Method and apparatus for controlling power consumption

DETAILED DESCRIPTION The present invention relates to a method and apparatus for controlling power consumption of a facility, building or simply a collection of one or more devices, by load shedding when power consumption is above, or is predicted to be above, a power surge setpoint, but only if electrical power on the spot market cannot be purchased at or below a set amount.
The apparatus and method of the invention optimizes power usage by taking advantage of the buying of electricity as a commodity on the spot market.
For example, buildings in deregulated markets may negotiate electric power supply contracts for power consumption.
The contract will guarantee the building a fixed rate cost for an amount of kWs to be used over a time period, e.
g.
, one month.
Energy engineers for the building will first have to determine the amount of power they will use over the month.
They will then purchase this power in advance, thus obtaining a favorable kWh rate from a particular utility company.
Once a building exceeds its negotiated contract terms, the building can then buy power on the spot market.
For example, if a utility customer negotiates a contract that allows 10,000 kWh per hour at 3 cents per kWh, the monthly utility cost will be $30,000.
However, if for any reason, such as unexpected hot weather, the building uses 12,000 kWh one month, the building will pay the $30,000 on the negotiated 10,000 kWh, then must purchase the additional 2,000 kWh on the commodity spot market.
Using forecasting or predicting techniques during the month based on prior usage profiles, weather forecasting, and current usage, the excess electric power requirement can be predicted or projected.
Periodically during the month, electricity can be purchased on the spot market if an excess power requirement is forecast and the spot market price is currently lower than a price setpoint, or, electric consumption can be curtailed by load shedding if the spot market price is unattractively high.
If the spot market price is below the price setpoint the additional 2,000 kWh are economically justified based on the beneficial use of the additional power