DIY Energy on the Farm
Until recently Mark Carter was running sheep and cattle on his 280ha property. He has now leased it out and is concentrating on energy developments.
Electronics has always been a hobby, and ten years ago, not long after he bought the farm, he started to work with Ralph Sims from Massey helping with energy related gadgets.
About eight years ago he built a new house and decided that he would rely as much as possible on alternative energy sources.
Wind power: He first worked on a wind turbine and controllers for it. He bought a second-hand power pylon, put a 1kw generator on top, attached a bank of batteries and added safety and control features.
"Most small turbines that you purchase or build don't have storm regulation or shut down mechanisms you just put them up and let them rotate and it seems that anyone can make a wind turbine, but the crunch comes when you have to manage them in storm conditions, he says.
My controller has met that need by being able to check when the batteries are charged and shut the system down, as well as shutting down in storm conditions. The controller also manages battery charging in a superior way if you are using multiple charging sources say, wind and solar cells. It incorporates quite a few things that aren't necessarily novel individually, but I have put them together and automated the system.
"Most farmers would be able to put in the foundations and set up a wind turbine. The electrical side is pretty straightforward too, it's a DC system much like a car battery with a charging system and regulator."
Solar panels: Four 80 watt panels on the roof also help charge the batteries. Six square meters of other panels provide hot water to the insulated cylinder that is sited above them so that the heated water naturally rises to it without the need for a pump.
Wood: A wetback stove is used for cooking, and also heats water.
Back-up: When the Carters are not cooking on the wood stove they use LPG, about one 15 kg bottle per month. The house is not connected to the mains supply so Mark has a back-up diesel generator, but when all things are running properly it is not needed.
Used vegetable oil as fuel: Recently Mark has also been working on running diesel engines on vegetable oils. He has a cottage next door that is connected to the national grid, and has adapted a small diesel engine to run on waste frying oil from restaurants. The cooking oil contains quite a lot of moisture that needs to be driven off and the oil must be filtered and preheated before running into the engine.
He is working towards a system that uses the waste heat from the engine for driving off the moisture and preheating the oil.
The engine is like the old style single piston Lister engine, but is brand new and manufactured in India. It has the advantage of being quite low revving, which suits the vegetable oil because it combusts a bit slower than diesel.
Linking to the national grid:
He has been experimenting using the engine to generate electricity and linking it with the national grid.
There are times when the cottage uses power from the national grid and times when it sends power back its like using the national grid as a storage device, he says.
It has to run only about 10 hours per month to be in credit.
This arrangement is unofficial (he is working on a project with Massey where it is being done officially) so it looks to a power company that he is just using a bit less electricity. The old style power meters with the turning discs will actually go backwards when power is fed back into the grid through them, so they keep in the record of his net position.
Getting official permission to do this is quite difficult power companies are interested in it from a research point of view but are reluctant to accept electricity from small-scale suppliers.
Power companies are likely to put in a two-way meter that measures energy going in and coming out, and then they will put suppliers on a contract where they will pay less for what you supply them than for what you use. In other words they will pay you the wholesale rate and charge you the retail rate, says Mark.
In time electricity companies will make it easier for small-scale generators to put energy back into the grid. This will help them shave their peak energy use, each little generator contributing at times of high peak load at the end of a long line.
For the future:
Mark is also working towards running a car on vegetable oil, and he has built controllers for doing that type of thing. Diesel engines will run on a 10-20% blend, he says, without any modification needed. His prime motivation is conservation.
"It seems that we are blundering on down a path where energy is running out and nobody is doing anything about it, people aren't really conserving and the environment is suffering. My objective has always been to try to become a bit more energy self-sufficient."
Reducing energy demand on the farm
For new dwellings, design them as passive solar houses to maximise the impact of the sun through the winter and shade it out in the summer. North facing windows, exposed thermal mass inside to take up the heat, very good insulation, double glazing.
Insulation is top priority for both new and existing houses and he recommends over- specifying the insulation.
The easiest thing to do in a new system is to put solar panels up to produce hot water. Mark prefers a passive system that has the storage tank up above the solar panels on the roof otherwise a small pump is needed to circulate water through the panels. The storage tank can have a small electrical element in it to top up the heat when there is insufficient sun. Control of that is important so that you do not get electricity competing with the sun.
Many farmers could put in the foundations for a wind turbine tower, and assemble the components themselves.
The components of the systems are expensive if you buy them off-the-shelf and economic payback is not that great at present. However, with energy costs going up that will change the situation.
Electronics has always been a hobby, and ten years ago, not long after he bought the farm, he started to work with Ralph Sims from Massey helping with energy related gadgets.
About eight years ago he built a new house and decided that he would rely as much as possible on alternative energy sources.
Wind power: He first worked on a wind turbine and controllers for it. He bought a second-hand power pylon, put a 1kw generator on top, attached a bank of batteries and added safety and control features.
"Most small turbines that you purchase or build don't have storm regulation or shut down mechanisms you just put them up and let them rotate and it seems that anyone can make a wind turbine, but the crunch comes when you have to manage them in storm conditions, he says.
My controller has met that need by being able to check when the batteries are charged and shut the system down, as well as shutting down in storm conditions. The controller also manages battery charging in a superior way if you are using multiple charging sources say, wind and solar cells. It incorporates quite a few things that aren't necessarily novel individually, but I have put them together and automated the system.
"Most farmers would be able to put in the foundations and set up a wind turbine. The electrical side is pretty straightforward too, it's a DC system much like a car battery with a charging system and regulator."
Solar panels: Four 80 watt panels on the roof also help charge the batteries. Six square meters of other panels provide hot water to the insulated cylinder that is sited above them so that the heated water naturally rises to it without the need for a pump.
Wood: A wetback stove is used for cooking, and also heats water.
Back-up: When the Carters are not cooking on the wood stove they use LPG, about one 15 kg bottle per month. The house is not connected to the mains supply so Mark has a back-up diesel generator, but when all things are running properly it is not needed.
Used vegetable oil as fuel: Recently Mark has also been working on running diesel engines on vegetable oils. He has a cottage next door that is connected to the national grid, and has adapted a small diesel engine to run on waste frying oil from restaurants. The cooking oil contains quite a lot of moisture that needs to be driven off and the oil must be filtered and preheated before running into the engine.
He is working towards a system that uses the waste heat from the engine for driving off the moisture and preheating the oil.
The engine is like the old style single piston Lister engine, but is brand new and manufactured in India. It has the advantage of being quite low revving, which suits the vegetable oil because it combusts a bit slower than diesel.
Linking to the national grid:
He has been experimenting using the engine to generate electricity and linking it with the national grid.
There are times when the cottage uses power from the national grid and times when it sends power back its like using the national grid as a storage device, he says.
It has to run only about 10 hours per month to be in credit.
This arrangement is unofficial (he is working on a project with Massey where it is being done officially) so it looks to a power company that he is just using a bit less electricity. The old style power meters with the turning discs will actually go backwards when power is fed back into the grid through them, so they keep in the record of his net position.
Getting official permission to do this is quite difficult power companies are interested in it from a research point of view but are reluctant to accept electricity from small-scale suppliers.
Power companies are likely to put in a two-way meter that measures energy going in and coming out, and then they will put suppliers on a contract where they will pay less for what you supply them than for what you use. In other words they will pay you the wholesale rate and charge you the retail rate, says Mark.
In time electricity companies will make it easier for small-scale generators to put energy back into the grid. This will help them shave their peak energy use, each little generator contributing at times of high peak load at the end of a long line.
For the future:
Mark is also working towards running a car on vegetable oil, and he has built controllers for doing that type of thing. Diesel engines will run on a 10-20% blend, he says, without any modification needed. His prime motivation is conservation.
"It seems that we are blundering on down a path where energy is running out and nobody is doing anything about it, people aren't really conserving and the environment is suffering. My objective has always been to try to become a bit more energy self-sufficient."
Reducing energy demand on the farm
For new dwellings, design them as passive solar houses to maximise the impact of the sun through the winter and shade it out in the summer. North facing windows, exposed thermal mass inside to take up the heat, very good insulation, double glazing.
Insulation is top priority for both new and existing houses and he recommends over- specifying the insulation.
The easiest thing to do in a new system is to put solar panels up to produce hot water. Mark prefers a passive system that has the storage tank up above the solar panels on the roof otherwise a small pump is needed to circulate water through the panels. The storage tank can have a small electrical element in it to top up the heat when there is insufficient sun. Control of that is important so that you do not get electricity competing with the sun.
Many farmers could put in the foundations for a wind turbine tower, and assemble the components themselves.
The components of the systems are expensive if you buy them off-the-shelf and economic payback is not that great at present. However, with energy costs going up that will change the situation.