At the start arrange a site visit and survey the complete site and landscape. Evaluate according to following methodology
- Understand client requirements and base case energy scenario, as well as the site specific structural and environmental scenarios
- Identify drivers and develop energy efficiency and renewable energy goals utilizing insight from the base case
- Select and prioritize criteria for differentiating between lighting and renewable technologies
- Assess existing energy schemes and renewable resources amply available at the project site
- Identify viable technologies that utilize available resources
- Match viable technologies to priority criteria
- Develop renewable energy project concepts and conduct evaluations of these concepts
In accordance to above methodology, we had the following choices:
Renewable energy: Wind, Solar PV, Wind-solar hybrid, Biomass gasification to electricity (waste from sewage, garbage and kitchen)
We Compared the pros-cons and narrowed down on Solar PV for renewable energy.
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Advantages
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Disadvantages
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Solar
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1. Solar energy as fuel is freely available
2. Long Life: 10% and 20% degradation in 10 years and 25 years respectively
3. No moving parts and hence does not produce noise and vibration
4. Low maintenance cost
5. Easy to install and minimum intervention to existing structure during mounting phase
6. Reduces the temperature of rooms (flat) below the roof
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1. No generation when there’s no sun ie. During night
2. Less generation during rainy season
3. Battery is required to run the load other than daytime
4. High initial cost (Rs. 100-120/Wp)
5. No wide usage in India
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Wind
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1. Wind energy is freely available
2. Electricity can be generated over wide range of wind speeds
3. Design Life: 20 years
4. Low initial investment(Rs. 50-60/W) as compared to Solar
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1. Need to be mounted at height and hence not suitable for places with height restriction such as near airport
2. Impacts the visual features of Building Elevation
3. Certain Minimum cut off wind speed (usually 3 m/s) is required for electricity generation hence low windy regions are not suitable
4. Generation is intermittent and seasonal
5. Turbine produces noise and vibration
6. Lower ie. 5 years standard warrantee
Higher maintenance cost
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Biomass
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1. Biomass (sewage & food waste) is freely available
2. Reliable because it can Generate electricity continuously (24 hours for 365 days operation) as long as biomass is fed
3. Design Life: 20 years
4. Lowest initial investment as compared to Solar & Wind (Rs. 40-50/W)
5. By products can be used as fertilizers
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1. Gasification to electricity is complex, technology intensive system and offers lower capacity factors
2. Needs a Isolated space for plant
3. Labor intensive as the waste requires sorting and conveying. Continuous monitoring is required to check input consumption cycles
4. Subject to constraint of feedstock availability and calorific values of sewage and food waste constituents
5. Higher maintenance of turbine generator system
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Let us take an example of city of Aurangabad in Maharashtra, India where the solar modules should be mounted at 200 to the horizontal ground level.
LESS GENERATION
- Installation of Panel:
Flat (parallel to ground & not related to latitude of place)
- Less capture of solar energy because the incidence of solar rays are at 1100 w.r.t. average position of sun in a year
OPTIMUM GENERATIONitude
- Installation of Panel:
200 to ground (At latitude angle of Aurangabad)
- Optimum capture of solar energy because the incidence of solar rays are at 900 w.r.t. average position of sun in a year
The solar radiation is amount of energy contained in sunlight falling on earth. It is measured in W/m2. Global solar radiation constant is 1300W/m2 and it is calculated by dividing the solar energy falling on earth by surface area of earth. The amount of solar radiation a location receives depends on a variety of factors:
- Geographic location - Time of day
- Season - Local landscape
- Local weather
Air Mass Index
The Air Mass quantifies the reduction in the power of sun light as it passes through the atmosphere and is absorbed by air and dust. Technically, it is the path length which sun light takes through the atmosphere normalized to the shortest possible path length (that is, when the sun is directly overhead). Earth has Air Mass Index of 1.5 and hence the global solar radiation constant become 1000W/m2.
The Air Mass is defined as:
AM=1/cos θ
where θ is the angle from the vertical (zenith angle). When the sun is directly overhead, the Air Mass is 1. The air mass represents the proportion of atmosphere that the light must pass through before striking the Earth relative to its overhead path length, and is equal to Y/X.
