Carbon Savings in a Somerset Market Town (Frome)

13 July 2007

Introduction

As the impacts of climate change on our daily lives become ever more apparent, and oil prices continue to rise, the case for energy descent becomes stronger.

While individuals can minimise their carbon footprint, and thus reduce their dependency on fossil fuels, the savings to be made become much more significant when carried out across a town.

This article highlights some carbon dioxide savings that the people of Frome – a Somerset market town – could make collectively.

Q1. If every Frome household who left their TV on standby, switched it off instead, how much CO2 and money would Frome save?

According to the 2001 census, the population of Frome = 24510

Assuming 3.5 people per household = 7000 households.

Assume 50% of these households have a TV that they leave on standby (the others switch them off, or don’t use a TV)

=> 3,500 households with a TV left on standby

Assume each TV is left on standby for 20 hours, and only used for 4, and that when in standby, each TV consumes 5W power.

=> Daily energy loss in Frome

= 3,500 households * 20 hours * 5W

= 350000 Whr

= 350 kWHr/day

Assume electricity costs £0.12/kWHr

=> Daily money wasted in Frome from TVs left on standby

= 350 kWHr * £0.12/kWHr

= £42/day

=> Annual money wasted in Frome from TVs left on standby

= £42/day * 365 days/year

= £15,330/year

Assume this electricity is generated from non-renewable sources, emitting 0.45kgCO2/kWHr

=> Daily CO2 produced in Frome from TVs left on standby

= 350 kWHr/day * 0.45 kgCO2/kWHr

= 157.5 kgCO2/day

=> Annual CO2 produced in Frome from TVs left on standby

= 157.5 kgCO2/day * 365 days/year

= 57487.5 kgCO2/year

= 57.5 tonnes CO2/year

Q2. If every Frome household avoided driving to the supermarket for their weekly shop, and went to the local shops on foot or public transport, how much CO2 and money would Frome save?

According to the 2001 census, the population of Frome = 24510

Assuming 3.5 people per household = 7000 households.

Assume 80% of these households shop once a week

=> Number of trips supermarket/week

= 80% of 7000 households

= 5600 trips/week

Assume each trip is a total distance of 2km (ie a fairly near by out-of-town, supermarket eg Sainsburys or Asda)

=> Weekly distance travelled by Frome households to supermarket and back by car

= 5600 trips/week * 2km/trip

= 11200 km/week

Assume the average car is reasonably efficient, and produces 180gCO2/km

=> Weekly transport CO2

= 11200 km/week * 180gCO2/km

= 2016 kgCO2/week

= 2 tonnes CO2/week

=> Annual transport CO2

= 2016 kgCO2/week * 52 weeks/year

= 104832 kgCO2/year

= 105 tonnes CO2/year

Assume car costs 20p/km to run (including fuel, insurance, tax, repairs, depreciation etc.)

=> Weekly transport cost

= 11200 km/week * 20p/km

= £2,240 / week

=> Annual transport cost

= £2,240 / week * 52 weeks/year

= £116,480

This figure is extraordinary. It shows the importance to the Treasury of tax on fuel – if the government extracts 50% of this revenue in tax (a not unrealistic figure), Frome residents are paying the Treasury over £50,000 a year, just to get to their ‘local’ supermarket!

Q3. If every household in Frome switched to a renewable electricity supplier, how much CO2 would be saved?

According to the 2001 census, the population of Frome = 24510

Assuming 3.5 people per household = 7000 households.

Assuming that the proportion who already use renewable electricity is less than 1% (ie negligible)

Assume that each household is reasonably frugal in electricity, and gets through 2 Megawatt hours/year, ie 2000 kWHr/year

=> Annual energy consumption

= 7000 households * 2 MWHr/household/year

= 14,000 MWHr/year

Assume this electricity is currently generated from non-renewable sources, emitting 0.45kgCO2/kWHr, or 450kgCO2/MWHr

=> Annual CO2 emissions from electricity consumption

= 14,000 MWHr/year * 450 kgCO2/MWHr

= 6,300,000 kgCO2/year

= 6,300 tonnes CO2/year

Frome would save approximately 6,300 tonnes CO2/year if all households switched to a renewable electricity supplier such as Good Energy.