In my previous two entries, I have presented the definitions and process for determining what Technological Development (read: engineering) would lead a community to be more Sustainable. In this post, I am providing a fictive example of such a process.
In my previous articles, I started with Icarus, the son of a brilliant engineer, who failed to understand the implications of the engineering design he was using. That ended badly for him, as is usually the case. As Professional Engineers, we have an obligation to ensure our clients are fully informed, which means we have to be fully informed. This example is meant as a demonstration of how we can become better informed of the implications ourselves, and uses real Canadian and Ontario data wherever possible. The numbers have not been tweaked for any particular result, and would likely produce other conclusions in some other community.
Dr. John Smith, P.Eng., a long-time resident of the Temiskaming area, has been told by his insurance company that because his principal source of space heat is a wood burning appliance (7 full cord/year), and his house is made of logs, he is going to have to pay $5000 per year in additional insurance. All of his neighbours in the same situation have installed baseboard electric, and have continued heating mostly with wood. He’d like to check to see if the conventional wisdom is actually the best idea.
He decides he has 6 alternatives available:
- Do nothing, and pay $5000 more per year, in addition to his electrical bill.
- Install Baseboard Electric heat, and provide 8% of his heat using electricity. Cheap to install, doesn’t have to use them.
- Install Geothermal heat, and provide 32% of his heat using electricity, with a COP of 5.5. Expensive to install, but he’s not getting any younger.
- Build an average Canadian new home, and heat with fuel oil or propane.
- Build a ‘green’ home, using a small pellet cooking stove for cooking, DHW, and space heat
- Build an ‘earthship’[1], using PassivHaus[2] approaches, and large south facing glass, using a propane stove for cooking
He chose a community as all the people and resources within 60 km of his residence. The Locally Used BioCapacity (LUBC) is 7.7 gHa/ca, slightly more than the Canadian average. He is calculating for a household of 4 people.
He expected that the time required for his household tasks will be essentially unchanged with any of these alternatives. The differences would be the time he takes maintaining his home (well built homes will require less), cutting and burning wood (well built homes will require significantly less heat), and the time of construction divided by the lifespan of the infrastructure.
He expected the Ecological Footprint for maintenance will be the national average, adjusted linearly with the time required. Half of the electricity, and generally half of the construction materials, come from outside of the community. A small amount of the resources used would come from unsustainable harvest from within the community. For the 6 alternatives, he found:
| Do Nothing | BBE | GeoExchange | New home | Green | Earthship | ||
| Install cost | $ | 4000 | 80000 | 228000 | 342000 | 193800 | |
| Fraction wood heat | 92% | 68% | 75% | 40% | |||
| Fraction electrical heat | 0% | 8% | 32% | ||||
| Total electrical demand | kWh/d/ca | 6.0 | 8.9 | 8.1 | 6.0 | 4.0 | 1.8 |
| Operate cost | $/year | 6401.60 | 2073.60 | 1890.33 | 1401.60 | 934.40 | 420.48 |
| Lifespan | yrs | 80 | 50 | 50 | 60 | 80 | 80 |
| PV | $ | 193333 | 57353 | 128637 | 266790 | 370219 | 206499 |
| Construction | min/d/ca | 0.02 | 0.34 | 0.81 | 0.91 | 0.51 | |
| Maintenance | min/d/ca | 11.55 | 11.55 | 11.78 | 8.66 | 5.77 | 5.77 |
| Time cost | min/d/ca | 11.55 | 11.56 | 12.12 | 9.47 | 6.68 | 6.29 |
| Household tasks | min/d/ca | 14.10 | 14.10 | 14.10 | 14.10 | 14.10 | 14.10 |
| Wood | min/d/ca | 1.63 | 1.50 | 1.11 | 1.22 | 0.65 | |
| Time Benefit | min/d/ca | 0.00 | 0.13 | 0.52 | 0.41 | 0.98 | 1.63 |
| Construction | gHa/ca | 0.01 | 0.05 | 0.65 | 0.65 | 0.16 | |
| Maintenance | gHa/ca | 0.38 | 0.38 | 0.40 | 0.29 | 0.19 | 0.19 |
| Wood | gHa/ca | 3.62 | 3.33 | 2.46 | 2.71 | 1.45 | |
| Electricity | gHa/ca | 0.64 | 0.95 | 0.86 | 0.64 | 0.43 | 0.19 |
| Fuel Oil/Propane | gHa/ca | 0.02 | 0.03 | ||||
| EF per Daly | gHa/ca | 4.13 | 4.00 | 3.12 | 3.50 | 2.08 | 0.27 |
| EF imported | gHa/ca | 0.51 | 0.67 | 0.66 | 0.81 | 0.63 | 0.30 |
| Mass of infrastructure | T | 0 | 0.1 | 4 | 67.2 | 67.2 | 2332 |
| Mass of resources used | T | 977 | 562 | 420 | 721 | 552 | 2340 |
| Mass of renewable resources | T | 977 | 562 | 416 | 591 | 422 | 220 |
| Mass of RR imported | T | 0 | 0 | 0 | 40 | 30 | 20 |
| Mass of RR local | T | 977 | 562 | 416 | 551 | 392 | 200 |
| Mass of NRR | T | 0 | 0 | 4 | 130 | 130 | 2120 |
| Fraction of NRR expiring | 1% | 100% | 100% | 40% | 50% | 1% | |
| Simple duration to peak | 0 | 0 | 0 | 0 | 0 | 0 | |
| Mass fraction not Daly | 0.0% | 0.0% | 1.0% | 12.8% | 17.2% | 1.8% | |
| Future time cost | min/d/ca | 4.630 | 6.068 | 5.956 | 7.331 | 5.749 | 2.732 |
| Time penealty | min/d/ca | 0.000 | 0.000 | 0.005 | 0.052 | 0.168 | 0.029 |
| Total time benefit | min/d/ca | -16.18 | -17.50 | -17.56 | -16.44 | -11.62 | -7.42 |
| WRT do nothing | min/d/ca | 0.00 | -1.32 | -1.38 | -0.27 | 4.56 | 8.76 |
| PV over lifespan | $/day | 6.62 | 3.14 | 7.05 | 12.18 | 12.68 | 7.07 |
| Sustainable value | min/$/ca | 0.00 | -0.42 | -0.20 | -0.02 | 0.36 | 1.24 |
This shows
- The existing system has a negative net time benefit. This doesn’t consider the much greater time cost that would be associated with not having a home at all.
- Geothermal has the greatest negative net time benefit, so is the least Sustainable. Baseboard Electric has the greatest negative sustainable value, so is the worst investment.
- Neither a conventional home nor a geothermal system will provide a net benefit to the community, although each are close to being as good as doing nothing, and there may be a manner to ensure that either could provide a net benefit.
- A ‘green’ home provides a benefit to the community as a whole, and is a positive investment.
- The ‘earthship’ provides the greatest Sustainable Value. Further refinement of the design may lead to using a minimum of unsustainable materials from outside the community.
Based on this analysis, Dr. Smith, P.Eng., decided to investigate the ‘earthship’ in more detail, to see which components could be changed to improve the Sustainable Value farther without impacting his perceived quality of life.
Choosing a different community would change the results significantly. It is easy to see how a community scale of ‘Ontario’ would reduce the amount of imported EF for each of the designs, and reduce the LUBC per capita, and thus change the future time cost associated with importing resources.
Currently in Canada, the difference between our current consumption and our current LUBC demonstrates we are not living within a Sustainable community. The difference works out to a time cost in the order of 10 min/d/ca, carried by each person in Canada to various degrees. The difference between ‘do nothing’ and Alternative 5 is approximately 5 min/ca/d, and the difference between ‘do nothing’ and Alternative 6 is about 9 min/ca/d. Both of these alternatives would move the community meaningfully toward Sustainability.
Just as the Wright Brothers and their balanced-forces-to-achieve-flight was not the end of the evolution of flight, so too will the practice of Sustainable Technological Development continue to evolve. This example, and the discussion that comes before it, provides some insight into that evolution. Without the Engineering profession adopting whole cloth the principals of Sustainable Development as they apply to our work, no efforts by others will amount to any real change on a planetary basis. On the other hand, if we lead the rest of the world by showing that a meaningful change can be achieved through measuring and designing for the right things, engineers can bring all of the ‘talk’ into ‘walk’.
With spectacular engineering, we will soar!
[1] http://earthship.com/
[2] http://www.passivehouse.ca/