Thursday, December 11, 2008
Arrest Climate Change
Tuesday, November 4, 2008
Slough Heat map - more details
- a plane flies overhead about 2 hours after sunset on a cold February/March night. It's done then so it's cold enough for people's heating to be on, but after the effect of the sun heating the roofing surface has faded.
- the measure is of how hot the roof is at that time. It clearly cannot know how hot the house is in the first place, so you can't make any firm assessment of how good the insulation is, just how much heat is being emitted at the time of surveying.
Wednesday, October 29, 2008
Notes on Cippenham planning committee
- many of the councillors focussed on the identity and motives of the applicant, rather than the merits of the application, in clear breach of the rules of the committee, and despite being warned by the committee officers
- Cllr Dale-Gough persisted in perpetuating myths about the efficiency of turbines, which even if were true, are outside the bounds of consideration of a planning committee, according to Planning Policy Statement 22
- A number of councillors expressed what appeared to be genuine outrage that the turbine would be connected to the National Grid, rather than directly to local homes. Cllr Swindlehurst went even further, comparing the turbine because of this unfavourably against the Slough Heat and Power power station, on the Trading Estate, even though that too is connected to the National Grid (as is every other power station in the country for the last 80 years, including houses with solar panel installations). I've tried to see the logic, but how can you prefer one installation to another, when the point on which you say makes the difference is exactly the same?
Core strategy supports renewable energy, outweighs impact on the landscape, but not local amenity.
Noise - likely input, information insufficient.
Shadow flicker - would be intermittent, and significant in Marcia Court.
Safety - access below blades, and most sites usually open land/industrial sites - turbine would be on a major route that local people could not avoid.
BAA - no objections.
New evidence from developer, does not provide any reason for changing recommendation.
New information on noise could be grounds for appeal.
Cllr Parmar
Renewable energy is a good idea, which he is not against in principle, but is opposed to siting the turbine in an urban area, which is the "wrong place".
Article 8 of the Human Rights Act - the right to a peaceful family life.
Turbine (including blade at highest point) would be higher than the London Eye and Big Ben.
Shadow flicker - telling residents to close curtains would be "ridiculous"
No evidence of any site selection process.
Noise from turbine would be "frightening" and "overbearing"
No bird/bat or vibration assessment.
No data on collapsing pattern. Green Park site is designed to collapse away from M4 into "safe" landing area - no such point on this site.
Effect on House prices.
Flicker - negative effect on health/sleeplessness
Effect on radar
Large petition from local residents/wind rats
Recomended refusal
Cllr Chohan
Cippenham Meadows - Labour
Started off a bit cheeky, speculating on the effect of the potential vibration on the bedrooms of his constituents.
Concerned about an overbearing "huge wind turbine". Did not think it appropriate for a local resident area, and that comparable turbines, eg Green Park, Reading, are not as close to houses.
Cllr Davis
Cippenham Meadows - Labour
Barratt Homes had not done the required research, and not concerned about local people. Suggested that a turbine should be close to the home of "Mr Barratt." Expressed opinion that "Barratt think that because it is Slough, they think they can do anything".
Planning decisions are supposed to assessed on the quality of the application, not the identity of the applicant.
Cllr Dale-Gough
Langley St Mary's - Conservative
Declared that wind-turbines are renowned for their ineffectivenees, and that there is no wind for 30% of the time, and have to be turned off in gales.
Whilst crowd-pleasing, this is inapplicable to this decision for 2 reasons:
1) It makes no sense to base a decision on "efficiency" of a turbine, when the fuel is free - http://www.bwea.com/ref/faq.html#efficient. Conventional coal power-stations are highly inefficient, losing a third of their energy during the process of burning coal to heat steam then cool it down again. Perhaps the councillor is confused with the "load-factor" - the proportion of energy the plant can produce compared to it's theoretical maximum.
2) It is irrelevant to the decision, according to Planning Policy Statement 22 key principle 6 : "Small-scale projects can provide a limited but valuable contribution to overall outputs of renewable energy and to meeting energy needs both locally and nationally. Planning authorities should not therefore reject planning applications simply because the level of output is small."
He then went on to say that a better site would be in the sewage works across the M4.
Perhaps a councillor for Langley, he could be excused for not knowing the geography of the part of the town he was talking about and making a decision on, but as a map shows, there are still houses close to his proposed site.
Foxborough - Liberal Democrats/BILLD Group
Britwell - Independent Britwellian Residents / BILLD Group
Cippenham Meadows - Labour
Monday, October 27, 2008
Slough Heat-loss map
Constructed from thermal imaging photos in March 2008, it claims to show the level of heat loss from all the houses in Slough. Potentially a great tool, but 2 questions come to mind ...
1) just when was the data gathered? To measure how much heat is being lost, the measurement has to be taken at a time when heat is being used within the house.
2) what does the scale 1-7 actually mean? Insulation is measured in "U" units - a measure of the way heat travels through a specific area - http://en.wikipedia.org/wiki/U-value#U-value
The SBC environment team are pretty friendly, and deserve full credit for organising this, so I hope to get some context for the data, pretty though the colours are .... tools like this are going to be increasingly more important as we try to close the energy gap - it's not enough to find new ways of generating energy, we need to reduce the amount we use too.
Thursday, October 23, 2008
Cippenham turbine refused
More details later, but I made a submission for an adjournment. The council officers report was quite thorough in detailing many of the local environmental impacts, but failed (in my opinion) to reflect that "wider environmental and economic benefits, whatever their scale, are material considerations and should be given significant weight." - from Planning Policy Statement 22: Renewable Energy
As far as I can see, the wider implications weren't considered at all.
Hopefully they will next time though ...
P/08770/066- Land adj to extension of Eltham Avenue, Cippenham, Slough
To the Planning Committee, Slough Borough Council
I propose that the hearing for this application be postponed, as the Officer's Report does not take sufficient account of the wider context that this application has been made in, and fails to meet the required considerations, as required by Government Planning Policy Statement 22 (Renewable Energy). I suggest that a new report be written, taking all the relevant factors into consideration.
In particular, the report states that "the development is considered to have an adverse affect on sustainability and the environment". However, in section 7.1, it correctly quotes Government Planning Policy Statement 22 (Renewable Energy) as saying that "wider environmental and economic benefits, whatever their scale, are material considerations and should be given significant weight.". Unfortunately, at no point in their report do they mention what these may be. I believe that the report is therefore flawed, and should not be admitted as valid guidance until they have been addressed.
It appears to me that the author of the report has concentrated solely on *local* environmental issues (such as shadow flicker and noise), but has failed to address the *wider* issues at stake. My personal assessment of what these issues are:
*) fossil fuel methods of producing electricity emit significant levels pollutants. These include CO2, which the most recent IPCC report states quite clearly is responsible for growing levels of climate change, and must be reduced. Other pollutants, such as sulphur dioxide, are also produced.
*) the UK is legally committed to producing 15 of all it's renewables by 2020. This means that wind-power must contribute 36% of all the energy in the UK by that point - http://www.guardian.co.uk/environment/2008/oct/19/renewable-energy-greenhouse-carbon-emissions
*) the UK now produces most of it's electricity using natural gas. The UK's indigenous supplies of gas have now been more or less exhausted, making us reliant on Russia for our supplies
*) 5.4 million people are now living in fuel poverty (10% or more of their income being spent on fuel bills - http://www.uswitch.com/news/energy/energy/54-million-households-in-fuel-poverty.cmsx Whilst this is a probably not much of a consideration for the kind of people who worry about house prices, a sizable proportion of Slough's population fall into this category, and a development of this nature will start to help them. This must be one of the core concerns of local government.
*) The UK is committing itself to reducing CO2 emissions to 80% of 1990 levels by 2050. Projects such as this are essential to this happening.
In short, the political climate is changing faster than the environmental one, and whether we like it or not, projects such as these are going to be not only more common, but in all likelihood *compulsory* in the future. Subject to the developers meeting the relevant concerns raised, and making commitments to improve energy efficiency in the local area, I personally believe this project should be approved.
However, since the report fails in its duty to provide a proper assessment of the "wider environmental and economic benefits" of the project, it seems only right that this hearing be put back until a period in which a valid report can be produced.
many thanks
Toby Evans
Friday, October 17, 2008
Refusal recommended for Cippenham windfarm
16.0 PART D: LIST OF REFUSAL REASON(S)Reason(s)1. Visual Amenity
The residential amenity of nearby existing homes will be adversely
affected by the size of the turbine and its proximity to those homes in
terms of visual amenity and sense of it being overbearing.
Consequently the proposal is not in accordance with The Adopted
Local Plan for Slough 2004 Policy EN1 (Design) and Policy 9 (Built
Environment) of the Local Development Framework Core Strategy
(Submission) November 2007 (confirmed sound August 2008).
2. Noise
The noise assessment is inadequate to judge the impact of noise on
residential property. Consequently it is unclear if Planning Policy
Guidance 24 (Noise) and policy 8 (Sustainability and the
Environment) of the Local Development Framework Core Strategy
(Submission) November 2007 (confirmed sound August 2008) can be
complied with.
3. Shadow Flicker
The assessed shadow flicker will have an adverse affect on residential
amenity such that the proposal does not comply with policy 8
(Sustainability and the Environment) of the Local Development
Framework Core Strategy (Submission) November 2007 (confirmed
sound August 2008) in terms of quality of design.
4. Safety
The rotor blades oversailling of a public highway, proposed public
building/car park and public recreation area is considered to be a
potential safety hazard or perceived hazard which is poor design and
will hinder use of these public recreation and transport facilities.
Consequently the proposal does not comply with The Adopted Local
Plan for Slough 2004 Policy EN 1 (Design) nor Policy 8
(Sustainability and the Environment) of the Local Development
Framework Core Strategy (Submission) November 2007 (confirmed
sound August 2008) in terms of quality of design.
It's a difficult one - it's a big turbine, and the proposed site is pretty close to the nearest houses- but there's an energy crisis looming, and we need to maximise all our opportunities for alternatives to dwindling and polluting fossil fuels. Turbines are still new and relatively unknown, it'll be interesting to see if and how public opinion changes.
5. TV reception
The need for mitigation measures to ensure television reception for
homes west of the site is not affected has not been fully agreed nor
secured such that the proposal is unacceptable. Consequently the
proposal does not comply with Planning Policy Statement 22
Renewable Energy companion guide.
Monday, August 25, 2008
Cippenham Wind-farm
A letter in the local paper last week (Slough Observer 22/8/08), pretty much the first comment there's been on the proposal, used figures from the local opposition group WindRats to say both that the developer would be making nearly £3m a year from the proposal (assuming full capacity) and that the wind speed is so low in the local area that it wasn't worth bothering with. Which is it?!
As usual, the truth lies somewhere these points (though in normal debate, different sides, not the same, tend to make the contradictory statements). Here's my letter and the workings behind it:
Tom Williams (Letters last week) states that his opposition to the proposed Cippenham wind turbine is based upon available sourced data, so perhaps his opposition could be turned into support. He rightly states that the average annual wind speed for the proposed site is just under 6m/s, a speed which would, from the manufacturers own statistics, produce about 0.25MW. This is only about one twelfth of it's maximum power (though Mr Williams and the Windrats.com website seem to assume 100% production when coming up with their £2.7 million figure), but this is only part of the story.
As any driver knows, wind-resistance increases significantly more the faster you get, requiring more petrol to accelerate from say 70-80 mph than from 20-30mph. This explains the difference in design between the Volvo and the Porsche. Happily, this effect also works in reverse - the faster the wind blows, then proportionally more energy a turbine can extract from the wind. In practice, what this means is that you cannot get an accurate estimate of the potential output of a turbine from the base average wind speed alone, but would need to survey the actual speeds on site over a period of months. I have no idea if this research has been done, but by using an estimation method used by the wind-energy industry, I calculate that this site and turbine would produce over 5000MW hours of electricity per year, enough for about 1200 houses and saving nearly 3000 tonnes of carbon dioxide emissions in the process (the exact workings available at 2cheap2meter.blogspot.com ).
As these figures approximately match the developer's figures, I hope that Mr Williams will now join me in giving support to this proposal on economic grounds. Wind-power is going to become more common as we struggle to meet our rising energy demands from dwindling and polluting resources such as gas and coal, and to me are far preferable to the "energy-from-waste" incinerators currently operating on the Trading Estate and soon in Colnbrook.
OK, the maths.
This is based on the formula given in the Beurskins and Jensen article "Economics of wind-energy, Prospects and Directions" in the July/Aug 2001 edition of "Renewable Energy World". It looks to give an estimate of the energy available from a particular wind-turbine site. It's only an estimate, and you need to do a proper site survey and then match that to the exact specifications of the turbine you intend to fit. But it gives you an idea.
The turbine is sited at grid reference SU946797 (SU9479), which from the UK Wind Energy Database gives an average wind speed at 45m above ground level (agl). However, the actual turbine will be higher than that, so the developers suggest a speed of 6.4 m/s
The basic formula is :
Annual energy production (kWh) = K Vm3 At T
Nice. What this actually means is:
K = 3.2 = a factor based upon the relationship between standard turbine efficiency and wind-speed distribution.
V - is the cube of the average wind-speed for the site. This is the key, wind-energy is all based on the fact that the energy you get is all based on the cube of the wind-speed. This means you don't get much to start with, but it starts to rise rapidly as the wind-speed increases. For our basic speed of 5.8 m/s this is 195, 262 for the higher estimate.
A - the swept area of the blade. It's expected to be 90m diameter, so that's 45 m radius, which is (PIr2) 6352m2
T is the number of turbines, which in this case is one.
So, multiplying those together, we have either:
3.2 * 195 * 6352 * 1 = 3,972, 512 kWh (3,972 MWh / 3.972 GWh) per year, or
3.2 * 262 * 6352 * 1 = 5,337, 294 kWh (5,337 MWh / 5.337 GWh) per year
To put this in some sort of context, the average household uses 4478kWh p/year of electricity, so dividing the total amount of energy expected to be produced by this household average tells us how many houses could be powered by the turbine, between 887 and 1192.
Measuring CO2 emissions and what might be saved is a bit of dark art, depending mainly on which energy source you say you're replacing (measuring against coal makes you look good, hydro less so, the most recent energy mix is the fairest, but it's still a guess), but the latest figure I've a respectable source for is 0.527kg for each kilowatt hour of energy generated.
So, to calculate the theoretical amount of CO2 saved, multiply the expected energy generation from the turbine by this figure of 0.527kg, giving a figure of between 2,093,513.58kg (2094 tonnes) and 2,812,753.82kg (2,812 tonnes).
This is pretty much in line with what the developer estimates (section 3.12, page 9) for a Vestax 3MW turbine.
And it's both a lot smaller and cleaner than the Slough Estates CHP/incinerator and the now-legendary Colnbrook incinerator ...
Tuesday, May 13, 2008
How big? How close?
Maybe I like it because of happy childhood memories of The Tripods, but I can't help feeling that this is a little misleading - they've sited the 125m turbines right behind Pontefract town hall, which does give the most impressive looming effect, but that's way closer to buildings than the actual siting will be.
What would be fairer would be to do the same photo using the same scaling, but with a cooling tower from the nearby Ferrybridge power station, which come in at a whopping 198m, 25% bigger than the 158m high Blackpool Tower (which seems to be standard unit of comparison for these things).
So why is a smaller, less polluting wind-farm more offensive than a much bigger, more polluting coal-fired station just a few miles away?
Perhaps it's an attempt to repeat this famous picture of Black Law of Scotland:
Again, quite arresting, but I'd like to see that from a slightly different view before I make my mind up ...
Monday, May 12, 2008
Bang go the batteries ...
This is bad.
We then found out the festival was cancelled 2 weeks ago - this is pretty bad, not least for the organisers who I've bumped into a few times here and there, and seem really decent people. It's also pretty bad for the young people of Henley and surrounding areas - I don't think the "official" Henley festival later in the year is going to make up for it, what with £60 a day, formal dress and the Gypsy Kings on a floating stage. Yet another victim of the new licensing & security laws that are driving so many worthwhile small events out ... but I digress.
Before leaving the van for the night (it was a lovely weather, and there's lots of worse places to be than Henley on a nice May evening), I did possibly the worse thing imaginable, looking back. My van came with a dual battery wiring system, so I put another battery onto the other connection. I thought it might help a bit. Looking back, this is just the first of the evening's events I'm blaming the vodka-redbull on
I'm no expert on batteries, but one thing I've learnt is that you have to be careful about matching them up in power ratings. If you connect differently rated batteries together, then the "weaker" one will drag down the more powerful one down.
The other thing to check, if you haven't been drinking all day, is if the second battery you're adding actually has any charge in it. It really does seem that if you connect a knackered flat 70 amp hour car battery to your pained 110 amp hour deep cycle battery, well ... things may not turn out well
There was blazing sunshine all day Sunday, and I turned the panels up at an angle to get the maximum power, but the input power never got much up above 2 amps, when I would have expected at least 3 amps from the conditions. Looking back, this was probably due to increased resistance from a dying battery, but I'm not sure.
During charging, the voltage struggled up to about 12.5 volts, but whenever I took the charge off to see how it was doing without, it dropped to about 10.5. This is very bad. Campsites can be a suprisingly socially hostile environment, especially when you've got a roof full of renewables and a flat battery
Luckily, my brother-in-law came to the rescue. Not only does he come with a supply of vodka and entire crates of Stella, he also had jump-leads. We tried a jump-start, and even with him revving his engine, all we managed to do was melt his leads! Even luckier, he also had a terrifying pair of industrial strength leads which finally got us going.
We limped back home, and the whilst the battery voltage was about 12.5 volts when we switched the engine off, it was down to about 10.3 after a few hours rest. The Elecsol Manual calls 10.7 v the bare minimum for their batteries.
We've had the battery for about 5 years now, the guarantee period, and it has had a hard life, so I'm not really complaining. Lessons to learn:
- keep an eye on your voltage levels, and switch off the load when you hit 11v (at the bare minimum, though you will find it will rise when the load is taken off)
- match your battery capacities if you link 2 or more up together
- avoid "maintenance" after a day of drinking vodka in the hot sun on an empty stomach
and this is without mentioning the wind turbine mounting and siting fiasco ...
Thursday, May 8, 2008
Beware the cheap eBay solar panels ...
less than 10 months later, and really only a few weeks of serious operation, and it's dead! No current at all, a mere 6volts on the multimeter (you expect to see about 16v)
so beware cheapo bargains ...
Update 13/5/08 - the eBay vendor has been in touch, and offered some possible solutions ...
Tuesday, May 6, 2008
When wind turbines go bad
http://whenwindturbinesgobad.blogspot.com
but out of context --- it'll be interesting to compare the actual audited dangers from wind-turbines, as opposed to coal (hugely lethal on a hardly noticed scale) or nuclear (usually extremely safe, apart from the odd continent-poisoning catastrophe). From what I've seen, the biggest danger associated with wind-turbines is the sudden "thump" when you fall off
Thursday, May 1, 2008
Darrington Wind Farm
It doesn't seem that the Bankable Models Which Enable Local Community Wind Farm Ownership guidelines are being followed particularly closely, and that a landowner has done a deal with a developer, with the locals feeling as if they're having a huge development dumped on their doorstep, to provide benefit for others, with little to them.
A local campaign group has been set up - the Pontefract Windfarm Action Group, who have been active in raising awareness of the potential impact the turbines could have. One of the earlier actions was to raise a blimp to the approximate height and location of the highest point of the turbine tip:
I'll keep tracking the progress of both the wind farm and the local campaign, but it was worth looking at a map of the local area:
by the side of the wind-farm, between the nearest houses, is the A1 dual carriageway, and just to the north is Ferrybridge, the coal-fired power station that marks the beginning of "Megawatt Valley", target of the first Climate Camp.
So the proposed turbines are undoubtedly quite big, but will they have the impact on the local environment as claimed by the local action group?
Tuesday, April 29, 2008
Mo' power!
Previously, I looked at the most very basic, budget system - 5w, straight onto the battery. This produces at most half an amp, which will make sure that your battery has more of a chance of starting if you've been parked up for a while, but nothing more.
If you're going to spend any length of time in your van, going to be using the lights, pump, radio or charging your phone, then you want something with a little more oomph. Unfortunately, it's going to cost a little bit more, and be a bit more awkward to set up, but nothing impossible, depending on what you want to do and how much you want to spend.
There's 3 basic components you'll be needing now:
- big solar panel
- charge controller
- leisure/deep cycle battery
Solar Panel
How big a solar panel you choose is up to you. You need ask 3 questions:
- how much power do I actually need
- how much space have I got
- how much money have I got
Watts | Amps |
12 | 1.0 |
16 | 1.3 |
32 | 2.7 |
64 | 5.3 |
but do remember, this is the manufacturer's rating of the panel, not what you're actually going to see. For my van, I started with a 32 watt Unisolar FLX-32
as the manufacturer intended, or how it looks actually lashed to the top of the van:
These panels are great. They're flexible - designed for yachts, being lashed to booms, sat on by hairy old sea-dogs, everything that the cruel sea can throw at them. Ideal too then for the naturally keen but clumsy. Here's the data-sheet for this series of panels
Model | Rated Power (Watts) | Rated Voltage (Vmp) | Rated Current (Imp) | Open Circuit | Short Circuit Current (Isc) | Dimensions (inches) |
USF-5 | 5 | 16.5 | 0.30 | 23.8 | 0.37 | 21.80” x 9.71” |
USF-11 | 10.3 | 16.5 | 0.62 | 23.8 | 0.78 | 21.80”x 16.70” |
USF-32 | 32 | 16.5 | 1.94 | 23.8 | 2.40 | 56.27” x16.70” |
I've highlighted the USF-32 output- 1.94 amps! More than enough to charge the phone. Unbreakable, manageable size, decent output - just one snag. Unisolar don't make them anymore ...
But there are plenty of other options, but bear in mind the size of the panel and how you're going to fix it to the roof. The guys at Solar Energy Alliance are a great place to start, but other outlets are available ... there's a lot more to say about panels, but I personally feel that 32w is the minimum you need for a van.
Charge Controller
These little rascals sit between the panel and the battery. They stop the battery being overcharged (you should be so lucky) and also stop the electricity flowing back out of the panel at night. The one I've used for years is the ICP 7 amp controller - as the manufacturer intended:
As you can see, it has 2 wires going in and out - red for positive, black for negative. The input from the panel has bare-wire, the output to the battery are rings to attach to the terminals. It's down to you to work out the best way of connecting everything together, I'll cover the way I've done it later.
If you've got power coming in from your panel, then the yellow light on the left lights up, in the eventuality you actually manage to fully charge your battery, the green on one the left comes on (it will also do this if connected to an active panel, but not a battery - check your connections).
Again, other controllers are available, but I've used this for years, it's nice and tidy, doesn't get in the way, and is reasonable value.
You'll need a charge controller if your panels are anything above 5w, but check the capacity of the controller, remembering the watts/volts rule. The 32w unisolar panel can produce about 2 amps, so the 7amp total for this controller is fine. My current full solar array can get up to about 5/6amps on a good day, and I have noticed the charge controller kicking in to slow things down. I haven't quite got to the bottom of that yet, but be careful to match your controller input to the total power of the solar panels.
Battery
The workhorse of your system. When the sun goes down, who's there for you? Not your solar panel, that's for sure. If it wasn't for the charge controller, the turncoat would be letting all your hard generated power leak out into the night.
Your battery is the foundation of your renewable energy system. Sun (and wind) are too variable to rely on at any particularly moment, and solar just isn't there when you need it at night, when you're rummaging around in the van trying to find the brandy (for example).
The type of battery you need is a leisure/deep cycle battery. These look like normal car batteries, are rated just the same at 12volts, but are specially designed to withstand repeated charge and more importantly, discharge. If you run a normal car battery flat more than a few times, then you'll kill it, and running down a battery flat can happen quite a lot.
I've used a 110 amp hour Elecsol battery successfully for several years now:
They come in all shapes and sizes, but expect to pay about £100. There's lots of rules and things to remember, but all you need to know for now is don't buy second-hand. You don't know where it's been, or what it's been through. Get yourself a nice leisure battery if you haven't got one in the van already - put it where the existing one is, it works just the same, plug in your panel and charge controller/diode and that's it!
I ran a 32watt solar panel, 7amp charge controller and 110 amp/hour battery for years - it sometimes went flat if things got left on for too long, but if the panel was left to charge the battery for a few hours without anything on the battery, it always charged enough to start the engine and get us off site
Friday, April 25, 2008
Basic campervan solar
Maplin are widening their range of solar products, starting from little personal pocket chargers to some fairly large ones - they're not necessarily the most efficient products, and you might be able to get better deals elsewhere if you know where to look, but Maplin are everywhere, and often run promotions. Check out their Alternative Energy section. You can also find all kinds of stuff on eBay.
What you get depends on how much you're prepared to spend, you get what you pay for.
All solar panels are "rated" (eg classified) in Watts. A watt is a measure of power. Technically, it's the ability to generate 1 joule per second. A joule? Pleasingly, a joule is the energy required to throw an apple up 1 metre in the air. So the Watt rating is how much power you can theoretically obtain from the panel. It's probably not going to be able to throw an apple very high though.
The battery you're going to be plugging into is going to be 12 volts. The current going in and out is measured in amps - the rule is that current equals watts divided by volts. So, in a 12v system, to find out what the current going in is going to be, divide the rated power in watts by12. As a reference point, mobile phones seem to draw about 0.5 amps when charging.
Maplin and eBay panels at the moment (April 2008) seem to start at 1.5 or 2.4 watts, both for about £15, then about 5w for £30-40. But bear in mind that this is theoritical maximum, and it's pretty unlikely you're ever going to see that. So our budget panels will give us ...
Watts | Amps |
1.5 | 0.13 |
2.4 | 0.20 |
5 | 0.42 |
feel the power! Even if you have a 5 watt panel in maximum conditions at midday with the angle right and everything, you're not going to be able to directly charge a mobile phone. But you will stop your battery going flat.
Installation of these panels is incredbily easy - just stick the panel on the roof, and run the cable down to the battery. Depending on what you've bought, you often get 2 big crocodile, like in jump leads. Attach each lead to the correct battery terminal (red for positive, black for negative), and that's it - you've got power! One thing to note - you've created an electrical circuit, with power being collected during the day from the solar panel, and sent down to the battery. Unfortunately, this is a 2 way process - at night, the power is going to flow back the other way. Unless you want the panel to heat the night sky, either make sure you unplug it at night (hassle, and you'll forget), or get a panel with a blocking diode (it'll say on the box).
Above 5w, you're going to need extra bits, but that's all you need to get started!
Thursday, April 24, 2008
Thar she blows!
it's at a Norwegian site, and it seems that the braking mechanism designed to protect it during high winds failed, with catastrophic results. Mechanical failure and problems are inevitable in any engineering process, but it's important to be aware of the consequences. That I should have enough wind to cause mine to explode ...
Article from the Copenhagen Post below
http://jp.dk/uknews/article1277616.ece
Minister demands explanation for windmill collapse
By The Copenhagen Post
Published 25.02.08 00:00
The climate minister will begin an investigation into two separate cases of Vestas wind turbines collapsing within the past week
The climate minister, Connie Hedegaard, is calling for an investigation to determine the cause of two violent wind turbine collapses in Denmark in the past week.
Both of the windmills were produced by Vestas, and Hedegaard's request to the Energy Board comes after other breakdowns both here and abroad have been reported in the past two months.
'The problems with the turbines abroad have had to do with poor maintenance, and if that's the case here, then I expect a clear report on how we can ensure this problem is rectified,' Hedegaard told Berlingske Tidende newspaper.
Her comments come on the heels of the government's new energy agreement ratified by parliament last week, which calls for the country to have 20 percent of its energy produced by sustainable sources by 2011.
In first of the two collapses, near the city of Ã…rhus, a 10-year-old windmill began spinning out of control during high winds. A recording of the explosion-like collapse shows one of the wing blades breaking off, casting debris into the three other wings and shearing the 60- metre tower nearly in half.
Vestas itself will also now conduct an internal investigation to determine why the wind turbines have been breaking down.
'We've still got about 35,000 wind turbines across the globe that are operating fine,' said Peter Wenzel Kruse, Vestas's spokesperson. 'But they're not infallible. We're doing what we can and learning from our mistakes.'
Farmer Keld Boye, who lives in Vig where the latest incident occurred on Sunday, was clearly shaken by the wind turbine's implosion.
'I drive my tractor and my wife rides horses out there,' he said. 'Just think if we'd been out there when it happened.'
A recording of the collapse can be seen on YouTube.
Tuesday, April 22, 2008
What's your point then?
Then one year at Glastonbury, probably 2003, I was roaming the site with the legendary FishEye Sam (which is possibly why I'm not too sure about the year), and came across the Solar Energy Alliance stall. Sam pestered Chris, the genial stallholder, about the grants system, whilst I spotted and started to covet a radio with a solar panel in its handle. It occured to me then that solar might not be just a far-off, industrial process, but something that is here and now, right in your hand ...
After unexpectedly having enough money left over at the end of the weekend, I found the stall still going on Monday afternoon and made the first of what has proved to be the first of many suprisingly expensive, but ultimately highly educational, purchases ... the solar radio was mine!
The next year, the ever erratic gas fridge that had come with the camper finally packed up. Just servicing it would cost as much as an electric one, a new gas one would be more than the entire van, even if we could find one to fit. I saw my chance, and idly pointed out that if we were going to to run an electric fridge, then we would probably need a solar panel, only a little one to make sure it all kept going.
And with that total and complete ignorance of what it actually was that I was doing, I ordered a basic system from Chris at Solar Energy Alliance, said "yeah" quite a lot when he tried to explain the specifics of what it could and couldn't do, and headed back to Glastonbury. When it wasn't raining, it was at least cloudy, but the beer stayed cold and the van started on the Monday afternoon - mission accomplished!
The next few posts will hopefully describe the system I've put together since that start, how I've worked out what each part does, and what else it might be able to do
Friday, April 18, 2008
it's here ...
it's a Marlec Rutland 503 which seems to be the best option to fit onto here ...
... a 1970's Bedford CF campervan. We've already got a few solar panels that go on there to keep the battery topped up, now I've got to figure out how to add the wind turbine without having it fly off and destroy itself/innocent passers-by, ripping the roof off as it goes ...
it's heavier than it looks, especially with the steel pole mounting kit. But it can be done, according to the Marlec image gallery, anyway ...
if it can fit on a Merc, it can go on a Bedford. Probably ...