Case Study: Agile City’s Small-Scale Power Stations
The retrofit of Civic House, a former printworks, has created a hub of activity that brings new life to a neglected corner of Glasgow in the form of small-scale power stations ‒ generating over twice as much electricity as the company consumes over the course of a year. The project is an exemplar for the creative reuse of post-industrial cities’ former factories and warehouses, which are often left to fall derelict despite their architectural value and cultural heritage. These buildings that once supported industrial growth – and an explosion in carbon emissions – can now support new green industries and a low-carbon future.
Understanding the History
Previously, this part of Glasgow was home to both the Port Dundas Electricity Generating Station and the Pinkston Power Station. These institutions provided power for the trolleybuses, early subway, streetlights, and national grid from as early as 1897. Pinkston Power Station was demolished in 1978 while Port Dundas Electricity Generating Station was demolished earlier in 1970. These areas became key areas in Glasgow’s infrastructure with a strong workforce living nearby. Unfortunately, in years since, the legacy of these impressive power stations diminished.This was partly exacerbated by the closure of the nearby canal to navigation and the introduction of the M8 as it severed the North of the city from the centre. However, there is a way forward to build upon the history of the area without reintroducing smog-generating smokestacks. Agile City has been working with Collective Energy to introduce small-scale power generation in Port Dundas.
Figure 1: Illustration by Collective Energy for proposed energy flow through Civic House as a small-scale power station.
Modern Local Energy Stations: Micro and Small-Scale Power Stations
So what is a small-scale power station? Small-scale or micro power stations are a component of microgeneration and hybrid energy systems. These systems combine different renewable forms of energy, for example solar and wind, to generate electricity. This energy is then either stored, used on-site, or fed back into an existing power grid. Micro power stations typically have an output of less than 3.68 kW while small-scale generators have an output between 3.68 kW and 50 kW. This is much lower than the average commercial power station which has an output greater than 5 MW. These small-scale power stations do not have the capacity to produce as much electricity as their commercial counterparts. However, they can reduce the carbon footprint of the businesses and communities that run them. Eventually, all the energy saved or substituted by renewable energy adds up across the power stations to make a big impact on reducing our carbon consumption. Even when a business doesn’t directly use gas heating, using the grid still produces greenhouse gases in the generation of electricity at large power stations throughout the UK. Small-scale power stations replace this energy with green sources.
That is why in 2018 Agile City initiated the refurbishment of the interior of Civic House. We began by commissioning Collective Architecture to conduct a feasibility study for an energy-efficient external retrofit. The retrofit would transform the building into an efficient small-scale power station. The feasibility study energy modelling – using the Passive House Planning Package – indicated that we could reduce the building’s heating demand by 86% (from 450kWh/m2/a to 60kWh/m2/a) while maintaining a temperature of 20oC throughout the year. Following the survey was the installation of a 270m2 50kW Photo-Voltaic (PV) roof array, an external insulation cladding system for the walls, new triple-glazed airtight windows and a mechanical ventilation and heat recovery system, along with an air source heat pump. These were supported by SP Energy Network’s Green Economy Fund.
Progress To Date
Figure 2: Comparison of energy usage and production across Agile City CIC by financial year.
Since the retrofit, the building is already fulfilling its purpose as a micro power station. During the 12 months from March 2022, Agile City used just 3,667 kWh of electricity. Meanwhile it generated 21,269 kWh of electricity, which equates to a net energy gain of 17,601 kWh. The co-working space and canteen were not in use during the first part of 2022, so we predicted the energy usage for 2023 to be a little higher. The chart above reflects this. As the building has become fully operational, the electricity generated by the PV array consistently outperforms the energy required for operation. In 2023, there was a net gain of 11,573 kWh despite the increased demand for energy across the two buildings.
The original estimate by AC Gold Energy for annual electricity generation by the PV panels was 33,866 kWh/yr. Unfortunately, we cannot predict this without a high level of error because of the variability of solar radiation (sunshine) each year. In 2023, Civic House generated 28,680 kWh. This amounts to 84.7% of original estimates for yearly energy produced. Comparatively, the average amount of sunshine in the UK over 2023 was 1435 hours. This is 90.1% of the average amount of sunshine recorded across the UK in 2018. Taking into account Glasgow’s higher records of cloud cover compared to the rest of the UK, producing 84.7% of original estimates for yearly energy production falls within a reasonable range for the operation of the solar panels. On top of that, Civic House operates as a successful example of a small-scale solar power station despite operating in notoriously cloudy Scotland!
Building for Success: Insulation in the Small-Scale Power Station
Figure 3: Estimated breakdown by Collective Architecture of Civic House’s annual heating demand before and after the retrofit (2018). Note that the units of measurement for heat flow is kilowatt-hours per square meter of floorspace annually (kWh/(m2a)).
It is important to acknowledge that a key component of producing surplus energy is making sure that the business consistently reduces its energy demand proportional to its growth. In Agile City’s case, we achieved this by reducing the demand for heating Civic House by installing external insulation and triple-glazed windows. As part of the feasibility study in 2019, the proposed reduction in heating demand was from 375,564 kWh/yr to 50,736 kWh/yr. Based on meter readings for 2023, Civic House is using 30,406 kWh/yr to warm the building using gas. This is around 20,000 kWh/yr less heating needed compared to the estimated heating usage post retrofit. It is also around 355,000 kWh/yr less than the original energy required to keep the building at a constant temperature throughout the year as calculated in the original feasibility study. Thus, we have reduced the energy demand of the building compared to the energy generated by the solar panels.
What Comes Next?
As Agile City Director Rob Morrison says, “Civic House demonstrates that not-for-profit local organisations have the power not only to save much-loved buildings and bring new life to post-industrial districts but also to become small-scale sustainable energy generators.” Agile City continues to observe and learn from Civic House and its users. In 2024 we are just finishing a round of renovations on our sister site, the Glue Factory. These renovations include the installation of a further 30 kW PV system. Adding another micro power station in the area will help reduce Agile City’s carbon footprint and provide novel opportunities for community benefit. These could include electric vehicle charging stations and education about local power generation strategies.
Figure 4: Physical and digital real-time energy performance interfaces to be instituted across Civic House and Glue Factory. Collage includes examples from Open Energy Monitor System and Emoncms web-app.
The next phase of the project will build upon this power generation to reactivate the public space around the building. It will attract more local people to the neighbourhood through music and gardening projects. Meanwhile, the project will spread the good that small-scale and community energy projects can generate. As seen in Figure 4, a combination of physical and digital interfaces will relay the energy usage within the buildings. We hope to create a modern version of the power station control room. Except at Agile City, the building users will be at the helm.
This article was written by Sebastian Taylor. They are the Community Connector at Agile City CIC with funding through the Step Up to Net Zero program.
Step Up to Net Zero is an initiative by Glasgow Chamber of Commerce. SUTNZ supports Glasgow SMEs in their efforts to reach net zero by funding six-month work placements who will help organisations take action towards net zero and circular goals.