The Greening of Hedgerley Wood

It seems that this issue has come out because companies have only recently been required to publish the fuel mix. And it’s going to shock a lot of people.

I had an authoritative response from someone in the business (who had better not be named):

“I am not surprised at this. Ecotricity is run by Dale Vince… He has persuaded everyone that ecotricity is the greenest of the green, not because it is, but simply because he says that he will plough the profits of his business back into only developing new renewable energy projects. At one level I understand this logic but when I look at it from a business perspective this is just what any “renewable energy company” would do. The fact is that RE is very profitable. It is only recently that companies have had to disclose their energy mix, and so you can actually see that…for many years honest, ethically minded people thought that buying from Ecotricity was the very best they could do when in fact a large proportion of their energy was coming from Nukes!!

This really is a triumph of marketing over substance and… I strongly suggest that you move back to Good Energy who do actually sell 100% renewable.”

So, taking this advice, we’ve switched back to Good Energy. According to electricityinfo.org they are the only UK supplier using a 100% renewable fuel mix.

Back to to the Carbon Account to update our footprint.

I’ve just got round to signing up to Torchbox’s carbon calculator - The Carbon Account. It’s quite the best I’ve used for a number of reasons. It logs detailed information about your particular vehicles and your energy supplier, looks up the latest information on them and presents your progress to reducing your carbon footprint in a really clear, evolving display. The result was higher than I expected (3.57 tonnes) but the reason for this turned out to be rather shocking.

The Carbon account uses information on the fuel mix used by the different energy suppliers from here. We were with Good Energy and they show up as using 100% renewable sources. But we switched to Ecotricity precisely because we were told that they were more truly green. But based on this information, they in fact only source 24% from renewables - with the same percentage coming from coal.

So what’s this about? Going Ecotricity’s web site, I can’t find any reference to their fuel mix. Instead they make great play with the fact that they are the largest investors in new renewables. But is this really the point? And should we switch back to Good Energy?

An interesting factoid from Green Futures.

I was amazed when I first read it and did some quick calculations. We are lucky enough to have around 350 mature trees (mostly beech as it happens) in our plot here at Hedgerley. Some are growing quite close together, so I took 200 as a round number to be conservative. Then at 1g per tree per minute, that would mean we are saving 105,000 tonnes of C02 a year. Or as an alternative prize we could claim guilt-free driving of 250 million kilometers. Crazy surely?

So I wrote to the editor, Roger East. His very charming reply said ‘we’ve goofed’. It should be been 1kg per half hour. They’ve corrected it now on the site.

But it’s still a very significant finding for us. It means that our woodland is saving us 10 tonnes a day, or 3,504 tonnes a year. Which makes our carbon footprint minus 3,500 tonnes.

But what does this mean? Clearly not that we can fly wherever we like and forget about our plans for PV. But it does mean we should be careful about any tree that we cut.

And we only have this saving because we happened to choose buy a house in a wood - it didn’t even cost more than a house not in a wood. And there’s more.

At around 100 trees per acre and with an acre of woodland costing around £2,000, this means that an average person with an average footprint of 10 tonnes could genuinely (not notionally) soak up their emissions at a cost of less than £20. Planting one tree in your garden or in shared woodland would, when it’s mature, go on saving around 18 tonnes of C02 a year.

And what about a campaign for more trees in our towns? Why not one in front of every house - with the householder able to claim the reduction to their carbon ration so long as they look after it?

So is all this still too good to be true? I’m still looking for the original source of the research in New Zealand that came up with these figures.

I’ve been trying to get away from theoretical figures to see what impact PV on our roof could actually have.

I measured our electricity use for the last 24 hours. With seven of us here, the washing machine used a lot and a certain amount of heating as the day was colder, I expected the total to be on the high side. But I was surprised that it turned out to be 60 kWh.

Then I found a useful site with very detailed stats from a house in Gloucestershire. They’ve put in 11 panels with a total output of 1.8kW at a cost (in 2004) of £11,300. And it’s producing between 7 and 10 kWhs a day. They are facing SW rather than S.

So even if we could afford the cost and the roof space for a 3Kw array it would cover at best a quarter of our electricity use.

Worrying.

Last year our attempts to grow more of our food were neatly nipped in the bud by Peter Rabbit. So now I’ve decided the only way is to put up anti-rabbit and anti-deer fencing.

Hopefully it will be effective is protecting the seedlings I’ve just put in. Plus the marigolds - the result of half-remembered old gardeners’ tales about protecting our crop from other pests not kept out by netting.

We went for the day with Devi, Matthew and Rosa to the Green Homes Show in Builth Wells. They were interested in wood-chip boilers, but were not altogether convinced.

I focused on the wind turbine stand by nextgenerationturbines.com. The one they were displaying looked pretty big to me.

In fact it was only 1.8 kW, which wouldn’t be enough for us. It’s a new model made in the US called Skystream 3.7 costing £6,500 without the base. It needs a 2 x 2 meter base, 1 meter deep. For a 5kW turbine we’d have to go for an older design like the Proven from the US that would cost around £20,000. The helix designs start at around £38,000.

They claimed that Skystream 3.7 will generate between 3,000 and 7,000 kWh per year depending on location and wind resource, so a Skystream could generate as much electricity as the average household uses in a year (4,700 units per year).

If a Skystream produces 5,000 units per year, this is worth up to £1,000 per year and will reduce carbon emissions by over 32 tonnes of CO2 over 15 years.

Leaving aside the two implied ‘ifs’, this suggests it would pay for itself in around 8 years.

But is it worth covering only part of our emissions, let alone our neighbours, if it’s their land we need to put it on? I asked about using 3 of these instead of one bigger one (=total of 5.4 kW and £24,000), so that each household could be separate. He said they would have to be 5 diameters apart. Probably not a good idea, since output increases exponentially with rotor diameter.

I was re-energised about the importance of growing our own food - and found this table helpful, showing which crops offered the best value.

And Dick Stawbridge from It’s Not Easy Being Green was practical and amusing - better than his on-screen persona.

One very interesting thing he said was that the best solar collector is woodland. OK so how do we make more use of ours? I looked up theoretical options for generating our electricity from heat (wood-burning stove), but there’s nothing available yet at a domestic level.

After the disappointments about finding a place for a turbine with enough wind, I’ve starting thinking about solar again. One way or another I am determined to start making our own electricity to balance out the amount used by the heat pump and all our media work.

I had thought that the roof was too shaded by the trees, but then I realised that the upper portion of the mansard was actually quite promising. So I’ve been doing some tests. First I put a small PV panel on the roof and made a series of measurements during the course of the day. I chose days before the leaves came on the trees and days afterwards - also sunny days and overcast days.

This was the position in mid May when all the leaves are on the trees. By 10.30 the mansard is almost clear of shadow from the trees on the East.

Then it’s clear all day - this is the picture at 3.0 in the afternoon:

By 4.30 the trees on the South-West are shading the other end.

In fact this afternoon shading can be reduced completely by trimming just two of the trees. So it looks pretty promising. The gables don’t have any effect on the top roof.

The other interesting finding was that, on the multimeter at least, there was little difference between sun and shade, and even little difference between full sun and a cloudy day. I must find out why this is - presumably it doesn’t apply to fully loaded systems.

Looking again at cost, PV is certainly expensive. But I’ve discovered that the grant for a charity is 50%. And, checking with EST, it seems that the charity has only to work in the building, not own it. The other thing is the rumour of prices always about to come down. Perhaps the best will be to get the first 1kW system up to prove things, and then add to it later with, hopefully, cheaper technology.

There were lots of comments on the blog when we first considered replacing our solid fuel aga with a Clearview stove and got the story from Walkers shop in Burford. Since then we’ve sold the Aga and put in a ground heat pump. This does a great job at heating the water and providing background central heating through the existing radiators. However this background heat never gets higher than 18 degrees C and we’d now like to get the kitchen warmer - with the possibility of a bit more heat reaching upstairs.

In fact when we first discussed the heat pump, Dave at Ice Energy said that many families in Scandinavia supplement their heat pumps with a wood-burning stove, so that’s what we’re going to try. Also our friends the Dysons have had a good experience with a Clearview from Walkers.

So today Henry Walker (son of the owner) came over with the engineer, Richard, to measure up and give us an estimate. It seems the old Aga space will work well, so hopefully we will have a really good system in place for the worst of the winter.

At OneClimate we’re thinking of a poll ahead of Bali.

Experimenting first with this one - from Facebook.

At the Sheldonian theatre in Oxford last Thursday 21st June 2007 former US President Jimmy Carter spoke movingly and candidly about his new book Palestine: Peace Not Apartheid and his 30- year involvement with the issue from the inside. He was particularly good in response to questions from the audience.

The lecture is introduced by the Principal of Mansfield College, Diana Walford. Click twice on the play button: