Small Wind Electric Systems: An Arizona Consumer's Guide

Small Wind Electric Systems 15Obstruction of the Wind by a Buildingor Tree of Height (H)HRegionof highlyturbulentflow2 H02979307m2 Hand trees, and it needs to be 30 feetabove anything within 300 feet. Youalso need enough room to raise andlower the tower for maintenance, andif your tower is guyed, you mustallow room for the guy wires.Whether the system is stand-aloneor grid-connected, you will also needto take the length of the wire runbetween the turbine and the load(house, batteries, water pumps, etc.)into consideration. A substantialamount of electricity can be lost as aresult of the wire resistance—thelonger the wire run, the more electricityis lost. Using more or larger wirewill also increase your installationcost. Your wire run losses are greaterwhen you have direct current (DC)instead of alternating current (AC).So, if you have a long wire run, it isadvisable to invert DC to AC.Can I Connect My Systemto the Utility Grid?Small wind energy systems can beconnected to the electricity distributionsystem and are called gridconnectedsystems. A grid-connectedwind turbine can reduce your consumptionof utility-supplied electricityfor lighting, appliances, andelectric heat. If the turbine cannotdeliver the amount of energy you20 Hneed, the utility makes up the difference.When the wind system producesmore electricity than the householdrequires, the excess is sent or sold tothe utility.Grid-connected systems can be practicalif the following conditions exist:• You live in an area with averageannual wind speed of at least10 mph (4.5 m/s).• Utility-supplied electricity isexpensive in your area (about 10 to15 cents per kilowatt-hour).• The utility's requirements forconnecting your system to its gridare not prohibitively expensive.• There are good incentives for thesale of excess electricity or for thepurchase of wind turbines.Federal regulations (specifically, thePublic Utility Regulatory Policies Actof 1978, or PURPA) require utilitiesto connect with and purchase powerfrom small wind energy systems.However, you should contact yourutility before connecting to their distributionlines to address any powerquality and safety concerns. Yourutility can provide you with a list ofrequirements for connecting your systemto the grid. The American WindEnergy Association is another goodsource for information on utilityThe farther youplace your windturbine fromobstacles suchas buildings ortrees, the lessturbulence youwill encounter.