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Electric Heat Pumps Are Key to Low-Carbon Homes and Buildings

An electric heat pump at a home in Edmonton. Photo: Roberta Franchuk, Pembina Institute

An electric heat pump at a home in Edmonton. Photo: Roberta Franchuk, Pembina Institute

Furnaces, boilers, and other heating equipment constitute one of Canada’s largest sources of carbon pollution. In fact, the burning of fossil fuels in homes and buildings — mostly natural gas and heating oil — accounts for around 12% of Canada’s greenhouse gas emissions. In order for Canada to reap the benefits of tomorrow’s low-carbon economy, we must transition away from these dirty fuels and toward emissions-free alternatives. Fortunately, solutions already exist — one of the most promising being the electrification of heating.

Electric heating technologies have been around for a long time, and in some parts of Canada electric baseboard heaters and water heaters are very common. These technologies are tried and true, and are also relatively clean, particularly in provinces such as B.C., Manitoba, and Quebec, whose supply of electricity is already low-carbon. However, these technologies are also relatively inefficient and therefore can be expensive to run, compared to popular options like natural gas furnaces. Thankfully, better alternatives exist today.

Heat pumps are the most promising alternative to fossil fuel heating for many kinds of buildings.  They have been around for decades, but have only recently been perfected for use in cold climates like Canada’s. These devices are much more efficient than electric resistance heaters, and can be used for space heating as well as water heating. Unlike older devices, modern heat pumps can deliver heat instantly and operate with very little noise, making them much more attractive to consumers.

Heat pumps can also be run “in reverse,” allowing them to provide cooling as well as heating.  As our homes and apartments become more efficient, with greater levels of insulation and airtightness, the risk of summer overheating increases, making the air conditioning abilities of heat pumps an important consideration for future-proof buildings.

The initial cost of a heat pump system depends on many factors, including the size, age, and energy efficiency of a home or building. Central heat pumps for space heating cost more than standalone “mini-split” systems, but can take advantage of existing ductwork for forced air furnaces. While a mini-split system may cost between $5,000 and $8,000, a central heat pump may cost $10,000 to $12,000 for a typical home, making the latter up to twice as expensive as a comparable gas furnace.

A modern “mini-split” heat pump unit. Photo: Synergy Home

A modern “mini-split” heat pump unit. Photo: Synergy Home

 

If a home or building is already heated with electricity, replacing electric resistance heaters and water tanks with heat pump technologies can lead to big electricity savings, and quickly pay back the initial investment. But replacing natural gas appliances with heat pumps is likely to result in smaller savings in many parts of Canada, where gas is significantly cheaper than electricity.

The low cost of gas remains a significant barrier to the adoption of electric heating, despite the environmental and efficiency benefits. One trend in the building industry that may help to address this issue is the increasing popularity of extremely energy-efficient buildings (like Passive House homes and apartments), which require so little energy for heating in the first place that a simple electric baseboard heater may be more than adequate, even on the coldest winter days.

Reaching Passive House–like levels of efficiency is feasible and increasingly affordable for new construction, but achieving this kind of performance is much more difficult for existing buildings. We know that many older buildings can realize big energy and cost savings through retrofits, and this should be encouraged. However, it’s unlikely that carbon emissions can be lowered to the levels we need in a cost-effective way without also switching the majority of buildings from natural gas to electric heating.

There are many benefits to electrified space and water heating — including the ability of a heat pump to provide air conditioning as well as heating, and the elimination of risks from gas and oil leaks. However, higher initial costs mean that these benefits and the carbon reductions that come with them are not enough incentive for many to make the switch. We need utilities, governments, and manufacturers to do more to encourage the adoption of these technologies and make them more affordable. In parts 2 and 3, we will explore some of these options.

By Dylan Heerema

Dylan Heerema is an analyst with the Buildings and Urban Solutions Program at the Pembina Institute, Canada’s leading clean energy think-tank. He lives in Vancouver. Learn more: www.pembina.org

This is Part 1 in a three-part series on electrification in the built environment.

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Nathan Wilson's picture
Nathan Wilson on Jan 2, 2018 3:22 pm GMT

Electric heat pumps are a good alternative to gas heat in rural locations. But in urban settings, district heat networks are a much better solution.

It is tempting to pretend the electricity that drives heat pumps is as clean as the average grid mix. But heating loads have very strong seasonal peaking, at a time of year that river flows (and therefore hydro power) are low, so we can expect the extra generation to power heat loads to be predominantly from fossil gas peaking plants, often low efficiency combustion turbines. This will get worse as more solar generation (with summer peaking) is added to the grid. Making matters worse, heat pumps operate at their lowest efficiency on the coldest days, when heat is most needed.

District heat networks (wherein heat is delivered to homes and buildings via a network of hot water pipes) are similar to electricity in that they can use any primary energy source; include those which do not emit CO2 or pollutants. So rather than offering electricity as the only energy carrier for zero-emissions energy, we should also be building district heat networks. There are many such systems today in European countries, with several (Finland, Iceland, Lithuania, Russia, and Sweden) getting half or more of their space heating from their networks.

Historically, heat networks have often been powered by coal, which has been cheaper than fossil gas. But geothermal energy, nuclear energy, and biomass have also been used. Biomass systems can be used with CC&S for a negative emissions energy source. Industrial waste-heat as well as Combined-heat-and-power systems have also been deployed.

Hot-water is also very suitable for thermal energy storage, which is cheap in tanks or even covered ponds. This can serve to smooth out evening demands peaks, or smooth the flow of energy from intermittent power sources like wind.

There are active programs to deploy new district heat networks today in the UK and in northern China; and China is even working on replacing its coal-based district heat sources with new non-polluting, super-safe, simple nuclear heat plants.

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