<prompt> Translate the following text to EnglishGharama za ziada zinazohitajika kuzalisha umeme chini ya kila moja ya matukio manne ikilinganishwa na kesi ya kumbukumbu ni muhtasari katika mchoro wa 5, katika bilioni ya dola za 1999.  <response>: The incremental expenditures required to generate electricity under each of the four scenarios as compared to the reference case are summarized in Figure 5 in billions of 1999 dollars. 