techstar | |

I want that one

Mark Walker analyses what you will need from a generator when going off the grid

Here I am living in semi-rural suburbia, concerned about the environment my children will inherit and frustrated by electricity bill increases and irritated by supply reliability. It’s time for me to take my three bedroom semi-detached house ‘off-grid’. But to me, ‘off grid’ isn’t just about the removal of or lacking an electrical connection. I also want independence – from government policies and legislation, big multi-nationals, dealerships, service organisations, in fact, anybody. So how do I do this?

Having learnt the hard way that off-grid power generation requires a machine much more robust than those air-cooled, high speed, super-silent (yeah, right!) things found on eBay, I realised that I would have to set my budget sensibly. My strategy was to go for a name that has a reputation of longevity and reliability, putting me in the $1000+ per kilowatt league occupied by Honda, Yanmar and Kubota.

Would I be happy with such an investment? Of course I would —  its state of the art technology, but there are a few things/features that they don’t give me.

For example, I want a generator that has re-useable filters (air, oil and fuel) that just need cleaning. I don’t want to have to pay excessive amounts of money to these multi-national companies for something that increases global pollution. It’s just not necessary. Am I asking too much?

I want a generator that is cheap (very) to service. I want it to be so simple that I could do it myself, or at least simple enough for a local mechanic to do it. I don’t want to be forced to use an approved Kubota service Engineer because I fear losing my (very impressive) warranty.

I want a generator with an engine so simple that I could strip the top end down myself, replace the valves, lap them in, all in my lunch hour and still have time to eat my sandwiches. Am I asking too much?

I want a generator that tells me it is well, just by the way it performs. I don’t want a CAN bus ECU refusing to attempt to start the generator because it has detected a fault #73669-b with the instruction “call your nearest dealership immediately” only to be billed a $100 call out charge to discover that my starting battery has reached the end of its life. I would have diagnosed that myself from the sound of the machine. Am I asking too much?

I want a generator that has been designed to last as long as possible – like they used to design things before the 1970s (when they discovered that ‘built in obsolescence’ is great for repeat business). I don’t want a machine whose components are all designed to fail simultaneously 13.45 seconds after the (very impressive) warranty expires. Am I asking too much?

Do I really need a three cylinder engine that will give me a perfect sine wave (with its associated additional service/parts costs)? My washing machine can cope with an imperfect sine wave (some can’t), my lights are all compact fluorescent, so they don’t care and my laptop will run on any quality electricity supply.

I want to pay less for my generator. If it was a single cylinder engine, it would be cheaper to make (and service) and more efficient. If it was made from cast iron it would be more efficient (conducts heat much less than aluminium), but no, the multinational engine manufacturers are obsessed with power density, so we have to have aluminium engines requiring us to pay more to Bosch to optimise their fuel systems so that compromise in efficiency caused by using aluminium is minimised.

I don’t care how much my generator weighs. Once it’s installed, I won’t be moving it. Do they think I want to take it for a walk every time the sun comes out? Does anybody care how much their central heating boiler weighs?

I want to be able to run my generator on different fuels, and not lose my warranty. The pub up my road still has to pay for their waste cooking oil to be taken away. I want to save us both some money and reduce both our carbon footprints by putting that waste cooking oil in my generator. Am I asking too much?

Why do I have to pay so much for my engine oil? I want to use that really cheap stuff from my supermarket. But no! In order for me to keep my treasured warranty, I have to use an extortionately expensive lubrication oil – so full of toxic additives that I have to pay again to have it disposed of safely.

I want to use a simple oil and after I’ve used it, I want to let the dirt settle and throw the clean stuff in my fuel tank with my WVO, diesel, kerosene, paraffin or whatever. Am I asking too much?

I want to be able to use the waste heat from my generator. With domestic sized generators, at least 70% of the calorific content of my valuable fuel goes to heat up the atmosphere. I don’t want to do that.

Did you know that the amount of heat dumped into the UK atmosphere whilst generating electricity is equivalent to half the nation’s heating demand? The amount of heat dumped into the atmosphere by US power stations is enough to meet the entire heating needs of Japan. I don’t want to be a part of that!

I did some digging around and asked a few Generator manufacturers (who claimed they offered Combined Heat and Power systems) if they could help. They said ‘no’; it’s not cost effective to build domestic scale CHP systems. Really!? Why!? It’s not rocket science! All I want is a heat exchanger that takes hot gases and puts the heat into water. That’s what a domestic boiler does and they’ve been around for half a century.

I can buy a ‘state of the art’ boiler for $1000. My annual heating costs are $1500. If my generator can provide my heating for free (as a by-product of generating electricity), which it can in theory, this little heat exchanger feature would pay for itself in 9 months. In what way is that not cost effective!?

Am I really, really asking too much? Apparently ‘yes’, so I’m going to build my own. Anybody want one?

Mark Walker is the Proprietor of Volvox (Engineering) Ltd.

Buy our book - OFF THE GRID - a tour of American off-grid places and people written by Nick Rosen, editor of the web site

17 Responses to “Off-grid generators – am I asking too much?”

  1. pdxr13

    Edison Batteries self-discharge rates are less than 1% per day, which is completely acceptable when the point is to time-shift solar or generator output to hours of darkness and quiet.

    Edison batteries are not what you would choose for a start battery on a vehicle that would sit for months without a trickle charger, but why would you intentionally do that to any battery?

    I’m hearing FUD (Fear-Uncertainty-Doubt) counter-marketing here.


  2. steveg

    we aer off grid and have ahd the chinese generators, dont bother. have tried an old english genertaor worked well but parts in short supply (not lister) have now decided on CHP and have bought a boat generator with all heat recovery in place, 6kvw constant in electricity and i assume about 12kw in heat? not plumbed in yet but with and estimated 2ltr per hour of fuel (we pay .80p per litre for red diesel) 18kw of energy for £1.60 running cost, so about .9p per kw, does this seam right? if yes i am on to a winner.


  3. Jason

    Making it yourself I think is the solution to your problem. So you get an old (OLD!) diesel engine from the 50s or 60s from a truck or jeep or something. These things will run on the used cooking oil you mentioned. And you link it up to an old electric golf cart or forklift motor.

    From there you can decide for yourself if you’re happy with the dirty electricity coming out of the motor, or if you’d like to run the whole thing through a battery bank.

  4. johnf

    It is possible to run a high compression engine like a lister off biogas . Biogas can be derived from any woody or grassy waste. Look at FEMA GASIFIER site.
    The Downdraught oildrum type produces a lot of dust and some tar which require separation before use. The Indian Govt. scientists develop the Updraught system which filters and absorbs tar and dries the fuel bin.
    Both systems pass all of their output (gas)(methane plus CO) into the engine which provides all the draught. The other output is very pure Char or Carbon which has real value.
    If the engine exhaust is properly treated there will be no trouble with pollution snoopers.
    One practitioner uses a bin full of Horse manure as
    an exhaust bio filter. Don`t laugh, it is full of UREA which is exactly the right additive to reduce NO2.

  5. Mark Walker (the author)

    I apologize for using that picture. It has clearly been misleading. I chose it as ‘tongue in cheek’ joke, that also had a reasonable picture of me.
    I am quite capable and happy to run my house on a 5kW CHP.

  6. Bill

    NiFe ‘Edison’ cells are expensive, but have one bigger disadvantage.

    They self-discharge like crazy.

    Unless you can keep them charged with an oversupply of cheap electricity (hydropower or you have enough wind to run a large turbine) forget them and stick with flooded lead-acid cells.

  7. larry and sandie

    Hi, look up Lister Petter diesel generators I have a 1969 6500kw runs 23hrs. on 2.5 gal diesel and runs on #2 diesel, used ATF, used filtered motor oil or veggie it used for 500 bucks and it is very easy to repair..

  8. diane

    I love my new solar generator. It is plug& play – I was able to set it up in a few minutes all by myself! I have it on my kitchen counter and use it for coffee and my fridge.

  9. Elnav

    People logged into this website are not just sheep. They are aware of the problems and seek education and solutions. $100 per month for electricity is pretty low for some regions and not because of profligate energy use. This is not a forum for just one area of the world. Utility rates vary greatly. While it is unrealistic to expect a $250 kit to replace your power utility connection ther are inexpensive methods to help people educate themselves about power use. In North America a $20 P4400 Kill a Watt meter can collect data on power consumption. It enables people to get real world data on their own appliances. Almost every website dealing with the subject of energy consumption has good advice on how to reduce consumption without necessarily lowering their standard of living or spending huge sums of money for alternative power sources.

  10. Ben Woodhead


    I don’t think thats completely accurate. I would say most people don’t even think of off-grid because they haven’t even heard of off-grid even being possible. At best most people think they can shave off a few dollars off there bill using a solar panel and thats about it.

    The second big thing is most people have no idea how much electricity or heat they actually use. They know its expensive and know they should do something but half the information out there is flat out marketing crap that has huge costs with little benefits.

    The last thing is when you start seeing 20,000 dollar solar install quotes versus your 100 dollar power bill it doesn’t seem to add up. In the long run its better sure but its a big kick in the squares for 100 dollar power bill.

    The worst part of it all is that electric consumption is increasing. Electronic companies spend far more money selling you items then the people selling renewable living. Yes saving the world might be an admirable goal but saving the world is still needs to be sold (convinced) to people just like anything else.

    In the end people are *sheep* so they just want to follow so things need to be easy and their is nothing about off-grid. It requires extensive knowledge and research and a huge commitment. I can’t just walk into and get an off-grid kit that comes ready to install for 250 dollar.. :)


  11. elnav

    Patrick is correct. Power Use is a key consideration when considering going off grid. So far the majority of people considering going off grid have been a minority because most people still think going off grid means huddling in the dark around a camping stove and solar powered LED lantern. The majority of people are not willing to give up common creature comforts like running water, indoor plumbing and toilets, enough light to really see by after sun down and the safety and convenience of modern kitchen appliances. For the most part the ordinary person who is now willing to consider going off grid is not financially able to foot the up front costs in a big power off grid home. We need a lot more attention and product development in order to have comfort and convenience comparable to an on-grid home but consuming only as much energy as can practically be delivered by an off-grid power source. CHP offers a good start on this concept.

  12. elnav

    There may be a minor glitch in buying a listeroid engine ready made, off the shelf. Since I do not reside in the UK I cannot speak to the local regulations but here in North America the only engines which you can now buy as new must conform to Tier III emissions stanadrds. However older EXISTING engines are grandfathered so if you happen to find a good used engine or rebuild an old model its okay. As to what comprises an old engine no regulations stipulates details. Its like my great grandfathers axe that is over 100 yesrs old. It has had three new handles and two new heads . . . but its over a 100 years old. Rebore a block, insert new liner or pistons, replace the injectors and balance up the old original flywheel and its still an old engiine. As long as you save the part of the casting where the serial number is stamped, its old.

  13. elnav

    Mark look up Lister or Listeroid engines as well as microcogen. There is a group of enthusiasts including a dealer in the UK who are experimenting with these venerable old design engines and they fulfil most of your energy demand. Listeroid refers to Indian made clones and I believe some chinese clones are also made. These engines are not small. Engine weight is in excess of 500 lbs for a one cylinder engine with a top RPM of around 900 but they are better run at slower speeds 600 0 700 RPM. The engine stands about 4 feet high. To get 50HZ the power head is belt driven to produce the desired frequency at the intended running speed selected for the engine. (Pulley ratio to suit)
    One guy living in Victoria BC in Canada heats his 2 story house with the waste heat from his Lister engine by storing heat in big tanks and a hydronic heating system, and generates power stored in a battery bank with power inverter(s) for domestic electricity. The basic design of the Lister makes it practical to run waste vegetable oil as the guy in Victoria does. Some of the group are also trying a multi fuel approach. Some technical issues are involved here. If you have sufficient money I suggest looking into NiFe type batteries because they have an incredible life span compared to lead acid. One company in the States is at present resurrecting and testing a group of these ‘Edison’ cells that are 75 years old and still functional. From what I have read so far you need to change the electrolyte every decade because its the electrolyte that wears out not the plates.
    Each cell only produces 1.2V so quantity 10 are needed for a 12V system. This is not practical for mobile vehicle use but in a house this is not so much of a handicap. The cost figures I have seen suggest these batteries cost about twice what similar capacity lead acid batteries do but as a function of total life cycle cost it does make sense. Ther is also a company in Australia but so far I have not located a european manufacturer. Doesn’t mean ther is not one just that I have not found their website as yet. Lister Engine parts availability is somewhat spotty and most of the microcogen group group simply machine their own repair parts . The old design makes this possible. No high precision machining is required and there are no dealers. You roll your own or find a friendly machine shop to help you. The emails I have seen suggest there are multiple manufacturing sources in India and china but quality may be variable so most of the guys end up doing a tear down and blue printing the engines when they first acquire them. At that point they can run indefinitely at 750 RPM . You can expect 4 kW of electrical powerfrom a single cylinder, plus an equivalent quantity of heat in terms of BTU plus if you also make an exhaust heat recovery muffler ( heat exchanger) you can gain an additional amount of BTU. The rule of thumb is 1/3 electriccal , 1/3 heat from coolant and 1/3 heat content from the waste exhaust heat as a calculation of the input fuel energy. Two cylinder Listers are also available. It does not meet every one of your requirements but comes close in most respects.

  14. Terry Maukonen

    Sounds like you want a well engineered product ( You know why schools turn out thousands of engineers a year – they’re hoping for a good one ) Quaility built (in a factory in China using slave labour)

    You know what I think!

    Every product made should be made to your specs

    Remember when a TV lasted 25 years, a fridge, a stove
    In 2008 I replaced my 1996 $1600 fridge when it quit working with a $100 1970 used fridge. Put it right there beside my $50 1947 used beer fridge.

    They would say that the 1947 fridge used more energy
    But how many barrels of oil did it take to build one fridge and power it for 60 years than it would take to build and power 5(x12 = 60) and power them (1 at a time) for 60 years. Iron ore, smelting, building and powering the factory, the people driving to work. The 1947 used amonia, the 1996 R134a have you read the MSDS on 134a. One word Propane – It would cut refridgeration costs by 30% and put the Dupont family in financial trouble ( 1 of only 4 companies in the world making these types of refridgerants).

    I think this leads us to your statment
    “independence from – government policies and legislation, big multi-nationals, dealerships, service organisations”

    How would the mutil-nationals turn their billion dollar quarterly profits? The same profits the government needs to tax? or more importantly what they don’t need layoffs(less income tax more social payments)

    Most of this wouldn’t even be a problem for you if it wasn’t for money – so realise that those who control the currancy of a nation controls you. Banks rob people of the hopes, dreams and goals, 1% at a time

  15. Off Grid Hipster

    I completely agree, there are certain times when you need more power. I.e. cloudy weeks, etc. I think there is nothing wrong using a lil fuel when you live a majority of life fuel free.

  16. Patrick

    I can’t argue with your logic or your itemized desires. I believe that your solution (build your own) is correct, given your criteria.

    That said, the “big picture” issue is power USE. What are you (not!) giving up that places some of the issues of getting, using and maintaining this behemoth squarely in your lap? It seems to me that your use of the term “off-grid” is very limited — to maintaining ALL of your present lifestyle! Real change can’t come from just “moving the furniture around (and thinking that you’re in a different room). For example, urban, Suburban, and rural lifestyles are different, and not just because of the scenery outside. No right thinking person put a farm house in the city, and vice-versa. Your monster generator will be a bit out-of-place in your neighborhood if some lifestyle choices don’t accompany its installation!


Leave a Reply