Solar Power

[KhaoYai]

It is very likely that I will be building a house in Nakhon Ratchasima next year. I want to install a full solar power system as part of the build. I am aware that it may take years to get any payback on the outlay - I am not doing this to save money, my reasons are environmental. The house will almost certainly be much the same as my current property and therefore have much the same power requirements - i.e.

 

2 x TV's

3 x Aircon units

1 x Electric oven

1 x Microwave

4 x Ceiling Fans

Low energy LED lighting throughout

 

The house will be occupied by 2 adults and one child.

 

Of course there will be all the other smaller things that are normal for a house (western lifestyle) but clearly, it is most unlikely that all these things will be switched on at the same time. For example, the electric oven will not be used much but the grill in it will be used more. The aircon units serve 2 bedrooms and 1 living room - living room on during the day, bedrooms on at night. However, much of the time, if the bedrooms are first cooled by the aircon, the ceiling fans are sufficient. Walls and loft space will be insulated and all windows and doors will be double glazed and fitted with low E glass.

 

I insist on hot water and will need to decide what sort of system I am going to put in to this house. I installed an Air Source Heat Pump system in my current home and so far I am very pleased with it. It enables me to have constant hot water supplying the thermostatic shower valves in each shower (2) and the kitchen.  I would very much like to install the same system in the planned house and I think this will probably mean I need a higher output solar system. The current heater is very similar to this one and is the smallest one on the list - 200l storage tank and stated as having an average power input of 1.2kw.

 

http://wordpress.utomedia.co/cripton/products/air-source-heat-pump/domestic/#.XVZ1nXt7nIV

 

I know very little about solar power - I believe it produces DC electicity and therefore needs a converter. The house will also be connected to the mains electricity supply so some form of coupling/automatic changeover device must be required?

 

I realise that power usage is very much a 'how long is a piece of string' situation but there must be some 'average' figures. I don't make huge demands on power but given that I am a westerner, I am likley to use more than the average Thai - i.e. aircon.

 

What I would like to know is - what size of solar system will I require and how many square metres of panels will that system require? Clearly the cost of such a system and associated switchgear is also paramount.

 

I'm not sure if I will fit the system myself (in conjunction with an electrician) yet - clearly I would need a cost comparison against a contractor to be able to make that decision. Any recommendations for a good solar power supplier/installer would be appreciated.

 

[BritManToo]

Assume you will get between between 1/2-1 unit a day per 330w solar panel (2m x 1m).

(I get 1/2 but another poster thinks he get 1)

Then work out how many units you use a day to calculate the number of panels you need.

Panels cost 4k, grid tie inverter cost 4k and can take 2 panels.

You can buy more expensive GTIs, but the costs remain fairly constant.

[Crossy]

Do you have grid power at or near your site?

 

[Naam]

2 hours ago, KhaoYai said:

3 x Aircon units

1 x Electric oven

1 x Microwave

good luck with "full solar"

[alacrity]

53 minutes ago, Naam said:

good luck with "full solar"

It's a rainy day. Sunshine girl.

It's a smoggy day. Sunshine girl.

It's a cloudy day. Sunshine girl.

Lessons to be learnt. Sunshine girl.

[tjo o tjim]

First thing you need to do is maximize efficiency and passive effects. A solar water heater might be your best approach from a cost perspective, but a heat pump hot water heater will provide some cooling as a benefit. 

 

If you want to be on-grid and net-zero, you need to talk to PEA/MEA on the tariff structure and requirements. A meter spinning backwards during the day and ending up at zero annual energy consumption without approval is asking for problems. (Good news is that the PV likely helps the local grid given the low penetration rates here.) 

 

Economically (and arguably environmentally) you are best off with the utility being your (main) battery. You want to segment your electrical system into multiple priority levels— must have, need to have, want to have, nice to have. Hot water and AC are the last priority, and cooking is second to last. 

 

If if you need to island mode during the day, it means you need to buy the batteries instead of using the utility, but no harm in using the utility to stabilize your own power. This simplifies cooking and the like. 

 

If if you want to be net-zero you are likely looking at a 16kW system, which would be about 50 330W panels that are about 1m x 2m each. I would suggest starting smaller than that, maybe 50%, but planning for the full build.

 

If you want to be off-grid, you would need three 240V battery strings  at about 250Ah each. (Very expensive and not an especially good idea.) Grid connection makes much more sense. (I would make sure you have a 48V, 200Ah battery for your more critical loads.)

[KhaoYai]

7 hours ago, Crossy said:

Do you have grid power at or near your site?

 

Yes, there's an existing house on the site at the moment but its coming down.

[KhaoYai]

2 hours ago, tjo o tjim said:

First thing you need to do is maximize efficiency and passive effects. A solar water heater might be your best approach from a cost perspective, but a heat pump hot water heater will provide some cooling as a benefit............

Thank you for your entire post but its getting a little technical for me.......batteries? I had no idea solar systems use batteries. I'm not so sure that any system on anything that uses batteries is so good for the environment. 

 

I'm not convinced for example, that electric cars that use batteries are quite the environmental saviour we are led to believe.  Its just possible that in reducing emmisons from cars, we may be solving one environmental problem but creating another - namely the replacement and disposal of batteries. Not forgetting of course, that the electricty used to charge the car's batteries is very liklely to be produced at a power station that emits gases that contribute to climate change. I have no idea of the figures but I wonder how much we save (total environmental cost) by using electric cars? - taking into account the environmental cost of producing, replacing and disposing of batteries + the environmental cost of generating the electricty needed to charge those cars. They may well still be a better alternative but electric cars are not without environmental costs.

 

A neighbour of mine was full of herself, claiming she was now totally 'green' because she had bought an electric car - that was until I pointed out to her that the power station serving our area of the UK still burns coal. She's not quite as smug now.

 

Still, I want to do whatever I can - I think each and every one of us has a moral duty to our children and grandchildren to try and do something to a avert the catasthrope that both ourselves and previous generations have set in place.

 

16kw? Really? I haven't done a lot of research but most of what I've read so far seems to indicate that 4kw is enough for a small house. I don't intend switching all of my appliances on at the same time.

 

There's still a lot of planning to do and of course I need to gain other views but its looking like a partial system may be better?

 

BTW, my current air source heat pump does emit some colling air but its an external unit so the only thing it cools is the garden.  Maybe a unit at the new house could be sited where its cooling could be utilised but them things ain't quiet when they're running you know?

[KhaoYai]

7 hours ago, BritManToo said:

Then work out how many units you use a day to calculate the number of panels you need.

How many units = 1kwh? Or is that one unit?

[eisfeld]

One unit is one kWh. For a house of your size I'd say around 5kW inverter size should do the trick. You can size your panels (yes they generate DC hence you need that inverter) a bit higher than the inverter peak output, usually 10% are fine. So 5.5kW in panels. Depending on the wattage of the panels that'll be 14-17 panels. Each as mentioned about 1x2m with a bit of space between them. Calculate 2.5sqm per panel roughly. Make sure they are facing southward and are not all too much tilted differently than the latitude of your location. Too lazy to look up the one of Korat but I'd guess around 16 degrees.

 

Forget batteries, they are too expensive and break way too easily here if connected to the funny grid unless you have a voltage stabalizer.

 

You can connect it to the grid (grid-tie) but the PEA wont like it unless you sign up for their rooftop solar program which pays you 1.8THB per unit that you send them. It's monetarily more efficient to not tell them and just let the meter spin backwards but you'll have to keep an eye on that meter and make sure you never run lower than the previous value. Usually it means you should turn your solar system off around the time the meter is being read. If you sign up for the PEA program then all is fine but your break even will be maybe in 8-9 years. Still a worthwhile thing to do. Grid-tie means btw that when the grid is down then your solar system is also down as it needs to sync with the frequency of the grid. With grid-tie you don't need any switching between solar and grid. Forget also off-grid without batteries, your solar generation will be way too inconsistent to run your house hassle-free.

[eisfeld]

8 hours ago, BritManToo said:

Assume you will get between between 1/2-1 unit a day per 330w solar panel (2m x 1m).

(I get 1/2 but another poster thinks he get 1)

Then work out how many units you use a day to calculate the number of panels you need.

Panels cost 4k, grid tie inverter cost 4k and can take 2 panels.

You can buy more expensive GTIs, but the costs remain fairly constant.

Do not use those shitty micro inverters and you should see more than 1 unit per day from a 330W panel. I have data from two installs in Phuket that are around the 7kW mark and do more than 1 unit per day as well. Best month was march where the system generated 972kWh which broken down to 330W panels would be more than 1.5 units per panel. June was the lowest this year with 736kWh which would be still more than 1.16kWh per 330W. Since panel sizes vary much I wouldn't recommend in thinking in 330W panels. Better to think in kWh (or units) generated per kW. You can estimate roughly 1400kWh per year per kW or something like 120 units per kW per month.

 

0.5kWh per 330W per day would mean about 550 kWh per year per kW which is very very poor.

BTW the micro inverter you posted in the other thread had only 1 input as far as I could see and 2 panels might provide too much voltage for it since you'd need to put them in series which would easily generate 60+V and I saw in the specs of it a very narrow voltage range of 30-40V.

[KhaoYai]

5 hours ago, Naam said:

good luck with "full solar"

 

4 hours ago, alacrity said:

It's a rainy day. Sunshine girl.

It's a smoggy day. Sunshine girl.

It's a cloudy day. Sunshine girl.

Lessons to be learnt. Sunshine girl.

Guys, it should be clear that I know very little about solar power - that's why I'm asking here. I say full solar because my desire is to have a house that can run entirely on solar energy when its available. I do however, intend to also have a mains connection.

 

I'm just starting to learn about this and may have to modify my desires - I realise that. I just seems that in a country with so much sunshine, relatively few houses use solar power.  The Thai's that I've talked to cite the the installation cost as their main reason for not using solar energy. We had the opposite (but same ????) problem in the UK where people were very slow to start insulating their houses until 2 things happened, a). Incentives were given to offset the cost of insulating existing houses and b). Legislation was introduced (and is ongoing) requiring all new houses to be built with a high standard of thermal efficiency.

 

It may seem harsh, and certainly the Thai's would complain but maybe the only way to get them to use solar power is through similar legislation. We all have to start realising that the things we consume have more costs than those that are stated on the price tag - most things have an environmental cost too.

 

I want to do what I can but I think that ultimately, its too late to 'save the planet' - humans, supposedly the species with the highest intelligence have destroyed it. In our seemingly incessant quest for more, bigger, better, faster, further we have consumed far more than this world can ever hope to produce. We have torn up natural habitats as if we are the only species that exists and the world population passed the sustainable level centuries ago. 

 

Nature is pretty good at taking care of itself - that's why a few thousand years ago much of the world's land mass was covered in trees. Some of the habitats that we destroyed (and continue to destroy), namely forests and rain forests, were also pretty good at soaking up some of the 'nasties' that we produce. What have we done? Produced even more 'nasties' and cut down even more trees!!!

 

To make a significant change, if indeed that is possible, I believe that the world's population and consumption levels have to fall massively and fast - the planet cannot sustain current levels. The reduction in consumption would mean a huge 'sea change' in how we live our lives and how our economic systems work. We would have to change from producing what we desire to what we actually require and need would have to overcome profit. 

 

Realistically, none of that is going to happen. Greed overcomes real time needs and selfishness is endemic in all of us - if only we would realise it. Few will accept massive reductions in consumption or will accept the huge reductions in childbirth needed for humans to become 'sustainable'.

 

New technologies may slow things down but the fact is, there are just too many of us, taking far more out than we put in and neither of those things are likely to change. However, we can all buy the future generations a little more time by doing what we can now. That is why I want to look at installing solar energy. I am one person in 7.5 billion but what could we achieve if we all changed our ways?

 

Here endeth the sermon  ????.

[Stevey]

Electric oven ?? ????????????????????

[KhaoYai]

2 hours ago, Stevey said:

Electric oven ?? ????????????????????

Your problem is? I already have an oven in my current home at Khao Yai. I don't use the oven much but I use the grill in it almost every day that I'm there. I wouldn't be without the oven, I'm not too good at learning other methods of cooking - I guess I'm set in my ways. Its there when I need it. If you find that funny, I'm pleased to have entertained you.

 

Yes, I'm a westerner, I don't sit cross legged on the floor and nor do I prepare my food there either. I don't make merit or go to the temple. Are you any different?

 

I'm clearly not the only person with an oven - the shop in Korat where I bought it has quite a few in stock. Thai's don't stock things that don't sell.

[KhaoYai]

I should have made it clear from the outset, I have no intention of only having solar power.

[Crossy]

6 minutes ago, KhaoYai said:

I should have made it clear from the outset, I have no intention of only having solar power.

 

OK, that was my reason for asking if there was already grid power at the site ????

 

In that case you size your solar for how much you want to reduce your bill by and how much you can afford.

 

A grid-tie system is the lowest cost option but if the mains goes off so does your solar (no batteries). If you want at least some power when the mains is off then you want to look at a hybrid system.

 

 

 

[BritManToo]

4 hours ago, eisfeld said:

BTW the micro inverter you posted in the other thread had only 1 input as far as I could see and 2 panels might provide too much voltage for it since you'd need to put them in series which would easily generate 60+V and I saw in the specs of it a very narrow voltage range of 30-40V.

It takes 2 in parallel.

[BritManToo]

4 hours ago, KhaoYai said:

To make a significant change, if indeed that is possible, I believe that the world's population and consumption levels have to fall massively and fast - the planet cannot sustain current levels.

Off topic but not true.

There's no world shortage of food (or anything else), it's just some people can't afford to pay for it, and farmers don't work for free. As for population levels, many countries have falling population (including Thailand), it's just some countries that need to fall.

[eisfeld]

4 hours ago, BritManToo said:

It takes 2 in parallel.

Ah right can do that too. Anyways I think those microinverters are way too inefficient for a full-house system of several kW. Plus I would worry about reliability and support. Better to get something from a known brand and without moving fans if possible.

[BritManToo]

14 minutes ago, eisfeld said:

Ah right can do that too. Anyways I think those microinverters are way too inefficient for a full-house system of several kW. Plus I would worry about reliability and support. Better to get something from a known brand and without moving fans if possible.

My theory was all the GTIs available in Thailand are unreliable, so better to buy one I can afford to throw away.

[eisfeld]

Just now, BritManToo said:

My theory was all the GTIs available in Thailand are unreliable, so better to buy one I can afford to throw away.

Micro Inverters maybe. I have only seen el-cheapo chinaware for those. The bigger brand ones for sure are not unreliable as those. You can get Huawei, SMA etc. which are pretty good. There are many commercial installations in the Megawatt range. They wouldn't use unreliable inverters because it takes quite a bit of money to build these systems and the people who invest are not super dumb ????

 

Standard warranty for brand inverters is 5 years and one can easily buy an extension to 10 years.

[BritManToo]

6 minutes ago, eisfeld said:

Standard warranty for brand inverters is 5 years and one can easily buy an extension to 10 years.

Not long enough, and I doubt anyone in Thailand will honour it.

I've spent under 10K and can afford to walk away.

You say spend 100k, it's not for me, doubt I'll even be alive in 5 years, or in Thailand if I am.

In 5 years time much better equipment will be available for half the price.

 

Never spend more in Thailand than you are prepared to walk away from.

[BritManToo]

7 minutes ago, eisfeld said:

hey wouldn't use unreliable inverters because it takes quite a bit of money to build these systems and the people who invest are not super dumb

As far as I can see, nobody on this forum has invested in this.

You said yours was free.

[Tayaout]

In my opinion electricity is too cheap in Thailand to go full solar. Solar pannel are not environmentally friendly to produce, transport and dispose of in 20 years. It make more sense if you are in a offgrid location. 

 

One of the most efficient system you can get is made by Tesla and you can use their website to check how much it would cost: 

https://www.tesla.com/powerwall

https://www.tesla.com/energy

 

Of course it will be a lot more expensive to do it yourself or import Tesla product to Thailand. If you have a lot of money or like DIY project then I guess it's ok ????

 

For cooking you should use gas or even better biogas: https://www.homebiogas.com

 

To heat water probably solar water heater are more efficient than solar electric pannel. Gas is probably better for on-demand stable temperature.

 

There is also solar oven that you put outside in the sun. They only work during the day but are ok if you put something to cook in the morning it will be ready at the end of the day. 

 

 

[eisfeld]

5 hours ago, BritManToo said:

Not long enough, and I doubt anyone in Thailand will honour it.

I've spent under 10K and can afford to walk away.

You say spend 100k, it's not for me, doubt I'll even be alive in 5 years, or in Thailand if I am.

In 5 years time much better equipment will be available for half the price.

 

Never spend more in Thailand than you are prepared to walk away from.

Can't agree with you there. They will honor it unless one fscks it up oneself. These are serious companies. If you think you wont be alive in 5 years then ok, no reason to plan long term. Sorry to hear that. I doubt though that in 5 years you can get inverters for half the price, the prices there did not drop as crazily as solar panels. And a big chunk of the price is installation which does not get cheaper really.

[eisfeld]

5 hours ago, BritManToo said:

As far as I can see, nobody on this forum has invested in this.

You said yours was free.

I didn't say mine was free, just that I'm not buying at local market prices. There are a bunch of Thai and Foreign-Thai companies that built solar farms in central/north-east Thailand. Each of them roughly 10MW. They are making a killing with the old feed-in tariffs. Nowerdays it's less lucrative but still worthwhile.

[KhaoYai]

13 hours ago, BritManToo said:

Off topic but not true.

There's no world shortage of food (or anything else), it's just some people can't afford to pay for it, and farmers don't work for free. As for population levels, many countries have falling population (including Thailand), it's just some countries that need to fall.

You misunderstand. I didn't say there was any shortage of anything - except perhaps, time. I'm saying that we all need to consume less and I'm not refering to food consumption, I mean everything. We have depleted the world's resources massively but more importantly, the production of goods of any shape or form has environmental consequences. Humans are probably the only species that obtain possessions for reasons of vanity or desire rather than need.

 

Population levels?  I'm fully aware that they are falling in some countries. It doesn't matter about that, there are just too many people, wherever they are. UN forecasts are that by 2040, the world population will reach 8.5 billion and 9.7 billion by 2050.  If we pollute the atmosphere and consume too much now - imagine the situation in 2050 with around 2.5 billion people.......billion!! more than there are now.

 

Its also almost a certainty that changes in technology won't compensate for that increase - the countries where the greatest population increase is taking place are also the poorest, are still using old technologies and indeed are expanding their use of them. India and China for example are still building coal fired power stations and have plans for many more. Others are also following suit: 

 

The promise of cheap electricity to fuel economic growth has driven this expansion. Coal generates nearly 40% of the world’s electricity, close to its highest share in decades. And there are now 78 countries using coal power, up from 66 in 2000. Another 16 plan to join the club, notably Egypt and the United Arab Emirates.

 

https://www.carbonbrief.org/mapped-worlds-coal-power-plants

 

The economies of those countries are also growing by and large. As their economies grow, so does their consumption - it just goes on and on.

 

The UK, for example boasts of having cleaned up exhaust emmissions from cars.  Whilst it is true that cars in the UK are now the cleanest they've ever been - there are millions more of them, negating any reduction in emmissions and in fact, increasing them.

 

We all need to do something and do it now. I feel very guilty about my carbon footprint - mainly because I travel by air to Thailand 6 or 7 times per year. Hopefully that will stop soon but in the meantime I looked at what I could do to reduce my footprint.  Without actually stopping anything, I have cut my annual car mileage by half, simply by forethought in combining journeys. I have 2 vehicles on the road in the UK, one is 15 years old, the other 13.  I see keeping them on the road (making things last) as an integral part of reducing consumption. My phone is looking a little sad and the screen is cracked - I am going to replace the screen and battery shortly, I don't need a complete new phone. I never buy things I don't really need and I buy decent quality that lasts.

 

However, all these reductions, if practiced by everyone, would have serious economic consequences - which is why I talked about a Sea Change in attitude in my earlier post.

 

If we actually want a planet, we have to treat it differently.

[KhaoYai]

9 hours ago, Tayaout said:

In my opinion electricity is too cheap in Thailand to go full solar.

I think I made it clear, I am not considering this for financial reasons.

[KhaoYai]

14 hours ago, Crossy said:

In that case you size your solar for how much you want to reduce your bill by and how much you can afford.

To know how much I can afford, I will need to know the cost.

 

My aim would be to supply all of my house's power when the system is working but I may have to modify that depending upon the cost.

 

I guess the very least I would like to do is to offset the increase in my electricity use caused by my water heater. Although I guess if that was all I was going to do, it would be better to fit a solar powered water heater?

[KhaoYai]

14 hours ago, Crossy said:

A grid-tie system is the lowest cost option but if the mains goes off so does your solar (no batteries). If you want at least some power when the mains is off then you want to look at a hybrid system.

Fortunately, in my area the power is fairly reliable. There have been quite a few outages in recent months but they were related to work on the grid serving the new Bangkok - Korat motorway.

 

Most of the cables in my area have been renewed recently and I'm not really too bothered about power cuts. So its sounds as if a system tied in to the grid, without a battery, is most suited to my needs.