Even if it was 1000 tons, it would still only be about $300 worth of power.
Depends on the spot price of power. Power on the open market (where utilities have to buy it to provide to customers) changes every minute. Its usually cheap at night until the early morning, starts to increase, and then spikes around 3-4pm (+_30-60 minutes, depending on the country).
If you delivered power when it was most expensive (ie high demand) and consumed it in the middle of the night, the arbitrage may work out.