Pathways to a Low Carbon and Sustainable Future

With ever increasing concern about Climate Change and the increased occurrence of weather-related disasters such as flooding, droughts, hurricanes, typhoons and the consequences of these events causing landslides and damage to property, loss of valuable and productive land and loss of life, it is important to consider how best to minimize the adverse impacts of Climate Change in the future. Individuals and Society should strive for net zero carbon emissions and if possible should explore opportunites to be carbon NEGATIVE – i.e. sequester more carbon than is actually emitted.

There are many approaches that can be taken from changing diets, methods used for transport to improved performance of energy use in buildings. Some approaches can have a direct and immediate impact such as switching off unnecessary appliances and thereby save money. Others can be effective even with existing technology to ensure, by careful management, that resources are used effectively. Yet others may require initial investment but can pay back handsomely in the medium to long term.

It is easy to be seduced by glamorous new technology and think one is doing their bit, but often there are more mundane actions which are more cost effective and require little expense to implement. Some people see paying for carbon offsetting as a way to make a contribution, but such strategies should only be used after other strategies have been explored, and, where possible, implemented. In the following example of energy use in buildings there should be a six step strategy, but this strategy is also relevant, with slight modification in wording in other areas, such as transport etc.:

N.K.Tovey MA, PHD, CEng. MICE, CEnv. Reader Emeritus in Environmental Sciences.

Environment and Sustainability Rotary Action Group (ESRAG) Director.

1. Raising Awareness

Switch off when not needed
Appliances left on standby can often be consuming as much if not more energy when on standby than when being used for the purpose for which they are designed. In July 2005 this was demonstrated on BBC Breakfast Television by Keith Tovey when a household in Sheffield was put under the spot light. The family had a CD/radio which they used for one hour in the morning and then left it on standby. The analysis showed that twice as much energy was used when on standby than that when in actual use. Televisions are another key example, and though modern TVs have a much lower standby consumption, older models could easily save 25% or more by individuals switching them off when not in use. A main consideration when buying a new appliance such as a television is to ensure it has no more than 1W consumption on standby.

A tumble dryer uses around four times as much energy per cycle as the equivalent washing machine. Drying clothes on a washing line saves energy, reduces carbon emissions and most importantly saves money. Reducing the frequency of using a tumble dryer by once a week will save around £10 per year.

In the case of transport, unnecessary emissions and also pollution arise from those who sit in their cars when they are stationary (e.g. in car parks, outside schools etc) with the engine running. Turning the engine off will also save the occupant money.

2.Effective Management of Energy Use

Fig 2. ZICER building at UEA

Energy use, even in old buildings, can be reduced with careful and effective management.   For newer low energy buildings such management is even more important and many, new ultra low energy buildings at buildings at the University of East Anglia have seen their energy consumption for heating reduced by 50% or more through creative adaptive management.  An example is the ZICER Building at UEA which won the low energy Building of the Year Award in 2005.   It has an ultra low heating requirement having quadruple glazing and an effective regenerative heat exchanger for air circulation.  It also has a large 34 kW photovoltaic array of solar panels on the roof and upper façade. 

When first completed, heat energy data was recorded at regular intervals and plotted against external temperature.    A trend line is to be expected as heating energy requirements rise as the external temperature falls. 

The results are shown by the red dots and line in Fig. 3. After sufficient data had been collected to cover all temperatures, the results were examined and it was found that modifications to the controls – such as siting of thermostats, operation of time switches etc resulted in a reduction of 57% as shown by the green points and line.   At the same time studies of thermal comfort were done both before and after the change in strategy and an additional benefit arose in that occupants of the building were more satisfied with their environment.  

A second example shows the benefits from collecting heating consumption data in a church.   The church in question is heated by three gas hot air heaters, and there is no other use of gas in the premises. 

Weekly data showed over the summer showed that though there was no heating on there was still gas consumption amounting to approximately 175 kWh per week coasting over £9 a week (Fig. 4). 

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Investigation showed that the cause was the pilot lights which were on continually.    This was proved when, for several weeks, the pilot lights were turned off.     When the heating season started again, just one pilot lights was left on continuously,   and the churchwardens would reignite the other two when they arrived before a service.    Overall there was a monetary saving of £200 a year and a carbon saving of over ½ tonne of carbon dioxide as a result of such action nvestigation showed that the cause was the pilot lights which were on continually.    This was proved when, for several weeks, the pilot lights were turned off.     When the heating season started again, just one pilot lights was left on continuously,   and the churchwardens would reignite the other two when they arrived before a service.    Overall there was a monetary saving of £200 a year and a carbon saving of over ½ tonne of carbon dioxide as a result of such action 

Figure 5   Electricity consumption in a large office building in Norwich.

Another example where effective management can reduce costs and carbon emissions in buildings if highlighted by the trends of electricity consumption in an office block in Norwich.  In a scheme to reduce energy and carbon emissions, low energy lighting was installed progressively through the building over a period of several months.  Monthly electricity consumption from 2003 to 2005 is shown in figure 5. 

During 2003 and early 2004 before installation of the low energy lighting began, there was a fairly constant consumption of   31800    kWh/month which represents the baseline consumption.   The improvements from low energy lighting are shown during the period July 2004 to February 2005, and thereafter there was a new baseline established which continued until May 2005 of 22800 kWh per month representing a saving in emissions of 55 tonnes CO2e,  and a monerary saving of £5000 a year.   

 

 

Subsequently, the consumption rose unexpectedly, and over the next 6 months, no less than an additional  57 tonnes were emitted costing an additional £11000.  When questioned in early January 2006, those responsible said there was a fault in the heating and air-conditioning system such that both were on simultaneously and fighting against each other.  They reported that it would cost over £1000 to fix, and were horrified to learn that they had wasted 10 times that amount in just 6 months.   This demonstrates the importance of good record keeping and management. 

In the case of transport, savings of up to 15% in emissions can be achieved at no extra cost by slow acceleration and minimising braking by taking the foot off the pedal early when approaching roundabouts and traffic lights.  For those with a hybrid, plub-in hybrid or electric vehicle, further savings can be achieved using the regenerative brake on slowing in preference to the foot brake. 

3. Installing More Efficient Appliances

In the case of buildings, the first priority here is to enhance the insulation levels in buildings and appliances  such as loft insulation, cavity wall insulation, double glazing, draft exclusion, and hot water tank insulation  etc. 

There have been significant improvements in the energy efficiency of many appliances using energy in buildings.   It is important not to change and appliance too early as the embedded carbon associated with the new appliance will minimise and may even negate benefits from changing.   However, all appliances do wear out eventually and will need to be replaced.   It is at that time decisions should be made to purchase efficient appliances even though the capital cost may be a little more.   Such examples of efficient appliances would include LED lights, “A” rated or preferably “A+(+) rated white goods,  efficient condensing boilers or preferably heat pumps.    Fig 6. Shows an example at the University of East Anglia where the central heating boilers were coming to the end of their lives after 30+ years in 1998.   Steps were taken to install combined heat and power generation.  These units provided much of the electricity and heat throughout the year with the old boilers are used occasionally if heat demand was high.   This installation, though costly at around £3 million, saved 34% in carbon emissions and a monetary saving approaching £1 million pounds a year in energy costs.   It has now paid back handsomely. 

Fig 7. A typical domestic air-source heat pump

4. Installing Renewable Energy

Once all the three steps above have been explored, options for installing renewable energy should be considered.  Individuals and organisations should not be swayed by the fact that renewable energy such as solar panels is a visible statement whereas more mundane actions such as loft insulation are invisible, and yet the latter can have a more dramatic effect on reducing energy consumption and carbon reduction as indicated in sections 2 and 3 above.    

Fig. 8 shows a domestic property in Norwich with a 1.25 kW array of solar photovoltaic cells, and a two panel solar thermal array.   The optimum orientation is not necessarily due south as is commonly assumed.    In East Anglia the optimum is actually 5 -10 degrees west of south.   This is because there is generally less cloud cover in the afternoon than in the morning in East Anglia.   

Fig 8 Solar photovoltaic cells (left) and Solar thermal cells (right).

The measured performance of these solar electric cells shows a load factor of 9.5% and a typical annual output is 1150 – 1200 kWh.    For the solar thermal panels, the measured annual output has averaged 850 – 900 kWh per annum.   However, the output from solar thermal panels is influenced significantly from the actual time of day that hot water is used.    Thus if a hot bath or shower is taken late at night or in the early morning, then the water storage tank will have much of its heat drained when the sun starts rising, and thus can collect more energy than if no hot water had been used and the water in the tank was still at a moderate temperature at the start of the day.    

 

5. Implementing Carbon Sequestration such as Tree Planting

Once all strategies above have been explored, and residual emissions can be offset by carbon capture schemes such as tree planting.    However, it is important that this should be done after all previous steps have been completed as a holistic approach covering all aspects is needed.   When planting trees it must be remembered that a sizeable percentage of new trees are likely to be lost within a few years from animal or other damage including fires.    

While it is possible to minimise most, if not all the carbon emissions from buildings by the steps above, other activities are less easy to see reductions such as travel and particularly air travel.   It is here that that the final step of carbon offsetting is important at the present time.

Fig 9. Tree planting -an effective way to sequester carbon.

 

6. Paying for Carbon Offsetting

Carbon offsetting should not be used so that one can continue with ones current lifestyle, All the previous should must be completed first. Carbon offsetting involves and individual or organisation to pay others who have opportunities to reduce their own emissions. There are several websites offering offsets which may involve tree planting or installation of additional renewable energy. provision of more efficient cookers in developing countries etc.     

These are more often than not quoted as a monetary cost to offset a flight  but other emissions are often more substantive and there is a serious question as to whether the costs charged reflect the true cost of carbon.    One Website for instance, (myClimate), suggests that a round trip from London to New York (Economy Class) causes the emission of 1.8 tonnes CO2 and can be offset for £39 per person (or £21 per tonne CO2).   However, recent analysis suggests that the true cost of carbon is rather more at around £75 per tonne suggesting a more realistic figure is £135 per person or £540 for a family of four.    

Carbon reduction strategies involving projects in developing countries must be carefully considered as to whether they do indeed reduce carbon emission globally.   Thus using offset funds to install solar PV cells in a village which previously had no electricity, though morally admirable, it will not help reduce carbon emissions.   On the other hand if the village had a diesel generator and this was replaced, then there would indeed be a genuine reduction.  Simlarly using the money to install more efficient cooking stoves such as the ones described by Keith Tovey at   Environmental Sustainability – Rotary Great Britain & Ireland – Posts | Facebook can make a substantial saving pf up to around 40 tonnes of CO2e  each year..    It is vital that any disbursement of funds collected from carbon offsetting do fully meet the criteria of additionality.