Fundamentally, intermittent and non synchronous in a grid context are "junk" power.
Rooftop solar:
Essentially it boils down to this, if you want to go "off grid", do it! But please don't expect everyone else to help you pay for doing so.
The only people who can actually make use of rooftop solar:
1. Firstly, single family home owners.
2. Secondly, single family home owners that can afford $20,000 plus to have a proper system installed
So what does that mean?
http://vancouver.ca/files/cov/housing-characteristics-fact-sheet.pdf62% of homes in Vancouver are apartments
Only 15% of homes in Vancouver are single family detached houses.
Of that 15% that are single family homes, a portion are rented homes, and many homes have secondary suites not included in the apartment total.
So maybe 12% of Vancouver homes can really take advantage of rooftop solar. Now you have to figure that a fair number of those homes don't have the right orientations or big mortgages that mean the owners don't have extra cash to buy a solar system.
So reality is that only the the top 5-10% of Vancouver residents by wealth can take advantage of solar rooftop - if they want to.
Every time a solar rooftop system gets hooked into the system, it costs BC Hydro money - on an ongoing basis. That pushes up rates for everyone.
So everyone else in Vancouver pays extra so the wealthiest 5-10% can reduce their hydro bills with rooftop solar. That's a wealth transfer from the bottom and middle to the top. That wealthiest top 5-10% can avoid doing that by paying extra for a couple of Tesla powerwalls, and a back up generator. Probably push their cost up to $35,000? Fine if they want to do that - completely disconnect from the grid.
What isn't fine is the rest of us paying extra so that the wealthiest can avoid hydro bills!
Rooftop solar, where widely adopted due to soaring electricity prices, is hitting the wall in some places
http://reneweconomy.com.au/utilities-move-to-kick-rooftop-solar-off-the-grid-15250/Arizona and other states are chopping the net metering rate for rooftop solar AND imposing transmission charges on what excess is allowed to sold.
So the big subsidies for rooftop solar are going away slowly, and when the subsidies disappear, installations plummet - because on their own, solar rooftop only makes sense for grid customers if the grid rates are very high - or the rest of us pay out for subsidies.
Commercial scale solar:
Commercial scale solar only produces at capacity in good weather, in the right seasons, and during daylight hours. That creates a "hole" in the electricity markets for other producers every day.
It also means that commercial scale solar is unable to supply electricity for peak evening demands, as solar ramps down to nothing during the evening just as demand is ramping up.
That mean that for the peak demand you have to turn either to other sources, or provide massive amounts of storage.
So what?
Firstly, if you go storage, that storage is costly to build, and costly to maintain. That storage also comes with efficiency losses. The most cost effective mass storage is pumped hydro - and it is only 80% efficient. Battery storage on the necessary scale is hugely expensive to build and very costly to maintain, and even less efficient. (Anybody ever had a battery that lasts forever??) If you are going to go pumped hydro (the most effective route) with its dam and reservoirs - and you have option of hydro electric facilities, why bother with all that nonsense in the first place? No matter how you slice it, the storage option is going to cost big money and add capital, financing, transmission, and operating costs.
Secondly, if you decide to go with other sources - best is a natural gas turbine generation facility - to ramp up peak demand supply, commercial scale solar has destroyed the base economics of that facility.
If you invest, say $200 million in a natural gas electricity plant, you will have a lot of fixed cost. In order to ensure that you can meet spikes and peaks in demand, you will need to staff it 24/7. The least efficient part of your generation cycle will be starting it up, and it costs money to shut it down as well.
Ideally NG plant want to sell as much electricity as you can to offset those costs. Now because of commercial solar, you are shut out of 1/2 to 2/3 of the market every day. That means you are going to have to get your ROI from about 40% of your potential. The only way you can achieve that is to up the price for the electricity you do get to sell. 100/40 = 2.5... so now that means instead of say $60/MWh, you need to charge $150/MWh. (That's assuming you don't have the double whammy of wind power to complicate things, what if the wind happens to be blowing during your short window of peak demand sales? It will further diminish your available market share. That has a big further effect. If that wind blowing chops your potential to 30% of the market, then the number is 100/30 = 3.333 x $60 = $200/MWh).
That gets further exacerbated seasonal factors.
http://www.brattle.com/system/publications/pdfs/000/005/348/original/Retail_Costing_and_Pricing_of_Electricity.pdf?1471279927 see page 34 for California seasonal variation.
So what happens with commercial solar is that it can not supply peak demand, and also ruins the basic economics of other sources (just as wind does).
So when you need that alternative source to cover the inability of solar (and wind) to meet peak demand - the alternative source becomes hugely expensive. That's why Costa Rica sees very reasonable and affordable electricity prices during the day, but a nasty $.36/kWh during peak evening hours.
This is an interesting calculation that puts the real world economics into perspective:
https://wattsupwiththat.com/2016/04/01/a-solar-power-plant-vs-a-natural-gas-power-plant-capital-cost-apples-to-apples/Wind power is somewhat less problematic, because sometimes the wind blows during peak demand periods - but certainly not reliably, nor predictably. It has the same economically destructive effects that drive up grid costs and cause all sorts of problems - and needs the same two potential solutions of either costly storage or high costs for alternate sources.
In the end, a predictable, renewable and reliable source like site C is far, far and away superior to wind and solar in a grid context.