Ground-source heat pump
Air-source heat pump
Accessories
What is a heat pump
Air stoves
Pellet boilers
Ducted air stoves
Hydro stoves
Accessories
Insert pellet stoves 
Wood stoves 
Wood boilers
Insert wood stoves
Charcoal oven 
The biomass market in Spain offers several options for eco-friendly heating: wood pellets, olive pits and wood chips. Each has its own characteristics in terms of performance, price, cleaning and regulations. In this article, we provide a practical, up-to-date comparison for 2025 to help you choose the most suitable biofuel for your home, boiler or stove.
If you want in-depth information about a single biofuel, take a look at our dedicated articles: Olive pits as a biofuel and Wood Pellets: the eco-friendly revolution in home heating. Here, we compare the three most popular options in Spain.
Energy performance: LHV and HHV
The Lower Heating Value (LHV) measures the usable energy available after accounting for moisture. The Higher Heating Value (HHV) includes the heat released when water vapor condenses.
| Biofuel | Average LHV (kWh/kg) | Average HHV (kWh/kg) | Comments |
|---|---|---|---|
| Wood pellets | 4,6 – 4,9 | 5,0 – 5,3 | Highly consistent, ENplus A1 standards. |
| Olive pits | 4,1 – 4,4 | 4,5 – 4,8 | Slightly lower performance than pellets, but excellent in adapted boilers. |
| Wood chips | 3,2 – 3,8 | 3,5 – 4,2 | Highly variable depending on moisture, making proper storage essential. |
Conclusion: wood pellets are the most consistent and efficient per unit of weight. Olive pits come close in performance at a lower cost. Wood chips require suitable equipment and adequate insulation.
Moisture, ash and clinkers
Biofuel quality directly affects consumption, cleaning and equipment maintenance.
| Factor | Wood pellets | Olive pits | Wood chips |
|---|---|---|---|
| Moisture | 6–10% (ENplus A1) | 8–15% (depending on supplier) | 20–35% (highly variable). |
| Ash | 0,3–0,7% | 2–3% | 1–5% depending on cut and species. |
| Clinkers | Very low | Moderate (high potassium → more clinkers) | Depends on the source; moderate risk. |
💡 Less moisture = better performance and less maintenance. Here, pellets are again the cleanest and most consistent option.
Regulations and certifications
- Pellets: they carry ENplus certification, which guarantees size, moisture, ash content and heating value. They are the most reliable standard and are easy to export.
- Olive pits: there is no equally widespread European certification, although UNE quality protocols have been developed in Spain. The key is to choose reputable suppliers that screen and dry their product.
- Wood chips: certifications such as Biomasud are recommended, guaranteeing moisture ≤25% and uniform particle size.
Prices in Spain (2025)
Prices fluctuate by region, availability and subsidies. Average figures as of September 2025:
| Biofuel | Average price €/kg | Cost €/MWh of usable heat | Availability |
|---|---|---|---|
| Pellets | 0,35 – 0,40 | 70 – 80 | High, throughout Spain. |
| Olive pits | 0,22 – 0,28 | 50 – 60 | Excellent in Andalusia and Extremadura. |
| Wood chips | 0,10 – 0,15 | 35 – 45 | High in Castile and León, Galicia and northern mainland Spain. |
👉 Olive pits and wood chips are clearly cheaper, but they require adapted boilers to avoid combustion and maintenance problems.
Impact on cleaning and service life
- Pellets: less residue → longer service life for the burner, turbines and heat exchanger. Light weekly cleaning.
- Olive pits: more ash and clinker → frequent cleaning (every 2–3 days during peak season). Self-cleaning grates are recommended.
- Wood chips: require more storage space and almost daily cleaning. Suitable for medium- to high-capacity installations (farms, warehouses, public buildings).
When should you choose each biofuel?
- ✅ Pellets: if you want convenience, maximum efficiency and standardized certification (ENplus). Perfect for single-family homes and users seeking low maintenance.
- ✅ Olive pits: a more economical and sustainable option in producing regions (Andalusia, Extremadura). Ideal for properly adjusted multi-fuel boilers.
- ✅ Wood chips: the best option for large properties, agricultural operations or shared projects (schools, industrial buildings). They pay off when storage space is not an issue and you want a low cost per MWh.
Conclusion
The comparison of pellets vs olive pits vs wood chips shows that no single fuel is best for everyone; the right choice depends on your home, your boiler and the storage space available to you.
- Pellets offer the greatest convenience and performance.
- Olive pits are the most economical choice, especially in producing regions.
- Wood chips are hard to beat for large-scale projects with sufficient space.
At Ecoforest, we develop stoves and boilers adapted to each type of biofuel because we know that making the right choice starts with understanding the differences.
