Academy Park, Leith, Edinburgh
Overview
This case study examines the possibility of retrofitting solar PVs to an existing sheltered housing complex on Academy Park, Leith. Benefits of this low & zero carbon technology include reducing electricity costs for the tenants, tackling fuel poverty, whilst at the same time reducing the carbon dioxide emissions.
This study investigated the potential for PV panels and assessed the following:
Location and type(s) of PV panels to maximise solar gain, including output and returns
Benefits of Feed-in Tariff in relation to provision of solar PVs
Restrictions on PV placement on buildings in conservation area
Changes to the government’s Feed-in Tariff scheme, and introduced stipulations
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Technical scope of study
The property on Academy Park comprises a four storey building, housing 38, one bedroom flats, with communal facilities including lounge, kitchen and laundry. It was constructed in 1993. It is hoped that a PV installation could reduce the dependance on grid electricity.
The roof area suitable for PV panels is estimated to be 115m² with a tilt of 35º. The building is orientated 35° southwest. The gable end to the right of the image above will cast a shadow over the roof, therefore the PV panels should be located to avoid this.
The total annual energy consumption for Academy Park has been calculated from electricity bills: 138,000kWh/year at a cost of £11,840 per year.
Cost Analysis
The cost analysis of the solar PV systems in this report takes into consideration and evaluates the following information:
Capital cost of materials
Labour to install such panels
VAT on labour & materials
Yearly estimated maintenance fee
Estimated inverter replacement (once every 20 years)
Decrease in solar panel efficiency
Feed in Tariff rate and its yearly increase in line with the Retail Price Index (RPI)
Savings made on electricity bill, based upon electricity price per kWh and its estimated increase with inflation
Electricity export at £0.31/kWh (if applicable)
A full breakdown of energy and income generation, cost of systems, and carbon dioxide savings are detailed in feasibility report.
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A SAP analysis was carried out for the flats before and after refurbishment. The Table gives the results for the two flat types estimated to have the highest and lowest SAP ratings after refurbishment. The analysis showed that excellent SAP ratings were achieved, above those which could be typically expected for refurbishment. Annual space and water heating costs were estimated to reduce by 84% for the top floor 1-bed flat and 79% for the first floor 3-bed flat. Corresponding CO2 emissions were estimated to have reduced by 58% and 26% respectively.
Top Floor 1-Bed Flat
SAP rating
Before: 1
After: 82
CO₂ emissions (tonnes/year)
Before: 6.5
After: 2.7
First Floor 3-Bed Flat
SAP rating
Before: 32
After: 97
CO₂ emissions (tonnes/year)
Before: 5.0
After: 3.7
U-values
Roof: 0.25 W/m²K
Walls: 0.45 W/m²K
Ground floor: 0.45 W/m²K
Fuel Costs
Estimated reduction: 80%
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At a meeting with the Association’s development committee it was clear that the tenants were very pleased with the refurbished housing, but that the high standard had been achieved not through the Association’s own knowledge but because an architect had been employed who was experienced in refurbishment. However, for future refurbishment projects the Committee is likely to use the SAP energy rating as a design tool. This will include asking the architect to achieve a specified minimum SAP energy rating value.
There have been some difficulties: the void behind the bay window has created draughts, the external insulation is not strong enough to hold satellite dishes and is subject to vandalism, and the original boilers have been replaced by cheaper and more reliable and efficient alternatives.
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