¹There are three principal reasons why the US should develop their own domestic oil and alternative fuel resources.  ²Firstly, we clearly need to reduce our dependence on foreign oil sources, especially those in countries hostile to America.  ³However, we accomplish this is irrelevant; it simply must be done. Second, reliance on our own resources will encourage us to work harder to conserve what we have through the development of new types of fuels and engines.   ⁴This will also create new technologies and industries, consequently, the economy will be stimulated by new jobs and evolving infrastructure.  ⁵Third, all of this will work together to help our planet on a global scale by removing our destabilizing influence from countries who don't want us their and acting as a catalyst for more advanced and planet-friendly energy sources and technologies.

1. error: pronoun antecedent agreement

fix: There are three principal reasons why the US should develop its own domestic oil and alternative fuel resources.

2. error: numerical transitions

fix: First, we clearly need to reduce our dependence on foreign oil sources, especially those in countries hostile to America.

3. error: style with however

fix: However we accomplish this is irrelevant; it simply must be done. (no comma)

4. error: comma splice with conjunctive adverb consequently

fix: This will also create new technologies and industries; consequently, the economy will be stimulated by new jobs and evolving infrastructure.

5. error: confusion of there, their, and they're

fix: Third, all of this will work together to help our planet on a global scale by removing our destabilizing influence from countries who don't want us there and acting as a catalyst for more advanced and planet-friendly energy sources and technologies.