M Tech: RET: Practice Questions

We discussed these questions in today's class. Try them today, we will discuss them in more details on Friday, Sep 12.

1. Q:

Country	Area (km2)	Sun hours per day	Energy Consumption (MWh/year)
United States	9,826,675	4	3,886,400,000
India	3,287,263	5	959,070,000
Brazil	8,515,767	4.5	455,700,000
Spain	505,992	4.5	267,500,000
UK	243,610	2.5	344,700,000

n(a) Determine which countries need to cover Maximum and minimum surface area to achieve total energy requirements from PV. Assume the PV efficiency is 15%.

n

(b) If a PV of 270 Wp is to be installed, what would be the most ideal location in term of maximum output.

2. Q: 

nFamily Smith is interested in buying a solar energy system. After some research on the Internet they have found two different systems that they are considering. System A is a PV system based on multicrystalline silicon solar cells and system B is a PV system based on amorphous silicon solar cells.

nSystem A: The efficiency of the multicrystalline silicon module amounts to 15%. The dimensions of the solar module are 0.5m by 1.0m. Each module has an output of 75 Wp. The modules cost €60 each.

nSystem B: The amorphous silicon solar modules have an efficiency of 6%. The dimensions of the solar modules amount to 0.5m by 1.0m. The output of each module is 30 Wp. The modules cost €20 each. The advantage of the amorphous silicon solar modules is that they perform better on cloudy days in which there is no direct sunlight. Installed in the Netherlands, this system gives, on a yearly basis, 10% more output per installed Wp than the multicrystalline silicon modules.

nBoth systems are grid-connected using a 900 Wp inverter. The total price of the inverter, the cables, the installation and other costs amounts to €1000. The solar modules are to be installed on a shed. The roof of the shed can only support 10 m² of solar modules.

nIn the Netherlands a PV system having multicrystalline silicon module generates on average 850 Wh per Wp in one year. The performance of both types of modules is guaranteed for 20 years. The price of electricity from the grid is €0.23/kWh. Assume that all the power produced by the PV system is completely consumed by the Smith family.

na) How much (peak) power (in Wp) can be installed for system A given the peak power of the inverter and the area available on the shed? How about System B?

nb) What is the price of a kWh of electricity (in €/kWh) generated by system A? System B?

nc) Family Smith is eligible for a municipal subsidy for sustainable energy that amounts to 15% of the initial costs of the PV system. Using this subsidy, how many years does system A need to be operational to earn the own investment back (assume that the electricity price of €0.23/kWh does not change)?  Calculate the same for system B.