Pilots - Slovenia
Sloevenian Pilot
The main buildings that are part of the SUPER-i Slovenian pilot are located in Trbovlje.
All the relevant details are presented below including the general description of the interventions, a more detailed technical analysis, a study of the environmental benefits associated with the energy efficiency interventions and a detailed financial evaluation of the various Public Private Partnership (PPP) contracts with a specific recommendation on the best contract that could be used to finance such investments.
- General description
- Technical Analysis
- Environmental Analysis
- Financial Analysis
General description of the Pilot and interventions
The Slovenian pilot comprises a single four-floor building comprising 26 apartments, located in Trbovlje, and was built in 2005. Given the recency of its construction, most of the components were built to high standards, and it is not considered cost-effective to replace the windows; instead proposed renovations involve refurbishment of the heating system, and the addition of insulation to the roofs and external walls.
Figure 1: Slovenian Pilot Building, built in 2005
Technical description and intervention
The improvements proposed to the building include injecting insulation into the exterior walls; these are 20 and 10 cm brick cavity walls.This is expected to reduce the heat lost through the walls by a factor of 4.
The other components of the building fabric are already built to a high standard, and it is not economical to upgrade them at this stage. Environmental and air quality benefits are likely to be achievable through the installation of heat pumps, but these are not included in the proposal, and it is not straightforward to model their economic returns.
We have also considered the addition of rooftop PV; the solar resource in the country is good and the grid is ~30% renewable, so significant emissions savings could be achieved, but the specifics of this building as a site for solar generation are not available.
Summary of Renovations
Here we summarise the modelled benefits of the renovations suggested by the housing associations, as well as additional potential upgrades not initially proposed by the HAs.
| Propposed interventions | Rating | Description |
|---|---|---|
 |
8 |
Savings of around 35% when significant additional lagging is added. The decision to improve the U-value of the walls seems a good one. |
We have also modelled improvements to the building not initially suggested by the HA; most of these are unattractive economically given the current build standard. Significant interventions, such as switching to heat pumps or adding PV, may be costly for a small scheme such as this one.
| Propposed interventions | Rating | Description |
|---|---|---|
 |
4 |
Building already built to high standard |
 |
4 |
Building already built to high standard |
|
Installing heat pumps |
7 |
Development proposes to supply heat using gas boilers, low carbon HP would reduce the emissions significantly, though may be costly for a small scheme. |
|
Addition of PV panels to building roofs |
6 |
A small development and the inclusion of rooftop PV and electrical storage may be costly or disruptive. Slovenia’s grid is only around one third renewable, so emissions reductions would be significant, though details to do precise modelling of the yield of a given panel, and to calculate how much generation would be used by residents and how much exported to the grid, are not currently available. |
Environmental impact assessment +traffic light system
Figure 2. CO2 emissions avoided considering the energy efficiency interventions for the Slovenian pilot.
Traffic light system
| Planned interventions | LCA | SLCA | Description |
|---|---|---|---|
|
|
6 |
6 |
Buildings are already built to a high standard. Social and environmental considerations should be taken into account (LCA and SLCA) when refurbishing. Not much LCA and SLCA impact is expected. |
|
|
7 |
6 |
Savings of around 35% when significant additional lagging is added. Natural materials should be considered (LCA), it is likely to be disruptive, and may require significant works to the building envelope given the existing insulation but on the other hand comfort will be increased, natural based paints without additives should be considered as they will increase the comfort and health conditions (LCA and SLCA) |
|
|
6 |
6 |
Buildings are already built to a high standard. Social and environmental considerations should be taken into account (LCA and SLCA) when refurbishing. Not much LCA and SLCA impact is expected. |
|
Installing heat pumps |
7 |
6 |
Development proposes to supply heat using gas boilers, low carbon HP would reduce the emissions significantly, though may be costly for a small scheme. Change of resident habits will be needed, residents may reject this measure (SLCA) |
|
Addition of PV panels to building roofs |
6 |
4 |
A small development and the inclusion of rooftop PV and electrical storage may be costly or disruptive. Slovenia’s grid is only around one third renewable. Environmental impact reduction in comparison with fossil fuels (LCA).
Significant energy savings may be achieved on electricity bills, which could positively affect residents’ budgets, depending on the ownership arrangements. Suitability for PV and funding models not clear at this stage (SLCA). |
Financial Analysis
In this section, we present the detailed cost – benefit analysis for each PPP contract. This analysis has been specifically tailored to the SUPER-i pilot buildings considering all the possible stakeholders involved.
