As my daughter pointed out, attention to the details of Harry Potter's world is also patchy. (1) As everybody knows, the Gryffindor Quidditch team includes several girls. As far as we could tell, all the players in this game are represented as boys. That is a huge demerit for this father of a daughter.
Pricing for Solar Photovoltaic (PV) Systems. Generally, Solar PV systems that generate electricity from sunlight cost between $1.95 to $6 per installed watt. Typically, the larger the system, the lower price per watt. Large commercial systems are typically well below $3 per watt. Residential systems, because of their smaller size are usually somewhat higher.
Solar panels are currently selling for as low as US$0.70 per watt (7-April-2012) in industrial quantities; the balance of system costs (inverters, racks, wiring, marketing) made the median price in 2011 of large (>100 kW) systems $2.60/watt in Germany and $4.87/watt in the US.