Saturday, January 24, 2015

Electricity Generation and Off-grid for Low Energy Houses

I was recently involved in two low energy house projects and they were both on rural, undeveloped land.  In these cases, I always ask, is it cheaper to have on-site generation and storage, or is it cheaper to be grid-connected?  Actually, I even ask this question all the time in the city, every time I get my electricity bill - the delivery charges are frequently higher than the electricity charges.

So dimensions of the question go like this:
  1. It is often something like $10k to $20k to create a new grid connection for a rural property.  Wouldn't it be nice to put that money towards electricity storage or on-site generation/both?
  2.  Sometimes there is a microFIT project involved - so if we are going to sell solar electricity to the grid, then we need the grid connection anyways
  3. Electric vehicle - If we are going to have an electric vehicle, then we are no longer purchasing gasoline, but must instead supply additional electrical energy to our vehicles as well as our house - well, do the math and you'll probably find that net zero may often be practical for our houses, but net zero including our transportation? - that can be quite an additional load, depending on how much one travels, or plans to.  While the vehicle can act as a big battery for the onsite storage of electricity, everytime I look at vehicles storing energy for the house, I come up short - either for the house, or for the vehicle - so in terms of timing, this option has yet to prove viable.
  4. Microgrid stability - In one project, there is kind of a significant computer activity in the house.  This owner is looking seriously at back-up generation, but one also needs a transition system - like a battery bank or an ultracapacitor bank  - basically a UPS that gives the generator the few seconds needed to come online in a black-out.  This house is also in a valley, so the back-up generator will be perfect to run pumps for flood protection - Even though we are in a big city, power outages frequently come when there are big rains.
    If we need back-up-generation AND the grid connection is costly, why not forego the grid connection altogether?
  5. Finances:  In one instance, the bank decided what to do, rather than the buyer of the land - The bank's position was this:  Build all services - septic, water, and grid connection, or we won't lend you the money to buy the land. - Sheesh!  They must not have heard of solar PV!  
This question always fascinates me - I get to go out looking for off-grid technologies.  So today I came across this on Gizmag:  
http://www.gizmag.com/power-pallet-20-gasifier-biomass-generator/32245/ - the power pallet.  This is a machine which eats biomass, and makes heat and electricity, and it is smallish - relative to many biomass machines.  it produces about 20kW, and costs about $30,000.  Kind of attractive if a grid connection costs $15k and  back-up generator $10k.

7 comments:

  1. The attraction will be user-specific, akin to the attraction of a hobby. Especially if your situation demands a backup generator ($15k). Given the need, why would you be spared the requirement for a spare just because you installed a biomass machine? Are biomass machines so fail-safe?

    ReplyDelete
  2. That should have been $10k back-up generator... If that is the need then the cost comparison is $40k (30 + 10) plus ongoing maintenance and feeding, versus $25k (15 +10).

    ReplyDelete
  3. A passivhaus or passive house is low energy home constructed by eco refurbishments in London with quality construction techniques and rigorous designs.

    ReplyDelete
  4. Your blog is awesome and really helpful for readers. The Eco Refurbishment is a London based environmental construction company.

    ReplyDelete
  5. Your blog is awesome and really helpful for readers. The Eco Refurbishment is a London based environmental construction company.

    ReplyDelete
  6. Your blog is awesome and really helpful for readers. The Eco Refurbishment is a London based environmental construction company.

    ReplyDelete
  7. I assume this problem is now solved by Tesla power wall :-)

    ReplyDelete