I have always wondered about the idea of installing a windmill on my roof. Without highlighting the companies I have been looking at the figures quoted by those companies that provide the windmills.
One says:
How much energy does it generate?
The xxx will generate around 10,000 kWh per year in a good wind site of 5.8m/s average. This is equivalent to five low-energy houses’ electricity demand, or the electrical needs of a twenty man office (i.e. lights, computers, servers, printers, faxes and phones)
Lets apply a bit of physics to this. kWh is a KiloWatt Hour. It is a measure of energy rather than power. If you have a single bar of an electric radiant heater (1 kW) on for an hour that provides the energy of a kWh.
If we even the figures out to calculate the average power we have to divide 10,000 by 365 days and then 24 hours. That gives you a power of 1.1 kW. Not actually as bad as it could be, but clearly not enough to power a 20 person office unless most of the equipment is kept off. (even if you multiply it up to 5kW by working hours.)
There is then the issue of having an average windspeed of 5.8m/s.
Wind Power has its role, but energy efficiency is the top priority.
One says:
How much energy does it generate?
The xxx will generate around 10,000 kWh per year in a good wind site of 5.8m/s average. This is equivalent to five low-energy houses’ electricity demand, or the electrical needs of a twenty man office (i.e. lights, computers, servers, printers, faxes and phones)
Lets apply a bit of physics to this. kWh is a KiloWatt Hour. It is a measure of energy rather than power. If you have a single bar of an electric radiant heater (1 kW) on for an hour that provides the energy of a kWh.
If we even the figures out to calculate the average power we have to divide 10,000 by 365 days and then 24 hours. That gives you a power of 1.1 kW. Not actually as bad as it could be, but clearly not enough to power a 20 person office unless most of the equipment is kept off. (even if you multiply it up to 5kW by working hours.)
There is then the issue of having an average windspeed of 5.8m/s.
Wind Power has its role, but energy efficiency is the top priority.
Comments
In some locations they will work, but the typical suburban rooftop gets too little wind and too much turbulence. A wind speed survey is recommended.
But with £1600 turbines appearing in B&Q next month, there is a risk of a big mis-selling problem.
Regards,
Thomas O. Gray
American Wind Energy Association
www.awea.org
www.ifnotwind.org