http://www.anesi.com/ussbs02.htm#fdftoa
This report by the Secretary of War completed in September 1945 documents the effects of allied strategic bombing on Nazi Germany.
There are some interesting takeaways
1. The 1943 attacks on the ball bearing factories in Schweinfurt resulted in large losses of US forces but
"there is no evidence that the attacks on the ball-bearing industry had any measurable effect on essential war production."
2. The attacks on Germany's fuel supply was far more successful "These plants were producing an average of 316,000 tons per month when the attacks began. Their production fell to 107,000 tons in June and 17,000 tons in September. Output of aviation gasoline from synthetic plants dropped from 175,000 tons in April to 30,000 tons in July and 5,000 tons in September." and even the Nazis privately admitted the disaster this caused, on June 30, Albert Speer wrote: "The enemy has succeeded in increasing our losses of aviation gasoline up to 90 percent by June 22d. Only through speedy recovery of damaged plants has it been possible to regain partly some of the terrible losses." The effects of this were made clear:
"Consumption of oil exceeded production from May 1944 on. Accumulated stocks were rapidly used up, and in six months were practically exhausted. The loss of oil production was sharply felt by the armed forces. In August the final run-in-time for aircraft engines was cut from two hours to one-half hour. For lack of fuel, pilot training, previously cut down, was further curtailed. Through the summer, the movement of German Panzer Divisions in the field was hampered more and more seriously as a result of losses in combat and mounting transportation difficulties, together with the fall in fuel production. By December, according to Speer, the fuel shortage had reached catastrophic proportions. When the Germans launched their counter-offensive on December 16, 1944, their reserves of fuel were insufficient to support the operation."
3. The decision not to attack Germany's electricity supply was a big missed opportunity
"The German power system, except for isolated raids, was never a target during the air war. An attack was extensively debated during the course of the war. It was not undertaken partly because it was believed that the German power grid was highly developed and that losses in one area could be compensated by switching power from another. This assumption, detailed investigation by the Survey has established, was incorrect.
The German electric power situation was in fact in a precarious condition from the beginning of the war and became more precarious as the war progressed; this fact is confirmed by statements of a large number of German officials, by confidential memoranda of the National Load Dispatcher, and secret minutes of the Central Planning Committee. Fears that their extreme vulnerability would be discovered were fully discussed in these minutes.
The destruction of five large generating stations in Germany would have caused a capacity loss of 1.8 million kw. or 8 percent of the total capacity, both public and private. The destruction of 45 plants of 100,000 kw. or larger would have caused a loss of about 8,000,000 kw. or almost 40 percent, and the destruction of a total of 95 plants of 50,000 kw. or larger would have eliminated over one-half of the entire generating capacity of the country. The shortage was sufficiently critical so that any considerable loss of output would have directly affected essential war production, and the destruction of any substantial amount would have had serious results."
So what if the allies had chosen to go after Germany's fuel supplies at an earlier date and attacked the electricity grid instead of ball bearing factories?