The Secretary of Agriculture (referred to in this chapter as the “Secretary”) is authorized and empowered to make loans, or refinance loans made or guaranteed by the Secretary under this chapter, in the several States and Territories of the United States for rural electrification and for the purpose of furnishing and improving electric and telephone service in rural areas, as provided in this chapter, and for the purpose of assisting electric borrowers to implement demand side management, energy efficiency and conservation programs, and on-grid and off-grid renewable energy systems.