At least in the UK, the solar subsidies were set in stone for 20 years at the time of installation; so even though new solar would get little subsidy I'm still getting the rates from five years ago when I installed my system.
Of course this makes the value proposition for moving power into the grid much worse, but it changes precisely nothing for power that you use from your panels (you are still getting 20 cents worth of power from a panel that has already been paid for by you).
For this reason it is best to rely on the subsidy as little as possible and maximise the power you use directly from the panel, either by changing your habits or by storing the power for later (in a battery). Sadly using batteries adds additional costs to this picture and is not currently worth it at all, even without subsidies.
How does that work? A new government can change the law and decide otherwise, well at least that is what they do here.
Given that there is not yet (as far as I'm aware) a tax on kWh used entirely from solar panels (ie not coming from or going into the net, but taken directly from panel generation) it should not matter very much whether or not the government decides to subsidise you. Do not count on a solar panel installation company to make such complicated calculations for you, they are most busy with either sowing unrest about government regulations or (more likely) giving you a fair-weather calculation that involves subsidies forever.
But that is quite hard for most people to accomplish, most people are not at home during daytime when the panels generate most. The time my washing machine actually consumes energy warming up the water is relatively short.
The largest part of the power consumption of my home owners association is spent on lighting, the other part on the elevator which is most of the time just idling and peaks when someone uses it.
Batteries are inefficient and still expensive. You could warm up a boiler for hot water during day but I think that is done more efficiently with a heat collector instead of pv->electricity->heat. You can warm up your house, but you have to have very good insulation otherwise most energy is lost by the time you get home.
Anyway, in practice the change in policy can have a huge effect in return on investment time.
Anything can happen in 4 years.
Do you want to be part of the problem, or part of the solution?
To get to my job.
> Why leave the house?
To get to my job.
> Why get a job?
So I can buy food and I won't starve.
> Why rent an apartment?
No clue, renting does not make sense to me, I bought.
> Anything can happen in 4 years.
Yes and you have to take that into account, make a risk analysis, think about the consequences and decided if it is worth it. Especially for long term investments. The chance my government will change the subsidy is certain (already announced), the consequences still unknown but they can turn out really bad. The chance they will turn out bad is large now that the two climate skeptic parties + the party that chooses economy over climate have a majority in the polls.
> Do you want to be part of the problem, or part of the solution?
Most people just don't have the money to spend on a problem which will not affect them for the next 10 years, unless it will benefit them.
With all due respect, the parent did not ask about the "most people". The question was about you.
Our plan was to use the maintenance fund to fund the panels. Money from the fund is not needed for the next 10 years, when the bitumen roof will need to be replaced. By that time the panels should have returned on its investment. Now let's say the laws will change and the panels will not return their investment, then all of a sudden everyone needs to put in a few k for replacing the roof, which, most of my fellow residents don't have.
About me: If I would have to choice to buy panels which will not return on it's investment, I'd probably spend the money on an electric car, solar thermal collector, heat pump, insulation, shower heat ex-changer or anything else which has a better roi.
Wow, I hope they like being under water.
But even then, the government changes at least every 4 years, how am I supposed to make a long term investment - (solar takes about 10 years for return on investment around here, with current regulation) - if I don't know if I will be screwed by the next administration? Especially now that the support for the "climate change denial party" is growing.