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Electric & Hybrid Drives Are Gaining Steam on the Waterfront
Marine News February 2, 2018
Demand for electric mobility is sweeping across the globe, and it’s
rapidly gaining traction in the marine industry.
The electric mobility revolution is largely being driven by the land
transportation sector. Industry statistics predict that electric vehicle
sales will surpass combustion engine vehicles within the next 20 years.
Many countries in Europe and Asia have already adopted aggressive
deadlines to phase out sales of combustion-powered vehicles, and some
cities such as London are planning to banish them from their roads
entirely. The same rules will likely also be extended to their waterways.
Some of the world’s largest auto manufacturers have announced plans to
convert their entire production from combustion to electric or hybrid
drives within the next couple of years. Recharging infrastructure will
quickly spread to meet the demand, in the same way that filling stations
became ubiquitous in the early days of motor vehicles. On the other
hand, recharging will be less of a problem in the marine industry, since
most docks and terminals already have shore power hookups.
At the recent International Work Boat Show, Marine News caught up with
Torqeedo, a German company that is at the forefront of bringing electric
and hybrid technologies into the light commercial marine marketplace.
Early Adopters
Torqeedo has been in business for 13 years, initially selling small
lightweight electric outboards for RIBs, dinghies, kayaks, canoes and
pontoon boats. Over time, the company has increased its horsepower range
and the complexity of its integrated systems. It is now equipping larger
leisure yachts and commercial workboats with electric outboards and
inboard systems with shaft or pod drives, in either all-electric or
hybrid configurations. Torqeedo claims to have more than 70,000 electric
motors in service. The product range runs from 1 to 80hp.
The primary limiting factor in electric mobility, according to Torqeedo,
is not the electric motor but energy storage technology. Happily,
batteries are getting better every day, again driven by automotive scale
R&D. The company projects that energy density in batteries will improve
by 70 percent over the next two years, while the cost in terms of
dollars per kilowatt hours will fall by one-half over the same time
frame. It’s noteworthy that Torqeedo has signed an agreement with BMW to
integrate marinized i3 automotive lithium batteries with its Deep Blue
systems.
The Case for Electric
There’s a compelling argument for electric propulsion – for specific
types of boats with specific usage patterns. Torqeedo itself concedes
that a pure electric drive system is not currently suitable for vessels
that travel at high speeds for long periods of time. On the other hand,
electric provides unique advantages over gas or diesel systems for
slower vessels with shorter run times. And hybrid solutions – although
more costly in terms of capital expense – can push larger boats at
higher speeds for longer times. Solar panel recharging can also extend
the range considerably.
The higher CapEx of electric or hybrid propulsion versus a comparable
engine running on fossil fuels is offset by lower OpEx; in terms of fuel
savings, reduced maintenance costs and increased uptime. Moreover,
electric prices are more stable than fuel prices, giving more
predictable costs. Torqeedo calculates that if a boat’s annual fuel
costs exceed $6,000, electric propulsion will yield a return on
investment in just a few years. After that, the savings really start to
kick in. Torqeedo offers a long-term battery capacity warranty of up to
nine years after commissioning, guaranteeing that the batteries will
retain at least 80 percent of their original capacity, even if they’re
being used every day. There are also intangible benefits, such as the
health of crew and passengers, by reducing their exposure to noise,
exhaust, vibration and fumes.
Sustainable Waterways
Municipal authorities around the world are actively searching for ways
to clean up their air and environment and improve quality of life for
their communities. One way to do this is to shift people-moving traffic
from congested roadways to waterways by creating fleets of electric
ferries and water taxis. For these applications, electric propulsion can
be an attractive alternative to meet clean-air goals. It’s been
calculated that one single 80 horsepower four-stroke outboard motor puts
out as much NOx and hydrocarbon emissions as 350 automobiles, so
electrifying workboat fleets will make a significant contribution to
reducing air pollution.
To meet this growing demand, Torqeedo is focusing on water taxis,
excursion boats and passenger ferries. The company points to a number of
successful deployments over the last 12-18 months.
The city of San Antonio, for example, has just put into service a fleet
of 43 electric passenger boats for its iconic River Walk downtown canal
system. The 27-ft vessels, designed by Metalab and built by Lake Assault
Boats, are each driven by a Torqeedo electric propulsion system that
consists of a 20hp electric outboard, 16 lithium batteries, with a built
in shore power connection for fast recharging. The barges seat up to 40
passengers and can be configured for multiple roles for tours, dining,
water taxis, entertaining and water parades. They cruise at about four
knots and can normally operate up to 12 hours without recharging,
according to the vessel operators.
The largest 100 percent electric passenger boat in Canada, the Queen
Elizabeth Dr., has been operating on Ottawa’s scenic Rideau Canal since
2016. The 75-ft excursion boat is powered by two Torqeedo Deep Blue 80hp
outboards – one at either end, since the boat is too long to turn around
in the narrow waterway. The vessel makes up to eight 90-minute tours at
4.5 knots per day. The operator reports a rapid ROI. The electric power
system was about $90,000 more than comparable gas-powered outboards, but
the higher original cost is offset by $26,000 per year in reduced
operating expenses, giving a break-even point in 3.5 years.
Separately, Watertaxi Rotterdam added the first hybrid vessel in its
fleet in 2016. The boat is powered by a Torqeedo Deep Blue 80hp electric
motor, with an integrated energy management system. Two 20kW generators
keep the batteries charged when operating at speeds up to 13.5 knots on
the River Meuse in the center of the city. The operator claims that the
new boat is 70 percent more fuel efficient than the other 15 water taxis
in the fleet.
Also in the Netherlands, the first purpose-built solar/electric
passenger ferry commenced operations at the Port of Harlingen in late
2017. The boat has a unique integrated propulsion system with two
independently controlled Torqeedo 8hp counter-steering pod drives fore
and aft, providing an extraordinary level of maneuverability. The boat
can be driven in a 90 degree angle to port or starboard, and perform a
360 circle in either direction within its own 28-ft length. The 48V
lithium batteries are automatically charged from the 12 rooftop
thin-film solar panels, and the boat can plug into shore power during
stopovers for an additional recharging boost.
Heavy Metal
Torqeedo insists that vessel size and weight are not a challenge for
electric propulsion. That’s because electric motors have an extremely
flat torque curve when compared to combustion engines. The high-torque
motor provides the power to drive a much larger propeller capable of
pushing very heavy loads. A case in point is a company operating
dredging barges in inland gravel pits in Germany. The quarry owner,
Kaspar Weiss GmbH, specified the zero-emission electric system for its
dredges to provide a highly efficient green solution to protect the
local groundwater and keep the air clean. The 44-meter barges, which
haul loads up to 120 metric tons, are powered by a Torqeedo Deep Blue
high-voltage system. The vessel typically moves about 500-600 meters at
a speed of about 3 knots, opens its trap doors, then drives back and
plugs in the chargers – about one to ten times per day. This owner has
also installed Torqeedo outboards on pusher boats used in waste
byproduct removal.