at their lowest levels in mid-winter and at their highest in spring.
British Columbia and Newfoundland and Labrador generally have low flows in late winter and high flows in the spring, except for the south coast of British Columbia, which has low flows in summer and high flows in winter. These variations must be considered in the estimated total energy generation expected from a site.
Ideally, minimum flow over the year should be taken to calculate the design flow to ensure that
power is available year-round. Normally, only a fraction of the available flow in the stream is used for power generation.
Therefore, FDC is less important as the size of system decreases. If the system’s generating capacity is less than 10 kW or so, FDC may not be relevant at all.
As an owner/developer of a potential hydro site, you may wonder how much power your site will produce. A more exact question is how much energy it will produce – it is energy in kilowatt hours (kWh) that we buy from or sell to the electricity supplier.
Energy is a measure of the length of time we have used or produced a given amount of power. For example, if you use 1 kW (1000 W) of electricity for one hour, you have used 1 kWh of electrical energy.
A site on a stream or river that has a highly variable flow (i.e., a wide range of flows with many highs and lows) may not produce as much energy as a river that has a smaller range of flows but that is more consistent on average.
A hydrologist or professional consultant can produce a flow duration curve (FDC) for a river or stream by ordering the recorded water flows from maximum to minimum flow.
This is a way to show the probability in graph form of how many days in a year a particular flow will be exceeded. (The area below the curve is a measure of the energy potential of the river or stream.)
The FDC is used to assess the expected availability of flow over time and the power and energy at a
site and to decide on the “design flow” in order to select the turbine. Decisions can also be made on how large a generating unit should be.
If a system is to be independent of any other energy or utility backup, the design flow should be the flow that is available 95 percent of the time or more. Therefore, a stand-alone system such as a micro-hydropower system should be designed according to the flow that is available year-round; this is usually the flow during the dry season.
It is possible that some streams could dry up completely at that time. Remember that for any water source, be it a river, stream or creek, there will be a difference in flow between winter and summer, and this will affect the power output produced by a micro-hydropower system.
Flow in the stream changes continually (sometimes daily) if precipitation has occurred; however, some generalizations can be made. In southern Ontario, rivers and streams are at their highest levels in early spring and are at their lowest levels in late summer. In northern Ontario and Quebec, smaller rivers and streams are usually at their lowest levels in mid-winter and at their highest in spring.
British Columbia and Newfoundland and Labrador generally have low flows in late winter and high flows in the spring, except for the south coast of British Columbia, which has low flows in summer and high flows in winter. These variations must be considered in the estimated total energy generation expected from a site.
Ideally, minimum flow over the year should be taken to calculate the design flow to ensure that
power is available year-round. Normally, only a fraction of the available flow in the stream is used for power generation.
Therefore, FDC is less important as the size of system decreases. If the system’s generating capacity is less than 10 kW or so, FDC may not be relevant at all.
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