Further Study

The research within this project has led to areas that show further potential for CO₂ savings. These areas have not been explored fully due for various reasons; time constraints, relevance, feasibility, potential or complexity. Some of the most interesting and promising ideas will be discussed with their predicted potential CO₂ reduction contribution.

Solar Thermal

The use of either a stand alone solar thermal system, or a hybrid PV/thermal system was considered. The expected output was to be in the region of 6.9GWh per year. This would equate to a potential CO₂ saving of 1562 tonnes per year. The reason this scheme was not explored fully was the demand matching situation. The highest heat demand is in the winter, and this would be the period in which there would be least heat produced. This was expected to hinder the economic value of such a scheme. However, there is still potential if sufficient thermal storage is achieved as hot water demand exists all year round.

Street Lights

Upgrading the street lighting within the community is an area of possible demand reduction. The current sodium bulbs are inefficient and consume a large amount of energy. If LED lighting was used then the consumption of street lighting in the area would drop by 50-70%.

The reduction in power rating could be as follows;
Town Street Light – 250W -> 112W
Pavement Lights – 150W -> 56W

According to the Sustainable Glasgow Report this could give a possible CO₂ saving of 0.5% across Glasgow.

Another option would be to turn the streetlights off during the hours 1am-5am, or dimming between these hours, with a further saving of between 30-50% on energy consumption. However this was dismissed for an inner city district due to the adverse effect on crime in the area that may result from insufficient street lighting.

Off the grid street lighting was also considered as a potential option. It was not pursued due to demand matching proving difficult for solar power as daylight hours conflicting with street light hours, and the modelling of the potential of small scale urban wind proves to be complex.

Fertiliser

Digesting sludge and municipal waste has been shown to improve the quality of these waste streams for fertiliser use although there is a need to ensure pathogen levels are low. Using sludge as fertiliser could be a significant method of offsetting the carbon footprint of agriculture if it is considered that chemical fertiliser would be needed to replace the nutrients it provides. However for this to be possible the pellets must meet the stringent limits in terms of heavy metal, and dioxin levels. These substances are difficult to remove once they are in the waste stream, and as such it is likely that a lot of benefit would be obtained from introducing limits to the sale of unnecessary sources of these contaminants and introducing education to show people that certain chemicals should not be poured down the drain.

Press Water

A large amount of water is removed from the spent grain when it is dryed. This water is known as press water and is high in nutrients and can be used in an anaerobic digester to produce biogas. It is expected that 22.9 million litres of press water will be produced per year, which could create as much as 160000m3 per year. If offset against the use of natural gas in the brewery this could account for a further saving of 196 tonnes of CO₂ per year.

Super Demand Reduction in Dwellings

Upgrading housing stock to a super insulation standard was all possible upgrades would produce a further saving of around 1,500 tonnes of CO₂ per annum. However, it was found that the extended payback period for such upgrades make this scheme less economically viable. It was decided then to upgrade to the most economic level.

Synthetic Trees

As mentioned in the literature review, the possibility of synthetic trees was considered. The CO₂ captured from the atmosphere could be in the region of 500-2000 tonnes of CO₂ per annum. This option was not pursued further due to the immaturity of the technology and the lack of a destination for the large amounts of captured CO₂.

Total Potential Further CO₂ Saving

The total contribution to reducing CO₂ emissions in the area by the application of these schemes is outlined in Figure 1.

Figure 1 – Estimated Further Potential

Further Possible Community Schemes

Research also identified areas of interest that would boost the community aspect of the area, whilst still providing potential CO₂ savings.

The introduction of large (possibly vertical) greenhouses that utilise excess heat and CO₂ from any local industry was also discussed. This would provide locally grown produce for the area and also reduce the amount of food transport required to supply the community.

The application of a microgrid will ensure energy generated within the area is used in it. This scheme is being trialled in a rural community where there is singular community grid connection. This has the benefits of any profit from exported energy being used within the community and minimisation of transmission losses.

Another area that was looked at was introducing internal doors into tenement closes which creates a draught lobby. This reduces the amount of heat that is lost from the flats in the block through what is usually a thermally inefficient close. Upgrading the lighting within the close to LEDs with sensing systems could also reduce the electricity consumption. An improved environment within the close would benefit the tenants.