In Alberta, Canada, we heat our homes with natural gas while powering our homes with grid-supplied electricity. Why do we heat our homes this way? Because natural gas is cheap. The raw cost of natural gas is roughly six times cheaper than electricity.
Then, why do we power our houses with grid-supplied electricity (it’s six times more expensive!)? I’m not certain about the answer to this question but after spending a year building houses as a site superintendent I’ve come to understand that the residential construction industry in Alberta is far too profitable to be driven by innovation. With respect to incorporating new technologies, we’re only barely starting to incorporate tech that was available 30 years ago. For example, heat-recovery ventilators (which transfer the heat from exhaust air to fresh air, giving you pre-warmed fresh air and saving lots of energy/money) have been used in Alberta since the mid-1980s and are only recently are beginning to be included in non-self-built homes. What’s even more troubling is that quadruple-pane windows (windows are the 3rd–largest source of heat loss in a house, after walls and roof), which have been widely available in northern Europe for over two decades, are not available at all. This lack of progress suggests that the reason we depend on grid-supplied electricity is because we don’t know any better; we just keep building and fail to ask if our current practices are the best one can do.
What are the alternatives to grid-supplied electricity? Continuous-use gas/liquid fuel electricity generators, photovoltaic panels, wind turbines, geothermal power, water turbines (from nearby streams), etc. For this post, I’ll be entertaining continuous-use natural gas (NG) generators: a NG pipeline delivers the fuel to power an external generator which, in turn, supplies the house with electricity. As more electricity is required, the generator works harder and consumes the fuel at a faster rate.
Continuous-use NG generators have become refined over the past few decades. Most are now equipped with liquid-cooled noise-reducing enclosures so that noise and weather exposure are not a problem. In addition, they operate at efficiencies well above anything a coal-fired plant can offer (up to 90%, as opposed to roughly 30% from a coal-fired plant). Producing electricity through combustion also produces heat as a by-product, and though a coal-fired electricity generation plant cannot deliver the heat by-product to you, an onsite generator’s coolant system can be coupled to a house to supplement heating during colder months.
There are many advantages to having onsite electricity generation: it is less expensive, more efficient, more effective, more redundant, more luxurious, and most importantly, it’s safer.
Cost considerations of NG continuous-use generators include the installation, maintenance, and fuel consumption. Because NG continuous-use generators produce electricity at a fraction of the cost of buying grid-supplied electricity, the fuel cost is substantially lower. Based on the energy requirements of a typical Albertan home, the NG continuous-use electricity generation system would save over $500/year based only on the difference in price of grid-electricity and NG (for the last 4 years). And, if grid-electricity was fully disconnected to eliminate the delivery fees (typically ranging from $30 to $60 per month), an additional $500/year savings would result. The initial up-front cost of equipment would be roughly $12-17K while annual maintenance is about 5% of the equipment costs. However, in order to compare the installation cost of the NG-powered house to a grid-powered house, we need to understand how such a system would impact the other mechanical systems within the home.
If a home is able to produce electricity from NG, it no longer makes sense to have a furnace. Furnaces are costly, large, slow, noisy, produce vibration, are inefficient, introduce a carbon monoxide health hazard, and are difficult to zone. Instead, homes would be heated using an inexpensive special electrical wire under the flooring that evenly warms the floor to a set temperature. This wire-based heating system is easier and less costly to install (saves roughly $3K-5K versus furnace-based systems), would not take up any space within the home, can very rapidly heat a home, would generate no noise, would not cause vibrations, is 100% efficient (yes, 100%), does not generate any carbon monoxide or other hazardous chemicals, and can be very easily zoned. This wire-based system would offer unparalleled luxury compared to the furnace-based heating systems. For example, every room in a wire-heated house can cost-effectively have its own thermostat that works by outputting continuously optimized heat flow to the room, avoiding the on-off cycles of furnace-based heating. If the thermostats are tuned to an overall smart-home system, it becomes possible to vary heating to specific zones. For example, one could reduce heating to the kitchen and living room between 1AM and 6AM or adjust a single bedroom to be warmer or cooler (or variable for those who prefer cooler temperatures at dusk and warmer temperatures at dawn) without impacting the entire house. With regards to fresh air circulation within the home, this process would be handled by an energy-saving heat recovery ventilator (HRV), as is standard in most modern energy-efficient homes (furnaces only cycle the old air while HRV systems actually distribute fresh air).
In regards to water heating, NG-powered homes would also operate using a different approach. Instead of a centralized water heater, an inexpensive instantaneous electric water heater is installed at each tap where hot water is needed. Many versions of these electric water heaters allow the user to digitally set the temperature of the water coming out of the faucet, all while requiring the input of a single water line. Therefore, instead of running two water pipes to each tap (one hot and one cold), only a single cold water line is run, which either turns into two lines (hot and cold) right at the faucet, or simply outputs the desired temperature via a single line. This method saves on plumbing materials and labour, generates an unlimited supply of hot water, and delivers the perfect temperature water instantaneously (rather than forcing the user to dump the old water while waiting for the temperature to catch up). By eliminating combustion-based hot water heating, this system is actually safer (no threat of carbon monoxide exposure), more efficient (100% efficient), produces no noise, take up almost no space (small units located under the sink or within the wall), and is less expensive to install and operate than the conventional combustion-based method.
Without a furnace or a hot water tank, the internal mechanical systems of an NG-powered home don’t require a large room and the equipment can all fit within a small closet. This size difference allows for new home design opportunities for tiny houses or even for homes without basements.
It may seem impractical that we are still dependent on grid-supplied electricity with all these advantages to powering our houses with NG but impractical doesn’t even begin to describe it. These generators, which typically run on NG, can also run on propane and landfill-recovered biogases, with the potential for conversion kits that would also allow them to also run on hydrogen.
Let’s consider how this approach to energy generation would hold up against some worst-case scenarios. If the community suffers a black out of the electricity grid, the NG-powered house is completely unaffected, while grid-supplied homes wouldn’t be able to turn on their furnace (furnace motors runs on electricity). If the community suffers a cut to the natural gas main line, this NG-powered house can switch to using grid-supplied electricity to maintain normal operation (though at an elevated cost) and would still be virtually unaffected by the cut-off (while others can’t heat their homes at all). Finally, if both electricity and NG are cut off to the home, a simple propane tank can be substituted to keep the generator running. Compared to the redundancy of the NG-powered house the grid-dependent house is backwards.
The NG-powered house represents a step towards safety, luxury, efficiency, technological progress, and energy freedom. As renewable energy generation methods are adopted, we need to ensure that our homes are technologically able to keep up to reap the benefits of such changes. These technologies will impact the types of energy that we can purchase (such as biogas, hydrogen gas or grid-supplied electricity) and will cause their prices to fluctuate. We should have the option to choose when we want to use a certain type of energy, whether it is a financially-motivated decision or a contentious decision (I would love to run my house completely on biogas). The current practice, which simultaneously depends on grid-supplied electricity and NG, is obviously going in the wrong direction. If you like the idea presented here, keep your eye out in the next few years for this type of home because I’d like to start building them this way (and follow me on twitter: @kpareyan). If you consider yourself an experimental early-adopter type of person and want to see a similar idea come to fruition, get in touch with me.