In our last two articles, we have considered how transport may change over the coming years. This is of course only half the story.

Clean energy production is possible within a city and there are many other technologies currently available, or just around the corner, which may revolutionise both the power grid and the quality of inner-city air.

Energy generation

It goes without saying that renewable energy sources will be critical to our future energy needs. Within city limits, solar panels are an obvious source of renewable energy, though space to place them is limited, with most being located on the rooves of buildings. There are, however, technologies on the horizon that may change this.

Several universities, including the University of Michigan, Michigan State University (USA) and Incheon National University (South Korea), are developing transparent solar panels, utilising light outside of the normal optical range. While these technologies are still in development – last year the University of Michigan achieved 8.1% efficiency (with a slight green tinge to the windows[1]) – scientists at Michigan State University have estimated that 10% efficiency is obtainable in a perfectly transparent (at optical wavelengths) panel[2]. This may not seem much when compared to the 15–22% efficiency achieved by normal solar panels, but the scope for use of transparent solar panels within cities is significant. For example, if the technology became commercially viable to replace of glass, the surface area which becomes available to place the panels more than makes up for the lower efficiency. One only has to look at 1, 2 and 3 Snow Hill to see the potential.

In addition, while it has not traditionally been the most obvious power source within cities, wind may prove useful on a smaller scale. Clever design of buildings can use the wind to reduce power consumption. A good example of this is the Manchester Civil Justice Centre, which is cooled by drawing air in through wind scoops facing the prevailing wind direction and channelling it through a network of ducts. The building also features technologies that reduce the amount of heating due to sunlight and groundwater cooling systems[3]. Clever designs such as this can significantly reduce the power requirements of large structures.

It is also possible to install wind turbines in a number of locations within a city. In particular, and aside from the obvious of putting vertical wind turbines on the top of structures[4], wind turbines could be used to recover energy from the exhaust of air-conditioning units[5]. The benefit being that an air-conditioning unit provides a stable airflow throughout the day, leading to predictable energy generation at the times when the air-conditioning is most required.

There is, however, one problem with moving to a solely renewable energy model - solar panels produce electricity when the sun shines and wind turbines are only effective when the wind blows. As we use more electricity in the winter and in the evening, when the sun is not shining, there must be a way to store the generated power, ready to be used when it is required. In short, grid level energy storage is required. There are a number of methods that may be available, though the most effective in the short term is battery storage. The benefit of battery storage is that:

(i) it is relatively easy and quick to install at a significant scale (see, for example, Tesla’s installation of the Hornsdale Power Reserve in 63 days from contract signing – though it is noted that some work had been undertaken earlier[6]);

(ii) assuming that legislation can be adopted to change who holds responsibility for car batteries, as life expired batteries are removed from cars, they may be used in homes to provide smaller, but wide-spread, battery storage;

(iii) next generation battery chargers could be designed so that electric cars themselves could act as battery storage. Such an option has been mooted for a number of years and companies such as EDF advertise it as saving costs for businesses[7].

Regardless of how it may be adopted, it is clear that energy storage will be critical for the future. The Government appears to recognise this fact and has recently changed planning rules so that large energy storage sites now fall under the jurisdiction of local planning authorities, as opposed to previously requiring development consent under the Planning Act 2008. This leaves the path open for large scale energy storage projects within the Birmingham area, perhaps in some of those former industrial areas that have been left in disrepair for an extended period.

Other technologies

Aside from changes in transport strategy and energy production, there are a number of other options that the city could consider when looking to improve its environmental credentials. These include:

(i) Increased green spaces – something which the city is actively trying to pursue;

(ii) Bio filters around the city – a technique that has been trialled in a number of cities across Europe. While a number of options exist, one that has been trialled in London is CityTree[8], which uses natural moss filters, contained within large wooden benches, to filter the air in the centre of towns;

(iii) Requiring new builds to use low carbon concrete – many cement producers (including Cemex and Tarmac) offer a low carbon concrete variant that may be appropriate for many types of construction.

Finally, there is also the holy grail of environmental technology – carbon capture. There are a number of technologies in development, many competing for the $100,000,000 X-Prize sponsored by Elon Musk[9]. If Birmingham wants to be seen as truly environmentally friendly, it must plan on being an early adopter of a working carbon capture system. Perhaps it could even consider offering its streets as a test bed for the technology.

The city must also look at opportunities that may present themselves in the coming decades. By way of example, by 2023 new build homes may not include a gas boiler. Given that 15% of the UK’s carbon dioxide emissions come from heating our homes[10], this would seem to only be a step on the way to a wider ban[11], which may come into force in the early to mid-2030’s[12]. This will inevitably lead to a significant reduction in the use of gas generally. Should gas be removed entirely as a service, we will be left with a vast system of sealed pipes with no purpose. What if this network could be put to another use? Could it be used to transport Hydrogen around the country, possibly for refuelling future vehicles? Maybe it could form part of a future carbon capture system, drawing air from around the country to central locations where the carbon dioxide may be removed, possibly by large scale Sabatier reactors. The possibilities are intriguing at the very least.

Conclusions and final thoughts

Birmingham is a city that has regenerated itself significantly over the last 20 years. The new Bullring, the Gateway, the reopening of the Grand Hotel and many more major projects still to be completed demonstrate the city’s desire to grow and improve itself. Perhaps the next step is for the city to look at green technologies and how they could be developed, tested and implemented throughout the city.

There are many technologies and initiatives which could help Birmingham to lead the way and present itself as an example of what can be achieved. The opportunities are there, it is simply a case of whether we can take them.

If you missed the previous articles in this trilogy, please click on each link to read part 1 and part 2 respectively.

References:

[1] Transparent solar panels for windows hit record 8% efficiency University of Michigan News

[2] Transparent Solar Panels: Reforming Future Energy Supply

[3] Manchester Civil Justice Centre - Mott MacDonald

[4] Wind turbine for city rooftops Results In Brief CORDIS European Commission

[5] Wind power plant from air conditioning exhaust using L Savonius wind turbine: AIP Conference Proceedings: Vol 2097, No 1

[6] Tesla's Giant Australian Battery Farm Is Now Online The Drive

[7] Vehicle to Grid (V2G): Generate savings from your Electric Vehicles

[8] START - Green City Solutions

[9] $100M Prize For Carbon Removal XPRIZE Foundation

[10] UK Gas Boiler Ban - Everything You Need to Know EDF

[11] Climate change: Ban new gas boilers from 2025 to reach net-zero - BBC News

[12] New gas boiler installations banned by mid-2030’s – Which? News