Uploading data to Google Powermeter (with C#)

In my last post, I described how I had registered a device to Google Powermeter. I've had a chance since to try uploading data, using the API instructions.

Data is sent to Powermeter using the HTTP POST command. If you're not familiar with this, this is a way of sending data to a URL without it being visible to the user, often utilised when submitting web-forms. However, web requests are not restricted to web-browsers, but can be made by any program with an internet connection. This means we can send data to Google Powermeter from any device capable of retrieving the raw data and accessing the internet.

The first step (as outlined previously) is to get the security information for your account by registering your device (you can delete and add as many devices as you like).

If you haven't saved the security data, then it can be accessed via the "Activation Information" setting from your Settings page, and it will look something like this:

hash=8e8abf8262aeb7bab4e24afc7beeb18c701c04ba,6c258c9f62fa8a137eba7fa35b5f58802fca2e56,d48ef4db13304c49d36fb81b20cabbe147f8ce34&token=CI2JxY-FxDk6_EJGPXejIkF&path=/user/23492384698234029827/23492384698234029827/variable/GibbonIndustries.GibbonEx3000.Home

We're interested in two pieces of data from here:

• "token" - this is a unique id number for this particular registered device, which you will need to include in every request
  
• "path" - this will form the core of the url will send all your data to

For now, we will be following the advice of the Google engineers, and only send "Durational" data, eg the total amount of electricity used between two specified points in time, in kilowatt hours. Make sure that when you create your device registration, you include at least one "durational variable" (eg dvars=1) when you make your original request:
https://www.google.com/powermeter/device/activate?mfg=GibbonEnergy&model=Gibbonex3000&did=1234&dvars=1

You can include as many durational variables as you like (eg submeters within your house, such as individual application monitor plugs), and these will be referred to as "d1", "d2" etc when you send your data. However, at the moment, it seems to rely on your common sense and guesswork to know which one is which.

OK, so we've registered the GibbonEx3000 meter, and want to start sending data to it. I'm a C#/.net developer, and all this is probably 200 times easier in some other language and there's probably better ways to write it in C# even, but this is how I did it - there's Python sample on the Google site.

First, you need to retrieve the data you want to send. Google only want this in 15 minute blocks, none of this "measuring every second" business. Some say that only by recording data at this level of detail can you understand what is really going on in your household consumption, but since there are 86,400 seconds in day, recording all this data for the number of people Google are aiming to reach is going to be a big headache (I've clocked up 3,876,373 records using my Current Cost since October 2009).

In the documentation, Google give this example, of 0.312 kWh being consumed between 3pm and 3:15pm on 21st May, 2008 (you have other ways of defining the time period, either a start or end date-time, with the duration). This is the data we want to send to Powermeter. I use a Linq query to generate these pieces of information from my raw data, there's no right or wrong way to do this, just whatever is accurate for your system and ends up looking exactly like this.

<entry xmlns="http://www.w3.org/2005/Atom" meter="http://schemas.google.com/meter/2008">
<meter:starttime uncertainty="1.0">2008-05-21T15:00:00.000Z</meter:starttime>
<meter:endtime uncertainty="1.0">2008-05-21T15:15:00.000Z</meter:endtime>
<meter:quantity uncertainty="0.001" unit="kW h">0.312</meter:quantity>
</entry>

However, we also have to supply two other pieces of information, the name of the meter (with the duration variable) in the url, and the unique key as part of the message header.

The url is built using the Google base address, the "path" as specified in the "Activation Information" and the Id of the particular duration variable we are going to use. In the documentation, this is given as the example:

https://www.google.com/powermeter/feeds/user/user-ID/security-zone/variable/variable-ID/durMeasurement

"user-id" and "security-zone" are the same 20 digit number (eg "23492384698234029827", and "variable-ID" is the duration variable (eg "d1") appended to the main device identifier (giving you something like this: "GibbonIndustries.GibbonEx3000.Home.d1")

To build this in C#, I've used the following code to generate the URL:

string userId = "23492384698234029827";
string deviceId = "Communergy.CurrentCost128.Home";       
string url = string.Format("https://www.google.com/powermeter/feeds/user/{0}/{0}/variable/{1}.d1/durMeasurement", userId, deviceId);

This gives me something like:
https://www.google.com/powermeter/feeds/user/23492384698234029827/23492384698234029827/variable/GibbonIndustries.GibbonEx3000.Home.d1/durMeasurement


You will also want to introduce your security token into your code at this point. In my example it's a hard-coded string, but you probably want to include this as a config option. Be warned, you must get this exactly right, and for some reason the security code is incredibly difficult to copy and paste (perhaps because it contains hyphens, so likes to split itself across lines). It took me about 15 goes over the course of an extremely frustrating hour to do this correctly. If you get it wrong, you will get a "401 - not authorised" error. Enjoy ...

Either way, I pass the constructed url, xml and token into my main method, which actually makes the request.

First, we convert the xml into bytes, and create a new HttpWebRequest, and set the length to the number of bytes in the converted XML:

//turn the xml into bytes
var bytes = System.Text.Encoding.ASCII.GetBytes(xml);
//create HttpWebRequest
var httpWebRequest = (HttpWebRequest)WebRequest.Create(url);         
httpWebRequest.Method = "POST";
httpWebRequest.ContentLength = bytes.Length;

We then set the content-type of the message to "ATOM", and add the token to the "Authorization" header, in the following format:

Authorization: AuthSub token="AUTHENTICATION_TOKEN"

You must include the double quotes around the token.

//set the required content type
httpWebRequest.ContentType = "application/atom+xml";
//set the token to the authorization header
string authSubHeader = string.Format("AuthSub token=\"{0}\"", authToken);
httpWebRequest.Headers.Add("Authorization", authSubHeader);

We then write the actual xml bytes to the HttpWebRequests request stream, and call the Response to submit the data:

//write  the xml bytes to the request stream
var requestStream = httpWebRequest.GetRequestStream();
requestStream.Write(bytes, 0, bytes.Length);
requestStream.Close();
var httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();             
{
  //Get response stream
  using (var responseStream = httpWebResponse.GetResponseStream())
  {                     
      using (var xmlReader = new XmlTextReader(responseStream))
      {
          response = xmlReader.ReadOuterXml();
      }
  }
}
httpWebResponse.Close();

If all goes well, there is no response, but you can excitedly rush to your Powermeter iGoogle gadget to see the data graphed, and your settings page will report "Status: Currently uploading data"


The code (posted in full below) is just a static sample, using hard-coded values, but is really all you need to get started - you will need to move your user Id and token values into a config file, and generate your request XML on the fly from your real data, and you probably want to do something about the ".d1" part as well.

I'm currently working on device-independent piece of client code, that currently reads Current Cost meters (Wattson/DIY Kyoto coming soon), which was pretty-much hard-coded to a dedicated server.

With the release of the Google API, I was forced to reconsider my design, and now use a much more flexible approach using the Command pattern, with different "Export Providers" being injected into the application controller. This allows any number of providers to be added, so Pachube, AMEE, Wattvision and hopefully Microsoft Hohm all await. If you're interested, it's all the source is available at http://communergy.codeplex.com/, but it's really not ready yet ..

Here it is:

static void Main()
{
   string userId = "23492384698234029827";
   string deviceId = "Communergy.CurrentCost128.Home";          
   string url = string.Format("https://www.google.com/powermeter/feeds/user/{0}/{0}/variable/{1}.d1/durMeasurement", userId, deviceId);


   string auth = "CI2JxY-FxDk6_EJGPXejIkF";
   string xmlEntry = @"
   
       2010-04-21T13:30:00.000Z
       2010-04-21T13:45:00.000Z
       0.642
   ";        

   var ret = PostXml(url, xmlEntry, auth);
}


public static string PostXml(string url, string xml, string authToken)
{
   string response = string.Empty;
   try
   {
       //turn the xml into bytes
       var bytes = System.Text.Encoding.ASCII.GetBytes(xml);
       //create HttpWebRequest
       var httpWebRequest = (HttpWebRequest)WebRequest.Create(url);          
       httpWebRequest.Method = "POST";
       httpWebRequest.ContentLength = bytes.Length;

       //set the required content type
       httpWebRequest.ContentType = "application/atom+xml";
       //set the token to the authorization header
       string authSubHeader = string.Format("AuthSub token=\"{0}\"", authToken);
       httpWebRequest.Headers.Add("Authorization", authSubHeader); 
             
       //write  the xml bytes to the request stream
       var requestStream = httpWebRequest.GetRequestStream();
       requestStream.Write(bytes, 0, bytes.Length);
       requestStream.Close();
       var httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();              
       {
           //Get response stream
           using (var responseStream = httpWebResponse.GetResponseStream())
           {                      
               using (var xmlReader = new XmlTextReader(responseStream))
               {
                   response = xmlReader.ReadOuterXml();
               }
           }
       }
       httpWebResponse.Close();
   }
   catch (WebException we)
   {
            
       throw new Exception(we.Message);
   }
   catch (Exception ex)
   {
       throw new Exception(ex.Message);
   }
   return response;
}

Setting up Google Powermeter

Google Powermeter is attracting a lot of attention in the home energy monitoring arena. Just the sheer reach and power of the Google brand are going to ensure it will be a major player.

So far, Google's focus has been on tie-ins with major energy utilities, whose customers already have wired-in smart meters in their homes. So far, what it has not dealt with are the millions such as myself who have internet-enabled monitors (either through a home pc, or with their own internet connection).

However, this changed last week with the announcement that their now-legendary Powermeter API will be publically available for all to use.

After a few false starts, and some patient help from the Powermeter team, I managed last night to register as a user. You don't need to be a registered provider (such as a utility), but you are responsible for uploading the data yourself to the web. It's an API, not a specific implementation for a particular monitor. However, a Python client library is supplied, once you've got your data out of your device.


The Getting Started page is pretty clear, once you get the hang of it. The documentation is aimed squarely at developers, who are writing a gateway to the API for their particular device or service, not standard users who just want to upload their data.

Before you do start, you will need a Google account (eg for Google Mail), and be logged in.

The API documents describe how to create a webpage for your website that your users will use to enroll to Powermeter. Once logged in, you have to create a webpage that will create a URL to post to Powermeter. This must take this format:
https://www.google.com/powermeter/device/activate?mfg=GibbonEnergy&model=Gibbonex3000&did=1234&cvars=1

Check the "Parameter details" section for details of what the different parameter values mean. You can customise the process by adding a return URL, otherwise you will stay within the Google pages.

Opening the link (which normally you would build within the page, but you can follow the link above or one like it) takes you to the "Activation" page



Confirm your details (including adding a geographic location), and if you have not specified a return URL, you will be presented with this page:



The "Authorization Information" is the unique key you will need to start uploading your data. If you specified a return URL, this will POSTed back to you in a particular format, so for automatic registrations you will be able to capture and store this. In this situation, take a copy of this manually, so you can use it in your API calls.


What you have to do now is master the upload API, but this doesn't look too complex - it's just wrapping up the standard SI units of time and energy, getting that data from your device in the first place is the hard bit.

Once your device has been activated, you have a set of options for how you want to display the data, including setting energy reduction targets:




Google have built an iGoogle gadget which you can place on your page and share with others:



(this probably looks a lot better once you start adding data ...)


So, there you go, that's how you activate a device on Powermeter, without being a customer of a subscribing utility. Anyone with a Google Account can do it.

I'll post again once I manage to upload data.

Weather station setup

The starting point of the whole system is a Maplin Weather Station. There's a few different ones on the market, but unless you're really serious, I think the critical thing your going to need is a wireless transmission from the outdoor weather station to your indoor base-station, and a USB connection from the base-station to your PC. The actual weather stations themselves to vary wildly in quality and performance, typical features to look out for are:

* temperature
* humidity
* rainfall
* wind-speed

Ideally, the thermometer should be inside a stevenson screen, to ensure readings don't get distorted by sunlight, and you want to make sure that you position your wind-gauge as high as possible to avoid wind-turbulance:





To fix mine, I got a 1.8m aerial from Screwfix, along with a mounting kit (that I can't find now), and attached it to my shed wall with the biggest coach-bolts I could find:



Early experiments siting the external thermometer/transmitter suggested that the plastic stevenson screen was absolutely useless, as I could identify the points at which the sun went behind, then re-appeared from the abandoned office block at the end of my street, by the sharp falls and rises in temperature.

Luckily, there's a massive rat-infested ivy swarming over my shed, and I managed to tuck the transmitter into there, keeping it sheltered from the heat:




This transmits a signal to the supplied base station, connected to an old laptop with a USB cable:


The supplied Easyweather software seems to be universally regarded as useless, not least because a memory leak guarantees it will crash if left running for any length of time, not ideal for this kind of software.

Instead, the entire world seems to love Cumulus from Sandaysoft:



With very little customisation, this can export your weather data to any number of formats, eg:
* a standard website
* twitter
* WeatherUnderground
* PWS Weather

Weather data, just like energy consumption data, always makes more sense when brought together and compared, and the last 2 sites particularly make an excellent job of this.

But come on, just uploading to somebody else's site just isn't exciting enough, no matter how well designed and useful it is - how do we get the raw data out so we can deal with it ourselves?

(to be continued ...)

From console to communergy

It's been almost a year since I wrote anything here. I got distracted, and I gave the link to a few people and never heard anything from them ever again - not quite the intention.

Anyway, I've been working on producing a personal home energy tracking system, since I acquired a Maplin Weather Station, and started to wonder how some of the things I've been learning on Open University environment and technology courses could be put to some use. I'd done a couple of spreadsheet and footprint exercises, but what has really been happening in our household energy consumption?

And how did I get from here:




to here



I've put this off for about a year, but I'll try and go through all the stages, not least so I don't forget why I've made some of the decisions that seemed to make sense at the time. In the meantime, you can see my personal home-monitoring site here , and the source code for the multiple-user version is here.

I'll try to stop complaining about Slough Borough Council's approach to renewable energy as well.

Another wind turbine planned for Slough

lock your doors, an application is in for another baby-eating wind-turbine in Slough!

Well, almost - there's an application on the Slough Council planning website

INSTALLATION OF A 40M GUYED WIND MONITORING MAST WHICH WILL BE REQUIRED TO MONITOR SITE CONDITIONS FOR A PERIOD OF 3-12 MONTHS 

The average wind-speed at this site, just north of Wexham Hospital, is about 6.4 m/s, which on a 3MW turbine means about 5GWh p/year. I don't know who is putting this application in, but at least they seem to be more serious and prepared than the last lot in Cippenham

Speaking with some of the councillors on the planning committee since the fiasco of the last hearing, there still isn't a policy on renewable energy in Slough, but they suggested that I raise this with the Scrutiny committee

maybe

Slough's energy use ...

Slough has approximately 45,000 households.

Each household uses approximately 4239 kWh each year in electricity (reference to come).

This means that Slough uses about 191,000,000kWh each year (or 191,000MWh, or 191GWh)

A 3MW wind turbine in Slough will produce about 3972MWh a year, or 4GWh. This is approximately 2% of the current electricity requirement for the town.

A household solar panel in the Thames Valley will produce about 2MWh each year, requiring approimately 2,000 such installations to produce the same amount of electricity as 1 3MW wind turbine, or 95,500 to meet the total requirement - over double the actual number of households.

That's the plain facts of electricity use in Slough.

Arrest Climate Change

Whilst visiting Slough Police Station (not "visiting") last night, I spotted this:

"burning fossil fuels has consequences" .... sounds much more sinister when it comes from The Plod ...

Slough Heat map - more details

The ever-excellent Environment department  at Slough Borough Council have shed some light on their new Heat Map.

It is very similar to the Haringey Heat Loss Map and most of the information on their site applies to the Slough one.

Basically:

• 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.

This means that a very poorly insulated house will appear "cold" if the owners are away and the heating off, and a very well insulated house look really "hot" if you're having a massive party and is full of people. Or you're one of the infamous Slough ganja farmers  ...

There's a little bit more to it than that, but that's basically it. It's a very useful guide, but not totally accurate energy survey. But wait, Slough Council have thought of that, and are offering free energy checks for local residents, with subsequent help with insulation, by ringing 0800 043 9569.  It's a relief to know that whilst some of the decisions of the planning committee seem to befar adrift from reality, other departments are getting to grips with the real problems in an effective way ...

Notes on Cippenham planning committee

Here's my view on how the decision was taken to refuse planning permission  for Cippenham wind-turbine, at the Slough Borough Council planning committee meeting on 22nd October, 2008.

The report to the committee recommended refusal on the following grounds:

• Visual Amenity
• Noise
• Shadow Flicker
• Safety
• TV reception

As my notes show, some of the committee members discussed some of these points - there's no getting away from it, the proposed turbine was very big and very close to people's homes. Whether the problems it might have caused would have been as big as they suggested, I'm not sure, but they were right to err on the side of caution. Wanting to be re-elected might have something to do with it as well, but that's the game. Fair enough.

However, what is more worrying is what seems to be a general lack of understanding of exactly what it was they were deciding upon. Every councillor declared themselves in favour of renewable energy, but only Cllr Plimmer asked to know what the council's strategy actually is on renewable energy, and wanted to know why it was there is no strategy. Other committee members seem happy to repeat myths and misunderstanding about renewable energy, and ignore the fairly clear rules about what their duties are in this regard:

• 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?

So, an expected, but still depressing outcome. Whilst this particular application probably isn't right for the intended site, it is clear that those responsible for making the decisions are not that well informed about what they are deciding upon. Will they use the same duff criteria when assessing future applications? Or will there be a strategy for renewable energy (which almost all the councillors claimed to be in favour of)?

Below is brief notes on what each councillor said, along with my comments in italics. The first speaker was the officers report, then the 3 councillors for the affected ward, then the committee members.

Officers Report
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

Cippenham Meadows - Labour

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

This was despite just hearing from the Officer's Report that BAA had no objections.
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.

Cllr MacIsaac

Wexham Lea - Independent / BILLD Group

All for "Green Energy", but not in housing estates

Cllr Dhaliwall

Central - Labour 

Is a full supporter of Renewable Energy, but "have to sensible". 

It should be somewhere it doesn't affect people, and this site would cause a lot of problems. 

Have to balance the benefits with the effects.

This would cause hazards to M4 users

As noted by several other committee members, the Green Park  turbine in Reading is right next to the M4, with no obvious ill-effects.

Cllr Swindlehurst

Cippenham Green - Labour 

Has no problem in principle with a turbine, and was quite excited when he first heard of the proposal, both as a landmark and the contribution to renewable energy it would make.

Believes these plans poorly executed, this is not the right site. 

Believes that Barratt with their close working relationship with Eton College (who sold them the land) could have come up with a better site.

Believes that Barratt are using this as a way of milking more money out of the sports-pitches which they were required to provide as Section 106 benefits, and the turbine would reduce the usage of the sports pitches

Applications are supposed to be decided upon their merits, not by speculation on the motives of the applicant

Is concerned about the structure collapsing.

Believes the idea has potential, but suffers from "shoddy execution"

Renewable energy is valid, but should be elsewhere.

Could be interesting, is a blight

Then spoke about the Slough Heat and Power power station, on the Trading Estate. Described it as using "good fuel", and expressed desire for it to supply more power. Declared that SHP currently supply power for 7-8,000 homes, and that this was the best route for renewable energy expansion in Slough.

Up to a point - SHP use both wood and FibreFuel, which according to the front page of their website is "Materials which are non-recyclable and would otherwise be sent to landfill are thus turned into a valuable resource",  but according to their "Raw Material s" page is made up of "mixed papers, magazines & junk mail, coated papers, laminates, adhesive labels, photographic paper, hygiene product rejects and pre-consumer packaging (not an exhaustive list)." So it's an incinerator, which is burning recyclable materials. But it's also a Community Heat and Power (CHP)  power station, which reuse the heat produced in electricity generation for heating local homes. So sort of "renewable", as it's not using fossil fuels, but perhaps not sustainable in the long-term as it depends upon a supply of a large amount of waste material, some of which could be recycled. Perhaps Cllr Swindlehurst was referring to the forthcoming Grundon Incinerator in Colnbrook, which was the focus of so much protest a few years ago.

Cllr Plimmer

Foxborough - Liberal Democrats/BILLD Group 

Asked if the council has any microgeneration strategy, as the officers haven't specified any details in the report?

strictly speaking, a 3MW turbine isn't really "micro", but it's a good question.

Officer Albertini replied that there is "broad support" for Renewable Energy, but there are no fixed standards

Cllr Plimmer considered that this kind of application is going to be coming up more often in the future, and that standards should be set now to avoid the committee having to make decisions on an undecided policy.

Officer Scourfield replied that there cannot be specific policies for everything, but the recommendation for refusal was based on general policies on amenity, safety etc. He suggested that policies may be formulated in more detail later.

Cllr Finn

Britwell - Independent Britwellian Residents / BILLD Group

Was amazed that the electricity produced will not go to Slough.

Whilst it would be nice to have an entirely local grid, this isn't how any power station in the UK works - they all link to the national grid, which then supplies homes through their own suppliers. I'm not really sure what difference it really makes, above the losses in transmission - it's not the same as buying local strawberries - "these electrons were made in Slough, see how the light burns brighter ...". That's not really how electricity works.

He then continued to talk about Barratts and their motivations for applying, to the point where Officer Wild had to intervene to remind him that applications are decided on their own merits, not the identity of the applicant.

Cllr Pantelic  did not take the opportunity to speak, though as she was sat next to Cllr Swindlehurst, may have drawn breath in preparation before he spoke again

Cllr Swindlehurst reaffirmed his view that he wants local power for local people, and that it is better to use the Slough Heat and Power for local renewable energy needs.

As the SHP website makes clear, they have not built the infrastructure for a local electricity grid, but feed into the National Grid as "Electricity output is sold under a Non Fossil Fuel Obligation contract.". Exactly how the Barratt turbine would have. So Cllr Swindlehurst opposes the turbine on the way it redistributes its electricity output, in favour of another system that works in exactly the same way, but with less sustainable fuel and more emissions. That does seem a little odd.

Cllr Dodds

Cippenham Meadows  - Labour

Wanted to know how deep the foundations were going to be. Concerned about safety, the disabled day centre, playing fields and changing rooms. 

Was pleased when she first heard at first that 1,500 homes were going to be built, which is approximately the amount of homes to be supplied by the turbine, so too was very surprised to find out the power was going to be fed into the National Grid.

Again, this is how all such systems work. No power station of any kind is able to maintain a constant supply of energy to meet the fluctuating demands of a single community, this is one of the design principles of the National Grid. By having a wide diversity of both sources and loads, the National Grid is able to "smooth out" any local fluctuations by a maintaining a much larger pool of electricity.

Wanted to know why solar panels couldn't be installed instead.

Good point, but no one solution is inherently better than another. Solar panels have a much lower output, are more expensive and so have a longer "payback" time. Of course, they do not work at night and are less effective in the winter when there is less sun available, and are not suitable for every house. There are very few, if any, installed in Slough apart from some very oddly positioned traffic ones. They're less intrusive, though this may not be the policy of the planning department - there does not appear to have ever been an application  to install one in Slough. The long-term solution has to be a mix of solar, wind and other renewables, along with better insulation and energy efficiency in general. 

Vote

The application was unanimously refused.

Slough Heat-loss map

SBC have published an excellent-looking "Heat Map" of Slough here.


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.

Cippenham turbine refused

As expected, the Slough Borough Council planning committee unanimously refused planning permission for the Barratt/Cippenham wind turbine last night.

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

Refusal recommended for Cippenham windfarm

The Cippenham wind turbine has been recommended for refusal of planning permission, at the forthcoming planning committee meeting on Oct 22nd:

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.

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.

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.

The recommendation seems mainly on grounds of "amenity", but that does seem to miss the bigger picture - increasing numbers of people in fuel poverty, and the potential catastrophic effects of climate change, both of which would be allieviated by projects such of this. They don't seem to have been considered at all. Where is the 80% cut in carbon dioxide emissions going to come from if we don't start making some hard decisions?

But the meeting still hasn't happened, so lets see ...

Cippenham Wind-farm

There's a proposal for a new wind-farm just down the road, in Cippenham, about here.

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 V_m³ A_t 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 ...

How big? How close?

Back to Darrington - this is one of my favourite photoshopped pictures ever of a windfarm:

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 ...

Bang go the batteries ...

or perhaps "fizzzz". Whatever, there's not much going on at the moment. We went camping at the weekend, planning to go the ever-excellent Come Together festival in Henley. Getting the beer cold, I noticed the voltage on the battery dropping scarily low, to below 11volts.

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 ...

Beware the cheap eBay solar panels ...

last year I got what I thought was a good deal on eBay for a 17watt solar panel



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 ...

When wind turbines go bad

A whole blog dedicated to malfunctioning wind turbines ...

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

Darrington Wind Farm

The village in Yorkshire I grew up in, Darrington, is being split over a proposed new wind-farm development. Well, "split" is probably the wrong word, "uninamously enraged" is probably more appropriate, at least to the people I've spoken to.

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?

Mo' power!

Mo' Power! the war-cry of the micro-generator - however much power you've got coming in, you always want more.

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

Remembering the "current = watts divided by volts" rule, on a 12v system you're going to be something like:

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 Voltage (Voc)	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