By Ken McEntee
This
look at electric horizontal grinders, courtesy of Composting News, is not intended to endorse or
promote any particular product or manufacturer. Attempts were made to
include input from all known North American manufacturers of
horizontal grinders.
Increasing
government regulations – particularly federal emission standards –
and a lower operating cost compared to diesel powered machines, are
driving demand for electric horizontal grinders, manufacturers say.
“We
are definitely seeing an increase in the popularity in electric
machines, and most of that is driven by cost of operation and cost of
ownership,” said Jay Van Roekel, strategic business unit manager at
Vermeer Corp., of Pella, Iowa.
Jason Morey, sales and
marketing manager for Bandit Industries Inc., Remus, Mich., said he
has seen a consistent demand for electric grinders in recent years.
“There hasn’t
necessarily been a large increase, but that may change a little with
this being the last year that we can do Tier 2 diesel engines above
750 horsepower,” Morey said. “Once the Tier 4 final rules go into
effect, I think electric is an option that more people are going to
consider.”
Machines
that are not Tier 4 Final must be in production by December 31 in
order to be sold in the U.S.
“Anything
relating to biomass is going electric pretty much,” said Tim
Griffing, sales manager, stationary line, for Continental Biomass
Industries (CBI), of Newton, N.H. “With emissions regulations
changing, if you don’t have to move the grinder, electric is the
direction that everybody is aiming at. In my business it is
increasing 5 to 10 percent a year.”
Manufacturers
say electric horizontal grinders provide myriad benefits in
stationary applications, but most see no potential for making the
machines mobile for off-site work using portable generators in the
near future. Hauling an electric generator that can power a grinder,
they say, defeats the purpose of eliminating a diesel engine on the
machine.
Electric
grinding equipment, according to Art de St. Aubin, president and CEO
of Rotochopper Inc., of St, Martin, Minn., is one of the most
dramatic and under-utilized means of minimizing costs of mulch
production.
“Electric
grinders have many advantages over diesel grinders, some of them
obvious – such as cost of electricity vs. diesel fuel and some of
them subtle and more complex – such as uptime vs. downtime,” de
St. Aubin said. “Costs for operating and electric grinder for 2,000
hours in a year can be as much as $50,000 less than operating a
diesel processing the same product due to less expensive energy costs
and lower maintenance costs.”
According
to Paul Clark, electric systems engineer at Peterson Pacific Corp.,
Eugene, Ore., the relative consistent cost of electricity, compared
to fluctuating diesel fuel prices, is a main reason why operators
consider electric grinders.
“In
some cases overseas, where diesel costs are really high, they will
only consider electric,” Clark said.
Grinder manufacturers
generally agree that an electric horizontal is likely to provide a
lower production cost per ton than a diesel powered machine if you
process material in a fixed location and have access to a three-phase
power supply.
“It’s
important for people to know that this technology has existed for
some time,” said Pat Crawford, vice president of products at
Diamond Z Manufacturing, Caldwell, Idaho. “It’s not some
mysterious application. We did our first electric tub grinder back in
1990. It has been around and proven for a long time.”
Either
electric or diesel grinders and shredders will do the same job on the
material, said Todd Dunderdale, senior area sales manager for
Komptech Americas, Westminster, Colo.
“The
real question is customer requirements, such as space, permit needs
or energy costs,” Dunderdale said. “Typically if a customer plans
on running inside a building they go with an electric unit. For
customers who desire to be mobile, then a track diesel unit is the
best.”
Following is a look at what
manufacturers of horizontal grinders for organic materials processing
are saying about the electric option.
Ideal for stationary
operation
Tim
Wenger, vice president of CW Mill Equipment Co., Sabetha, Kan., said
electric grinders are ideal for stationery grinding operations.
“Municipal
operations, for example, are typically more centrally located in that
wood waste is dropped off at a certain location,” Wenger said. “An
electric machine is a big pro in that aspect.”
“If
your work requires you to move the grinder to the product, a diesel
is the correct choice,” said de St. Aubin. “Electrics are often
chosen for facilities that wish to place a grinder in line with a
conveyor that handles wood waste. You will often see them at the end
of sorting lines in construction and demolition waste applications or
in consumer waste applications. They are popular for processing green
waste for compost, pallets for mulch, waste wood for animal bedding,
among many other uses.”
Electric powered grinders,
Van Roekel said, “will do all the same things that our diesel
powered machines will do. It is basically the same machine. It is
used for pre-processing and product sizing, it can be initial grind
or a regrind or even a final grind. They can be inside or outside, at
a plant or a regional yard where material like green waste comes in.
We see electrics used for more of a 24/7 type of an operation where
they are working the same job and the same material day after day as
opposed to a diesel that is going to go to a site for four to five
hours for a day or two and then move to the next site.”
Originally,
Van Roekel said, the market for electric machines was driven by
efficiency of operation compared to diesel engines.
“Over
time, we’re seeing regulations pushing more people toward electric
power,” he said.
Operating
a stationery electric grinder offers convenience and efficiency of
maintenance, said John Snodgrass, who is in technical sales at West
Salem Machinery, Salem, Ore.
“All
of your parts and tools are centralized on site,” Snodgrass said.
“That’s one of the big
advantages of having the stationery horizontal grinder.”
According
to Morey, “If you don’t need to move around, electric makes a lot
of sense as long as you have the infrastructure to support it. Bandit
is known for making mobile equipment, but out horizontal grinders can
be put into a stationery electric application at any time.”
Cost savings
“Even
at today’s diesel prices, an electric machine can be about $30 an
hour cheaper to run,” said Clark, citing in part a recent analysis
done by one of Peterson’s customers. “You have to take into
account that there is an initial up-front capital cost because you’re
adding more controllers and you may have to get more power capacity
installed to your site. At today’s lower diesel prices, the
electric machines will, in a reasonable time, break even, then you
will start to see a gain in payback.”
Clark
said the additional up-front costs to power a new site could range
between $150,000 and $200,000, including costs from the local power
utility and an electrical contractor.
“If
you already have power, it’s relatively inexpensive,” Clark said.
Van
Roekel said depending on hours of operation and maintenance
practices, the operating costs of an electric grinder can be about
half the costs of running a diesel machine.
“The
machines themselves are comparably priced,” he said. “The extra
costs come with your drive panel that controls the electric power to
the motor. It could be a soft start panel or a variable frequency
drive (VFD) panel with which the motor acts more like a diesel
engine. Then you have the electric power lines that go to the grinder
and the panel, so those are the additional install costs, but that it
is soon made up for in the lower operating costs.”
Electric
grinders offer cost savings associated with routine maintenance as
well, de St. Aubin said.
“Besides
savings on diesel fuel, electric grinders eliminate the costs and
downtime associated with maintaining a diesel engine, radiator and
clutch, including oil and filter replacement, coolant exchange, air
filter replacement and clutch fluid and filter replacement where
applicable,” he said.
Wenger
agreed.
“The
nice thing about an electric motor is not having to maintain the
diesel engine,” he said. “You don’t have gas tanks and turbos
and air filters and radiators and head gaskets. That’s one of the
biggest reasons most of our customers have gone electric initially,
and then years ago we had the fluctuating diesel prices.”
According
to Snodgrass, the absence of road hauling equipment also reduces the
cost of an electric machine.
“You
need to have the brakes, the chassis and all of that other stuff to
move a mobile unit,” he said. “You don’t have that on a grinder
that is staying in one place.”
“As
long as the (electrical) power is at a decent rate, then the electric
machines are definitely cheaper to run,” Morey said. “You’re
eliminating filters and diesel fuel and you’re going to have all
the Tier Four emission components on these (diesel) engines, so there
is going to be an even greater savings when it comes to the Tier Four
compared to electric.”
Kollin
Moore, electrical engineer with Morbark LLC, Winn, Mich., cautions,
however, that the resale market for electric horizontals could be a
limited compared to diesel machines.
Another
disadvantages of an electric machine, Dunderdale said, is the need to
have a mechanic who is proficient on electrics, “which is often
hard to find.”
Longer life
“Far
and away the biggest difference between diesel customers and electric
customers is the quantity of hours that they put on the machine in a
year,” Van Roekel said. “The electric powered machines run way
more hours than diesel powered machines. It comes down to
maintenance, but electric motor will last longer. We see an excess of
30,000 hours on many electric machines. We don’t assume that diesel
will go more than 10,000 hours.”
de
St. Aubin agreed.
“Besides
reduced routine maintenance and downtime, electric grinders offer
considerable savings on long-term maintenance and operation,” he
said. “Electric motors also tend to have a longer life span.
Electrics provide constant dependable performance with reliable
uptime. They are extremely reliable machines with some still in
service with more than 30,000 hours on them.”
Moore
said electric motors typically last up to two or three times longer
than diesel engines.
“If somebody has had a
diesel machine for years and then they go electric one of the things
they radically notice is that there are no longer any oil changes to
do, you don’t have to change filters,” Clark said. “There is a
lot of mechanical maintenance involved with diesel. With electric,
once you get them set up right, you’re not touching those motors
for maintenance for 10,000 to 15,000 hours depending on how much
you’re grinding, so there is a tremendous reduction in overall
maintenance cost when you go with an electric machine. I think the
life span of an electric machine is longer, as the diesel has
clutches and things that wear out pretty quick. With the electric
machine, belts and consumables will wear out, but the drive train
itself is fairly robust and maintenance free.”
Better performance?
Moore
cited the following advantages of an electric horizontal grinder
compared to a diesel powered machine: Cleaner, more efficient power
source with no emission regulations to meet, quieter operation, less
maintenance, less expensive to operate, lower capital cost and less
chance of catastrophic fire.
“A
more consistent end product is the result of the more consistent RPMs
the unit runs at,” Moore said. “Diesel powered machines have a
bigger variance in engine RPMs.”
Comparing
the relative grinding power of comparably sized diesel and electric
motors is one area where some manufacturers disagree. Most sources
interviewed suggested that electric motors can provide more power
directly to the rotor than a comparably sized diesel. Pat Crawford,
vice president of products for Diamond Z, Caldwell, Idaho, disagreed.
“I
disagree 110 percent,” he said. “Electric grinders do not perform
exactly the same way as combustion engines with the horsepower and
torque curves. A lot of people think that if you run a 1,000
horsepower diesel you can get away with 700 horsepower electric, but
we go the other way. The reason is the fixed RPM with an electric
motor. If you run a variable frequency drive (VFD), that would help
the situation a little bit, but you still wouldn’t have the range
of RPM utilization that you would have on diesel.”
Clark,
however, said electric motors can deliver more power than their
diesel counterparts.
“In
some applications we can provide more grinding power with electric
motors compared to our largest diesel motors,” Clark said. “An
electric motor puts more direct horsepower on the rotor instead of
losing efficiency through the clutch. Sometimes you need that extra
power directed directly to the rotor. The other piece of it depends
on the type of motor controller you have. You can, for short bursts
of time, can deliver up to another 50 percent of the power of that
motor. For example, you can turn a 600 horsepower electric motor into
a 900 horsepower motor for short bursts of time if the rotor demands
it without compromising the integrity of the motor.”
Morey
agreed.
“With electric you can run
a lower horsepower and get high horsepower capabilities,” he said.
“In our experience it’s almost two to one from the feedback we
get.”
According
to Snodgrass, “With a 1,000 horsepower diesel, that is not 1,000
horsepower available to grind with compared to an electric where you
get the full 1.000 horsepower.”
Griffing
said electric grinders offer a better torque curve than diesel
powered machines.
“I
would say comparing a 600 horsepower CAT diesel engine with a 600
horse electric motor, the electric will increase your power at the
rotor by a minimum of 25 percent,” Griffing said.
Dunderdale
said the available grinding power is the most
important question to consider.
“Buyers
should be aware that an electric high speed grinder requires the same
amount of horsepower that its diesel counterpart has,” Dunderdale
said. “Typically a 1,000 horsepower grinder needs a 1,000
horsepower electric motor to run it since it is direct drive. However
for our Crambo, for example, the 500 horsepower mobile unit is only
240 horsepower in the electric version because you don’t have the
loss of power as you do with the diesel to run the hydraulics. There
is far less electrical consumption from a 250 horssepower motor than
from a 1,000 horsepower. Also when considering a 1,000 HP electric
grinder, you must also have to purchase expensive soft starts in
order to not overload the power supplier. This can be very
expensive.”
Beefier machine
Engine
comparisons aside, Griffing said because stationary electric grinders
aren’t governed by Department of Transportation specifications like
mobile units, the machines can be configured to meet the needs of an
operation. That means they can have larger hoppers and longer
discharge conveyors.
Wenger
echoed that.
“Because
they aren’t restricted by road hauling regulations, stationary
grinders can be built to larger capacities,” he said. “When you
install a 150,000 pound machine it’s going to last forever. When
you take away the transportation aspects, it frees you up to build a
grinder for more strength instead of transportation.”
Snodgrass
agreed.
“Grinders
that are going over the road have some limits on things like width
and weight,” he said. “If you don’t have to take your grinder
on the road, a stationery machine can be much wider with a larger
diameter rotor. You can get into tremendous capacities,”
Operating requirements
“Electric
driven grinders can be used anywhere there is enough power to drve
them,” Griffing said.
Manufacturers
generally said minimum requirements generally include three-phase
power with a minimum of 460-480 volts at 60 hertz. Having adequate
electrical power at the installation site is important, and not
always simple to achieve, some manufacturers noted.
“A
lot of people assume that because they have a lot of power or voltage
coming to their facility that they are set,” Crawford said. “But
they may already be using most of their capacity. You can have three
phase, 480-volt power available, but you also need to have sufficient
amperage. Everybody has the voltage, but not everybody has the
amperage.”
Required
amperage, Crawford said depends in the horsepower of the motor.
“Lower
horsepower machines don’t need that much amperage,” Crawford
said. “But you have to consider that in-rush – what it takes to
start the motor - can be eight times what it takes to operate the
motor.”
Power
to electric grinder motors is controlled using one of two types of
controller: a soft starter or a variable frequency drive (VDF). A
soft starter helps to protect a motor
“With
soft start panels you tend to lose a little bit of power, but they
are less expensive,” Van Roekel said. “If you’re regrinding it
really doesn’t require the full horsepower anyway. It depends on
the application. So soft-start is good for some jobs. If you’re
doing more taxing work, you may want to look at the VFD panel. The
VFD panel is something we believe is the secret to good
productivity.”
Clark
said Peterson’s machines required between 1,000 and 2,500 amps
depending on the size the motor.
“If
you’re going to use an electric machine, you need to be sure that
you have a power supply that can handle it,” Morey said. “If you
don’t have a big enough power supply then there is going to be a
problem running the machine.”
Wenger
said power drops can damage motors.
“Most
problems we’ve had with the electric tubs, particularly on
starting, have been from power drops, especially in the summertime,”
he said. “People generally say 460 volts is the requirement, but
sometimes the voltage in that system can fall to 440. When voltage
drops, amperage goes up and that can trip out the power. I tell
people to have the utility top the power up into the 505-volt range
to protect against drops in voltage, and that usually takes care of
the problem. It’s not a big deal – they just adjust it at the
transformer.”
Clark
said Peterson recently had a customer who was experiencing low
voltage.
“It
looks like the power company didn’t plan fully for situation,” he
said. “It causes the motors to work a little harder and they get
hotter. The way you handle that is to work directly with your
electric utility company and tell them what you are planning to do so
they can plan accordingly.”
Michael
Spreadbury, Peterson’s marketing manager, added, “That is a
conversation you need to have very early on the purchasing process.
You need to get the utility involved and you need to talk to your
local electrical contractor.”
Having
access to sufficient power, Spreadbury said, is not always a given.
“If
the infrastructure isn’t there it isn’t going to happen,” he
said. “A customer in the Midwest would die to have electric. But
the power company just will not put in the infrastructure.”
According
to Griffing, “One downfall of the electric driven grinders is
having enough power available to your site. Not all sites are close
enough for the amperage required to operate large horsepower motors.”
Wenger
agreed.
“Location
and proximity to power is a consideration,” he said. “Some of
these mulching operations can be in remote locations, so the ability
to get adequate power can be a hindrance. It might cost a couple
hundred thousand dollars to get lines run to you if you are a
distance away.”
Market trends
“The shredder/grinder market has grown
over the last couple of years and is forecasted to continue to grow,”
Dunderdale said. “We have seen an increase in the number of
stationary machines typically because larger facilities are now being
planned because of industry consolidation.”Tightened regulations in engine air emissions will increase the cost of diesel machines, making electric motors more attractive for the appropriate applications, manufacturers agree.
“Due to emissions standards becoming more strict, electric drive is becoming more popular,” Griffing said.
“The increased costs for Tier 4 diesel powered machines will be substantial,” Crawford said. “I think you’ll see machines that are not Tier 4 Final on the market through the first quarter to the first half of next year, but we’re already seeing a pickup in demand for electrics.”
Peterson
also expects stronger interest in electric machines.
“With
onset of Tier 4 and the significant price increases that it is going
to entail, we are going to see more and more applications where, of
the machine does not have to move, we’re going to be quoting more
electric machines,” Spreadbury said.
Wenger
said sales and inquiries for electric grinders increased a few years
ago when diesel prices bumped upward.
“Now,
with the changes in the emissions regulations, people are taking a
closer look at electric power,” he said. “We make a lot of
electric tub grinders, but any of our diesel horizontals can be made
with an electric engine.”
According
to Moore, Morbark has seen the demand for electric grinders slowly
increasing, especially during times when the price of oil has been
elevated.
“Regulatory influences, whether they are about
emissions, dust or noise, are definitely switching people over to the
electrics,” Van Roekel said. “The bulk of Vermeer’s horizontal
grinder sales are diesel powered, but electric machines have been
reducing the gap over the past five years.”
Making it mobile?
New
technology has made many electric products more mobile. Horizontal
grinders are unlikely to be one of them, manufacturers agree.
“To
make an electric machine mobile you would need a pretty big diesel
generator, which isn’t cheap,” Van Roekel said. “You’re kind
of defeating the purpose if you’re running a 1,000 horsepower
generator and then you have to move the panel with it to control the
motors. You’re still going to have the noise and air emissions from
the generator.”
That,
Wenger said, is one of the few downsides of an electric grinder.
“They
are not mobile at all,” he said. “You would need a 2,000
horsepower generator to power up a 1,000 horsepower grinder. You’re
better off just getting a 1,000 horsepower diesel engine. I had a
customer who wanted to take an electric grinder from town to town to
town to do custom grinding and he pitched the towns to provide the
electricity. That would have necessitated each town to set
transformers of adequate size to power the machines. It wasn’t
going to happen. The economics just aren’t there.”
De
St. Aubin said that portable configurations using quick-connects are
available, but power availability is essential.
“The
site must have adequate three phase power available,” he said.
Griffing
said quick-connects at adequately powered sites allows an operator to
move an electric to two or three different locations.
“It
works great, but you need to have soft starts at each of the
facilities,” he said.
Wenger added that one customer has two locations
powered up on his site so he can move an electric tub grinder back
and forth.
Snodgrass
noted a similar situation.
“I have seen yards where they have a semi
portable situation,” he said. “They will have a crude pad and the
ability to get power to it so they can process X amount of tons and
when they are finished they can pack it up. The control panel is a
part of the unit, so they can pack it up and move it to another part
of the yard. It isn’t something that you would run for a week –
you probably would run it for a year at a site. But generally, if you
are dragging a generator around you are defeating the purpose.
Converting to electric
Wenger
said converting an existing diesel powered horizontal grinder to
electric is simple.
“We
are quoting a project like that now,” he said. “I customer in
California has a diesel grinder and they were not able to get an air
quality permit. Our quote is pull off the 1,000 horsepower diesel
engine and put on a 500 horsepower electric. It is a pretty simple
conversion. It’s not a bad things to do. When a diesel engine goes
bad, instead of a new $60,000 diesel engine you can put the money
toward a conversion. It is probably going to cost you $100,000 by the
time you buy the motors and starters. But you’re going to make that
up in lower operating costs.”
Griffing
said diesel-to-electric conversions are becoming increasingly
popular.
“We’re
seeing more and more of it now, especially in California with the
regulations getting stricter,” he said. “If you’re not going to
be moving it you might as well convert it. To buy a new diesel engine
or have one rebuilt, they’re about the same price to convert, so
you’re better off going with the electric.”
What to consider
Before
making the decision to install a horizontal grinder, you need to know
your local codes, Van Roekel said.
“There
will be some safety regulations,” he said. “If you are under a
roof there will be some kind of rules to prevent an explosion or a
fire problem. It is high voltage, so you need to lock-out-tag-out and
other proper safety and maintenance practices. Don’t try to
eliminate maintenance schedules. A 24/7 operation is not going to
want to turn it off very often, but you still need to clean the
machine and check the cutters and screens.”
Moore
noted that local laws may have restrictions relative to operating
hours and start up times.
Before
purchasing an electric grinder, Wenger said, be sure to do your
homework.
“Talk extensively with everyone involved,
be it the contractor who is pouring the concrete where the electric
machine is going to set or the local electric company,” he said.
“Are there certain times that the grinder should not operate as to
not interfere with electric power elsewhere else, and make sure all
of the people involved in the preparation for the grinder are in
contact. Communication is key.”