Solar equipment panels are generally warrantied for 25 years, but maybe 40 years.  Inverters are warrantied for 10-15 years, but can last 20 years.  Generally, panels face south & are tilted to match the local latitude.  Too weighty (2 – 4 ) lbs per square foot to be installed on a roof.  Could a mounted on a shade structure (let cows rest under it) or a rack on the ground.  Annual savings in TYLER are $784 per year or 11 cents.  CERTAINLY WORTH CONSIDERING!!