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Published on December 15th, 2013 | by Shrink That Footprint

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My Story Of Carbon Footprint Calculation



Originally published on Shrink That Footprint.
By Lindsay Wilson.

My Carbon Footprint

Writing a blog about reducing your carbon footprint is much, much easier than actually cutting your footprint.

This post is where the rubber meets the road. It details my carbon footprint from 2012, the things I did, the things I didn’t do, and my struggles along the way.

I did the data for this post back in January but didn’t publish then, as the blog was brand new. Now that 2013 is coming to an end and I’ve almost got another year of data, I though I should dust it off and walk you through my footprint.

Btw: this post is a whopper so don’t be scared to scroll to what interests you. It goes through a summary, housing, travel, food, products, and services.

My Carbon Footprint in 2012

In 2012 my carbon footprint was about 4.67 t CO2e. This is a little bit under the global average for personal emissions.

In this calculation I include all the emissions that result from my share of spending on housing, travel, food, products, and services. This includes the full climate impact of my spending by accounting for length of the supply chains associated with purchases of energy, food, products, and services.

The calculation is done with our own carbon calculator, using adjustments to the carbon intensities where necessary.

My Carbon FootprintThe breakdown of my 4.67 t CO2e is as follows. Housing (1.2 t), travel (0.9 t), food (1.4 t), products (0.6 t), and services (0.6 t).

The three biggest components of my 2012 footprint are natural gas (653 kg), driving (663 kg), and electricity (312 kg). This is similar to a typical UK resident, though my emissions are quite a bit lower.

In terms of the calculation, both the housing and travel numbers should be very accurate, as I’ve done them using units of fuel. I think I’ve done a pretty decent job with the food calculations, and services are quite homogeneous so not too bad either. The product figures are likely to be the most inaccurate as you can’t be sure your purchases have similar emissions to typical products in those groups.

Finally, as a calculation of my personal footprint, this figure does not account for my share of government and construction emissions in the UK. This would add about 3 t CO2e to my figure. Net UK land use emissions are pretty negligible.

Now, to explain what we are doing, what we aren’t doing, and why . . .

My Housing Footprint

In our house the main challenge is keeping warm while avoiding a big emissions. Throughout 2012 we were a 3 person household. So my emissions above are a third of our total household footprint.

This picture below is our place. It is pretty standard ex-council semi from the 1950s, although it has been nicely refurbished and we have added some solar panels.

Our house

The major sources of household emissions in 2012 were natural gas (653 kg), electricity (312 kg), and waste (170 kg). Together in the house we used 9,300 kWh of natural gas for heating and hot water, 1500 kWh of grid electricity, and generated about 10kg of waste a week, less after composting.

Heating and Hot Water Emissions:

Reducing heating emissions is the biggest struggle in our house. Since buying our house 3 years ago, we have insulated floors, the loft (attic) and walls, replaced a few windows, and also replaced the old boiler with a more efficient one (still natural gas). We keep the house pretty cold (around 12-15 C), with the exception of the main living area, which we heat well (18-20 C).

We also have a wood burner which we use pretty regularly. We use straw briquettes (CO2 absorber last summer) and waste-wood kindling, as I don’t like the idea of burning virgin wood that is decades old. As is the standard, I don’t count these emission here (if I did, they would add 400 kg). This said, I still have mixed feelings about burning biomass, even short rotation stuff, both on a CO2 and particulate level.

I have investigated in detail the possibility of externally cladding our house with insulation. I really like this idea, and aiming for the passivhaus retrofit standard, but it would require a new roof and the payback time is horrendous for us as our heating bill is currently pretty low. So, for us, it is a super expensive way to cut carbon that I’m unlikely to do any time soon. I can get much more bang for my buck elsewhere.

Hot water actually accounts for a little over a third of our gas use. The only strategy we use to reduce this is to use less, and to ensure the boiler temperature isn’t too high. This is becoming an increasing struggle now that we have little kids who have regular baths.

Electricity Emissions

We’ve had solar panels on our house since August 2011. The solar (3.29 kWp, Sanyo panels, Fronius Inverter) has produced almost exactly 3,300 kWh each of the last two years. This is 50% more electricity than we use over the year, but of course our production occurs at different times to use. I’ll show you what I mean using some data.

Over the two days of December 8 and 9, our solar panels produced 8.6 kWh of electricity while we used 9.3 kWh of electricity. Seemly pretty good. But if you look at the hourly data below, you can see that most of the solar electricity was exported during the day and that consumption occurred primarily from 4-11pm when the panels were not producing.

Our solar production

Click on the image to expand it.

You’ll see the solar production in green, with Monday the 9th being a pretty sunny day for December in England. In the red you can see our usage, with a spike at 5–6pm each day as we prepare dinner. The nighttime usage is the fridge cycling on and off.

It is obviously better in the summer when production hours extend, but you get the picture. As we are grid-tied on the feed-in tariff, that isn’t going to change.

In 2012 we used 1,950 kWh of electricity. 575 kWh of this was solar power, with the remaining 1,375 kWh from the grid. We exported 2,725 kWh to the grid, which does our bit to improve the fuel mix on the grid.

In my calculation of our emissions I use the grid factors (including upstream emissions) for our grid share, and a typical solar value (50 g CO2e/kWh) for our solar stuff. I don’t subtract the grid export from our numbers, because I think negative values for export are a little silly (unless you can make short rotation biomass work with carbon capture).

We don’t really do anything with the solar, other than to make sure it hasn’t tripped and to use the washing machine while the sun shines (that is the red spike at 11am Sunday). Instead we focus on our uses of electricity by actively using an energy monitor and improving the efficiency of our lights or appliances where possible.

My Travel Footprint

2012 was one of my best years for travel emissions at just under 1t CO2e. More than two-thirds of this came from car travel, the rest was mostly a monthly train trip to London. I managed to avoid flying in 2012, something that doesn’t always happen.

I have two main modes of transport that I use on a weekly basis, our car and my bike (pictured below).

My car

I love my fabulous old dutch bike from my time in Holland. It is great for trips around the town we live in. And my 3 year old son yells weeeeeee from the back seat as we go down the hill, which makes me cycle more. I also walk a lot, as the town isn’t that big and everything is within 20 mins walk.

Driving Emissions

Our only family car is the 1.4 L diesel Skoda Fabia Estate in the picture. I read a review once that called it the perfect car for two kids and a vasectomy. This is spot on. It is a very thin car with a surprisingly roomy boot for its size. But between two car seats you are lucky to fit a hand bag, let alone a passenger.

In 2012 the Skoda clocked 6,780 miles, which is pretty similar to previous years. Because we don’t need it much in our small town, these were mostly highway miles, generally with two and often with three people in the car.

Because it is a pretty small and efficient car, and we drive mostly on highways, we average about 60 MPG (UK) — that’s 50 MPG (US) or 4.7 L/100km. When you look at these numbers it’s worth remembering diesel emissions are about 15% higher per unit of fuel than gasoline. The downside from the diesel is higher particulate emissions, even with a filter.

Given we have 2,700 kWh of solar electricity that goes to the grid, we could have an electric car. This is something I might look at in the long run, but given how much we currently drive and the UK grid mix, I don’t feel having an electric car at the moment would do much to reduce emissions in a cost-effective way. Moreover, we are pretty frugal and have never owned a car newer than 4 years old, so an electric is a little decadent for us at this point.

Flying Emissions

Although I managed to avoid flying in 2012, flying is and remains my biggest problem when it comes to my carbon footprint.

Back in the year 2000 I was on holiday and drove from my home in Sydney up to see my brother in Brisbane. It was my first break in a while so I stopped in Byron Bay for a week to try and learn to Surf. I never made it to see my brother.

I met this English girl travelling with some friends, gave them a lift back to Sydney, ended up in New Zealand . . .

13 years later I live in the UK, with two little English kids. My parents live in Australia. I’ve got a brother and sister there too, and another brother in New York. My five closest friends live in New York, Tel Aviv, Geneva, Sydney, and Canberra (they are all Australian). I’m suffering an acute case of what George Monbiot would call love miles.

Although we happily use high-speed trains in Europe, there is no practical low-carbon alternative to flying when it comes to trips like London to Sydney to see family. It is what it is, and I hate that. I will fly more in the future, and each time that I do I will completely blow my carbon budget for that year.

Let me show you what I mean:

Flying

No prizes for guessing in which of the last three years I flew to Australia. In 2011 my emissions from one return flight between London and Sydney were equal to all my other emissions that year.

The problem with flying isn’t that it is a huge footprint on a per mile basis. It is simply that you can travel such vast distances so quickly. If you fly a lot, it will quickly dominate your carbon footprint.

If you notice me starting to write posts about offsetting in the future, it probably means I’ve got a flight looming. To me it really is the hardest part about cutting my footprint.

In all other areas of life, I feel like there is a clever mix of behavior and technology that allows me to cut carbon without sacrificing my lifestyle too much. With flying I feel the opposite, it is hugely constraining and stops me going places I would like go to see people I dearly miss.

My Foodprint

In 2012 my foodprint was about 1.4 t CO2e, decent by UK standards but a little over the global average. Here is my foodprint from 2012 broken down into food groups:

Food carbon footprint

Dairy is my major source of emissions, although my foodprint is quite well spread. The majority of my calorie intake comes from breads, grains, snacks, fruit, and vegetables. The beef and lamb emissions come from just one or two serves a month, such is their high carbon intensity.

I have three basic tactics for reducing my foodprint. They are to eat more low carbon foods, to waste less food, and to grow my own food. I also take steps to avoid food that is flown in from abroad, but as I have detailed before, food miles are not a good thing to make your primary focus when it comes to food emissions, as they are not nearly as important as what you eat or what you waste.

1: Eat more low-carbon food

In terms of food choices, I still eat meat and dairy, but am trying to cut down. I’ve found it pretty easy to reduce beef and lamb (the most carbon intensive foods) consumption but have had less success with reducing dairy. Although my cereals, vegetables, and fruit emissions are moderate, these supply a great deal of calories. So, going forward, tackling dairy and further reducing meat consumption are my best options.

2: Waste less food 

We are pretty hot on food waste in our home, and I’ve documented the system we use in our how to save money on food waste video series. The project we did this year weighing it has reduced our food waste further.

You can watch me demonstrate the global food waste problem (by wasting tomatoes) below:

3: Grow your own

By far the most enjoyable part of tackling my foodprint has been the chance to grow my own. In 2012 we had strawberries, corn, beans, broccoli, salads, various herbs, aubergine (eggplant), peppers (capsicum), carrots, courgettes (zucchini), and a huge load of tomatoes.

Most of all I adore growing tomatoes. I grow them from seed, in peat-free compost, using only natural light. They need to be watered each day, and looked after. But from July through the end of November we swim in tomatoes. I end up giving them away, making passatas, chutneys, sauces . . .

My Stuff Footprint

According to my calculations the emissions that resulted from purchases of stuff were about 600kg CO2e in 2012. This is the hardest one to calculate, and it wouldn’t surprise me if this isn’t that accurate, simply because the data has too many assumptions in it to be that accurate.

Compared to the average UK resident I just don’t buy much new stuff. A lot of what constitutes my footprint are the typical non-durable purchases of normal life, or materials for DIY projects.

I buy second-hand goods where possible, upcycle what I can, and generally am not that bothered with a lot of products, as I think too much stuff can crowd out more important things in life. If anything, I’m actively trying to purge the number of possessions I have, though this is a slow process. You can check out some recent upcycles below.

My Services Footprint

Services are by far the least carbon intensive way to spend money. In most cases I actively encourage others to spend more on services if that reduces their spending else where. My main reason for cutting down on service spending is to try to save money. Our service budget is pretty minimal, and includes boring but necessary stuff like banking, telephone, internet, car, as well as the odd bit of holiday accommodation.

The graph below showing the average carbon intensity of spending in the US gives you an idea of why cutting your service footprint should be your last priority. Moreover, many services like education and health aren’t exactly discretionary.

paytheman

My footprint in context

Although I am passionate about helping people take steps to reduce their carbon footprints, I don’t think such actions are the biggest climate levers we have. In fact, when you get serious about your footprint, you’ll quickly realize how important things like carbon pricing, innovation policy, and efficiency legislation are to helping you improve your own footprint.

This much said, individual action is still important.

Almost 70% of global greenhouse gas emissions are paid for private consumption. This means that people the world over, and the wealthy in particular, have enormous potential to cut emissions simply by changing the way they spend. Diverting a little money to improving insulation, getting an efficient vehicle, and insulating your house can reap very large emissions reductions. Moreover, I find that the process of understanding and tackling one’s own footprint can serve as a bridge to help everyday people gain an interest in broader action that is generally intangible for them.

Getting into the nitty-gritty of your own emissions also provides tremendous context as to the scale of the challenges we face. I am perpetually amused by people who think a ‘single solution’ like renewables, or nuclear, or efficiency, or CCS, or innovation, or carbon pricing, is going to be sufficient to stabilize the climate. You can’t possibly think that if you’ve had a proper look at the data. We have many different levers we need to use, and we could really do with some more too.

I’ll show you what I mean by putting my personal footprint of 4.7 t CO2e into the context of a 2C global carbon budget.

In the graph below, I show how the average personal carbon budget globally will need to decline over coming decades in order to have a chance at staying inside 2C of warming by 2100. This is based on the UNEP emissions gap budgets and global population forecasts from the UN. The grey section is our business as usual scenario (BAU) trajectory.

Carbon Budget

My personal footprint of 4.7 t CO2e in 2012 is just a little below the global average from 2010 of 5t.

This figure compares well to a North American’s at around 20 t, or a European at 10 t (you can see some examples here), but is much higher than in poorer Asian, African, or South American nations. In fact, half the world’s population have personal footprints of 2 t or less, largely due to the fact that they have limited access to energy.

In order to limit warming to 2C above pre-industrial temperatures, the global average would need to drop to below 2t by 2050.

How would I get my emissions from 4.7 down to 1.5 over the coming decades without greatly reducing my standard of living?

Let’s look at it by sector:

  • Housing: improve insulation, switch all heat, water and electricity to low-carbon electricity.
  • Transport: use bikes, eBikes, public transport and electric cars, all powered by low-carbon electricity. No flying.
  • Food: further shift to low-carbon foods, minimize food waste, improved food production inputs.
  • Stuff: better materials and manufacturing, greater recycling rates, improve product life, less stuff.
  • Services: reduced emissions from power supply, buildings, and manufacturing.

In each sector, the answer is to squeeze more life out of less carbon.

In the long-term, that means electrifying everything possible and switching totally to low-carbon electricity supply (a gargantuan task). This means no natural gas for heating, no gasoline or diesel for fuel, as well as buying goods with fewer and fewer fossil fuel inputs.

My emissions would then result solely from the processes of making and moving stuff. Some of these areas will not be decarbonized any time soon, things like steel, shipping, and other materials. Viable carbon capture and storage would help a lot in improving industrial emissions. Flying will remain a problem.

If you are prepared to live a very low energy life, then having a low–carbon footprint is not hard. But this is not what the vast majority of people, myself included, actually want.

The real challenge is to create a low-carbon lifestyle that people are actually happy with. That doesn’t mean having a mansion and a private jet, but it does mean a comfortable place to live, some decent transport, a healthy diet, decent stuff, and good access to services.

So, that is my footprint and some global context. If you made it this far, congratulations ;-) For some simple ideas to shrink your own footprint, check out our free eBook Emit This: 13 Strategies for Squeezing More Life Out of Less Carbon.

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About the Author

Shrink That Footprint is a resource for squeezing more life out of less carbon. We are an independent research group that provides information to people interested in reducing their climate impact. Our core focus is understanding, calculating, and reducing personal carbon footprints.



  • Peter Gray

    Thanks for a nice service, showing us how much net carbon comes from various activities. Please allow me a few sobering observations:

    1) Only a microscopic fraction of humanity is likely to go to the considerable trouble (as you’ve demonstrated) of calculating their carbon footprints. An even smaller fraction will do anything significant with that information. Even the writer is undoing years of conservation effort with an occasional flight to Australia.

    2) We could do away with the need for these footprint calculations by simply imposing a tax on every ton of carbon in all fossil fuels.

    3) Properly taxing fossil carbon is likely to make air travel into a luxury good, at least in the short to medium term, if not indefinitely. That’s life, and far better than the huge implicit subsidy we’re giving air travel now. A tax will also provide an incentive to produce biojet fuel.

  • wattleberry

    If we restrict flight to over water only it will make a major contribution, maybe adopting Elon Musk’s ideas. Anyway, who knows the limits yet on electrically powered planes? Even the need for non-recreational travel diminishes with better quality cyber communications.
    Useful progress is taking place on ships, with computer controlled sails and solar contribution as efficiency improves.
    How about enlarging the green area of the landscape by irrigation with huge increases in water availability from solar-powered desalination plants?

    • Peter Gray

      I wouldn’t count on electric airliners for many decades, if ever. The theoretical max delivered energy density of lithium-air batteries is comparable to jet fuel or gasoline, and if the many technical challenges are worked out, those batteries might be usable in cars, but there are some major problems in long-range aircraft:

      1) On a 787 or 747, max fuel at take-off is 43-44% of gross weight. As fuel is burned along the way, the plane gets much lighter and uses less fuel per kilometer, extending its range. Batteries don’t get any lighter en route, so getting the same range means giving up payload, translating to higher $/passenger. That’s assuming real batteries can reach the theoretical max, which never happens in the real world. Any shortfall will only make the electric disadvantage worse.

      2) For structural reasons, a large fraction of aircraft fuel is in the wings. It’s easy to put liquid fuel through a small opening, but swapping out batteries would require large openings, making the wings, and maybe fuselage, heavier for the same strength. Range goes down and/or $/passenger goes up. The alternative of recharging non-removable batteries will increase idle time and cost.

      3) Airliners are very costly, durable capital investments, and safety issues make the industry rightly conservative and skeptical. So big changes take a looong time to be implemented, even if/when they’re shown to be practical.

      Instead of waiting for unlikely or very distant technofixes, why not ask ourselves whether airline passengers (and air shipping) for some reason deserve a free ride on their CO2 pollution?

      • wattleberry

        That’s why I said ‘who knows’. It was still included, though, in anticipation of a possible acceptance of slower and less demanding air travel in the event of minimising the over-water component of journeys by very high speed routing over land where possible. For instance, the ultimate challenges of Europe to Australia could be met via south Asia and to America via north Asia.

  • Wayne Williamson

    Very nice article. I like the going gallager(sp) on the tomatoes. As you’ve done, the first step in reducing your footprint is to know what it is and pick off the ones that have the biggest bang for the buck. Thanks again.

  • Mik Aidt

    Inspiring. Thank you, Lindsay Wilson. About cars: I found these guys inspiring with what they do: http://climatesafety.info/?p=5613

    About flying: yes, I agree with you – no easy way out there.

    1) You can buy indulgences: Some airlines have a tick a box to tick if you want to fly CO2 neutral. These are airlines which either help finance some tree planting projects in the third world for the money that comes in to that account, or they are involved in the process of developing new fuel types, based on bio-fuels etc.

    As I understand it, the CO2 you have been responsible for pulsing into the atmosphere by taking a two-hour return flight is equal to the amount which two trees suck back from the atmosphere in their lifetime. So if you finance the planting of just two trees, you can allegedly in some way travel with a clear conscience. (Is that correctly understood?)

    2) You can prioritise environment above low-budget prices. One can for example be much more aware of what airline you choose to fly with. There are some, such as Virgin, who lead in the airline industry concerning the fight against climate change and who really work hard to make a difference and become sustainable businesses over the years. You can support this effort by purchasing the ticket from them – disregarding what the price is. It is not all about getting the cheapest airline ticket.

    3) Simply being cautious about how often you fly is a first step in the right direction. No one says that we need to slash emission going from 100 to 0 percent in one year. If only we manage to cut, for example, 40% down on CO2 emissions over the next 7 years, then we are still fairly ok running to avoid the climate catastrophe. So, if you in the coming years you manage to fly 10% less than the previous year, for example, then you are still on track.

    A little more on the subject here
    http://climatesafety.info/?page_id=14 # travel

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