Heating with pellets (biomass) here in Galicia Spain
Here in the deepest Galicia the choice of heating is limited. Specifically if one looks for a "central calefaccion" powering a 250 m2 stone/brick house(s) with pipe runs of 20m+.
It is also important for us that we can leave this unattended for at least 24 hours and it should also be a feature. It also needs to deal with power outages - Tough brief -
Discarded directly:
Heating with electricity is out, as this tariff has just been abandoned. Gas, as we have no pipes and a tank would be problematic is not an option either.
Coal is pricey here, dirty and produces a lot of soot and smeary dust.
Wood is plenty and at 200 Euros a trailer load reasonably cheap and sustainable.
Both of these require a lot of management, storage space and produce a lot of waste.
They also require precautions for overheating on pump and power failures.
Thus there are requirements like emergency heat dissipation or run such installs via heat storage / exchangers.
This left heating with oil or wood pellets.
Heating oil requires safe storage (tanks), smells and boilers are normally not a feature. The fuel price can go only one way - up.
We also wanted this to be a feature - see the flames and increasing the efficiency by installing it inside our new kitchen rather than in a cellar or bodega.
This simply left us with a compact pellet oven (biomass). We selected a Spanish make by Ecoforest as they have one that delivers 27Kw!
The install is dead easy as the oven includes everything (controls, boiler, heat exchanger, pump and expansion vessel). No need for an extra tank (oil) or an extra buffer tank. Pellet bags can be stored wherever it is convenient but dry.
Just the feed and return from our heating pipes. No extra pump no extra expansion or buffer vessel.
Running costs
To truly compare this we have to apply some math. Oil is quoted in BTU per liter, whereas pellets usually are quoted in Kcal per Kg. The heating and oil industry don't intend to make this comparable - do they?
1BTU = .252 Kcal
1Liter of heating oil on average has a density of .85 (850gr per liter).
1 Liter of heating oil has 34750 BTU = 8757 Kcal - or - 1Kg oil = 10,300 Kcal
1 Kg or pellets has 4,600 Kcal (average some have 4,200 some 4,800)
Thus 2.25 Kg pellets = 1Kg of oil (10,300 Kcal) or 1.9 Kg pellets = 1 liter of heating oil
At present Feb./March 2008 medium quantities of Oil (B grade) cost around 0.75 Euro / liter delivered.
We buy pellets per pallet (1+Ton / 70 bags of 15 Kg) at around 280 Euros delivered or 0.27 Euro /Kg.
So like for like
10,300 Kcal in oil = 0.88 Euro
10,300 Kcal in pellets = 0.60 Euros
We used about 3 tons of pellets resulting in a fuel bill saving of approx. 400 Euros.
Other running costs are alike. Both systems need electricity for fuel delivery and electronics.
Yes, a pellet oven requires some management. Running it full tilt, I clean (ash) this every 2nd day. Now with average usage I do it about twice a week. This takes me about 20 minutes each time. If I'd be paid out of the savings it would translate into a 15 Euro/hour earning.
More details about management of our choice of oven
PS: There may be a grant available for installing biomass heating, I'll update when I get it.
PPS: It's nearly carbon neutral - only production and transport generate extra CO2
