exhibit 10. 21 sales contract seller : renewable environmental solutions, llc contract no. 0901 530 north main street carthage, missouri 64836 customer : carlisle power transmission products, inc. 2601 west battlefield road p. o. box 3258 springfield, mo 65807 effective date : this agreement shall become effective on the first day following the completion of commissioning of the boiler system conversion ; i. e., when the boiler is fully capable of continuously burning renewable fuel without interruption or undue operator attention. commodity : renewable diesel fuel. quantity : approximately 1. 35 million gallons annually. contract price : 1 ) during the period beginning on the effective date and continuing for one year : $ 0. 59 / mmbtu below the monthly delivered natural gas cost or the monthly u. s. residual fuel oil retail sales by all sellers price, whichever is lower. ( this price reflects a 23 cent per mmbtu discount for renewable fuel purchase and a 36 cent per mmbtu payment to customer for repayment of conversion capital ). 2 ) during the period beginning immediately after the expiration of one year from the effective date and continuing for one year : $ 0. 57 / mmbtu below the monthly delivered natural gas cost or the monthly u. s. residual fuel oil retail sales by all sellers price, whichever is lower. ( this price reflects a 21 cent per mmbtu discount for renewable fuel purchase and a 36 cent per mmbtu payment to customer for repayment of conversion capital ). pricing basis : customer ’ s invoice for natural gas delivered to customer ’ s facility, including all applicable taxes and fees, if any or the monthly u. s. residual fuel oil retail sales by all sellers price, whichever is lower. pricing method & adjustment : each delivered load will be invoiced at the contract price based on the lower of the customer ’ s invoice price for natural gas for the prior month or the monthly u. s. residual fuel oil retail sales by all sellers price. each quarter, all purchases for the period will be adjusted to “ true - up ” for the actual natural gas cost for the period or the monthly u. s. residual fuel oil retail sales by all sellers price, whichever is lower. payment terms : net 45 days for all delivery invoices. true - up invoice amounts to be either added or deducted from the next applicable delivery invoice amount. delivery terms : delivered to customer ’