Actually, it looks like most of it will be replaced with increased transmission efficiency, hydro, and other sustainable energy sources.
NY State already has a target to generate 50% of its energy from sustainable sources. Closing Indian Point is not likely to thwart that goal.
No, it will be replaced with natural gas, which has already replaced much of the coal fired generation in NY state. If you are frightened about gas pipelines, just wait until the 4 nuclear plants in NY state are phased out. There will be a pipeline building boom.
New England governors a couple years back gathered for an emergency meeting. Why? Because coal fired power plants were being phased out faster than the pipeline capacity for natural gas could be expanded. There was a real threat in 2014 that much of New England could be blacked out during cold winters. The price of natural gas spiked in New England due to the delivery restraints.
Hydro is already built out. You are not going to build more dams. The only other hydro option is to buy it from Canada. Vermont does this and the electric rates up there make NJ look cheap. Canada hoses Vermont (hydro is normally cheap.. in Buffalo, commercial hydro rates are around $0.04 per kWh).
Solar, wind, biomass? Here is a chart of what was generated in 2015 (source: Energy Information Agency):
Even if you could magically make solar and wind generate enough power (you won't), it has a fatal flaw. It is not 24/7 and it is not dispatchable (able to ramp up and down based on demand). Unless you plan to strip mine the planet for lithium, cadmium, and nickle, you will never have the storage capacity to make any of these "green" power sources viable. Gas turbine generators (which are not energy efficient compared to a combined cycle plant) have to be on standby to immediately fire up should it get cloudy or the wind changes speed. A baseload power plant (the big ones) can't adjust there output +- by more than 1% per hour typically.
Further, citing the potential benefits of nuclear doesn't make the problems of Indian Point go away.
It's too close to one of the most populated cities in the world; it's had lots of small leaks of radioactive isotopes into the Hudson; the cooling system kills fish in the Hudson; it turns out to be sited on top of a fault line.
Just about every power plant needs a place to dump heat (nuclear, coal, oil, combined cycle natural gas). You need a body of water or you need cooling tower. Oyster Creek is being shutdown in part because of the cost of building cooling towers.
As for radioactivity. Its tritium. There is a post somewhere where on JCLIST where this was covered. You can buy tritium glow in the dark jewelry. You will get far more radiation exposure from taking a airplane flight or maybe even from your granite counter tops in your home than you are from Indian Point.
While no one likes the idea of having a nuclear plant for a neighbor, if we really want another nuclear power plant, it ought to be somewhere else.
Nuclear will come back. NY state nukes are 40+ years old (i think they are all 2nd generation). Entergy put theirs through a service life extension program, which extended their operation for about 20 more years. When gas was expensive (up until about 2009) nukes were the cheapest 24/7 power out there (excluding hydro). Low gas prices is what is making the old nuke plants not worth running. Generation 3+ nukes are already being built and generation 4 are in the design stages.
Gas won't be cheap forever:
There are 8 LNG plants under construction in the USA (1 I think just went into operation) that will be exporting gas to Asia and Europe.
GTL plants (turns natural gas into oils, naptha, lubricants, methanol, gasoline) have been built, are being built, or are in the planning stages. Plus natural gas in an important chemical feed stock. Once oil prices go back up again, a lot of the gas produced (what isn't exported) will be turned into higher value products (gasoline, plastics, diamonds, jet fuel, diesel, etc). Prices will rise as a result and will hit the pocketbooks of anyone dependent on natural gas generated electricity.