Green power generation

[Proper Job]

I’m looking at installing a couple of solar panels (2 x 85W). Not because I want to go green, but more because I’m lazy and the less I need to rely on running my engine/generator, the better.

 

To me the case for power generation by solar or wind is strengthened in boats as they already have much of the expensive infrastructure as part of their essential equipment (batteries, invertors etc)

 

Looking at some of the published government case studies for micro generation in domestic applications, the figures just don’t stack up!

Solar thermal hot water: 65 to 85 years payback

Solar PV: 55 years payback

Wind turbine: 15 years payback

 

All of the above do not take into account, maintenance and life expectancy of the equipment

 

I know it’s not about saving money, but reducing your carbon footprint. But……

[wonderdust]

Save your money, enjoy the warmth!

[carlt]

I don't think those government figures take into account the boats, that don't have a mains hook-up, which spend far more on generating electricity, than the average house.

 

My Panels paid for themselves after about 3 months of not running the generator.

[richardf]

I believe there is a new scheme being launched shortly, it is an attempt to get our sustainable energy figures up. If you invest in a turbine, PV panel or whatever - you can sell that energy back to the grid for 30p a unit. Bearing in mind you can buy power at 10p a unit, that is a significant amount of money. I know of several people who are investing in wind turbines for this sole purpose. Not sure how long this scheme will be in place for, but I know of several of our customers who are doing it.

[RLWP]

I believe that Germany has a scheme like that for micro-generation.

 

Richard

[Phil Ambrose]

I don't think those government figures take into account the boats, that don't have a mains hook-up, which spend far more on generating electricity, than the average house.

 

My Panels paid for themselves after about 3 months of not running the generator.

 

Agree with Carl on this one, though I did not run a genny but relied on very expensive shore power but cheaper than fueling a genny. I reckon after a year it will be another 12 months before I get my money back, but in the scheme of things that is not bad at all. Should add we have a lot of heavy draw stuff, as I have said before my wife said " We may live on a boat but I am not camping"

 

Phil

[County4x4]

The situation probably hasn't been helped by various companies promoting these things to death and chasing sales even where the prevailing conditions are unsuitable. B&Q actually stopped selling domestic wind turbines when a study by Which magazine (if I remember correctly) showed that when the majority of these gable end turbines were hooked up to an inverter 24/7, they were actually consuming more power than they produced!

 

I would also think that the avergae boat dweller has a much better appreciation of where their power is coming from, and changes their pattern of use accordingly, using less, and certainly wasting much less than the average person living in bricks and mortar, where whole houses are often lit uplike a football stadium as soon as the sun sets.

 

Not practical on a boat perhaps, but a number of people are now getting into combined heat and power schemes for their homes where they're running old Lister C/S engines on vegetable oil and reaping the exhaust heat for domestic heating, as well as running generators to feed into their domestic supply through an inverter.

 

I think these things can work - but it's not something that will work for everyone - a lot depends on your location and the surroundings you have.

 

On a boat - maybe switching to woodfuels would be a good green step as these are considered carbon neutral.

 

Andy

[RLWP]

T<snip>

 

Not practical on a boat perhaps, but a number of people are now getting into combined heat and power schemes for their homes where they're running old Lister C/S engines on vegetable oil and reaping the exhaust heat for domestic heating, as well as running generators to feed into their domestic supply through an inverter.

 

<snip>

Andy

 

Apart from the veg oil that's exactly what a boat does. Where do you think the heat in your calorifier comes from?

 

Richard

[Proper Job]

I don't think those government figures take into account the boats, that don't have a mains hook-up, which spend far more on generating electricity, than the average house.

 

My Panels paid for themselves after about 3 months of not running the generator.

I understand what you are saying and agree with you. A lot of the cost for a shore based domestic system must be in the installation of the battery, inverter and other systems. These are already on boats and need to be maintained etc, irrespective of if you have solar panels or a wind turbine

 

I would also think that a solar panel will help with extending battery life (not so much deep cycling and keeping the topped up better)

 

I just wonder (realistically) how viable it is on domestic shore based systems

[Naughty Cal]

I would also think that the avergae boat dweller has a much better appreciation of where their power is coming from, and changes their pattern of use accordingly, using less, and certainly wasting much less than the average person living in bricks and mortar, where whole houses are often lit uplike a football stadium as soon as the sun sets.

 

Interestingly since we have bought the boat our home energy bills have plummeted. We are much more careful at home with our power consumption (plus we are hardly ever there)

[Proper Job]

Apart from the veg oil that's exactly what a boat does. Where do you think the heat in your calorifier comes from?

 

Richard

And who say's you can't run your engine on veg oil?

 

It just depends if you want to smell like a mobile chip shop

[carlt]

I just wonder (realistically) how viable it is on domestic shore based systems

Probably as viable as a house...not very.

 

One thing I've been looking into (though not entirely relevant, on a boat) is to buy the equipment and financing it by adding it to the mortgage.

 

The repayments, minus the saving on mains power, would, I think provide more disposable income than if I were to just give it all to Eon.

[nb Innisfree]

Compared to self generation 15p per KWh is VERY cheap, no contest.

[FadeToScarlet]

I’m looking at installing a couple of solar panels (2 x 85W). Not because I want to go green, but more because I’m lazy and the less I need to rely on running my engine/generator, the better.

 

For me, convenience. The wind genny, when it's windy, has put up to 48 (supposedly) Ah per day back into the battery. The next step is 130 watts of solar, in low-profile stick-on panels, that are unobtrusive but give a big charge. Friends who have these panels managed to last for nearly 2 months without running the generator. Certainly, we can now last just over a week between running the generator if we're frugal and don't run the fridge- which we don't need to do at all, now it's cold, as a box outside does the job just as well. Until the milk freezes and you get lumps of ice on your cornflakes.....

 

I'm paying for the convenience of not having to get out, lug around, plug in etc. the genny, and possibly with longer battery life, through keeping them constantly charging, even if at times the demand outstrips the charge, rather than deep cycling.

[Roger Gunkel]

Looking at some of the published government case studies for micro generation in domestic applications, the figures just don’t stack up!

Solar thermal hot water: 65 to 85 years payback

Solar PV: 55 years payback

Wind turbine: 15 years payback

 

All of the above do not take into account, maintenance and life expectancy of the equipment

 

I know it’s not about saving money, but reducing your carbon footprint. But……

 

I always get really irritated by these government quoted figures. What are they based on, who comes up with the figures. For instance, 'Wind turbine:15 years payback' ? What does that mean? Does it mean getting an approved contractor to install a wind turbine capable of producing all the power requirements of a typical house? I would think it would take a lot more than 15years to break even. On the other hand, my Rutland 913 cost me about £65 second hand including fitting new bearings. As my Marina electric costs 25p per unit, it only needed 260 Kw generated to break even. On the sort of wind we have been getting, (not a lot) thats about 2 years, but in a better location considerably less.

 

'Solar Thermal hot water: 65 to 85 years payback'. Normal house, Everest thermal water installation, £6-10000? I agree with the figures, BUT! Black plastic container on the roof throughout the Summer months, constant warm to hot water, payback time immediate.

 

To me, there are many ways to approach green energy, but payback time is irrelevant, its about independence and availability of hot water, power etc that may otherwise be strictly limited.

 

Roger

[Gibbo]

Solar thermal hot water: 65 to 85 years payback

Solar PV: 55 years payback

Wind turbine: 15 years payback

 

The first figure I simply don't believe. Solar thermal hot weater is by far the cheapest to install. The problem with trying to do calculations on these systems is that there are quite a lot of guesses involved so even if one tries, someone comes along to argue the point so it never reaches a conclusion. Two square meters of solar thermal panels will provide all the hot water a family of four needs for 6 months of the year.

 

The second figure could well be correct. I think it's a bit longer than reality. But what it means in truth is this:-

 

Solar PV: Payback: Never. It will never pay for itself.

 

Quite simply because the solar panels will have stopped working before the payback day is reached and will have to be replaced.

 

Wind turbine, I reckon somewhat longer than 15 years. But again, it's not even worth trying to do sums on it because it just leads to arguments.

 

On the subject of selling it back to the grid, Why not charge a battery bank up at 10 pence per unit, then discharge it and sell it back to them at 30 pence per unit. That stacks up. There is something wrong somewhere. Probably the "30 pence" figure.

 

None of which applies on a boat. If you have no shorepower, I think they're all worth having.

[Phil Ambrose]

And who say's you can't run your engine on veg oil?

 

It just depends if you want to smell like a mobile chip shop

 

Seem to remember seeing an article in WW sometime ago where they ran something like a Lister on veg oil. It did entail a three stage filter system and the oil had to initialy pre heated but it worked fine, or so the article said.

This is not to be confused with mixing white spirit with filtered chip shop oil.

[Justme]

Our PV "pay back" (see below) is running at 11 years. It changes with the cost of red diesel, how much power we actually use & how much power we actually get from the sun. OH & any repairs / replacements we need to do.

 

The reason ours is so low is we have NO mains at 10-15p per kwh. So our yard stick is genny produced power at about 51p per kwh.

 

 

The reason I use "pay back" as a term above is because thats how most people will see it. In our situation we have already "paid back", HOW I hear you all shout. Well as we have NO MAINS it would have cost £10-20k to get mains installed here. We have spent far less than that to set ourselves up with pv/genny. Our ongoing costs on red are less than the elec would have cost from the mains.

 

For us going green was a no brainer.

[David Schweizer]

When B&Q were marketing wind generators, I took all the details and worked out the cost effectiveness of purchasing one and measured the costs against power from the grid. As Gibbo says, it is impossible to be very accurate because of so many variables, most of these can be averaged, but what cannot be accurately assessed is the progressive rise in Domestic electricity costs from the grid, never the less I had a go.

 

We live in a fairly windy place, (in fact the name of the village is believed to originate from ancient Saxon meaning Windy Place) so I took this into account apportioning 25% more wind speed than the regional average and assumed that this would be available for 75% on the year. However both these assumptions are probably excessivly optimistic. Using these figures I calculated how much power I would generate, and came up with an average number of units per year I would be generating, and therefore not purchasing from the Electricity company. I also estimated that Domestic electricity would rise at an average of 15% per annum.

 

I assumed that I would be able to obtain the maximum grant against the cost of the equipment, which was conditional upon a requirement for the equipment to be installed by an approved contractor, and made no allowances for maintenance costs. I did not include any figures for selling back any power because, based upon figures provided by the manufacturer, my calculations suggested that even at nightime it was unlikely that the turbine would produce any significant surplus.

 

The final outcome of my, probably over optimisic, calculations was that I would recover the cost of the initial outlay within 25 years. However the estimated life expectancy of the equipment was 20 years.!! so it was a non starter on economic grounds, and I did not proceed. Unfortunately I threw the calculations away so I cannot substantiate my conclusions. I also consequently discovered that would probably have been unable to get Planning Consent for the instalation of a Turbine because of the inevitable proximity to other properties.

 

Now, when it comes to Solar panels, I am more interested, we have a huge tall roof which faces exactly south. If the Government were willing to offer me a substantial grant towards some of them, I could be interested, and I know I would be ablle to get Planning Consent for them. But without a grant I doubt that they would be cost effective.

Edited October 24, 2009 by David Schweizer

[ditchcrawler]

The situation probably hasn't been helped by various companies promoting these things to death and chasing sales even where the prevailing conditions are unsuitable. B&Q actually stopped selling domestic wind turbines when a study by Which magazine (if I remember correctly) showed that when the majority of these gable end turbines were hooked up to an inverter 24/7, they were actually consuming more power than they produced!

 

I would also think that the avergae boat dweller has a much better appreciation of where their power is coming from, and changes their pattern of use accordingly, using less, and certainly wasting much less than the average person living in bricks and mortar, where whole houses are often lit uplike a football stadium as soon as the sun sets.

 

Not practical on a boat perhaps, but a number of people are now getting into combined heat and power schemes for their homes where they're running old Lister C/S engines on vegetable oil and reaping the exhaust heat for domestic heating, as well as running generators to feed into their domestic supply through an inverter.

 

I think these things can work - but it's not something that will work for everyone - a lot depends on your location and the surroundings you have.

 

On a boat - maybe switching to woodfuels would be a good green step as these are considered carbon neutral.

 

Andy

Russell Newbury are now building a new one, Vat free and I think you can even get grants towards the cost of it.

 

The first figure I simply don't believe. Solar thermal hot weater is by far the cheapest to install. The problem with trying to do calculations on these systems is that there are quite a lot of guesses involved so even if one tries, someone comes along to argue the point so it never reaches a conclusion. Two square meters of solar thermal panels will provide all the hot water a family of four needs for 6 months of the year.

 

The second figure could well be correct. I think it's a bit longer than reality. But what it means in truth is this:-

 

Solar PV: Payback: Never. It will never pay for itself.

 

Quite simply because the solar panels will have stopped working before the payback day is reached and will have to be replaced.

 

Wind turbine, I reckon somewhat longer than 15 years. But again, it's not even worth trying to do sums on it because it just leads to arguments.

 

On the subject of selling it back to the grid, Why not charge a battery bank up at 10 pence per unit, then discharge it and sell it back to them at 30 pence per unit. That stacks up. There is something wrong somewhere. Probably the "30 pence" figure.

 

None of which applies on a boat. If you have no shorepower, I think they're all worth having.

The efficiencies in charging and discharging batteries would probably use up the money earned.

I have a friend who has just built a wind genny from a kit and uses it to heat an indoor swimming pool, whenever the wind is blowing the pool is warming up.

[Gibbo]

The efficiencies in charging and discharging batteries would probably use up the money earned.

 

I don't think they would.

 

I know our former mathematician used to spout on about having to put back 50% more than you get out but if the charging voltages are carefully regulated, and the batteries properly maintained, charge efficiency of lead acid batteries can approach 95%

 

Add in the losses for the charger and the inverter of (say) 20% in total and 1kWh of purchased electricity will produce about 750 watt hours of "reconstituted" electricity.

 

If it's being bought at 10 pence per kWh and sold at 30 pence per kWh that makes a wacking great profit.

 

The problem is, the figures I've seen for the grid buying back electricity are nowhere near 30 pence. More like 15 pence.

[ditchcrawler]

I don't think they would.

 

I know our former mathematician used to spout on about having to put back 50% more than you get out but if the charging voltages are carefully regulated, and the batteries properly maintained, charge efficiency of lead acid batteries can approach 95%

 

Add in the losses for the charger and the inverter of (say) 20% in total and 1kWh of purchased electricity will produce about 750 watt hours of "reconstituted" electricity.

 

If it's being bought at 10 pence per kWh and sold at 30 pence per kWh that makes a wacking great profit.

 

The problem is, the figures I've seen for the grid buying back electricity are nowhere near 30 pence. More like 15 pence.

I think this 30p is something that the government has just announced, The chap who heats his swimming pool was on about it Thursday evening.

[Chris Pink]

I’m looking at installing a couple of solar panels (2 x 85W). Not because I want to go green, but more because I’m lazy and the less I need to rely on running my engine/generator, the better.

 

My 60W solar panel saved me around £60 in petrol this summer, so payback in 4 years. But the most valuable thing is not having to get petrol and the hassle and noise of getting the generator out.

[richardf]

The problem is, the figures I've seen for the grid buying back electricity are nowhere near 30 pence. More like 15 pence.

 

This site seems to suggest that it can be more than 30p!

http://www.reuk.co.uk/Feed-in-Tariff.htm

[ditchcrawler]

This site seems to suggest that it can be more than 30p!

http://www.reuk.co.uk/Feed-in-Tariff.htm

Do you think this is keeping the price of solar panels artificially high