Generation Electric

Pamela May 2 is an electric-drive trip-boat with batteries charged by eight semi-fl exible solar panels. The vessel is operated almost entirely using the solar input, the shore line being connected only when necessary in less favourable weather.

Alternative Propulsion Boating Group member David Strucke explores the options of solar and wind power on inland waterways cra

With the principal aim of promoting a reduction in the use of fossil fuels and their harmful emissions, IWA’s Alternative Propulsion Boating Group has been researching electric drive for inland waterways cra , together with options for power generation (both on and o board) and storage. The topics covered so far have included solar and wind, examined here, together with shore line availabili and pes of ba ery storage, for the various cruising boats on our canals and rivers. Existing steel narrowboats, wooden cra and GRP cruisers may present di cult challenges when you’re considering changing the motor om internal combustion to electric drive – but there are many smaller improvements that could also signifi cantly reduce fuel consumption.

New or renovated cra , if designed with electric drive and specifi c choices (note the plural) of energy source, should aim to be at least ‘net carbon neutral’ – and ideally use no fossil fuels in normal applications. Either way, the improved e ciency that electric drive o ers can always be appreciated. In cases where a generator is installed to charge the ba eries (sometimes referred to as a ‘serial hybrid’ a er motor industry application, as opposed to a ‘parallel hybrid’, which incorporates a conventional engine), there are still choices you can make in terms of pes of fuel and technology – a conventional generator adapted for ‘bio’ fuel or powered by a fuel cell, for example. In all cases, however, the possibili of wind or solar power o ers the chance to reduce fuel and emissions – possibly to zero.

RUN BY THE SUN

Solar panels

While the sun’s energy is ee to use, solar panels can present you with a signifi cant up ont cost. Monocrystalline or polycrystalline are the most common pes of solar panel available, and usually come fi xed in a rigid ame. In practice, polycrystalline panels are slightly less e cient in terms of power per unit area, but are a li le cheaper to manufacture.

A more expensive alternative – although under continuing development so prices are coming down – are semi-fl exible panels, suitable for fi xing down onto a curved roof, for example. These are currently between two and four times the price per wa than the rigid pes, and require a li le more area for each wa generated. They are, however, considerably lighter and, if assembled securely, are durable enough to walk on. They are produced using thin fi lm techniques, sometimes referred to as ‘amorphous’.

Area, power and cost

From current data, the area required is, on average, about 0.5 square decimetres per wa for rigid panels, which is very consistent over the range of about 20W to 360W panels (except a few ‘ideal’ examples that appear slightly lower). It’s worth noting, however, that the nominal power ratings given for the panels are normally the ‘maximum output’ – the amount of energy gathered under ideal sun conditions. This is seldom achieved, of course, but assuming panels are tested under controlled conditions, the ratings are comparable.

When installed on a boat, a near-horizontal a itude would face the sky at all times, meaning at least some solar energy can be guaranteed during daylight hours. When moored, however, ensuring the panels are oriented due south and

Wind generators come in a variety of designs. Each have their merits but there’s no one-type-suits-all solution.

angled up about 40 degrees (or, even be er, motorised to follow the path of the sun) will help towards reaching the maximum possible level of output for the longest part of the day.

The cost of purchasing rigid panels is also fairly consistent across the di erent ranges currently available on the market, averaging about 92p per wa . The most cost-e ective units appear to be about 80p per wa . Semi-fl exible pes require an average of 0.6 square decimetres per wa , and research showed that this costs around £1.95 per wa om one supplier, and even more om another – so shop around!

In practiCe

It may be of assistance to consider the use of solar panels in, say, three ranges: ■ Small, for appliance charging and lights etc. For example, a 10W-50W solar panel with a single, small car- pe ba ery. ■ Medium, for domestic 12V supply to include powering a idge. This might be two x 80W panels and the usual two or three domestic ba eries. ■ Large, for propulsion motors. This may require anything om a single 160W solar panel for an outboard motor in an open boat, to an array of at least eight large solar panels for a 48V system and goodsized ba ery bank on larger vessels.

These systems could be kept separate for simplici (i.e. isolated om each other) on cruising vessels, as in the event of a fault on any one system, the other would be una ected while repairs were taking place.

BREEZY BOATING

Wind generators

Windmills utilise very old technology, and simple windpowered chargers for small ba eries have certainly been around since electrici became available in the 19th century. During the 20th century many DIY guides showed how a suitable fan with belt drive could be linked to a car dynamo (later an alternator) or arranged to charge 6V, 12V or 24V ba eries with a car- pe regulator. Since the 1940s, the Rutland and other makes of small wind generators have been widely used on yachts and in coastal areas.

Wind fans fi xed on poles are not very practical for cruising boats. Rigid solar panels can be angled towards the sun while moored.

Inland use

Sheltered housing estates and other built-up, urban areas simply do not experience the consistent winds that allow fans to be an e ective way of generating power – unless the fans are mounted on a high pole, which is less convenient, more hazardous, and o en unsightly to neighbours. Flat, open landscapes are naturally windier, and marinas situated in these pes of countryside surroundings may permit a pole to be fi xed to a static boat.

On inland cra that are continually cruising and where headroom is important to clear bridges, a wind generator is not especially convenient – on the rare occasion that you fi nd yourself on suitable moorings, you would have to remember to rea ach the fan and pole. However, the use of a wind generator at moorings, if considered appropriate, would o er additional charging and therefore use of power a er a period of windy weather – which of course could occur at night as well as day, unlike solar.

Size, power and cost

Several suppliers can be found o ering fans in a range of sizes. A 1m-diameter fan would give a nominal output of 200W at a wind speed of 23mph, and cost about £250. Larger models o er ever-increasing outputs – possibly at lower wind speeds – but, of course, come at higher prices. Comparisons between the pes of models on the market are complicated as suppliers and manufacturers quote performance in di erent ways. Research is therefore needed for each specifi c use.

Connecting up

Shore line connections (with approved outdoor socket systems) are now more common for both general use and charging of larger ba eries. Any electric-drive ba ery system would be provided with such a socket for charging overnight. Future innovations include higher charging rates where cabling and supply is possible, which might o er useful energy transfer in as li le as a couple of hours or so.

Although electrici is ‘carbon neutral’ at point of use, its original generation may well be environmentally harmful if created through the burning of fossil fuels, rather than obtained om sustainable sources. If possible, look for a landbased energy supplier with good green credentials to plug into, in addition to harnessing your own solar and wind power. Controls are available that can handle multiple inputs om solar panels, wind generators and shorelines, ensuring optimum charging in a combined system. The main lesson here is that use of the boat’s conventional diesel engine or generator for charging ba eries for domestic use can nowadays be replaced by the use of alternative, sustainable sources. This is of particular relevance to boaters residing in cities, where regulations might restrict the running of engines of moored boats in order to cut pollution. Both wind and solar technologies can, and should, be used to reduce our dependence on fossil fuels by cra on the inland waterways, whether passenger, hire, commercial or private boats, both while cruising and at their moorings.