MOGTAR KANYIRI
UEB3562725
CS CLASS A
1. Mention the main components of a typical PV system and state their functions.
2. Differentiate and state three advantages and disadvantages of each of the
various types of solar systems.
3. What is hydropower?
4. Mention 3 advantages and disadvantages of a typical hydropower system?
5. Why is hydropower renewabable?
6. Mention and define any two of the biomass conversion
7. How does a solar pv system work?
Answers
1. Solar panels:They convert light energy (photons) into Direct Current (DC)
electricity through the photovoltaic effect.
Inverter:Converts DC electricity into AC electricity.
Charge controller:Regulates the voltage and current coming from the panels to
the battery to prevent overcharging and damage.
Battery:Stores excess energy produced during the day for use at night or during
power outages.
2. Grid-Tied Systems:This is the most common residential setup. You are connected
to the local utility grid, using it like a giant battery. When you produce more than you
need, it goes to the grid; when you need more, you pull from the grid.
Advantages
Cost-Effective: The cheapest system to install because you don't need expensive
battery banks.
Net Metering: You can often earn credits on your utility bill for the excess energy
you send back.
Simplicity: Fewer components mean less maintenance and a faster return on
investment.
Disadvantages
No Power During Outages: For safety reasons, these systems shut down during a
blackout to prevent "back-feeding" electricity into lines workers might be fixing.
Grid Dependency: You are still subject to utility rate hikes and grid instability.
Low Control: You can’t choose when to use your "stored" energy (the grid decides
the value of your credits).
 Off-Grid Systems:These are completely independent of the utility company. They
require a massive battery bank and a backup generator to ensure the lights
stay on during a week of cloudy weather.
Advantages
Energy Independence: No more electricity bills, ever. You are your own utility
company.
Remote Accessibility: The only viable option for rural areas where extending the
main power lines is too expensive.
Sustainability: Forces a high level of energy consciousness and 100% reliance on
renewable sources.
Disadvantages
High Upfront Cost: Batteries are expensive, and you need a lot of them to ensure
reliability.
Limited Capacity: If your batteries are empty and it’s raining, you run out of power.
You have to "budget" your electricity.
Complex Maintenance: You are responsible for the health of the batteries and the
backup generator.
 Hybrid Systems:The "best of both worlds." You are connected to the grid, but
you also have a local battery backup.
Advantages
Backup Power: Unlike a standard grid-tied system, your lights stay on during a
blackout thanks to your batteries.
Peak Shaving: You can use your stored battery power during "peak hours" when the
utility company charges the most.
Flexibility: You can start with a small battery and expand later, or choose to go fully
off-grid eventually.
Disadvantages
Expensive Hardware: Requires a specialized "Hybrid Inverter" and batteries, making
it pricier than a standard grid-tied setup.
More Points of Failure: More complex wiring and components mean more things
that could potentially need repair over 25 years.
Space Requirements: You need a dedicated, temperature-controlled space for the
battery units.
3. Hydropower is a renewable energy source that generates electricity by
harnessing the kinetic and potential energy of moving or falling water.
4. Advantages
 High Reliability and "Base Load" Power Unlike solar or wind, which are
intermittent (the sun sets and the wind stops), hydropower is highly predictable.
Large reservoirs allow operators to control the flow, providing a steady,
"always-on" base load of electricity to the grid.
 Long Lifespan and Low Operating Costs While they are expensive to build, a
well-maintained hydropower dam can last 50 to 100 years. Once the initial
construction is paid off, the "fuel" (water) is free, making it one of the most
cost-effective forms of energy in the long run.
 Energy Storage (Pumped Hydro) Hydropower can act as a giant battery. During
times of low electricity demand, water can be pumped to an upper reservoir.
When demand spikes, that water is released to generate power instantly,
helping to stabilize the entire electrical grid.
Disadvantages
 High Upfront Costs and Long Timelines Building a dam is a massive civil
engineering feat. It requires enormous amounts of capital, years of
environmental impact studies, and a decade or more of construction before a
single kilowatt is produced.
 Environmental and Ecosystem Disruption Damming a river floods the upstream
area, destroying forests and wildlife habitats. It also blocks the natural
migration of fish (like salmon) and alters the water temperature and silt levels,
which can harm downstream aquatic life.
 Displacement of Communities Because large-scale hydropower requires a
massive reservoir (a man-made lake), it often necessitates the flooding of
inhabited land. Historically, this has led to the forced relocation of entire towns
and the loss of indigenous lands or archaeological sites.
5. Hydropower is renewable because it relies on the earth’s natural water cycle
driven by the sun to constantly replenish the water source.
6. Pyrolysis is a thermochemical process that involves heating biomass to high
temperatures (typically 400°C–900°C) in the near-total absence of oxygen.
 Anaerobic Digestion (Biochemical Conversion) Anaerobic digestion is a
biological process in which microorganisms (bacteria) break down organic
materials—such as animal manure, sewage, or food waste—in an environment
completely devoid of oxygen.
7. Solar PV systems use cells to convert sunlight into electricity. The PV cell
consists of one or two layers of a semi conducting material, usually silicon. When
light shines on the cell it creates an electric field across the layers causing
electricity to flow. The greater the intensity of the light, the greater the flow of
electricity.