Originally Posted by SDChristian
Cliff's notes would be appreciated.
The article by Nigel Calder is a full four pages of two columns per page. I'll try to sum up a couple of things, but basically the whole article is a summary of the state of the art and the players involved.
The biggest thing I saw was that DIYers have not been able to successfully develop either a serial
or parallel hybrid system that meets any criteria for money spent in development and cost of operation versus gas or diesel propulsion alone. The tradeoffs are too great and the control systems require massive amounts of money, time, and expertise because they are hyper-complicated.
In regard to serial
systems: "There was a lot of nonsense spoken of and written in the early days of serial development about one horsepower being the effective equivalent of up to four diesel horsepower.... Unfortunately, this simply isn't true. Although there are some potentially significant gains with an electric motor (out of scope
for this article), if a serial hybrid is to have the equivalent performance under power of a conventional installation
, it still needs a powerful electric motor, with a powerful generator, both of which are expensive."
"The other critical problem with serial systems is the nature of the duty cycles on a boat." He says that boats require large continuous power to maintain speed, unlike cars which need large power to get up to speed and then little at speed. The generator then must be run continuously to power the boat (unless the boat putts along at a much lower speed which is not good in adverse conditions like current
, rough water
, wind direction, etc.). And it is very inefficient using a generator to power the boat since it goes through so many systems. He does say that "serial may make sense for other reasons, like noise
, less maintenance
, no vibration, no exhaust
fumes, the ability to generate power under sail and sleeping silently overnight without a generator running."
He quotes Timo Jaakola of OceanVolt on this. Continuing, he also suggests the ideal application of serial is a fast cruising cat with high air conditioning
loads: the propulsion loads are relatively light, the house loads are relatively high, and the vessel can regenerate significant amounts of energy when under sail.
He then discusses the development of pure electric boats "which are very effective for short-distance operation if there is then shorepower available". A generator can supplement this some but if it has to be run continuously it makes no sense. He says this is not a "true hybrid" system as it does not have the "complex control systems....to optimize operation and efficiencies.
For serial hybrid he mentions Fischer Panda
and two companies he says have the staying power to continue: Torqueedo at the high powered end of the marketplace, and OceanVolt at the relatively low-powered end. Torqueedo is still in development and OceanVolt is delivering systems (all electric now but developing hybrid systems). He has a high opinion of OceanVolt and their "beautifully engineered electric machines up to 15kW".
There is a lot more about this part.
Parallel hybrids: Fischer Panda
has begun adapting it tech to parallel hybrid - for low speed maneuvering in superyachts. "No attempt has been made to provide sustained electric propulsion at anywhere near cruising speeds." He discusses Greenline powerboats as the most successful implementation of parallel hybrid using large lithium battery
banks "enabling the use of overnight air conditioning
"So far the only well tested (fully integrated parallel hybrids) comes from Hybrid Marine
in the UK." The 40' offshore
cruising sailboat "Seaweed" is described. Also the use of these systems in canal boats.
He discusses how much effort is being put in to serial and parallel hybrid systems in superyachts, with most of the work centered in Holland
, especially regarding the "hour of power" for getting in an out of harbor with zero emissions.
The next section discusses Software
Challenges. "To be successful, any hybrid system, whether it is serial or parallel hybrid, needs to have a control system that is, in effect, a whole-boat energy management system." He discusses lithium batteries as the only current
tech that can store the massive amount of energy required but at a cost of money and BMS's. He then discusses the advances in lead acid batteries - thin plate, carbon in negative plates, or carbon foam plate grids.
"...dogged perseverance, and an increasing body of real-world experience is finally beginning to deliver reasonably well-tested and proven parallel and serial hybrid systems." Calder has put on a few systems and ripped them out in the past but he says we are "at a point where there are one or two systems that I would be willing to put in my boat and take offshore
My thought - of course, Calder will have significant sponsorship from the vendors to promote them to his wide audience.
This is only bits and pieces of the article. The Cliff Notes per an amateur.