House with roof panels

Going off grid

Inexpensive and Simple

When many of us hear the term ‘off-grid’ in terms of our homes, it’s easy to think it must be difficult or costly to get a off-grid, however it is actually very easy to implement and not terribly expensive. When viewed in line with typical utility bills, it simply makes sense.

A typical off-grid system might range from $20-$30k to purchase, which is a significant upfront investment for most of us, but seen over the duration of a mortgage, it would actually translate into a very manageable monthly payment, e.g. $170 / per month. This is actually more affordable than many typical monthly utility bills for homeowners.

All change…or at least, a significant shift

At this point in time, almost every off-grid project requires a generator, because the sun is not always shining and the wind is not always blowing, and the capacity for storing the energy generated by these sources in batteries simply hasn’t developed sufficiently.

The problem with conventional off-grid systems is that they require propane or gas, which are petroleum based fuels. As we all know, this represents a simply unsustainable energy supply. Which is why we turn to biofuel.

Why not use readily available bio-fuel?

We recommend using a generator that can burn vegetable oil or bio diesel.  These are the fuels of the future as they are non-petroleum based and renewable.

A European company, Gelec Energy, has a great selection of generators, including ones engineered for use with vegetable oil/biofuel.

With this technology, no one is reinventing the wheel; they are simply making use of existing diesel technology developed over 100 years ago. After all, deeply concerned about the pollution that accompanied the age in which he lived, Rudolph Diesel originally designed his engine so that it could run off peanut oil…

As a fuel, bio diesel is also reasonably affordable, costing as little as $.60 per litre, compared to much closer to a dollar per litre for gas at the pump.

What this looks like

In the summer period (mid-March to mid-October) an off-grid house is designed to run off solar PV panels and batteries. In the winter period (mid-October to mid-March) it’s engineered to run off a combination of solar PV, batteries, and the generator.

On average, a full-size family home will use 24 kWh per day in the warmer months, and 30 kWh per day in the cold season. The house can run directly off solar PV when the sun is shining, but here are the factors to consider for overcast days:

  • Battery storage is 15 kWh.
  • Batteries experience on average .5 charge cycles per day during the summer period and one charge cycle per day during the winter period.
  • Batteries cost $15,000 and are guaranteed for 3,000 charge cycles which equates to a battery lifetime of 12 years. This averages out to $1,250 per year.
  • Generator cost is $15,000; with limited run time it should last approximately 30 years, resulting in an annual cost of $625.
  • On average, the generator needs to produce 15 kWh per day during winter. The generator can do this with 1.5 L used vegetable oil or biodiesel: 1.5 L x 150 days = 225L x $0.60 per litre = $135/year.

Total annual costs

  • Cost for bio diesel approximately $0.60 per litre = $135 per year
  • Generator cost amortized over 30 years = $625 per year
  • 6 kW solar array and inverter $15,000 to last 50 years or more = $300 per year
  • Batteries amortized over 12 years = $1,250 per year

Total = $2,310 per year. We conservatively estimate that this is 50% less than what most full-size family homes cost to keep heated and cooled when connected to the grid.

Interested to know more?

We’re happy to answer questions about how to take your home off-grid, particularly if you’re building new and want to know the best decisions to make upfront to maximize energy saving potential. Give us a shout today.

Related reading:

Going Solar: the EkoModel Home
Your House Needs a Solar Engine, and We’ve Got It


EkoBuilt's passive house solar engine

Your House Needs a Solar Engine, and We’ve Got It

The Eko Solar Engine - passive house infographicsWe now have the opportunity to take houses off the grid and power them with energy completely derived from the sun. Your home can work smarter and save you money all year round.

At EkoBuilt, we’ve invested a lot of time and know-how into developing the perfect solar engine for your home, and we’ve created a special infographic to easily convey how it works.

This simple, fully documented and proven complete building solution is completely unique and makes it extremely easy for anyone to achieve energy independence. Our solar engine uses the latest available technologies to make this not only possible but affordable – NOW!

The beauty of the system is that you can apply it in part or in its entirety, depending on your situation.

Want to learn more about the Eko Solar Engine?

Click here for full details.

Click here to get in touch with us to explore what you need for your home.


Going solar: the EkoModel Home

While solar energy is often associated with passive homes, it isn’t for the reasons that you might think. You can read more about this in our How to Solar Power Your House post from June 2016.

In real terms, a passive house will use under 15 kWh per square metre, per year. The EkoBuilt Model Home will make use of a 6kW solar array to meet its total energy needs for roughly six months/year.

EkoBuilt’s demonstration passive house just west of Ottawa in McNab-Braeside will have a small companion solar installation to cover its total energy needs (this includes energy to power a water heater, the heating/cooling system, and of course general lights/electricity use):Aquion battery to be used by EkoBuilt's demonstration passive house project

For all of the details, you can download these one-page info sheets that we’ve prepared:

Aquion batteries info sheet [pdf]

Hanwha Q cell panels info sheet [pdf]

If you have questions or would simply like to learn more about how a very modest solar installation could help with your home building project, please feel free to get in touch.

Sept 2017 Note: The Aquion salt water batteries used by the EkoModel Home are still an option, but the company recently changed ownership, and we’ve been advised that new units won’t be available until spring 2018.

How to solar power your house

House with roof panelsWe are frequently asked about solar panels and the passive house model.

Although solar panels are included in many passive house projects, the fact is that they are not part of the core design elements or criteria for a passive house.

Solar panels are certainly a good companion to a passive house, but not perhaps for the reason you might think.

Passive House vs Off-Grid

Unlike home building that is focused on being ‘off the grid’, passive house design has a different agenda. Passivehouse is concerned with creating extremely low energy buildings which are inexpensive to operate. The central concern of a passive house is really just to dramatically reduce the need for external energy inputs, thereby making it cheap to run. (In real terms, a passive house will use under 15 kWh per square metre, per year.)

Most off-grid homes tend to rely on fuel (oil, gas or propane) to operate a water heater, as well as the heating and cooling system(s). Geothermal is also common, but can be expensive to implement.

The superbly low energy requirements of a passive house design make it a great candidate for an off-grid project, as the need for additional energy input – from solar panels, for example – is so low. This makes the inclusion of a solar photo-voltaic system or array (an installation of solar panels) very cost effective, as it can be considerably smaller to meet the much reduced energy demands of the passive house.

The EkoBuilt Model Home will make use of a 6kW solar array to meet its total energy needs for roughly six months/year. Watch for future posts on our own installation.

Passive House & Solar Energy

Any home designed using the passive house standard begins with the ‘site’; the home will be optimized to face south if at all possible in order to maximize solar exposure.

Preferred siting of a passive house will be due south or within 15 to 20 degrees of south. Having said that, even in a wooded area the most efficient home to build is a passive house.

Building on the principle of southern exposure, in optimal circumstances between 25 to 35% of the home’s southern wall will comprise windows. With modern window technology, passive house is the only proven style of home where windows are actually used as part of the heating system. Solar gain in winter from well positioned windows is essential, and strategic shading helps with cooling in the warm months.

This focus on making the most efficient use of the sun results in a home that is not only extremely inexpensive to run, but also superbly comfortable.

Intrigued to find out more about our own solar project? Follow the blog or give us a call, we’d be glad to tell you more.