No more gas heating in the existing - PV Magazine Germany

... let's put it this way: this is anything but compatible with the Paris climate protection agreement.If we only become climate neutral 2050, we put our CO2 budget so strongly that we will land at a little over two degrees global warming after the current state of research.Many think that you can also compromise with the climate.In the end, however, this amounts to the question: What damage does our civilization survive?

In discussions about heating systems, one often hears: we could get climate -neutral faster than up to 2050, but this is unrealistic.Heating will probably be the last sector that is completely decarbonized.Therefore, it is still justifiable to incorporate efficient gas heating.What speaks against this argument?

We can just roll it over.An old building may need 30.000 kilowatt hours a year for heating.Natural gas causes 0.2 kilograms of CO2 emissions per kilowatt hour.The residents cut six tons of CO2 a year for building heating, even with efficient natural gas heating, out.In Africa, however, emissions are only one ton of per person per year for the entire life.That just doesn't work.

Can one also argue based on the 2050 climate goals that in 15 years it is no longer possible to burn as much gas as all the gas heaters burn in existence?

Around 2050 to be climate -neutral, you can install the last gas heating in 2025 if you run out of 25 years of service life.Some of the old gas heaters are in operation for longer, sometimes 30 years and more.Then you should install the last one this year.If we want to adhere to the Paris climate protection agreement, we have to become climate -neutral by 2035.That means we definitely need a installation stop for new gas heaters now.

Another argument is like this: It is unrealistic to achieve a renovation rate of four percent in the stock.There are no resources for that.Therefore, it cannot work at all to renovate all buildings by 2050 and to create the gas heaters.

I would say that too.But then the question is what you mean by renovation.If you pack every building, including insulation, roof insulation and so on, then of course it will be difficult.But if you only replace the heating everywhere, it works and is not an issue at all.

Current issue

We published the interview in the November edition 2020 of PV Magazine Germany in our focus "Installation questions".In the issue we answered some of the questions that turned out to be central in our installation survey.There you will also find a question and answer article regarding the use of heat pumps in existing buildings.

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We later burn green hydrogen or solarethane or wind methane in the newly installed gas heaters.What speaks against this plan?

Yes, if people are willing to spend three times for their gas bill, then this will certainly work.

Is this a forecast for the price of the green hydrogen in ten years?

Today green hydrogen costs between 15 and 20 cents per kilowatt hour;A natural gas delivery to the German border just two centers.Then the distribution network costs are added, which would also be used for the hydrogen.You will probably get the hydrogen price down a bit, but it will still be at least one factor of three higher.And we will not be able to provide it in Germany in the quantities.This means that you have to start concluding contracts with someone who builds up hydrogen production very strongly.

As an alternative to gas heaters, the heating of the houses can be electrified, for example with heat pumps.However, these are becoming more and more inefficient, the higher the flow temperatures are.In existing buildings, high flow temperatures are usually required.What is the solution?

Heat pumps usually have an annual number of three or more.For a kilowatt hour of heat you only need 0.3 kilowatt hours of electricity.Efficiency drops at very high flow temperatures.In the end, however, even electricity direct heating and a fan of heating are better than the gas heating.Because we will no longer have a gas in the future.Unless you make green hydrogen.You have at least 30 percent losses.So you need 1.3 to 1.4 kilowatt hours of electricity to produce a kilowatt hour of green hydrogen.If you heat the current directly, you only need a kilowatt hour of electricity for a kilowatt hour of heating energy.So the fan of heating is still better than the hydrogen heating.

A heat pump usually has a higher number of annual employment even at high flow temperatures than the direct heating, so it is even better.Economically, however, it becomes more expensive than with gas heating when the job becomes worse.

Unfortunately, the current fuel price does not reflect the discussion and thus favors wrong decisions when choosing heating.Fossil natural gas is significantly cheaper today than electricity.That is why we have to move the tax load from electricity to the natural gas as quickly as possible.

And what about the power consumption peak in winter that the heat pumps generate?Don't we need hydrogen for this?

When storing electricity, we cannot avoid the hydrogen.But if we have a gas boiler and operate with hydrogen, then we push the whole 30.000 kilowatt hours via the inefficient hydrogen chain.On the other hand, if you use an efficient heat pump, you need almost 10.000 kilowatt hours on electricity.For this we can use larger parts directly in winter.Of course it is not always available.But even if we covered 30 percent of the time with hydrogen, the need is still significantly lower than if we fire green hydrogen into gas heaters.