Natural gas in the home
Residential users fall into two main categories :
- Individual houses
- Apartment buildings
For each of these categories, the main domestic uses of natural gas are :
- hot water
- and even NGV transport with home filling of a NGV vehicle
In individual houses, there are individual systems for heating and hot water. In apartment buildings, there are different possibilities:
- Individual apartments may produce their own heating and hot water,
- heating and hot water production may be centralised.
There may also be other variants, e.g. : heating may be centralised and hot water individual, etc.
Below, we describe the appliances employing natural gas for heating, hot water, cooking and NGV transport for each of the categories: “individual house” and “apartment building “.
Natural gas appliances are economically competitive and help make homes energy-efficient. The use of natural gas is fully compatible with the most efficient and up-to-date methods of building insulation. The latest innovations in gas appliances are increasingly efficient and consistent with the new environmental policies introduced in France and Europe (3X20 Package, Grenelle de l’Environnement). Moreover, with the gradual introduction of the new French Thermal Regulation RT 2012 for new buildings, natural gas’s market share for domestic use has been growing significantly since 2010 in France.
All domestic natural gas appliances can also use biogas (gas produced from agricultural or household waste).
In 2010, the proportion of individual houses in France with natural gas heating stood at 34% (compared with 35% electric and 22% oil). The number of homes with natural gas heating continues to rise: 3.6 million individual houses in 2000; 5.2 million in 2010. Many are being converted, in particular from oil to gas heating.
Note that the direct use of natural gas for heating helps to reduce CO2 emissions. Indeed, for equivalent heating conditions, natural gas produces fewer CO2 emissions than coal or oil – or even electricity: in cold snaps the electricity used to supply electric heating systems comes from nuclear and hydroelectric sources, significantly reinforced by thermal production methods that produce CO2 emissions with an energy efficiency of between 40 and 60%. It would therefore seem wise to eradicate these efficiency losses in electricity production by using natural gas directly in homes.
Domestic uses of natural gas – Individual houses
For heating, gas is used in boilers. The boiler is connected to a system that circulates a heat-bearing fluid (generally water) which supplies radiators or heated floors. Since the 1990s, condensing boilers have been increasingly successful. Their design combines high energy efficiency (recovering the energy contained in the steam produced by the combustion process) with simplicity and convenience. Boilers are also used to produce domestic hot water. In certain indoor installations, hot water is produced by a water heater that is independent of the heating system. Hot water can be obtained from an instantaneous water heater or a hot water storage tank. These appliances are either fitted with a chimney outlet pipe or an outlet valve running through the house wall.
Gas is also traditionally used in cooking. For food preparation, gas is used to fuel cookers comprising a cooktop and an oven. The oven can be a separate unit from the cooktop. Cooking appliance manufacturers have developed a range of products that offer a combination of convenience and safety. Gas offers a wide range of food preparation settings: from low-level simmering to high-temperature cooking.
Since late 1990s, many innovations have come onto the market.
Combining solar thermal collectors with natural gas heating offers an all-year hot water and/or heating installation in which a significant proportion of the energy comes from rooftop solar thermal collectors. The gas acts as a standby and backup for renewable energy if there is insufficient sunlight, and in the case of hot water to ensure adequate comfort levels.
Boilers can also be fitted with a system that produces electricity at the same time as heat. These micro co-generation boilers are called ecogenerators. The electricity is produced either by a thermodynamic mini-engine (Stirling engine) or by a catalytic system.
Gas can also be used as a fuel for vehicles. This application is similar to domestic uses, because a light natural gas-powered vehicle can be charged from a mini filling station in the garage of the house. In some markets, light vehicle manufacturers supply a range of natural gas-fuelled vehicles (Natural Gas Vehicles : NGV). NGV powered by compressed natural gas (consisting essentially of methane) should not be confused with LPG vehicles, which run on liquefied petroleum gas (butane, propane).
NGV emit less CO2 per kilometre than vehicles powered by other fuels and are no different in their everyday performance from today’s standard petrol or diesel vehicles.
In apartment buildings, individual apartments can have their own heating and hot water appliances, in which case they are the same as those used in individual houses. So when describing apartment buildings here, we will mainly refer to communal heating and hot water systems. It should be remembered that some apartment buildings may have centralised heating, but individual hot water production.
Domestic uses of natural gas – Apartment buildings
Apartment buildings that use natural gas for heating are fitted with systems for circulating a heat-carrying fluid (generally water). The water is pumped between the central boiler (generally located in the basement of the building) and radiators or heating floors in the apartments. The boilers are more powerful than single dwelling boilers, although they incorporate the same technological advances (condensing boilers, the strictest operating conditions and emission standards).
These central boilers also produce hot water, which is distributed to the apartments via the building’s internal distribution network (except where apartments have individual hot water appliances).
Various innovations are being developed to equip buildings for heating, hot water production and even electricity production.
In newer apartment buildings thermal solar panels are increasingly being used in combination with natural gas boilers so that heating and hot water can be provided all year round, even when the sun is not shining. Natural gas is combined with a renewable energy, providing the necessary flexibility and additional comfort and convenience.
Some buildings are fitted with natural gas heat pumps which increase the energy efficiency of heating and hot water installations by drawing heat from the environment using a natural gas-powered heat pump system.
Some buildings are fitted with cogeneration systems (cogeneration engines). This system produces heat for heating and hot water along with electricity which can be consumed locally but which is generally fed back into the power grid.
The latter two systems – natural gas-fired heat pumps and cogeneration – are more suitable for larger apartment complexes, where they reinforce and optimise economic efficiency.
The use of natural gas as NGV fuel for private vehicles is also an option in apartment buildings. Garages can be equipped with individual or shared systems for filling residents’ private vehicles with natural gas. Since apartment buildings are usually located in towns, residents can also opt for fast refilling in service stations that sell NGV fuel.