Electric pressure washers save fuel and can be used indoors.  For industrial applications check out the DeWALT DXPW1200E 1200 PSI @ 2 gallons per minute pressure washer.  It uses a 120 volt high induction motor and a maintenance free industrial triplex plunger pump.  The 1-1/4″ steel frame is designed to last on the job and the big tires get you through any terrain. It includes 5 quick connect nozzles:  0°, 15°, 25° 40° and soap.  In our tests the unit worked well for low pressure applications.  We would however  like to see a 50′ hose instead of the included 25′ hose.  DeWALT covers this product with a 1 year warranty.  For more power check out some other pressure washers we have reviewed.