Using Steam to Generate Electricity

In answer to the many inquiries we receive about this topic, here are some things to consider.

First, you need to decide how much electricity you need to generate. Get your last electric bill out and see how many kilowatts you used last month and divide that number by the number of hours in the billing cycle to get the number of kw hours you need to generate per day (generators are rated in kwh). This will give you the average load. But you also need to think about your peak load, times when you are running the most number of appliances, utilities, etc. You can estimate this by adding up the amounts listed on the labels of each appliance, etc. Your generator should be sized to handle the peak load unless the generator is charging batteries and the batteries are sufficient for the peak load.

Next, you’ll need to set up a system to include an engine, a boiler, and a properly-sized generator, plus all the accessories to make them connect to each other and work correctly.

Then, once everything’s up and running, you’ll need to tend to the system: if you’re firing with firewood, you’ll need to tend to the fire about every 15 minutes. Unlike a fireplace where you just let the logs simmer, if you actually want to produce enough heat to generate electricity, you’ll need a good roaring fire. And then there’s the all-important water level in the boiler, which is critical to safe and effective operation. You’ll need to manage the water level very frequently to make sure it is correct. Of course, you could buy a fully automated boiler that has automatic fuel feed and water control for something like $20,000. The fuel feed here will be either gas or oil, and doesn’t accommodate wood or coal or any other “free” fuel you might have.

Here are some specifics about our engines and what you might expect to do with them. Our largest engine, the single-cylinder “M” engine, will produce about 4 kilowatts per hour (kwh) of electricity when connected to a generator, the compound about 6 kwh. In a compound engine, the steam goes into the smaller cylinder, then exhausts to the larger cylinder to expand further. This gives more work for the same amount of steam. Contrary to what most people say, it does not double the horsepower of a single-cylinder engine; it’s more like 2/3 more. The compound engine can also be built as a double simple (i.e., both cylinders receive high pressure steam) and produces about 8 kwh. We have not tested our engines for long-term electricity generation and do not warranty them for this use.

All of these engines can be used up to 150 psi boiler pressure, and 450 degree steam (this is mild superheat). You will need to evaporate about 5 gallons of water per hour per horsepower. The “M” and the compound will need a boiler with a minimum of 30 sq. ft. of heating surface, and the two-cylinder double simple would need about twice that amount.

Cost. The “M” single-cylinder engine ready to run with governor is about $4,000. A 30 sq. ft. boiler would probably run about $10,000. To this you will need to add at least two water feed pumps, as well as a safety valve (only if attended to at all times, two if automatically fired), water gauge and other plumbing for about $1,000. The generator itself will be $500 to $1,000. So all told, you’re looking at at least $15,000 to $16,000 to get started with a 4,000-watt system.

Bottom line: it’s not inexpensive, and it is not a fully automated system. Although you can certainly generate electicity with one of our engines, they were originally designed for use in steam boats. In addition to these engines, we build steam boats, so this is our area of expertise. While we can give you some pointers on generating electricity, we are not experts in this, and do not use our engines for this purpose ourselves.

If you still have questions after reading the above, call us and we can discuss further.