If we take the case of Germany vs Ireland as an example, the parity in Germany was helped by the PV subsidies which actually increased the cost of electricity:
[In Germany:] The per unit contribution to RES expansion increased from 1.33 cent/kWh in 2009 to 6.35 cent/kWh in 2016 leading, among other effects, to a residential electricity retail price increase from 21.4 cent/kWh to 27.7 cent/kWh which made self-consumption continuously more attractive altogether (Johann & Madlener 2014). [...]
Unlike in Germany and
many other countries, however, the Irish REFIT does not provide support for solar energy so far. Moreover, REFIT is levied by the Public Service Obligation (PSO), i.e. it is paid for on a per household rather than on a per unit basis. As a result, residential electricity retail prices (per kWh) have not increased to a similar extent. They amount to approximately 18 cent/kWh, which is much lower than in Germany.
So from this it seems clear that parity is more or less equivalent with higher prices. (Also of note, Ireland still has pretty high electricity prices compared to other EU countries; Germany has the highest.)
Also, as explained in a brief paper, but should be rather obvious, grid parity is an average of costs/prices. It's not a magic number at which all consumers switch. A given consumer may face a price that is higher or lower than that, depending on a good number of factors:
PV costs per watt vary due to many factors including
module, inverter, wiring & racking component costs,
mounting difficulty depending on roof type or ground
conditions, labor costs, and profit margins. Costs per kWh
in the first year of production will depend on insolation, tilt,
orientation, shading, local soiling conditions, and the many
smaller loss factors that affect real system performance.
Lifetime costs per kWh produced (on a levelized or other
basis) will depend on discount rates or cost of borrowing,
investor expectations, module & system degradation,
system availability, inverter replacement costs,
maintenance, etc.
All of these factors vary from site to site, contractor to
contractor, product to product, and investor to investor.
There may be an “average cost” but there will also certainly
be a range.
Similarly, the value of the savings from a PV system on a
per kWh basis varies significantly from customer to
customer (often even between those on the same rate
schedule) usually on both the production and consumption
side of the calculation. It will vary on the consumption side
because of the customer’s usage patterns with respect to
time-of-use electric rates, total consumption on a tiered
electric tariff, current demand charges and the customer’s
ability to eliminate or reduce demand charges with PV and
load management and/or rate schedule switching to a nondemand
rate schedule.
And since the parity is also driven by tax incentives (at least in the US case):
Variations across tax status (residential, commercial, nontaxable),
residential tax bracket, Alternative Minimum Tax,
Corporate vs. Non-Corporate business tax rates, and state
tax rates will affect system net cost, and the cost of energy
produced from identical systems.
Likewise for the expected return on PV/renewables investment:
There is also a range in customer expectations of an
acceptable rate of return that would entice them. This is
evidenced regularly in the financial markets all over the
world. As interests rise (or are pushed higher), investors
move towards money funds, CDs, bonds, and treasuries and
away from equities. Within many well-managed portfolios
there is usually some diversity among the assets owned.
High-risk securities need to be estimated to pay a higher
return to be worth the risk, yet investors still put some of
their money in “safer” investments for the security. It
happens within an individual, and it certainly happens
among investors. Some investors won’t touch high-yield
“junk” bonds while others love them.
The same will be true of how solar is viewed. Some see it
as safe enough that the yield is acceptable. Others don’t
know enough about it, don’t trust it, and will wait until it
becomes safer, or pays a better return before they are
attracted. This is the distribution of expectations in action. [...]
They author knows of two anecdotes where a large
potential customer could have earned up to 20% Pre-Tax
IRR on a large PV investment, but chose to pass because he
had another business that could do even better, and it was a
business that he understood, unlike PV, which was new to
him. The other case was a couple with a modest lifestyle
(their energy usage was in Tier 1 & 2 of PG&E’s rates), but
their response to the presentation of a 5.6% IRR was, “It’s
better then our savings account, let’s do it”. Each of these
customers had very different hurdles due to their varying
levels of comfort with PV, and their varying desires to earn
the highest rate or return they could.
The Daily Mail article you linked for the costs (which is describing a Stanford study proposing a vision for Green New Deal) is about a massive government investment program that would replace all fossil fuel.
In the U.S., this roadmap—which corresponds to the energy portion of the Green New Deal, which will eliminate the use of all fossil fuels for energy in the U.S.—requires an upfront investment of $7.8 trillion. It calls for the construction of 288,000 new large (5 megawatt) wind turbines and 16,000 large (100 megawatt) solar farms on just 1.08% of U.S. land, with over 85% of that land used for spacing between wind turbines. The spacing land can double, for instance, as farmland. The plan creates 3.1 million more U.S. jobs than the business-as-usual case, and saves 63,000 lives from air pollution per year. It reduces energy, health, and climate costs 1.3, 0.7, and 3.1 trillion dollars per year, respectively, compared with the current fossil fuel energy infrastructure.
I don't know how many PV panels are in those 100MW farms, but for the wind farms:
Most of the commercial-scale turbines installed today are 2 MW in size and cost roughly $3-$4 million installed.
250K of those is basically $1T just for those. And the Stanford study is proposing 5MW ones, which would probably cost double ($2T) etc.
16K solar farms of 100MW is humongous too. Wikipedia has a list of large farms... which is much shorter than even 1K, worldwide.
If we take the costs from the Pavagada Solar Park at $1B per 1000MW, we need another $1.6T for the solar farms (and they'd probably cost more to build in the US.) The market of solar panels may be oversupplied, but probably not to the tune of trillions of dollars of overstock...
So if you expect the market to produce the same total replacement, you'd have to wait a fair bit, as clearly some investments are better than others...