Camco International, has just bought BRADSHAW Consulting, a software business which helps companies in the UK and United States to find ways of reducing their carbon emissions, energy consumption and waste for up to £1.5m.

I'm all for computer software playing a bigger role in carbon accounting - if only because there might be less room for selective interpretation of what is a carbon-offset, as recent controversies attest whether over biofuels or tree-planting or something else.

Still, whilst you could theoretically keep track of all your emissions at the micro level, I still think there's one giant hole in carbon accounting; at the macro level. What about the energy input produced from bought-in goods?

That is to say, if a firm buys computers/electronics components online from www.anymanufacturer.com, have they any idea how many carbon emissions that took to build the at least 90% or so of components that were made in China or Taiwan?

Was that energy powered by coal, nuclear or hydropower?

Right now for those firms, these are impossible questions to answer. And for the forseeable future, rightly or wrongly, China has no intention of decoupling economic growth from rising carbon emissions. So whatever Western firms think they're doing at the micro level to reduce carbon emissions, their reductions will quickly get overtaken by China's record-breaking coal-fuelled economic growth.

Low Carbon Accelerator, the first AIM-listed private equity fund to invest in alternative energy companies, has already got quite an interesting spread of investments - 8 in total.

The one that really caught my eye was their £4.5 million investment in Proven Energy, a highly respected manufacturer and installer in small wind turbines, ranging in size from 2.5 kilowatts to 15 kilowatts. Proven wind turbines are deemed to be the most solid and reliable on the market, not least because they are "heavy metal" and therefore unlike conventional megawatt class turbines, can work in hurricane force winds. Obviously it helps the firm that they are based in Scotland, where the climate can be unforgiving and for many, electrification by the national grid is not a possibility.

But it's the urban application that fascinates me. Here's a Proven wind turbine I drive by quite regularly on the Wandsworth Roundabout in London.

I'm always drawn to look at it and I have to say, it is almost never not turning at quite a speed. I gather that BP are rolling back their solar programme for their petrol stations and using micro wind turbines where possible instead - the economics are simply much better. Small wind turbines have been bashed in the media quite a bit, but I still think that in cost, output and potential, they will still beat solar pv hands down, for some time to come.