# Family Smith is interested in buying a solar energy system. After some search on 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.

System 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 75 Wp output. The modules cost 60€ each.

System 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 advanage 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.

Both 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.

In 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.

a) 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?

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

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

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

e) 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).

f) The same question as e) but for system B.

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1. Cheater

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2. a) 765
c)0.232

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3. 900
600
0.112
0.12

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4. We are going to build a PV system on a roof of 10m2, and we have two possible PV modules:

(1) A first generation module with efficiency ç=18% and cost of 0.80€/Wp.

(2) A second generation PV module with efficiency ç=10% and cost of 0.40€/Wp.

The non-modular costs are 100€/m2.

Note that the irradiance under standard test conditions is 1000W/m2.

What is the cost in € of implementing a PV system for the entire roof using first generation technologies?

What is the cost in € of implementing a PV system for the entire roof using second generation technologies?

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5. Are you from India?

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6. 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 their own investment back (assume that the electricity price of €0.23/kWh does not change)?

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7. Excellent

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8. 900
600
0.112
0.12
8.309
9.22

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