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purpletigronThe Hockerton Housing Project (HHP) near Nottingham describes itself as: the first earth sheltered, self-sufficient ecological housing development in the UK. Their stated aim is for project members to live a holistic way of life in harmony with the environment, for which all ecological impacts have been considered and accounted. The residents of the five houses recycle water and other materials, with the aim of minimizing pollution (including their net carbon dioxide emissions). The houses are apparently amongst the most energy efficient dwellings in Europe.
In April 2002, HHP was finally able to start running their own National Grid-connected wind turbine, generating electricity. As the six of us have been wondering whether this was even possible, and HHP have not yet had time to write up all the details of their project, it seemed like a good idea to organize a visit to see the turbine in action, and talk to their renewables `main man', Simon Tilley. Simon was happiest with a group of no more than three people, and in the end, N, D and I were the lucky winners :-)
It took us longer than we'd hoped to get to Hockerton, in N's LPG-converted Range Rover (because getting around Nottingham is just Like That). However, a quick call on my mobile to Simon gave him the chance to pass the extra half-an-hour digging potatoes in their allotment. Just past 14:30, we pulled up the tarmac drive to The Gables farm and parked amongst a collection of various practical and aged vehicles. We walked past a little hut which D insisted must be a composting toilet (N and I rather poo-pooed this suggestion), and found Simon Tilley laying down tools and pulling on his shirt and hat (a Tilley hat, perhaps?). We shook hands and did the introductions, and then walked on past a small field of sheep, towards a mysterious and inviting `linear hill' with what looked like solar (photovoltaic/PV) arrays along the ridge.
Helena Tilley was working in the gardens, and I spotted a lush raised bed of strawberries, and various growing willow sculptures. Simon immediately invited us to walk up on to the roofs of their houses, up the earth-sheltering `hill' on the north-facing side of the `terrace'. Just a gentle amble, past nettles and more
butterflies than Dave or I had seen all summer, and there we were - beside a row of brand-new PV arrays, simply fixed onto long plastic stone-weighted buckets, standing on the flat paved ridge of the roofs (trivially easy to install and maintain). And so began the tour proper:
HHP is `all electric': the houses require no space heating, and their water pumps, cooking and normal appliances are all electric. They thought hard about wood stoves and gas cooking, but because the houses are designed and built to be airtight except for intentional ventilation, these were rejected because of their on-the-spot emissions. The water heating uses heat pumps, not passive solar heating - the whole of the southern elevation is glazed, with internal `raffia-work' blinds.
Simon explained that their choice of cooking fuel effectively determined their decisions on renewable energy overall. They considered other `autonomous' situations, such as canal barges - which use diesel-heated solid hobs which could be run using locally produced biodiesel (basically, an Aga run on hydrocarbons produced from new plant growth) - and `ecowarrior favourites', such as closed wood stoves (e.g. as used by Prof. Sue Roaf in her Oxford Eco House for heating), before adopting electricity. He reckons that for electric cooking, hobs are more efficient for large volumes, and microwaves for smaller volumes [I need to think more about surface-area/volume effects here!]. The Tilley household now uses about 3000 kWh/yr of electricity (~8 kWh daily in summer, about 15% higher in winter), only ~10% of the UK average for a similar sized house and family.
The HHP residents decided to keep their old appliances, and upgrade them to highly energy efficient models as the old ones reached the end of their useful lifetimes. Fridges and freezers are the main area for improvement, with new models consuming as little as 1/6 the electricity as the old ones. Improving domestic energy efficiency is a vital pre-requisite to becoming self-sufficient in renewable energy - it is very difficult to affordably and locally generate the amount of energy that an average UK household uses.
In terms of reducing cost per unit generated, the three main domestic-scale renewable electricity sources are currently ordered: water microturbine, wind miniturbine, PV arrays. HHP does not have suitable water resources for microturbines, and so focused first on wind power. They are just commissioning PV arrays because they received substantial grants from Scottish Power and the DTI. They have a 6 kW wind turbine, with blades which are 5.5m in diameter, on an extra-tall 26m tower, needed because their site is relatively low-lying and tree-lined. This system is costing ~4,500 pounds / kW, compared to ~18,000 pounds / kW for PVs, ~1,500 pounds / kW for a 30kW wind turbine (with c. 12 m blades) and ~1,000 pounds / kW for a 1.5 MW wind turbine; I've found a US water microturbine which claims an installed cost for a 50 kW system of just US$350 / kW! The mix of PV and wind (or water) turbine of course helps to balance renewable power generation, as the weather tends to provide either wind (and water), or sun :-)
No less than four planning applications were needed to get permission to erect the wind turbine, due in large part to their nearest neighbour being a NIMBY counciller (against the project, living withing 200m, and on the planning committee! NIMBY : Not In My Back Yard) To finally get accepted, they had to change the proposed turbine siting, get the help of the council officers (the full-time civil servants, who unlike the politicians, understood and supported the project under the Local Agenda 21 framework), and... for the NIMBY to move away! The "Special Planning Guidance on Wind Energy" which the council officers produced (but HHP largely drafted) is available from the Newark and Sherwood District Council (Without the SPG, the politicians were saying "We don't know what to do - we don't have any specific guidance on this..."). The main written objections to the first three planning applications were on the grounds of: possible noise; possible road traffic incidents being caused on the nearby A612 and A617; and visual intrusion. There were also `verbal rumblings' concerned with: bird-strike, electromagnetic pollution, and catastrophic blade-sep - these didn't need to be addressed, as they were never formally submitted!
In fact, the turbine is very quiet indeed, far quieter than normal rural noises, and the sounds of aircraft and road traffic passing - the noise objection was thrown out, as was the objection that gawping drivers might cause crashes. None of the other posited problems have materialised in the first 4 months of operation, either.
The visual intrusion was considered, however, and this `loss of amenity' weighed against the likely environmental benefits and found to beacceptable. HHP produced conceptual line drawings of how the turbine and tower would appear from various vistas, from photographs taken of a hot-air-balloon hovering at 26m over the proposed site.
The chosen 6 kW wind turbine is less popular than the 600 W and 2.5 kW smaller modes, apparently. HHP went with a company called Proven, who are based in Scotland. The Proven design is a simple pivot downwind folding system to cope with gales in the Hebrides - as the wind speed rises above the safe threshold, the turbine blades simply start closing into a downwind cone, continuing to generate electricity at the maximum safe rate for the conditions.
The tower also tilts - using a counter-weight and a tractor, they can reasonably easily bring the turbine to the grown for annual servicing. The main alternative design, produced by the US company Bergey was an upwind geared system, which has to be parked in high winds to avoid damaging the gears and blades. More designs and systems are becoming available, for example from a Nottinghamshire company called ISKRA apparently. At 20kW (d=11m), there is also the Gazelle and another at 30 kW (d=12m). The EcoTech centre near Swaffham in Norfolk, England has a 1.5 MW turbine with 66m diameter blades on a 67m tower sounds well worth a visit.
The main problems which HHP have encountered with the wind turbine itself are: the wrongly sited junction between the turbine down-cable, and the incoming transmission cable (inside the tower instead of in a separate junction box!); a dry joint in one of the three power output phases, overspecification of the counterweight (necessitating the tractor to lower it, instead of the winch originally installed), and poor post-installation customer service from Proven. (Note: the tower was a special order, because of the extra height needed to crest the surrounding trees.)
To find out whether wind turbines and PV are appropriate on a given site, one should set up a weather monitoring system (useful also to any gardeners) including an appropriately mounted anemometer (wind gauge) and bolometer (solar heat moniter, D's thinking about a design called a Golay Cell, but a photodiode might be easier in practise :-) But there are also wind maps available as a first check whilst site hunting. The former Energy Technology Support Unit (ETSU), now part of Future Energy Systems within AEA Technology have a wind map, which predicts a median of ~6 m/s at 26m on the HHP site - it will be interesting to see what HHP measure once they have proper data-logging in place. There are also good Danish information resources: http://www.windatlas.dk/, http://www.windpower.org/, http://www.windturbinewarehouse.com/ all look useful.
Now on to the details of National Grid connection, finance, performance and payback. HHP considered batteries as an alternative to grid connection, but concluded that, sincethey were already on the National Grid, batteries were not a viable option: expensive, inefficent, complicated. HHP are hoping to generate ~14,000 kWh/yr for a total installed cost including VAT at 5% of 26, 000 pounds (this doesn't include annual and unplanned maintainance costs). HHP is physically in the East Midlands Electricity (EME) region - this is their Distribution Network Operator (DNO). The DNO handles physical issues of connection, and safety (see http://www.pv-uk.org.uk/technology/permissions.html for a discussion in the context of mains-connected PV systems). The main trick in getting permission and connect to the UK Grid seems to be, finding the right person at the DNO who actually understands what you are trying to do! (HHP were originally sent forms relating to large-scale power station connection...). The grid-connection agreement includes a failsafe requirement - if the Grid goes down (a `power cut'), there is a specified time (in milliseconds) within which HHPs generators must also shut down to avoid damaging the National Grid equipment - this means, HHP will still suffer a power cut despite having their own generating equipment! [I don't know if it is possible to configure a fall-back stand-alone mode, to both protect the Grid from damage, and the domestic supply from significant interruption?] A point to note is that the standard EME grid connection contract included a requirement for significant, expensive insurance cover against Grid damage caused by the connecting generation system if it is a business.
Because HHP bought a complete system from Proven, including grid-connection systems already well known in the UK for PV installations, they were easily able to satisfy the safety requirements. From HHPs perspective, Proven installed the generation-side equipment, EME installed the grid-side equipment and joined the two, and that was that - almost :-) There is a UK company called Wind and Sun" which do design, supply and installation of wind and solar systems (for BP Solar amongst others), and they can probably name the correct person at every UK DNO.
HHP have exercised their right to buy electricity from a company other than their DNO: Powergen, who are currently charging ~6p / unit for National Grid supplied electricity. This gives a nominal 40 year payback time for HHP's wind turbine system. However, HHP got financial help: a grant from Powergen via a green tariff trust fund (currently available for up to 50% of the project, on the basis that HHP would e.g. give public tours, and publicity); and a loan from the Co-operative Bank for the three out of five families who couldn't raise the cash for their shares of the remainder. About 18 months ago, all the five HHP families started putting into a Co-op savings account the amount of money which they would have been spending on average domestic electricity bills, and they will continue paying off the Co-op loan at that rate: this made it very easy for them to get the loan, and means they will pay it off in just 7 years.
The next interesting point about grid connection, is metering. If you have two meters - for inward and an outward supply - then VAT, currently at 5%, is payable on both transactions! Because of this, it is currently illegal in the UK to have just one meter installed which is capable of going backwards, as that means the VAT cannot be calculated (hopefully, the rules will change as domestic-scale renewables become more common?). HHP have not yet started to sell power back to the National Grid, as their system is not yet full commissioned. The two metering regimes which are available are called `net metering', in which your electricity supply company only charges you for your net usage (and you have to pay the VAT man on the gross transactions; Eastern Electricity apparently do a very primitive version of this, by give you a flat 50 pound annual discount on your bill!), and `positive rate', in which the electricity supply company sets a higher buy-back rate - because of the currently political and regulatory climate, some electricity companies (notably, SWEB, who have a lot of wind turbines in their region) will pay a premium for `green electricity', since they have statutory renewable energy targets to meet (and presumably, can sell `green energy' tariffs at a premium to their customers). SWEB will install your two meters, and pay ~7p / unit for what you sell them (charging ~ 6p / unit for what they supply) - the meters have also to be monitored on a half-hourly basis for VAT purposes.
HHP did not need to supply any extra equipment: Proven and EME did it all. Obviously, it was important to get the correct inverters: HHP have SunnyBoy systems (designed for PV, as the name implies), which required only minor modification - most small wind turbines are currently off-grid, but UK-proven purpose-built wind power electrics will presumably become more common as on-grid turbines increase in number. The power system uses three-phase electricity, and only two of the three phases which actually supply the HHP houses receive wind-generated power; likewise, another one of the phases will not be connected to the PV; this is how HHP have decided to balance their electricity network.
Simon Tilley noted the useful USA magazine, "Off the Grid" for advice on all such matters - I couldn't find a Web page for them, but did find another similar publication: Home Power Under USA law and practise, I understand that you don't have to tell anyone about setting up grid-connected generators, you just `plug and pray' :-)
The wind turbine produces what is technically known as `wild AC', which means, electricity unstable in current, voltage and frequency. The system first rectifies this to `wild DC', and then using a `superinverter', produces AC which is stable in frequency and voltage, with variable current. Data-logging systems were not included in Proven's standard installation, so HHP intend to set up a their own system so that they can properly monitor the wind generation system performance. So, no in-use data available from them as yet - it might be another 18 months before all the data we'll want will be available.
Coming to the end now, Simon Tilley recommended the British and European Wind Energy Associations for more information. He gave us a useful brochure of alternative energy projects in the UK produced by the Energy 21 Trust(which promotes education and research in sustainable energy, water, building, waste management). He noted that getting the planning permission involved lots of Parish meetings, and it's very important to work closely with the local community from an early stage, keeping them informed, educated, and hopefully on your side. He pointed us to some DETR (as was, now probably DEFRA) publications: "General Information Report 53: Building a sustainable future: Homes for an autonomous community", in which HHP is profiled as an example of so-called `best practise', and "New Practice Profile 119", likewise.
Oh, and we saw a beautiful large, dark moth (with red and white blazons on its wings) as we sat in the Tilley's conservatory drinking tea and eating chocolate biscuits (not moral chocolate, actually! :-)
And then we paid our (very reasonable) tour fees, walked back to the car (past what Simon confirmed is a non-yet-commissioned composting toilet, for the allotment gardeners), confused Simon with our stealthy vehicle - he didn't notice the Range Rover, blending in perfectly with the `smallholders vehicles' which live on site - said hello to a very enthusiastic and friendly ginger cat (very much like![[livejournal.com profile]](https://www.dreamwidth.org/img/external/lj-userinfo.gif)
purplejavatroll's Finn), and drove home to for our delicious lamb casserole which G had been looking after :-) A very interesting and enjoyable afternoon... very exciting!
In April 2002, HHP was finally able to start running their own National Grid-connected wind turbine, generating electricity. As the six of us have been wondering whether this was even possible, and HHP have not yet had time to write up all the details of their project, it seemed like a good idea to organize a visit to see the turbine in action, and talk to their renewables `main man', Simon Tilley. Simon was happiest with a group of no more than three people, and in the end, N, D and I were the lucky winners :-)
It took us longer than we'd hoped to get to Hockerton, in N's LPG-converted Range Rover (because getting around Nottingham is just Like That). However, a quick call on my mobile to Simon gave him the chance to pass the extra half-an-hour digging potatoes in their allotment. Just past 14:30, we pulled up the tarmac drive to The Gables farm and parked amongst a collection of various practical and aged vehicles. We walked past a little hut which D insisted must be a composting toilet (N and I rather poo-pooed this suggestion), and found Simon Tilley laying down tools and pulling on his shirt and hat (a Tilley hat, perhaps?). We shook hands and did the introductions, and then walked on past a small field of sheep, towards a mysterious and inviting `linear hill' with what looked like solar (photovoltaic/PV) arrays along the ridge.
Helena Tilley was working in the gardens, and I spotted a lush raised bed of strawberries, and various growing willow sculptures. Simon immediately invited us to walk up on to the roofs of their houses, up the earth-sheltering `hill' on the north-facing side of the `terrace'. Just a gentle amble, past nettles and more
butterflies than Dave or I had seen all summer, and there we were - beside a row of brand-new PV arrays, simply fixed onto long plastic stone-weighted buckets, standing on the flat paved ridge of the roofs (trivially easy to install and maintain). And so began the tour proper:
HHP is `all electric': the houses require no space heating, and their water pumps, cooking and normal appliances are all electric. They thought hard about wood stoves and gas cooking, but because the houses are designed and built to be airtight except for intentional ventilation, these were rejected because of their on-the-spot emissions. The water heating uses heat pumps, not passive solar heating - the whole of the southern elevation is glazed, with internal `raffia-work' blinds.
Simon explained that their choice of cooking fuel effectively determined their decisions on renewable energy overall. They considered other `autonomous' situations, such as canal barges - which use diesel-heated solid hobs which could be run using locally produced biodiesel (basically, an Aga run on hydrocarbons produced from new plant growth) - and `ecowarrior favourites', such as closed wood stoves (e.g. as used by Prof. Sue Roaf in her Oxford Eco House for heating), before adopting electricity. He reckons that for electric cooking, hobs are more efficient for large volumes, and microwaves for smaller volumes [I need to think more about surface-area/volume effects here!]. The Tilley household now uses about 3000 kWh/yr of electricity (~8 kWh daily in summer, about 15% higher in winter), only ~10% of the UK average for a similar sized house and family.
The HHP residents decided to keep their old appliances, and upgrade them to highly energy efficient models as the old ones reached the end of their useful lifetimes. Fridges and freezers are the main area for improvement, with new models consuming as little as 1/6 the electricity as the old ones. Improving domestic energy efficiency is a vital pre-requisite to becoming self-sufficient in renewable energy - it is very difficult to affordably and locally generate the amount of energy that an average UK household uses.
In terms of reducing cost per unit generated, the three main domestic-scale renewable electricity sources are currently ordered: water microturbine, wind miniturbine, PV arrays. HHP does not have suitable water resources for microturbines, and so focused first on wind power. They are just commissioning PV arrays because they received substantial grants from Scottish Power and the DTI. They have a 6 kW wind turbine, with blades which are 5.5m in diameter, on an extra-tall 26m tower, needed because their site is relatively low-lying and tree-lined. This system is costing ~4,500 pounds / kW, compared to ~18,000 pounds / kW for PVs, ~1,500 pounds / kW for a 30kW wind turbine (with c. 12 m blades) and ~1,000 pounds / kW for a 1.5 MW wind turbine; I've found a US water microturbine which claims an installed cost for a 50 kW system of just US$350 / kW! The mix of PV and wind (or water) turbine of course helps to balance renewable power generation, as the weather tends to provide either wind (and water), or sun :-)
No less than four planning applications were needed to get permission to erect the wind turbine, due in large part to their nearest neighbour being a NIMBY counciller (against the project, living withing 200m, and on the planning committee! NIMBY : Not In My Back Yard) To finally get accepted, they had to change the proposed turbine siting, get the help of the council officers (the full-time civil servants, who unlike the politicians, understood and supported the project under the Local Agenda 21 framework), and... for the NIMBY to move away! The "Special Planning Guidance on Wind Energy" which the council officers produced (but HHP largely drafted) is available from the Newark and Sherwood District Council (Without the SPG, the politicians were saying "We don't know what to do - we don't have any specific guidance on this..."). The main written objections to the first three planning applications were on the grounds of: possible noise; possible road traffic incidents being caused on the nearby A612 and A617; and visual intrusion. There were also `verbal rumblings' concerned with: bird-strike, electromagnetic pollution, and catastrophic blade-sep - these didn't need to be addressed, as they were never formally submitted!
In fact, the turbine is very quiet indeed, far quieter than normal rural noises, and the sounds of aircraft and road traffic passing - the noise objection was thrown out, as was the objection that gawping drivers might cause crashes. None of the other posited problems have materialised in the first 4 months of operation, either.
The visual intrusion was considered, however, and this `loss of amenity' weighed against the likely environmental benefits and found to beacceptable. HHP produced conceptual line drawings of how the turbine and tower would appear from various vistas, from photographs taken of a hot-air-balloon hovering at 26m over the proposed site.
The chosen 6 kW wind turbine is less popular than the 600 W and 2.5 kW smaller modes, apparently. HHP went with a company called Proven, who are based in Scotland. The Proven design is a simple pivot downwind folding system to cope with gales in the Hebrides - as the wind speed rises above the safe threshold, the turbine blades simply start closing into a downwind cone, continuing to generate electricity at the maximum safe rate for the conditions.
The tower also tilts - using a counter-weight and a tractor, they can reasonably easily bring the turbine to the grown for annual servicing. The main alternative design, produced by the US company Bergey was an upwind geared system, which has to be parked in high winds to avoid damaging the gears and blades. More designs and systems are becoming available, for example from a Nottinghamshire company called ISKRA apparently. At 20kW (d=11m), there is also the Gazelle and another at 30 kW (d=12m). The EcoTech centre near Swaffham in Norfolk, England has a 1.5 MW turbine with 66m diameter blades on a 67m tower sounds well worth a visit.
The main problems which HHP have encountered with the wind turbine itself are: the wrongly sited junction between the turbine down-cable, and the incoming transmission cable (inside the tower instead of in a separate junction box!); a dry joint in one of the three power output phases, overspecification of the counterweight (necessitating the tractor to lower it, instead of the winch originally installed), and poor post-installation customer service from Proven. (Note: the tower was a special order, because of the extra height needed to crest the surrounding trees.)
To find out whether wind turbines and PV are appropriate on a given site, one should set up a weather monitoring system (useful also to any gardeners) including an appropriately mounted anemometer (wind gauge) and bolometer (solar heat moniter, D's thinking about a design called a Golay Cell, but a photodiode might be easier in practise :-) But there are also wind maps available as a first check whilst site hunting. The former Energy Technology Support Unit (ETSU), now part of Future Energy Systems within AEA Technology have a wind map, which predicts a median of ~6 m/s at 26m on the HHP site - it will be interesting to see what HHP measure once they have proper data-logging in place. There are also good Danish information resources: http://www.windatlas.dk/, http://www.windpower.org/, http://www.windturbinewarehouse.com/ all look useful.
Now on to the details of National Grid connection, finance, performance and payback. HHP considered batteries as an alternative to grid connection, but concluded that, sincethey were already on the National Grid, batteries were not a viable option: expensive, inefficent, complicated. HHP are hoping to generate ~14,000 kWh/yr for a total installed cost including VAT at 5% of 26, 000 pounds (this doesn't include annual and unplanned maintainance costs). HHP is physically in the East Midlands Electricity (EME) region - this is their Distribution Network Operator (DNO). The DNO handles physical issues of connection, and safety (see http://www.pv-uk.org.uk/technology/permissions.html for a discussion in the context of mains-connected PV systems). The main trick in getting permission and connect to the UK Grid seems to be, finding the right person at the DNO who actually understands what you are trying to do! (HHP were originally sent forms relating to large-scale power station connection...). The grid-connection agreement includes a failsafe requirement - if the Grid goes down (a `power cut'), there is a specified time (in milliseconds) within which HHPs generators must also shut down to avoid damaging the National Grid equipment - this means, HHP will still suffer a power cut despite having their own generating equipment! [I don't know if it is possible to configure a fall-back stand-alone mode, to both protect the Grid from damage, and the domestic supply from significant interruption?] A point to note is that the standard EME grid connection contract included a requirement for significant, expensive insurance cover against Grid damage caused by the connecting generation system if it is a business.
Because HHP bought a complete system from Proven, including grid-connection systems already well known in the UK for PV installations, they were easily able to satisfy the safety requirements. From HHPs perspective, Proven installed the generation-side equipment, EME installed the grid-side equipment and joined the two, and that was that - almost :-) There is a UK company called Wind and Sun" which do design, supply and installation of wind and solar systems (for BP Solar amongst others), and they can probably name the correct person at every UK DNO.
HHP have exercised their right to buy electricity from a company other than their DNO: Powergen, who are currently charging ~6p / unit for National Grid supplied electricity. This gives a nominal 40 year payback time for HHP's wind turbine system. However, HHP got financial help: a grant from Powergen via a green tariff trust fund (currently available for up to 50% of the project, on the basis that HHP would e.g. give public tours, and publicity); and a loan from the Co-operative Bank for the three out of five families who couldn't raise the cash for their shares of the remainder. About 18 months ago, all the five HHP families started putting into a Co-op savings account the amount of money which they would have been spending on average domestic electricity bills, and they will continue paying off the Co-op loan at that rate: this made it very easy for them to get the loan, and means they will pay it off in just 7 years.
The next interesting point about grid connection, is metering. If you have two meters - for inward and an outward supply - then VAT, currently at 5%, is payable on both transactions! Because of this, it is currently illegal in the UK to have just one meter installed which is capable of going backwards, as that means the VAT cannot be calculated (hopefully, the rules will change as domestic-scale renewables become more common?). HHP have not yet started to sell power back to the National Grid, as their system is not yet full commissioned. The two metering regimes which are available are called `net metering', in which your electricity supply company only charges you for your net usage (and you have to pay the VAT man on the gross transactions; Eastern Electricity apparently do a very primitive version of this, by give you a flat 50 pound annual discount on your bill!), and `positive rate', in which the electricity supply company sets a higher buy-back rate - because of the currently political and regulatory climate, some electricity companies (notably, SWEB, who have a lot of wind turbines in their region) will pay a premium for `green electricity', since they have statutory renewable energy targets to meet (and presumably, can sell `green energy' tariffs at a premium to their customers). SWEB will install your two meters, and pay ~7p / unit for what you sell them (charging ~ 6p / unit for what they supply) - the meters have also to be monitored on a half-hourly basis for VAT purposes.
HHP did not need to supply any extra equipment: Proven and EME did it all. Obviously, it was important to get the correct inverters: HHP have SunnyBoy systems (designed for PV, as the name implies), which required only minor modification - most small wind turbines are currently off-grid, but UK-proven purpose-built wind power electrics will presumably become more common as on-grid turbines increase in number. The power system uses three-phase electricity, and only two of the three phases which actually supply the HHP houses receive wind-generated power; likewise, another one of the phases will not be connected to the PV; this is how HHP have decided to balance their electricity network.
Simon Tilley noted the useful USA magazine, "Off the Grid" for advice on all such matters - I couldn't find a Web page for them, but did find another similar publication: Home Power Under USA law and practise, I understand that you don't have to tell anyone about setting up grid-connected generators, you just `plug and pray' :-)
The wind turbine produces what is technically known as `wild AC', which means, electricity unstable in current, voltage and frequency. The system first rectifies this to `wild DC', and then using a `superinverter', produces AC which is stable in frequency and voltage, with variable current. Data-logging systems were not included in Proven's standard installation, so HHP intend to set up a their own system so that they can properly monitor the wind generation system performance. So, no in-use data available from them as yet - it might be another 18 months before all the data we'll want will be available.
Coming to the end now, Simon Tilley recommended the British and European Wind Energy Associations for more information. He gave us a useful brochure of alternative energy projects in the UK produced by the Energy 21 Trust(which promotes education and research in sustainable energy, water, building, waste management). He noted that getting the planning permission involved lots of Parish meetings, and it's very important to work closely with the local community from an early stage, keeping them informed, educated, and hopefully on your side. He pointed us to some DETR (as was, now probably DEFRA) publications: "General Information Report 53: Building a sustainable future: Homes for an autonomous community", in which HHP is profiled as an example of so-called `best practise', and "New Practice Profile 119", likewise.
Oh, and we saw a beautiful large, dark moth (with red and white blazons on its wings) as we sat in the Tilley's conservatory drinking tea and eating chocolate biscuits (not moral chocolate, actually! :-)
And then we paid our (very reasonable) tour fees, walked back to the car (past what Simon confirmed is a non-yet-commissioned composting toilet, for the allotment gardeners), confused Simon with our stealthy vehicle - he didn't notice the Range Rover, blending in perfectly with the `smallholders vehicles' which live on site - said hello to a very enthusiastic and friendly ginger cat (very much like
purplejavatroll's Finn), and drove home to for our delicious lamb casserole which G had been looking after :-) A very interesting and enjoyable afternoon... very exciting!
![[identity profile]](https://www.dreamwidth.org/img/silk/identity/openid.png){kind=small}
no subject
Date: 2002-08-26 08:01 am (UTC)I wonder about their qualms about gas, though, and the reasons for the qualms. Our house, too, is airtight except for intentional ventilation, and gas is a staple here. No one ever told us that might be a problem, and in fact, given how common gas is here for *everything*, it would be very odd for something to be all electric. Any ideas about this?
-J
no subject
Date: 2002-08-26 09:24 am (UTC)I presume you have good carbon monoxide moniters? That is the main qualm.
no subject
Date: 2002-08-26 10:48 am (UTC)Iain and I have been semi-interested in much smaller scale home wind power to supplement our grid source, since Alberta gets quite a bit of wind. So I found this quite informational.
A couple of corrections -- the link to windpower.org has an extra comma in it. And the last paragraph ("Coming to the end now, Simon Tilley ...") has a missing closing a tag for one of the links.
Now I get to spend a little time following up on some of the links!
no subject
Date: 2002-08-26 11:00 am (UTC)Anyhow, glad to be of service :-)