..."stimulus" and "investment" this way:

--stimulus is the sort of short-term spending you do in a recession to immediately create economic demand. the spending needs to impact the economy as quickly as possible, and it should be large enough to have a substantial economic effect (a mistake, according to paul krugman, that caught up obama in his march '09 stimulus bill). this is the classic "fix the roads, fix the sewers" kind of spending.

--investment spending occurs over a period of years or decades and is not related to the emergent needs of the economy. instead, the investment is intended to have a long-term impact on the economy. that is the sort of spending that is represented by rebuilding the electrical grid into a "smart" grid and the installation of all that other new green energy infrastructure. the long lead times required for this sort of spending make it less favorable for use as an emergency stimulus for the economy--even though this is exactly what we need going forward.

as for the tva and bpa references: the idea was to demonstrate that there is precedent for the federal government owning generation, transmission, and distribution assets. there is no reason why those can't be green assets, such as windmills--and there is no reason, in the end, why we should subsidize some company's desire to sell us expensive green power when we can own inexpensive green power that we sell ourselves.