The outcome of the project showed that significant CO2 savings could be made in an urban area with this proposed model and its various schemes. Dennistoun was chosen as a case study as it has many different types of building, such as industry, commercial and domestic sectors and is representative of many other urban communities.
When using this model for an urban community the first step is to identify the sectors with large energy consumption and carbon footprint as this is where the largest impact can be made. This could be found from obtaining data from the relevant authorities or industries in the area. The next step is to perform an analysis, similar to this project’s checklist, to identify the sectors to look at for the highest potential savings. In this case study the priority areas were identified as industrial and the domestic energy use.
Once the areas for carbon reduction have been identified, the relevant schemes for each area can be investigated. This project model utilised the resources in an inner city area with various degrees of innovation. All the systems investigated in this project could be transferred to other inner city districts in the right circumstances however some schemes proved to be more successful than others which would be suggested to apply first. Due to the climate in the in Glasgow it was found that there is a high demand for hot water and space heating and this provides a large potential for CO2 savings. This is highlighted by the fact that the most effective CO2 reduction systems, the biomass CHP using alternative fuels and demand reduction, tackled space heating and hot water.
The biomass CHP plant has been shown to be the most effective method of reducing CO2 emissions. Biomass is not sustainable for adoption on a large scale in the UK if it is fuelled entirely by energy crops or virgin wood chips, so it is recommended that the potential for alternative fuels such as waste or by-products from the area is investigated. In this case study spent grain from the brewery was used as fuel, however it is clear that most communities will not include a brewery. Innovative thinking is required to identify resources that are available in the area and then design the biomass CHP plant accordingly. Other communities may have access to other fuels that could be used, such as sawdust, waste wood, agricultural and food waste, waste from saw mills, the construction industry or large bakeries.
In the Dennistoun case study only 3% of the fuel in the biomass plant was supplied by microalgae as there was a large supply of spent grain fuel available from brewery. In communities which have a less biomass fuel available a larger proportion of microalgae could be used. The advantage of microalgae is that it does not require an overly large area to cultivate it, so it is easily transferable to other urban areas with unused space. The microalgae photobioreactors could easily be stacked into pallets or be placed on the side of buildings. Another advantage of microalgae is that it helps absorb some of the carbon dioxide from industry in the area and be turned to fuel, which can be seen as a way of recycling carbon dioxide.
Domestic demand reduction is also seen to be a very effective way to reduce emissions and could also be easily replicated in all areas, rural or urban. Demand reduction is an essential component of reducing emissions in an urban community as the potential for generating renewable electricity in urban areas has been shown to be limited. Demand reduction, particularly through improved insulation and efficient boilers was seen to have a large potential CO2 saving, though the capital costs required for a whole community are also relatively high. The analysis for this was carried out in a typical inner city area in Glasgow and could be transferred to various types of urban communities. As well as this, the analysis covered a large variety of building types, such as detached housing, tenement flats and council flats that could be found all around Glasgow and the UK.
Energy from waste did not provide a large CO2 saving for the community, as it was proposed to be part of a larger citywide scheme, but the cost per tonne CO2 saved was very competitive with other methods so it is recommended that this should be considered for other communities. This system is possibly the most transferable of all the areas of investigation. This is primarily due to the scheme only adding a stage to the sewage process, utilising energy from what would otherwise be a waste product and an existing sewage plant can be easily upgraded to take in this facility.
Other systems were found to make important contributions to the CO2 savings, and could be easily transferable to a wide variety of areas, however it would be important to analyse their potential in the specific area. The case study shows that there is potential for wind turbines in urban areas, though there could be issues in terms of legislation and planning. Other areas have been identified in Glasgow such as Ruchill and Queen’s Park that could be suitable for large wind turbines as there are suitable elevated areas however this would require further investigation. It was also apparent from the transmission assessment that the energy saving made from reducing transmission losses does not outweigh the greater potential of more suitable rural locations.
The photovoltaic system could also be transferred to other areas. It was shown in this project that photovoltaics are currently far too expensive in relation to the benefits gained in a climate with low solar resources. However with feed in tariffs accounted for, a PV scheme in such an area could hold potential for economic gain. As photovoltaic technology develops the prices are forecasted to drop, and efficiencies are expected to rise, which could make it a more economically feasible option with a greater impact on CO2 emissions.
It is important that each scheme is cost effective so it is recommended that the capital and running costs as well as the capital cost per tonne of CO2 saved are compared for the specific community. To calculate this, the capital cost could be divided by the savings of CO2 or a period of time, 20 years in this case study, to find £/tonnes of CO2 saved for each scheme. A comparison of each scheme can then could be carried out to see which are most suitable.
It can be seen that all the schemes could be transferred locally, nationally and indeed globally if the project’s model is used as part of creating a net zero carbon urban community. It has been found in this project that it is important to identify the biggest contributors to the carbon footprint of the community and then use a combination of the various schemes to reduce the emissions. Through this model it can be seen that sectors of the urban community are no longer treated separate entities. It is more important to try to link the different schemes to fully reap the benefits of carbon reduction for the whole community. An example of this is the waste from industry which can be used to supply energy to both the industrial and domestic sectors.
It is important, if an urban community were to apply this model, that the focus would be on enhancing the energy interactions between different sectors of the community. The community must carry out its own research to identify resources that could be used effectively and apply innovative ideas to reduce their carbon footprint.