Fuel cell or operating costs, photovoltaics and solar thermal?

Greetings,

I am currently working on the heating topic.
We are taking over my grandparents’ house and property, built in 1948.
I don’t even need to list the current condition here, since we are aiming for a complete renovation anyway.
A gas heating system is present.

Planned are the roof, facade insulation, new windows with triple glazing, underfloor heating in the bathroom, and a new heating system in general.

I am now pondering back and forth.

I came across the fuel cell heating systems from, for example, Buderus and Viessmann and find the technology really great, but I wonder if it makes sense to still depend on natural gas now. In the end, it is a great technology, but it is based on natural gas. Even my electricity would then come from fossil fuels, and I don’t really find that idea very cool.

Alternatively, I have considered simply replacing the old gas heating system with a condensing boiler and installing proper solar thermal and photovoltaic systems on the roof. Combined with a sufficiently large buffer storage and a battery in the basement, I should be able to get through the bright season emission-free. In winter, the condensing boiler would probably also start up along with the fuel cell to cover heating peaks.
However, the roof surfaces are oriented ONO and WSW, which is not optimal.
The plot is really very large, though. There would be the possibility to just place the modules somewhere in the garden.

I find the topic of micro-CHP otherwise really good, but in the end, the lights go out for me too when the gas valve is turned off.

Does anyone have an opinion for me?

Thanks

WSW is great after all. Electricity in the afternoon, when you are usually at home rather than in the morning. I would go for photovoltaic, I would skip solar.

And there are more options. Combined heat and power plant, wood log boiler, pellet heating, water-bearing fireplace in the living room, a small heat pump for the warm months.

Are you installing underfloor heating?

It seems to me you just skimmed through.

First of all: the fuel cell also counts as a combined heat and power plant, so your statement is somewhat confusing in relation to my question.
Otherwise, as I said, underfloor heating only in the bathroom, meaning mixed operation.
Solar thermal energy is important to me otherwise. I don’t want the gas heating to start for every little bit of hot water.

Thanks for the opinion on [WSW], I hadn’t seen it that way before.

I think of a cogeneration plant more as a chugging diesel in the basement, but yes, fuel cells are also cogeneration plants. Mixed operation means rather high flow temperature – so heat pumps (even as only part of the solution) are basically ruled out. The problem with solar thermal I see very clearly: it’s useless in winter, and in summer there is an excess of hot water. Solar thermal is actually just a relic from times when photovoltaics were still so expensive. And just to be able to build cheaply with a gas boiler in new buildings. Is wood – also in parallel – an alternative? You speak of a yard, do you have forest and equipment to take care of the wood?

I actually would. There are 4,000m² of forest on the property. But I am somewhat skeptical about fireplaces. The reporting over the past few months that a lot of pollutants are also released into the living area, especially fine dust, scares me. If in the end I have exhaust values in the living area like on a main road, I don’t find the idea of a crackling fire so appealing anymore. On the other hand, I want to design the renovation to be as age-appropriate as possible right from the start. Now it may not be a problem for me to chop wood. Whether I will still say that at 70, I don’t know. On the other hand, who knows what will be in 30-40 years.

Hm, I am undecided.

Of course, it would be nice if you could later switch a fuel cell heating system directly to hydrogen. Then the concept would at least be future-proof.

Anyway, thanks in any case for the impressions.

[..] but in the end my lights go out too when the gas valve is turned off.

Who the hell is supposed to turn off the gas valve?

It would of course be convenient if you could later convert such a fuel cell heating system to direct hydrogen. Then the concept would at least be future-proof.

Take a look where the hydrogen for such systems comes from: natural gas.

What is the lifespan of such fuel cell heating systems anyway? The only number I could find comes from Focus Online and mentions about 10 years, with a tendency to increase.

I don’t know what you imagine under future viability etc., but in 20-30 years a lot will have to be renewed anyway.

If topics like environment, future and independence are really important to you, the only sensible thing is to go completely with underfloor heating plus heat pump. Plus photovoltaics. Would that be feasible in your renovation / "complete refurbishment"?