2/17 Weekly Brief

Design

• Hydrology
• Last week was spent working on the design for the intake weir.  More resources were found and a sketch of the top-down view of the intake location was found.  Equations have been set up in Mathcad documents but calculations cannot be complete until more information is known.
• Questions to consider:
• Do we have a cross section of the river where the weir needs to be placed? If not, what is the approximate depth?
• What is the average river velocity?
• There was once mention of the religious and cultural constraints on using the total water supply to power the turbine. Is this a factor in our design? If so, what kind of constraints does this place on the amount of water which can be diverted?
• Are there pictures of the river itself?
• Geotechnical

• During the summer months, when rain fall increases, the chance of landslides also increases substantially. Clays and silts are effected greatly by this fluctuation as their properties change at various water contents. Compaction of soil for the foundation of civil works such as the weir is an essential component of creating long lasting structures. The weir allows for control of the water flow rate as it navigates to the turbine.  If this structure fails, the energy supply may be interrupted and damage to the entire system is a possibility.

• Questions to consider:
• What material will be used for the weir?
• What is the height of the water is falling to get to the turbine?
• How much water/what is the depth of water behind the weir expected to be?
• How far away from the turbine is the weir being installed?
• What is the natural flow rate of the river (probably varies widely with rainfall)
• Is water for drinking taken directly from the river?
• Does the river water get extremely thick or muddy? If so, how does this effect the turbine?
• Mechanical
• 
  
• Power distribution
• For this week, the team worked primarily on three parts: loads, mapping, and line configuration.
• First, the information given by ACREST was used to calculate the maximum load. According to ACREST, the typical use of electricity per household is four lamps, a phone charger, and a radio. From this information, the load per household was calculated as 300W and the load for the 20 households as 6 kW. The load for ACREST machines is still needed to be calculated; however, not enough information is yet known about them; assumptions will be made. Two main points should be noted about these calculations:
• The calculations are for the maximum load and do not include the energy losses.
• Google earth was chosen as the most ideal mapping program for this semester (GIS in the future, when more experienced GIS users are on the team)
• Therefore, the map from ACREST was translated into English and used to organize the input so that it would be easily understood. Finally, the team learned from the textbook about different types of line configuration. Because the grid system will be growing, it was concluded that the best line configuration for our system is a single phase, two lines even though its cost is higher than the other line configuration. A single phase, two lines has the potential to add more lines to switch to another line configuration, and by doing so, the capacity would increase by 2 to 4 times, depending on the line distribution. However, if the village already uses the single phase, two lines, an upgrade might be considered to a higher configuration if budget is limited.
• For the next week, first I am hoping to collect more information about the electricity use to improve my estimated calculation for the load. Second, I will type my work for the load and line configuration and make them available at the Google Drive. Third, I will continue reading the textbook to learn about conductors and start comparing different type of them. Choosing conductors seems a complicated task, so most likely it will take more than one week.
• Questions to consider:
• Locations of the houses that will be in the grid system
• Power consumption of ACREST machines (power, current, voltage, power factor)
• Line configuration currently used in the village
• Information about the conductors used in the current grid system

Assessment

• Environmental Impact
• Ecological impact of micro-hydropower is minimal. However, these effects can be magnified when the stream is small due to a part of the stream being diverted from its natural flow. Stream flow minima are set by the United States Environmental Agency in order to make sure that the ecosystem of the river is not affected.
• Main effects of hydropower ecologically impact plankton and algae. This would trigger a bottom-up cascade effect. The cascade effect could then effect vertebra, fish, birds, and ultimately people.However, most hydropower plants that have impacted the ecosystem have done so in a negative way. 
• Questions to consider:
• Is the area agriculturally active? If so, what kinds of crops are grown in the area?
• Are there pre-existing sediment or water quality issues?
• Is a reservoir present with the system?
• What metals make up the turbine and are these metals treated to prevent corrosion?
• Water quality issues exist down stream from the hydropower turbine. This is because of the impoundment that may occur from a hydropower system. There are various problems that may occur from hydropower in a river such as: changes in oxygenation, temperature, stratification potential, pollutant inflow, propensity for disease proliferation, nutrient capture, algal bloom potential, and the release of toxins from pre-existing sentiment. 
• In addition to the previously mentioned issues, turbidity issues may occur in the body of water.  This can cause the water to reduce in quality due to stirring up sediment on the banks of the river. Also, the banks may erode more quickly due to this turbidity. 
• Corrosion of the turbine is a concern in terms of it impacting water quality. Corrosion of metals in general has a lot of variety. A main factor of this is the material of which the corrodible surface is made out of. Different metals have different corrodibilities. 
• More corrosive factors:
• Low hardness
• Low alkalinity (<50mg/L of calcium carbonate)
• Water quality can impact the agriculture of an area as well. If the water is high in certain minerals, the livelihood of plants may be negatively impacted. The three most important nutrients to plants are potassium, nitrogen, and phosphorous, so any water quality issues that may impact those nutrients would be a problem.
• Social Impact
• Conducted preliminary research on hydropower technology in general in preparation for the first essay due February 20. Found that hydropower is one of the most important renewables for electric power production. In fact, it provides about 20% of the earth’s electricity. In micro-hydropower, there is usually no dam or water storage and therefore is extremely cost-effective and environmentally sound energy resources.
• The technology aspect of micro-hydropower in general can be summarized as such: a turbine converts the potential energy from falling water to a usable form of electricity. Each turbine is different, and they all have a specific power characteristic that depends on speed of water flow. It is important to have a consistent flow of water in order to produce consistent power. Therefore, one consideration that the environmental impact assessment team that I am also on is going to explore is how to compromise for any reduced flow conditions as Bangang is in a semi-arid region of Cameroon.  
• The team will more thoroughly and eloquently delineate the positives and negatives of micro-hydropower.
• Made minimal changes to the IRB narrative
• Added sources to the bibliography
• Helped the environmental team design a work plan similar to that of the SIA team.
• Networked with a visiting anthropologist who works on dam issues
• Economic
• NA
• Construction Management
• NA