$1 billion is nothing for a country. In term of personal income or personal value, yes its a huge money. There are countries like India whose economy is already in Trillions of dollar. For such a huge economy country providing 1 billion is nothing. But again it does not mean that India is giving this money for free. This is loan money.
Remember the African billionaire wanted to invest something around 800 million dollars in Nepal. Nepal remittance is more than 3 billion dollars. Nepal is self sufficient country. Other than investing money is building big ass house in KTM, the Nepali people can invest those money in the country development. This does not mean that building a big house is not the economy but in a long run this does not improve the country's economy.
I have seen many people in Nepal who are ready to spend $100K to build a house. Instead of that, if only 100 of those people gather and invest that money in some project, this could be enough for big project in Nepal.
One thing I really liked about Modi is he is openly declaring that Nepalis are not doing anything for the development. He said u are laying on the pile of gold (water) and expect someone else to come and use that gold for you.
I researched about the money needed to build the Rs.29696 crs== 3 billion dollars. This is equivalent to the Nepal's remittance money. If those electricity produced out of those 5600 megawatt is sold, I bet Nepal would levitate from its current situation.
Although it seems little obscure, but it not out of the reach. I bet there would be countries flooding to invest in energy sector in Nepal if only Nepal is able to successfully complete one big project.