Hybrid ship propulsion: further tests by DNV GL show improved energy efficiency

hybrid-Viking-Lady-2“The battery hybrid installation has been tested in sea trials, which showed that a 15 per cent reduction in fuel consumption, 25 per cent reduction in NOx emissions and 30 per cent reduction in GHG emissions can be realised in practice, especially for [Dynamic Positioning] DP operations”, said DNV GL in a statement on November 2014.

The news follow suits announcements received in recent years about other tests and actual feed-back from hybrid engine installations by Foss Maritime and others on tugs, oil&gas field assistance vessels and large yachts.

Related post (in Italian) about the hybrid marine engine sector >> here.

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Overview of current development in electrical energy storage technologies and potentials.

Electrical energy storage technologies with challenges to the UK energy systems.

Electrical energy storage technologies with challenges to the UK energy systems.

Comprehensive scientific article about #storage technologies up-to-date from Science Direct. A must-read for storage professionals.

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A new project of a prefabricated wooden house energy self-sufficient

A new prefab wooden house project from OneBuilding. The project is designed to be energy self-sufficient specifically in mild climates areas but is easily adaptable to a wide range of latitude and climate situations.

The concept includes specific features to make manufacturing, logistics and installation as easy and seamless as possible. The walls are made of multiples of 62,5-cm-wide panels to provide for production automated systems and are assembled in multiples of 2,45 meters to meet transportation requirements.



The roof orientation and tilt are adjustable according to the latitude of installation for maximum solar energy gain.

The walls have a massive isolation for a high living comfort and the lowest energy use for internal climate control.

The global power draw can be produced by a solar system connected to a battery bank and a back-up generator (gas or diesel) in case of off-grid configurations.



Many different internal layouts are available according to the building’s use – internal panels are fixed in built-in stud in the floor for easy changes during the building’s life.

The project was specifically addressed to quality building developments by a market-leading contruction company in Italy.

The concept can be applied to meet high-end consumers, still keeping a very low-cost pricing for the building’s structure. We would be happy to give more infos, please contact us here.

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Off-grid power from a portable stove – cool design with many features

BioLite camp stove with power generator

BioLite camp stove with power generator

Here’s a cool item for off-grid goers on the move: you get heat and power from your own fuel, like simple wood found on your way. Actually the idea from BioLite comes a long way back, from the observation that almost half of the world population cooks their food from open fires – regardless of the toxic exhalations and the damages to the food. The portable stove delivers heat from a close chamber preventing the food to be exposed directly to the flames. But the cool feature is the tiny embedded thermolectric generator: it is rated to deliver 10W of power – enough to power up small appliances (an i-Pad is credited to require 5 W at 5 V  – although with i-Pad you’d better pay more attention to the actual power requirementes) or LED lights or whatever you might need in an emergency situation or on a camp or simply at off-grid dwellings.

The manufacturing company has been funded by VCs, and looks ahead to sell into many of the African countries, where people with no – or extremely poor – power grid close-by are increasingly expanding the adoption of mobile phones.

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Off-grid LED lighting system

off-grid LED lighting system from Carmanah

off-grid LED lighting system from Carmanah

This is how it looks a professional LED lighting system. The top-pole mounted battery is self-cooled by the chimney-effect and is shaded all the time, it is also far away from pilferers. The smart power-management system prevents the battery’s deep discharging and the accidental overheating during the charging cycle. The mounting system looks (and is) really sturdy and storm-proof. From Carmanah, Canada.

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Fire-resistance of solar panels on wooden roofs

solar-modules-fire-roof-topThe fire-resistance of solar panels on wooden roofs is a frequently asked question by property owners and authorities in charge of releasing building permits.

One point to be addressed is the possible increase of the flammability of the roof, and its effects on the building’s safety. Another concern is about the exposure of first responders to the risk of electrical shock in case of fire on a building with solar panels on the roof-top.

We checked the international safety standards and the testing procedures set by the stanadrs, and discussed the subject with constructors and installers in an effort to answer the following questions:

1) Can solar panels trigger and transmit a fire?


Fire-testing – Source: TUV Rheinland

Solar panels from major manufacturers comply to the IEC 91730 standard. According to the IEC testing procedures any product matching the test is guaranteed as capable of [1] not inducing any fire if subject to fire close to its surface, [2] not transmitting fire in case of a burning material left on its top – as it might be the case of a blazing object blown by the wind – and [3] do not loose its structural resistance during the test. Testing procedures from the TUV Germany are available here.

Another point is the fact that the only inflammable point of a solar panel is the junction box, which is made of uninflammable material, but it may host a flame triggered by electronics components, in case of a failure in the isolating material of the wiring connection. The worst that we have seen is that the PVC which the junction box is made of melts down, but the fire did never receive fuel enough to keep burning or to spread the ignition to the roof.

junction box burned | source: http://www.gulfsouthsolar.com

junction box burned | source: http://www.gulfsouthsolar.com

Our statistic (based on about eighty solar plants under maintenance service since 2008) shows that it happens in less than 0,001 % of the installed panels, and actually it happens soon after the installation and regardless of the installation mode – which let us believe that the cause is a defective production.

Indeed, as a junction box burns out, the DC circuit connecting the panels along a string opens up with two effects: to isolate the faulty panels from the other, and to stir an alert into the string monitor system (if there is one installed).

2) Can a solar panel increase the chance of flammability of a wooden roof?

There are two facts about fire: [1] fires go bottom-up (unless there are accelerants increasing the fire’s ignition point toward other directions); [2] fires require fuel, heat and air to keep burning.

[1] Solar panels are mounted on the top of the outer roof’s layer, so there’s no way the flames can spread underneath; the mounting structure is made of Aluminum and steel; cables and connectors are made of flame-retardant material. Even in case of strong winds from the panels’ side of the roof, the lack of consistent fuel in the back of the modules prevents the ignition of the roof’s outer layer and the timber beams underneath.

[2] The commonly used roofing system (clay tiles, tin roofs, asphalt built-in coverings) are made of original flame-retardant raw material. In any other case – as is the case of wood shingles – it is advisable to install a flame-resistant intermediate layer on top of the non-flame-retardant layer as additional safety.

Generally speaking, we can assume that solar panels do not add the fire-resistance risk of a wooden-roofed building, provided that the roofing cover has been correctly built of a commonly available flame-retardant material.

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Why open a Charging Station for Electric Vehicles

EV-charging-station-Frisco-USTo open a Charging Station for Electric Vehicles may be a good business opportunity, according to our simulation.

We’ve runned a draft model to simulate the economics of an EV recharging station deployed at an existing gas-station. The model assumes the electricity costs of Italy (Italy has among the highest cost in the EU).

The model considers the infrastructure costs required to set up two plugs connected to a 50 kW AC/DC station (DC for fast charge) and the operational costs connected to run the station 12 hours/day operator-assisted and 12 hours as a pure self-service.

To simplify the model it is considered the most popular EV on the market as the standard car (Nissan Leaf). By tuning the number of kWh delivered per day and the the local cost of the electricity, the models delivers the pay-back time of the investment.  Some of the features included in the investment could be added in a second phase to lower the start-up capital: the roof over the plugs, the fast-charge DC inverter.

The business would benefit from cross-selling services during the recharging time, taking between 30 minutes to 2 hours like refreshings from the local bar, additional car-services: car check-up, motor oil, car wash (internally).

Start-ups like the British ChargeMaster or the Dutch Fastned are already down to the network-deployment phase, and seem to confirm the realism about a similar business model.

The beckoning idea is that the major hindrance perceived by prospect EV buyers is the range – not price, not design, not the lack of a broad product line. Though the overnight charge allow the car for a minimum 120 km even in tough winter conditions, the fear of remaining stuck out of juice appears to being overcoming all the other advantages of an EV against a gas-fuelled car.

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How distributed storage, microgrids and renewables work together efficiently | by ILSR

Baseload-storage-graph-ILSR25-03-2014. A comprehenisve report [download here] from the ILSR (Institute for Local Self-Reliance) highlights the way distributed storage, microgrids and renewable generation can operate hand-in-hand to the benfit of customers, grid-utilities and the environment. Worth the downloading.

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How Microgrids are shaping their future. Right now.

Microgrid_2Microgrids are bound to become a considerable element in the energy landscape across the world.  Microgrids have been historically implemeted to power up remote sites and manage isolated grids or as a robust back-up generation source for mission-critical users. However the benefits from microgrids in the current energy landscape – as reported by a variety of pilot and commercial projects – have promptend big players to enter the market. In an interesting webinar from Greentechmedia   [here the pdf with slides show (12 Mb)] the Microgrid landscape and its operational benefits are discussed by experts.


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Nature’s article about the rechargeable revolution.

USA | The Nature-battery-status-2014US Joint Center for Energy Storage Research (JCESR) won a 150 M$ grant from the Department of Energy (DOE) targeting the research for batteries 5x denser in energy per kg and 5x cheaper than the current Li-ion batteries. And this by 2017. They must be sure that in the storage tech the rush for efficiency is all a matter of testing, which is the costly side of research. There are different storage technologies potentially suited to meet the target, but history tells us that not necessarily the early birds are the more successful. More money in the research would bring in more trials and more competition from around the world for what would be one of the biggest disruption in technology of the next years. To the benfit of the distributed generation and the off-grid systems. Read the interesting full article from Nature  >>here.

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