Alternative power options for an average household. (2010)
The purpose of this document is to give some guidelines in the decision making process when you
are considering alternative energy solutions to reduce power consumption on to city power or Eskom.
ESKOM
The woes at Eskom are well known and are having a profound impact on both the national psyche and the national economy. The mood in the country will not get better, and the growth rates will not improve much, before power supply improves.
It seems as if that improvement will not occur before the middle of 2016 – about 18 months’ time. It is all about capacity and the dates that capacity will become available.
The numbers tell the story: the current short fall of power is about 2 000 MW. To manage that deficit the entire system must be run flat out leaving little room for maintenance and forcing the use of expensive diesel-run generators. It also means that if the slightest thing goes wrong (which it of course always does) power supply is interrupted. That is what the 2000 MW shortfall means. The only way to cope with that is to install new capacity.
When will the new capacity be available?
The first new unit (794 MW at Medupi) is scheduled to start producing by middle 2015, followed by two more units a year of about 800 MW each. Eliminating the current 2000 MW short fall will require 3 x 800 MW units. That can be installed by the middle of 2016, if all goes according to schedule.
But it is not enough to cover the 2 000 MW short fall. One also needs more capacity to be able to shut down parts of the system to do maintenance. The decision since the 2010 World Cup to “keep the lights on at all costs” has extracted a price in poor maintenance. At the weekend of writing this, for example, Eskom reduced output by 4 000 MW thus causing power interruptions across the country. So we will need another 2 x 800 MW units to help cover maintenance interruptions. Those two units can be commissioned by 2017.
Eskom is also desperate to stop using the open-cycle gas turbines during peak periods. They are REALLY expensive to run (last financial year R10.5 billion). In addition there is old equipment that has to be replaced. Both these require further new capacity, taking us to 2018 before we are out of the woods.
This schedule, which Eskom again confirmed at the Investment Analysts Society last week, suggest that the tipping point for the better will only be reached by 2016; by 2018 it is only possible to be out of the woods; and by 2020, when all 12 units from Medupi and Kusile are up and running, there can be decisive improvement. All of this is on the assumption that 2 x 800MW units come into production every year from 2016 onwards.
Private sector
In the meantime a lot of private sector investment in capacity is also taking place. 1 000 MW of renewable energy has already been connected to the grid. In total 4 280 MW (that is 89% of the size of a Medupi or a Kusile) have been contracted between Eskom and various private sector players. Currently Eskom is spending about R1.6 billion a month buying power from these various private producers. A multi-billion rand industry has developed and it is set to get much bigger.
A further round of bids by private producers will be released soon, including for a 2 500 MW coal-fired power station. If these investments indeed take place, it could take private sector MW capacity close to the combined capacity of both Medupi and Kusile. The private sector is entering electricity generation in a substantial way. This will help to improve power delivery by 2018.
Very much as an aside, a long term goal of the Mbeki government back in the 2000s was that 30% of SA’s power must eventually be generated by private players. By estimation indicate that by 2018 12% to 15% could achieve.
are considering alternative energy solutions to reduce power consumption on to city power or Eskom.
Why should I look at alternative power?
ESKOM
The woes at Eskom are well known and are having a profound impact on both the national psyche and the national economy. The mood in the country will not get better, and the growth rates will not improve much, before power supply improves.
It seems as if that improvement will not occur before the middle of 2016 – about 18 months’ time. It is all about capacity and the dates that capacity will become available.
The numbers tell the story: the current short fall of power is about 2 000 MW. To manage that deficit the entire system must be run flat out leaving little room for maintenance and forcing the use of expensive diesel-run generators. It also means that if the slightest thing goes wrong (which it of course always does) power supply is interrupted. That is what the 2000 MW shortfall means. The only way to cope with that is to install new capacity.
When will the new capacity be available?
The first new unit (794 MW at Medupi) is scheduled to start producing by middle 2015, followed by two more units a year of about 800 MW each. Eliminating the current 2000 MW short fall will require 3 x 800 MW units. That can be installed by the middle of 2016, if all goes according to schedule.
But it is not enough to cover the 2 000 MW short fall. One also needs more capacity to be able to shut down parts of the system to do maintenance. The decision since the 2010 World Cup to “keep the lights on at all costs” has extracted a price in poor maintenance. At the weekend of writing this, for example, Eskom reduced output by 4 000 MW thus causing power interruptions across the country. So we will need another 2 x 800 MW units to help cover maintenance interruptions. Those two units can be commissioned by 2017.
Eskom is also desperate to stop using the open-cycle gas turbines during peak periods. They are REALLY expensive to run (last financial year R10.5 billion). In addition there is old equipment that has to be replaced. Both these require further new capacity, taking us to 2018 before we are out of the woods.
This schedule, which Eskom again confirmed at the Investment Analysts Society last week, suggest that the tipping point for the better will only be reached by 2016; by 2018 it is only possible to be out of the woods; and by 2020, when all 12 units from Medupi and Kusile are up and running, there can be decisive improvement. All of this is on the assumption that 2 x 800MW units come into production every year from 2016 onwards.
Private sector
In the meantime a lot of private sector investment in capacity is also taking place. 1 000 MW of renewable energy has already been connected to the grid. In total 4 280 MW (that is 89% of the size of a Medupi or a Kusile) have been contracted between Eskom and various private sector players. Currently Eskom is spending about R1.6 billion a month buying power from these various private producers. A multi-billion rand industry has developed and it is set to get much bigger.
A further round of bids by private producers will be released soon, including for a 2 500 MW coal-fired power station. If these investments indeed take place, it could take private sector MW capacity close to the combined capacity of both Medupi and Kusile. The private sector is entering electricity generation in a substantial way. This will help to improve power delivery by 2018.
Very much as an aside, a long term goal of the Mbeki government back in the 2000s was that 30% of SA’s power must eventually be generated by private players. By estimation indicate that by 2018 12% to 15% could achieve.
So what can I do
Please note by changing your power consumption behavior could also make a big difference in your total power savings.
Why should I look at alternative energy sources?
• Cheaper energy (Saves you money in the long term)
• Lower carbon footprint. (Help the world with global warming problems)
• Help ESKOM (Help South Africa's Electricity supply Company to cope with demand and eliminate blackout)
1. Power saving tips.
1.1 Light
Replace all your filament lights 60 and 100 watt globe with 7W CFL Lamps or even better if you could re-place them with 3W multiple cluster led units. Some of the cheaper LED light are not so bright so check them before you purchase.
1.2 Stove
Best option is to re-place your electrical stove plate (hob) with a gas unit. This needs a qualified gas installer with certificate. There is also electrical and gas combination stoves with 3 Gas burners and one electrical plate which could also be a good combination if you forgot to order your gas supply in time. Most of the mayor city areas have a local gas company's that will deliver 80 kg gas cylinder to your house. ( I recommend you get two Gas cylinders so you always have one spare.)
Gas at the moment is about 40% cheaper that electricity but I have heard that the price will be
regulated in the near futurer and could then be more expensive.(2010)
1.3 Fridge / Freezer and ice Makers
Apparently double door fridge / freezer with freezer at the bottom is more economical than fridge freezer in separate units. Ice makers are also not very economical. The fridge and freezer that also have automatic defrost capability also add addition power consumption. Also when selecting a fridge to run on standby invertor configuration it is important to try and get a mechanical thermostat temperature control unit as the electronic thermostat wont work if the invertor is in standby mode and you will have to run your invertor in full on mode. Not the best economical mode. Also look for the lowest power consumption fridge freezers.Refrigerator's using gas heater is not very efficient and the new electrical compressor fridge freezers are much more efficient and you could easily run them from Solar power system with the necessary DC to AC pure sine inverters or directly from batteries on the 12v versions.
1.4 Swimming pool pump.
Salt electrical swimming pool chlorinator is using additional power and would normality need to have the filter pump to run additional periods to produce enough chlorine than just using ordinary chlorine.
There is now low power alternatives with water pressure and current consumption monitoring that would optimize the water flow by adjusting the electric motor speed and would regulate the pump speed for most effective power usage. (apparently up to 50% reduction in power consumption)
2. Energy Alternative's
2.1 Gas
2.1.1 LP gas (about 40% cheaper than Electricity calc at 2010)
Gas stove, heater and gas geysers for warm water can be used. This will reduce your power
consumption. The best option here is to change your fireplace to gas and convert your stove to gas and leave your geysers to be change to solar water panel system on the roof. Gas heaters for winter are also a very good alternative to electrical heaters. (installing a gas fireplace for electrical heaters is also a good alternative to Electrical heaters for the winter months. (My gas heater use about 9Kg gas for about 2 weeks running heater every night for about 4 ours.)
2.1.2 Methane gas
Methane gas can be harvest from a French drain system by installation of a sealed French drain gas harvesting system but apparently human waste don’t produce much gas. The harvesting of animal waste is much more efficiency in particular Cow dung. Not sure if this system would be viable in the city.
2.2 Wind
2.2.1 Turbo prop Turbine (best alternative for high elevated areas)
Wind turbines depend on position and height for maximum return. This basically means that
it would be cost effective on high positioned areas like mountain ridges.
There is also the limit in size that would be acceptable in residential area. I have found that bigger than 1Kw generator tend to be too noisy on high wind speeds. If I remember correctly, the regulation in the city also limit the turbine not to be higher than 3 meter higher than the highest point of your house roof. The higher the output voltage of the turbine and the thicker the wire diameter, the better the efficiency. Try and install the wind turbine as high as possible as I made the mistake not installing it high enough and away from any tree or house roof. Your turbine must be higher than your house roof. So 48v system would normally be more efficient than a 12v System. Remember you would need a turbine maximum wind brake protection system to limit the turbine speed if the wind speed is to fast to protect the turbine blades from disintegrating. Most turbine kits come with regulator and over speed dump protection system.
2.2.2 Solar electrical panel's
Solar panel angles towards the sun is very important. Best is to get the average angle at 12 midday in the middle of winter and 12 midday middle of summer of your area and try and set the solar panels directly 90 degrees to this angle. There is also special regulators (MPPT) that will charge pump (step up) your batteries on cloudy days and could give you an additional 12 to 30% efficiency of solar system and is very similar to a wind turbine, the higher the voltage, the lower the loss in cable resistance and therefore better charging. Depending on your application, I would suggest to get a 48V system if you Solar panels combined power is more than about 300 W. (you could use a Grid-Tai iverter with build in MPPT that would not need batteries.
2.2.3 Inverters
Stand Alone / Off -Grid (High maintenance cost due to the battery live time replacement cost)
Most stand alone / Off Grid inverters will produce the 220V AC power from battery that was charged by Solar, wind or Generator.
Power inverters selection is very important as there are a lot of inferior inverters around.
Pure Sine wave inverter with automatic standby mode (no fan) as well as an over and under voltage protection. The Standby systems are very important and make sure your inverters
have this functionality. The cheaper inverters don't shut down their cooling fans and normally don't have low power standby modes when no power is consumed from the inverter.
Mostly popular in Europe. This system does not have a battery or related battery equipment.
It has one function only. It feeds all electric power generated by the solar panels or wind turbine through a mains synchronized high quality inverter and offsets the power you would normally consume from the City Power. It slows, stops or reverses your electricity meter depending on the time of day, the loads present and the size of the solar or wind system system installed. This is an extremely popular system because there are no batteries to replace. For areas where there are few electricity power failures this is an ideal system. These systems are expandable. They are simple in nature, comprised primarily of the solar panels or wind turbine and mains synchronized high quality inverters.
At the moment,this system is still illegal in South Africa, (2017) this system is now legal in mot of the big municipalities with the exception of systems producing more than 1 megawatt and which are approved by Eskom or the relevant authorities. Some municipalities will give a special licence if approached. Cape Town has approved some houses.
Don't let your electricity bill go negative it seems that most of the municipality account system cant mange negative numbers yet. The Grid-Tai inverters is alo very expensive as they need special monitoring capabilities to disable the inverter when your city power is shut down. (This means if you have load shedding you will not have power from Grid-Tai inverters). This shutdown feature is very important as it will protect the workers from being electrocuted while working on the /City Power grid to resolve the technical problem.
The smaller gas generator (below 7KW) is normally Petrol carburettor versions that were converted for gas. This could be ideal where you are situated on main gas lines and getting gas from city gas. You also get massive megawatt gas turbine generators for industrial use 5.0 Hydrogen. (Very efficient 50% but expensive technology)
2.2.3 Inverters
Stand Alone / Off -Grid (High maintenance cost due to the battery live time replacement cost)
Most stand alone / Off Grid inverters will produce the 220V AC power from battery that was charged by Solar, wind or Generator.
Power inverters selection is very important as there are a lot of inferior inverters around.
Pure Sine wave inverter with automatic standby mode (no fan) as well as an over and under voltage protection. The Standby systems are very important and make sure your inverters
have this functionality. The cheaper inverters don't shut down their cooling fans and normally don't have low power standby modes when no power is consumed from the inverter.
2.2.4 Grid-Tai ( not a good option if you have load shedding)
Mostly popular in Europe. This system does not have a battery or related battery equipment.
It has one function only. It feeds all electric power generated by the solar panels or wind turbine through a mains synchronized high quality inverter and offsets the power you would normally consume from the City Power. It slows, stops or reverses your electricity meter depending on the time of day, the loads present and the size of the solar or wind system system installed. This is an extremely popular system because there are no batteries to replace. For areas where there are few electricity power failures this is an ideal system. These systems are expandable. They are simple in nature, comprised primarily of the solar panels or wind turbine and mains synchronized high quality inverters.
At the moment,
Don't let your electricity bill go negative it seems that most of the municipality account system cant mange negative numbers yet. The Grid-Tai inverters is alo very expensive as they need special monitoring capabilities to disable the inverter when your city power is shut down. (This means if you have load shedding you will not have power from Grid-Tai inverters). This shutdown feature is very important as it will protect the workers from being electrocuted while working on the /City Power grid to resolve the technical problem.
2.2.5. Hydro power generation.
Hydro is not really an option for a house except if you have a big river or waterfall running through your yard.
3.1 Water turbine
3.1 Water turbine
Water turbines can be used in a small river, fountain or anywhere you could store water on an elevated area and then having a pipe system connected from the elevated reservoir to the turbine. The turbine can then be switched on when you need power. The higher the pressure and volume of the water flowing through the turbine the more power can be generated.
Whats nice about water turbine systems is you can store the power energy in the dam when you don't need it, therefore don't need any or very little batteries to store your energy.
4. 0. Generator Petrol / Gas / Diesel
4.1 Petrol Generator
(Low energy efficiency 18-20% but low set-up cost)
4.1 Petrol Generator
(Low energy efficiency 18-20% but low set-up cost)
Petrol Generators are normality very noisy and if you don't have proper secure brick building that could obscure the noise with a special exhaust system, you will have complaining neighbors. Generators can normally not be run at night due to the noise level. Generators are definitely
the most economical for a standby system but in the long term if you run the generator every day it would properly cost you more than a solar panel system.
Most petrol Generators are from 0 to 7Kw.
You could improve the efficiency of generators by using the exhaust gas in a heat exchanger to warm your geyser water for your house.
4.2 Diesel generator (Low energy efficiency alternative 18-20%)
Most Diesel generators are the bigger generator from about 4 – 50KW +
Noise is the biggest problem with the bigger generators. Their fuel consumption is much better than petrol generators (power per rand sent) There life span is normally longer than the high reving petrol generators.
4.3 Gas Generators (Low energy efficiency alternative 18-20%)
The advantage of Hydrogen gas is that you could store the energy in gas format and will not disappear in time such as in battery systems. The lifespan of Hydrogen storage tanks is probably longer than battery systems (It would definitely be the better option to store energy rather than in a battery.) The technology is still on the expensive side but is slowly coming down in price.
5.1 Hydrogen Fuel Cell
A Fuel Cell will convert Hydrogen into electricity with no mechanical moving parts.
Fuel Cells is also much more efficient compared to a petrol or diesel combustion engine generator.
5.2 Electrolyser
Electrolyser is an electrical cell that will convert Water into hydrogen using electricity as a power source to generate hydrogen and oxygen. You then store the gas in a Hydrogen tank to be used when electricity is required. The purity of the water is important to extend the live span of the Electrolyser
6. Solar Geysers
Direct and Indirect Solar geysers.
Direct is the type where you warm the water that you use. Indirect is where a heat exchange is used to transfer the heat to the water that you will be using.
One example of a direct geyser is the vacuum glass tubes that warms the water directly.
The things you should consider is not so much the direct / indirect witch mostley influence only the water pressure and efishinsy. (If you have pitched roof a direct system will give you anove water pressure. If you have a flat roof and you don't have the height for your solar geysers you mite have to consider the high pressure / indirect system.
If yo have a family of fore (4) I would recommend two 200L geysers or at minimum of one of 250L. The reason is that if you bath or shower at night and in the morning the water will not be that worm in the morning as there is no sun during the night to warm the water, Why? well you have mixed the could water that refilled the geyser at night with some of the warm water that was left in the geyser and there for you water would not be that hot in the morning.
If you have two geysers you could change your usage pattern by bath or showering at night use the one bathroom with the one geysers and then use the other bathroom with the other geysers still have all its warm water for the morning. (or you could get a bigger geysers (bigger storage tank) to compensate for the could water that is added at night)
The things you should consider is not so much the direct / indirect witch mostley influence only the water pressure and efishinsy. (If you have pitched roof a direct system will give you anove water pressure. If you have a flat roof and you don't have the height for your solar geysers you mite have to consider the high pressure / indirect system.
If yo have a family of fore (4) I would recommend two 200L geysers or at minimum of one of 250L. The reason is that if you bath or shower at night and in the morning the water will not be that worm in the morning as there is no sun during the night to warm the water, Why? well you have mixed the could water that refilled the geyser at night with some of the warm water that was left in the geyser and there for you water would not be that hot in the morning.
If you have two geysers you could change your usage pattern by bath or showering at night use the one bathroom with the one geysers and then use the other bathroom with the other geysers still have all its warm water for the morning. (or you could get a bigger geysers (bigger storage tank) to compensate for the could water that is added at night)
7.0 Identifying your power configuration.
Where is my external DB board the one with the Electricity meater? (This is where you will install your generator input and generator isolation switch.
Where in your house is your DB board with all the lights,plugs and geyser trip switches. (switch them off, (Then identify the different applyens that use that specific trip switch one by one and add labels on the DB board so that you can disable some of them when running from generator.) you might also load shed certain things in your house)(Geasers and swiming pool pups would be the first thing to disable)
(E.g. Don't run washing machine and fridge at the same time)
Where is my external DB board the one with the Electricity meater? (This is where you will install your generator input and generator isolation switch.
Where in your house is your DB board with all the lights,plugs and geyser trip switches. (switch them off, (Then identify the different applyens that use that specific trip switch one by one and add labels on the DB board so that you can disable some of them when running from generator.) you might also load shed certain things in your house)(Geasers and swiming pool pups would be the first thing to disable)
(E.g. Don't run washing machine and fridge at the same time)
7.1 Partial substitution of your city power.
This is where you only run the critical systems in your house from your own alternative power source but still use City power for the rest. (lites and fridge freezers)
This is where you only run the critical systems in your house from your own alternative power source but still use City power for the rest. (lites and fridge freezers)
7.2 Fully off Grid system (Totally self sufficient)
This in normally only in rural arias where there is now alternative power source and you generate all your own power.
This in normally only in rural arias where there is now alternative power source and you generate all your own power.
8.1 How to calculate and identify your approach to covert to an alternative resource.
Look at your utility bill and look at kw usage per moth.Then try to calulate your usage on the spread sheet above so you can get to about the same usage. ( not a perfect signs but will give you some indication.)
Look at your utility bill and look at kw usage per moth.Then try to calulate your usage on the spread sheet above so you can get to about the same usage. ( not a perfect signs but will give you some indication.)
9.0 Take a phased approach
Reduce your electricity consumption.
Look at alternative energy sources. (Gas Solar,Water ...)
Reduce your electricity consumption.
Look at alternative energy sources. (Gas Solar,Water ...)
9.1 Identifying the quick wins.
Solar geyser is possibly your first action. (could save from 5 -20%)
Convert your stove and fireplace to gas this will also give you cooking capabilities during load shedding..
Lower power consumption Swimming pool pump.
Solar geyser is possibly your first action. (could save from 5 -20%)
Convert your stove and fireplace to gas this will also give you cooking capabilities during load shedding..
Lower power consumption Swimming pool pump.
Change all your lights to low power versions preferable LED type.
Solar panels or wind turbine to charge batteries and run all your lights and fridges/freezers
10 Identifying electrical appliance that you can easily put on a solar or wind power system.
10 Identifying electrical appliance that you can easily put on a solar or wind power system.
Solar as primary one system where you are at a low elevated area with low wind speeds.
Wind turbine is normally a backup for solar system. The reasoning behind this as there is almost always wind if the weather is bad and you have less solar power in bad weather conditions except if you stay in a high elevated area. This means the wind and solar compensate for each others shortcoming.
10.1.7 Petrol / Diesel generator for emergency power (backup).
This is properly the most economical way to get you over the (Escom load shed periote)
This is properly the most economical way to get you over the (Escom load shed periote)
10.1.8 Power control and automation. (monitor your consumption and savings by recording your power saving (ROI) and capacity available during the day and night so you can adjust your power usage patterns to the available power. (you will possibly always have more power during the day if you have solar system so don't try and store everything in batteries and then try and use it at night.Use it when it is made during the day, this way you don't need so much battery capacity to store you power for when you don't have sunlight) (Batteries are expensive and it will make your system not that cost effective.)(E.G Run your washing machines during the day)
10.2 Power monitoring.
Power monitoring is crucial when you are using alternative power source like Solar and wind turbines. You need to know how much power you have at all times, especially if you are off the grid. When there is lots of clouds conditions or did the wind turbine generate enough? ..... You need to establish when you are running out of power way in at advance so that you can make backup plans. Best is to have a Generator backup system when something go wrong with the main alternative supply system. You would also need to know if someone left lights on the whole day and drained all the batteries or you ran out of gas ......
Here is link to a power monitoring products available local http://www.giga.co.za/ocart/index.php?route=product/product&product_id=262&search=pow
There is a couple of opensource projects that allows you to control and monitor your energy system.
http://openenergymonitor.org/emon/
Here is link to a power monitoring products available local http://www.giga.co.za/ocart/index.php?route=product/product&product_id=262&search=pow
There is a couple of opensource projects that allows you to control and monitor your energy system.
http://openenergymonitor.org/emon/
10.3 Manual power switch over.
You could switch your alternative power on and off depending on your need.
The manual option is not the preferred method as you want your house to have power continuously. This only becomes a problem if you are not at home and you can't monitor your power source. (this is not an option if you are running your fridge freezer and need to keep it running.
10.4 Automatic power switch over.
This is the best option and should keep your power on while you are not there or the power source has failed therefore the other power source can take over until you are back to resolve the problem. (Definitely a yes if you have enough power to run your hole house. If your backup power supply can not supply enough power to run your hole house this will not work. ( You mite only have a backup for you refrigeration with automatic fail over switch)
Here is a diagram of a typical configuration for your house. (Please note I would use string inverters for a new design. 150 to 400V solar panel voltage)
Here is a diagram of a typical configuration for your house. (Please note I would use string inverters for a new design. 150 to 400V solar panel voltage)
This document was written to possibly assist you in make some of your alternative energy choices.
I hope it helps ;-)
I hope it helps ;-)
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