how many cyclists does it take to replace a light bulb?

Cyclists reduce carbon emissions. Light bulbs increase carbon emissions. In each case, how much? Though the comparison is frivolous, Cycling England has asked: if commuters switched to bikes for Bike to Work Week, what would be the saving in CO2 emissions? Here's what they found.

A June 2007 report commissioned by Blue Rubicon for Cycling England (unfortunately not available online) says that if all the car and bus commuters in England were to switch to bicycles for one week, each would save on average 33 kg of CO2 over the week. That's a total of 341,154 tonnes of CO2. Of course, it's not reasonable to expect all commuters to switch, so they calculated that those who travel less than 5 miles per commuting journey could still produce savings of over 44 thousand tonnes of CO2 emissions in a week, which is equivalent to the emissions from heating 16,740 houses for a year.

Oh yes, the lightbulbs. A 60 W incandescent lightbulb burning continuously for 5 days uses 7.2 kWh. If the electricity it uses is generated using natural gas (much cleaner than coal) then the bulb is responsible for just over 3 kg of CO2 emissions for the week. A commuter using an average petrol car to travel 1 mile produces nearly 3 kg of CO2 emissions per week. So there's your answer: a commuter travelling a mile to work who switches to cycling would replace one lightbulb. A random statistic, if ever there was one.

The average Briton is responsible for producing 11 tonnes of CO2 a year, and 21% of this is from using cars and buses. Commuters currently using bicycles in England save an estimated 5 thousand tonnes of CO2 emissions a week. But the number of cyclists is going down. Another report from Blue Rubicon (this one online) shows that in England:

In the last ten years, the average number of bike trips has fallen by more than a fifth - from 18 to 14 trips a year. 69% of people cycle less than once a year. Only 43% of people aged over 5 own bikes.

The challenge is to pass on the enthusiasm for cycling from parents to children. Nearly half of all mothers have never cycled regularly, and 91% of children have never cycled to school. Increased distances from home to school may be part of the reason for the decline, but the report suggests that the biggest obstacle is parents' fear for their children's safety - despite government statistics that show a decline in the number of road accidents involving children.

Cycling England has launched a programme to improve cycling in six demonstration towns. One of them, Aylesbury, reported an increase of 25% in cycling in the first three months of 2006 compared with the same period in 2005. Part of the project is improving cycling infrastructure, which is an important component of any efforts to improve safety for cyclists. And they are building some cycle routes in new housing areas before the houses are built, sending a clear signal to homeowners that there is an alternative way to get to the town centre. Cycle Aylesbury - an online resource for cyclists - reports that cycling is now the main mode of transport for over 10% of residents.

future of coal

Efficient system design is one of the keys to addressing the harmful effects of modern life on the environment. Not only energy efficiency, but also making full use of whatever resources are consumed. This requires treating waste from one process as a resource for another. Many industries extract full value from raw materials, but only where it makes financial sense. One of the most important places (from a carbon perspective) where this does not happen is at coal-fired power stations.

Much as we'd like to wish these monsters away, they aren't going anywhere anytime soon. In his new book Lights Out, Jason Makansi quotes from an article by Jeff Goodell observing that the world is planning to build new coal-fired power stations with a total capacity of 1350 GW, by 2030. To put this expansion programme in perspective, it's roughly equivalent to doubling the total currently installed capacity in the US and China combined.

Sir Nicholas Stern has suggested that South Africa should bury its carbon dioxide emissions from coal power stations, but there are risks with this approach, and they are not minor. Sequestration underground is not a proven method, and a major leak would literally suffocate all life around it, since the carbon dioxide would displace oxygen. The challenge with this approach is not unlike that faced with long-term storage of nuclear waste: for all practical purposes, the material must be contained forever.

Schemes have been suggested to make use of CO2 instead of storing it, for example as a way to accelerate plant growth inside greenhouses; but there are other harmful emissions from coal-fired power stations that need to be captured, converted or used elsewhere to reduce the impacts of burning coal.

Makansi suggests treating the power station as a coal refinery, much like a petroleum refinery. Coal can be used to produce ethanol, hydrogen, gasoline - in fact all the energy products that come from a petroleum refinery, and more. With this approach, electricity is just one of a number of energy output streams. Harmful emissions, which in some cases are removed from the exhaust by converting them to benign gases or solids, can be used more productively. The sulfur in coal produces sulfur dioxide, which is valuable to the fertilizer industry as ammonium sulfate, and is used in gypsum in the construction industry. Oxides of nitrogen can also be used in fertilizer as ammonium nitrate. Fly ash, bottom ash and slag are other byproducts of coal-burning that are useful in the construction industry. Using fly ash in the manufacture of concrete in fact reduces the (substantial) energy required to produce it.

The difficulty is that there is little incentive for power stations to be developed in this way, or for other industries to use these potential byproducts; and there is certainly no incentive to switch to renewables on a scale that will make a difference to reliance on coal. Externalities like social and environmental costs need to be factored in so that efficiencies and synergies and low-carbon energy sources make financial and economic sense. Until then, the best we can hope for is environmental laws that require scrubbing the power station exhaust fumes to reduce harmful emissions; but in a low-carbon world, that's not going to cut it.

solar-assisted coal

South Africa's short-term energy crisis is lack of generating capacity to meet peak electricity demand. A two-pronged approach could relieve Eskom of its headache: reduced consumption (adopting more efficient technologies in homes, offices and factories, and using heating and cooling systems with lower energy requirements) and adding distributed generation of electricity. Some aspects of this strategy would be quick to implement, given the necessary political will and incentives to get things going, and the slower aspects shouldn't be any slower than building big new power stations.

But the bulk of electricity is likely to come from large power stations for some time, so the key choice is between coal and nuclear power, each with its inherent risks. If coal remains the dominant fuel of choice for Eskom, then the biggest environmental issue is carbon emissions. Australia's CSIRO is doing research in a number of fields related to energy, including postcombustion capture (PCC), which is a method of captuing carbon dioxide from flue gases. Though not proven at an industrial scale, PCC is said to capture 85% of CO2, which would dramatically reduce GHG emissions (assuming the captured carbon can then be sequestered or used in some other process, another big "if"). A drawback with PCC is that it requires energy, so either the power station must suffer reduced efficiency, or another power source needs to be added to operate PCC. CSIRO is looking into solar thermal collectors to provide that source, which would be an interesting synergy between solar and fossil fuels.

The CSIRO is also looking at solar thermal systems designed for heating, cooling and electricity generation for individual buildings. These are not just for small-scale applications, but for buildings the size of shopping centres.

stackable car for stacks of choice

MIT researchers are working on an electric car that can be stacked. The innovative technology would reduce space and emissions - which is great - but if it succeeds in improving mobility it will be thanks to how it is used as much as to how it is made. Gil Friend points out parallels to some other attempts to improve personal mobility.

Most of these mobility examples use some form of what are now being called New Mobility Hubs. The modern incarnation of these hubs started in Bremen, Germany, and have spread in Europe and jumped the ocean to Toronto, Canada:

Today, Toronto has a wealth of traveling options, including public transit, taxis, car sharing, bike rental, bike sharing, and pedestrian networks. The effort to interlink these various options is gathering steam, with an initial HUB launched in April of 2006, at Exhibition Place / Liberty Village.

The key to these hubs is providing an innovative systems-based approach to transportation that provides viable alternatives for meeting travel needs.

ethanol smog - welcome to the future

I've said before that ethanol doesn't reduce emissions, but here are some specifics that show that I was right - and wrong. Emissions models at Stanford University are showing that E85 will in some respects be worse than regular petroleum, accordingto Mark Jacobson.

Along with many of the same pollutants as gasoline, a large amount of unburned ethanol gas escapes into the atmosphere. That vapour readily breaks down in sunlight to form acetaldehyde, which can send ozone levels soaring. While ethanol-burning cars will emit fewer carcinogens such as benzene and butadiene, they will spew out 20 times as much acetaldehyde as those using conventional fuel, Jacobsen found.

With growing concerns related to food security, the only remaining benefit of ethanol seems to be reduced reliance on fossil fuels.

the Tupperware party is over

From the EU's Framework Programme, facilitating international cooperation in research on sustainable development:

A significant fraction of fossil fuels is consumed as non-energy use, i.e. as feedstock for the manufacture of synthetic materials and chemical products, e.g. plastics, paints, solvents, lubricants and bitumen. In the long run, these products contribute substantially to CO2 emissions. In Western Europe, non-energy use represents 11-12% of the total amount of fossil fuels for final consumption. In other parts of the world, the manufacture of non-energy products is increasing very rapidly, e.g. in China. CO2 emissions from non-energy use continue to be a major source of uncertainty in national greenhouse gas (GHG) emission accounting. The NEU-CO2 network has been working on this issue since 1999.

UK raises the bar on emissions targets

The UK government yesterday issued a draft climate change bill setting out five-year targets to reduce CO2 emissions by 60% by 2050.

sinking to the depths

It seems the oceans as a carbon sink may play a bigger role in mitigating CO2 emissions than previously thought. If true, that would help counter global warming, but at what cost to marine life? The changing ocean chemistry may, for example, affect deep-sea corals and shelled organisms.

building codes going green

Edinburgh, Scotland, has taken a bold step, requiring developers who build more than ten flats or houses, or developments with an area of more than 1000 square metres, to provide ten per cent of the development's power through renewable energy sources on site. Edinburgh wants to reduce CO2 emissions by 60 per cent by 2050.

Update: The mayor of Salt Lake City in Utah thinks that an ordinance to provide incentives for private developers to construct buildings to high-performance standards (such as LEED) would be the way to reduce a city's emissions. Salt Lake City has already required buildings using city funds to be LEED-certified.

it's a long road

Fourteen percent of worldwide greenhouse gas emissions are attributable to transport. One of the strategies to reduce CO2 emissions from vehicles is to introduce alternative technologies, but progress is slow. Not only are manufacturers dragging their heels, but even if zero-carbon vehicles were being mass-produced today, it would still take decades to completely replace the current worldwide fleet.

In the UK there is now an action and advisory group, the Low Carbon Vehicle Partnership, whose members share a commitment to accelerate the shift towards low-carbon vehicles and fuels. It is independent of government, but works with various UK government departments.