The estimated energy that can be recovered and utilized on the surface is 4.5 Ã 10 exajoules, or about 1.4 Ã 10 terawatt-years, which equates to roughly three times the worldâs annual consumption of all types of energy. The amount of usable energy from geothermal sources varies with depth and by extraction method.
1 Keep records for 7 years if you file a claim for a loss from worthless securities or bad debt deduction. 2  Keep records for 6 years if you do not report income that you should report, and it is more than 25% of the gross income shown on your return. 3  Keep records indefinitely if you do not file a return.
How Long To Keep Records. You must keep your records as long as they may be needed for the administration of any provision of the Internal Revenue Code. Keep records that support an item of income or a deduction appearing on a return until the period of limitations for the return runs out.his chapter explains the benefits of keeping records, what kinds of records you must keep, and how long you must keep them for federal tax purposes. Tax records are not the only type of records you need to keep for your farming business.