Eco-sheet Gas vs Electrical Heating


Concerns about CO2 and climate change are greater than ever. Residential heating is responsible for a considerable part of CO2 emissions that go into our atmosphere.

The objective of this case study is to compare the environmental impact of a heating system using a gas conventional boiler and other using electrical heaters at the point of use. The simulations were made taking into account the conditions for a normal house and a low energy house. Several electricity generation mixes were also used in order to assess the impact of electrical heating in different countries.

The results show that electrical heating has great advantages when clean electricity generation is in place, e.g. using renewable energy sources or nuclear energy.


 

Comments

Hans De Keulenaer's picture

There are certain elements not taken into account in the study, which we will probably never be able to take into account:

  1. Heating systems have a different environmental profile, but also a different cost. It would be interesting to compare a gas-heated and electrically heating house at the same cost, where the cost differential is invested in increased insulation.
  2. It would be equally interesting to investigate this cost differential in green generation methods.
  3. A further refinement at the systems level would be to take the externality of intermittency into account. For example compare the option of battery storage, or via hydrogen with demand management.
  4. The next logical step would be to take this to the passive or even zero-energy home. But probably gas heating will cease to be an option in houses with very low energy demand. Otherwise, modelling the intermittent operation of a gas boiler to provide small heat pulses into the building shell may be a challenge.
By Hans De Keulenaer 27/09/2007
Benoit Dome's picture

Oil heating

  • boiler 2,000 ~ 3,500 euro
  • condensing boiler 4,500 ~ 5,700 euro
  • tank few thousand euro
  • water distribution + radiators

Gas heating

  • boiler 1,700 ~ 2,300 euro
  • condensing boiler 2,100 ~ 5,900 euro
  • water distribution + radiators
  • system cost ~ 90 euro / square meter

Heat pump

  • 10,000 ~ 12,500 euro
  • 20% extra cost for radiators

Electric heating

  • up to 100 euro per radiator installed
  • ~ 1,500 euro for 4 kW storage heating installed

By Benoit Dome 04/10/2007
Benoit Dome's picture

the submitted costs or budget don't actually included various points for discussion eg gain of space, thickness of the floor gained in the case of renovation, ...
we have to try to make a good list regarding all those topics and review it regarding construction and environemental views

By Benoit Dome 22/10/2007
Hans De Keulenaer's picture

Sergio:

2 further considerations:

  • the eco-sheet is valid for the weather in Northern Europe, where relatively low negative temperatures need to be catered for during the winter months. In Mediterranean climates, which have both cooling and heating requirements, and less extreme temperatures during the winter month, it will be hard to do better than the air-to-air heat pump.
  • when choosing electricity or gas for space heating, the choice for cooking and hot water heating is likely to be electric or gas as well.
By Hans De Keulenaer 22/10/2007
Anibal T de Almeida's picture

Dear Sergio

This is an interesting topic. In my group we have investigated this issue a few years ago and wrote a paper published in the Journal Energy and Buildings, November, 2003. Available here: doi:10.1016/j.enbuild.2003.11.003 

Its not only the energy carrier, but also the conversion technology which is the decisive factor.

In my opinion neither makes sense electric resistance heating, nor gas boilers. It is just not the fuel cycle. Gas will become increasingly less available...

The solution is (after all cost-effective improvements have been made to the building envelope) to use either biomass and/or high (significantly higher than 3) COP heat pumps.

In my home I have heat pumps with a nominal COP of 4.3, meaning that the seasonal average value is probably larger than 5. Gas boilers become hopelessly wasteful by comparison.

By Anibal T de Almeida 26/10/2007
Hans De Keulenaer's picture

Since gas and electricity are priced differently as energy carriers, it is plausible that consumers will set their heating systems to a higher comfort level for the lower priced energy source. After all, the economic law of demand still applies - lower price = higher demand.

By Hans De Keulenaer 08/11/2007
Sergio Ferreira's picture

Hans,
I agree that in some cases low price = higher demand, however, we can find many examples where a higher price is the result of a higher demand. In the particular case of energy (in a broad sense), that applies!

Maybe price is still a conditioning factor in our energy options, but the environmental concern, the hurdle are other factors that have a high weigh in our decision nowadays...
I live in an all electrical house. It was not my choice, but it is very practical, safe, and provides me a high level of comfort.
In the future, if I have to choose, I will probably choose an all electrical system again, instead of having an electrical installation plus a biomass boiler plus a gas cooker!
One contract, one invoice, less hurdle, more comfort and safety. And with the increase of green electricity, probably far less environmental impacts.

By Sergio Ferreira 02/01/2008
Jacques Dubost's picture

Profile from energy carrier depends on use : Electrical heating is mostly used in winter periods with peaks in the morning and in the evening.So the power generation mix to be used is neither base-load nor average mix, but rather semi-base or peak power generation.

As an example, a newly installed electrical heating in France would typically use electricity generated by a mix of 67 % natural gas (combined cycle + gas turbines), 10 % oil, 13 % coal, and only 10 % nuclear.

The CO2 emissions for electrical heating will be around 600 g CO2/kWhe, which is more than twice the emissions from gas heating with a condensing boiler.

By Jacques Dubost (not verified) 03/01/2008
Hans De Keulenaer's picture

Interestingly, the national energy efficiency action plan for Denmark (p12) mentions that for low-energy buildings, the ban on electric heating will be lifted. Also the requirement to connect to district heating or natural gas systems will no longer apply in this case.

This corroborates the point of this article, that for low and ultra-low energy dwellings, the heating systems may be quite different from today's. 

By Hans De Keulenaer 24/01/2008
Hans De Keulenaer's picture

It's important to distinguish individual & aggregate demand. An individual consumer has probably a quite inelastic (downward sloping) demand curve, so the demand increase from the lower price of gas versus electric heating (per kWh) is likely to be low, unless the price becomes so low that the consumer stops caring.

The current rise in energy prices is probably due to an income effect on the aggregate demand curve, pushing prices up the supply curve. At least that's what the conventional theory says.

But in this context, let's also remember a quote that Amery Lovins likes to use: "The technical and implementation options -- the everyday work of energy efficiency practitioners -- are mostly unknown, however, to those econometricians who lie awake nights worrying about whether what works in practice can possibly work in theory."

By Hans De Keulenaer 24/01/2008
Hans De Keulenaer's picture

Thanks Jacques for your comment. This is a consequence from electrical system operation which we are discussing in the future power systems group.

In low energy dwellings, the heat demand can be postponed quite easily without affecting comfort level, so that it does not need to take place during peak demand.

Using accumulation heating, it should be possible to acquire the daily heat budget at base load (or periods of high wind & no electricity demand). 

 

By Hans De Keulenaer 24/01/2008
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