In certain types of proposals, broader impacts tend to take up even more space.
The first thing to do is contact the program director.
Consider whether the time spent preparing multiple proposals would be better spent preparing just one.
The different types of broader impacts are elaborated at several NSF Web sites (GPG Representative Activities, General Information, Division of Chemistry, ACS Showcase, Division of Materials Research (DMR), and DMR Highlight Request).
I suggest you go beyond explaining the broader impacts and applications in science/engineering, education of graduate students, publishing and presenting, and teaching.
This article provides suggestions and ideas about how to make your next National Science Foundation (NSF) proposal more competitive.
NSF provides proposal information in a variety of ways: Dear Colleague Letters, Program Descriptions, Announcements, and Solicitations.Not all research is hypothesis-driven, but a hypothesis helps focus a proposal and avoids the appearance of a fishing expedition.Provide enough detail for the reviewers to evaluate the quality and extent of the planned activities.This factor is critical for the success of renewals and future submissions.Before resubmitting a proposal, consider each of the reviewers' concerns and, if you want, contact the program director to gather further insight into how the proposal might be improved.Be very clear about what you expect to accomplish scientifically, why it matters, and how it's different from what others have done. Finally, ask yourself: If the project is successful, will it make an important impact?Explain in your proposal why you want to do the work–-your motivation and the scientific rationale.If you do not have documented expertise in the area, consider adding a co-PI who has that expertise or waiting until you have some preliminary results.A strong application always demonstrates an appreciation of the background of the field, with appropriate references to the results of others.Discuss any overlap in your project description, specifying what is new.If the problem you're addressing is complex, it may be imperative to assemble a multi- and interdisciplinary team.