District Heating with Biomass in Orozko, Basque Country, Spain


This project promoted by the Orozko municipality aims to meet the thermal demand (heating and warm sanitary water) through a centralized system which has biomass as its main source of primary energy. The project is implemented in two phases: the first phase provides heating for the sports centre and the elementary education centre. The second phase is a district heating network for a new housing development.

Results and impacts

Start Date: 2010. 

Reductions of greenhouse gas emissions:• Municipal buildings: 105 t CO2e/year• 432 houses: 835 t CO2e/year

Annual economic savings:
• Municipal buildings: 37%
• 432 houses: 43%

Renewable energy capacity installed p.a.: 2,440 kW

80% of the energy delivered will come from biomass.

Aims and objectives of this sustainable energy action

This project supplies a range of 432 houses and 2 municipal buildings (the school and the sports centre) with warm sanitary water and heating through a centralized system of biomass. It avoids chimneys and heat generating installations in buildings because the whole system is centralized, saving energy and using renewable energy. This system will prevent the emission into atmosphere of 940 tons of CO2 per year.

With regard to users, the District Heating aims to save more than 15% of the energy expenses. The saving in the initial investment is 22%.

Technical and financial implementation

The technical characteristics of the project are:

• Phase 1: Heating demand: 1.2 GWh/y; Installed heating capacity: 440 kW.
• Phase 2: Heating demand: 3.6 GWh/y; Installed heating capacity: 2 MW (1.4 MW with biomass and 625 kW with natural gas)

A buried ring of heat distribution will bring heating to each plot. Each plot has a shutoff valve at the entrance to each block. The set of installations will be supervised and controlled from a central control room. The storage silo for biomass will have 14 day capacity.

The type of contract is an administrative concession to 25 years to a temporary union of companies formed by an ESCO and a company for the supply of biomass. Over 40% of the total investment has been funded by a non-repayable grant from the Basque Regional Administration.

Lessons learnt

The installation of district heating centralized system offers several advantages: avoids chimneys and installations of heat in buildings, improves the quality of air, average savings higher than 15% compared with traditional systems, savings on the initial investment of more than 22% and savings of required surface for installations.

However, the urban situation of the points and the timing of the projects made more appropriate the implementation in this case of two separate centralized biomass installations.

Both district heating systems and ESCO are infrequent in the region. The lack of experience in this type of services makes sometimes difficult to convince authorities, other key stakeholders and the public about their benefits.

How this action could be replicated

In Southern Europe, centralized district heating installations are not usual because the smaller amount of heating requirements reduces their economical feasibility, so people tend to be reluctant to implement them. However, their use leads to improvements in the energy efficiency and for this reason they are being promoted by the Government. 

The use of biomass in rural areas also improves the sustainability of the energy system, making use of a renewable fuel which is not fully exploited. In this case, energy saving and the use of renewable energy are put to work together in one installation.


The project promoter is the city council of Orozko. Giroa is an energy service provider which is responsible for the management of the installations, while Enerpellet is responsible for the supply of biomass.

Contact details

Ente Vasco de la Energía - EVE
Alameda de Urquijo, 36 - 1º. 48011, BILBAO
T: (34) 944 035 600

Álvaro Pérez de Laborda; alaborda@eve.es

Further information