Reliable solar-powered refrigerators are creating economic opportunities for remote, rural towns

In Wainika, a remote village north of Vanua Lavu, Fiji’s second largest island, villagers depend on fishing for their livelihoods. However, the nearest market to trade fish is a laborious two-hour drive and a 45-minute boat ride away. Keeping their fish fresh, without refrigeration, during this journey used to be impossible for Wainika’s villagers, until a renewable-powered solution presented itself.

The installation of a standalone hybrid solar photovoltaic (PV) refrigeration system has drastically changed the economic prospects of the village. Installed at the village community hall, the system enables villagers to chill their fish in preparation for the journey to the market, and helps power lighting and phone charging outlets.  A backup diesel generator ensures the operation of the freezers during long cloudy periods.

“The new freezers have helped our community generate income, improve food conservation methods and support a better lifestyle in Wainika,” explains Epironi Ravasua, Wainika’s village chief.

Wainika solarSolar PV panels on the roof of Wainika community hall

Ravasua’s records show that between December 2015 and February 2016 Wainika’s freezers stored approximately two tonnes of fish.  In addition, the community no longer has to purchase ice or smoke the fish in order to preserve them. In other words, the system earns back around USD 12,500 per year using a system which cost around USD 14,000.  An additional benefit is that the system can also be used for other functions such as phone recharging services.

The Wainika hybrid system comprises 1.4 killowatt PV modules coupled with a 2,500 watt diesel generator and battery storage to power three energy-efficient freezers. Since the inception of Wainika’s solar-powered fridge project in December 2015, four more systems have been installed on the islands of Yanuca, Tavuki (Kadavu), Mali and Kia.

“With the fridges, we’ve been able to expand our range of merchandise and now sell ice creams and ice candies — a novelty for the village kids and elders alike,” says Epeli Boteanakadavu, Tavuki’s solar refrigeration caretaker. “We’re now looking to form a committee to look after the funds generated from these sales and those from fish storage.”

First sale for a woman entrepreneur in Mali islandFirst sale for a woman entrepreneur in Mali island

Renewable energy security

According to IRENA’s Renewables Readiness Assessment (RRA) of Fiji, the archipelago, like other Pacific Island countries, depends heavily on imported petroleum-based fuels. “The fluctuation of global oil supply affects not only energy security, but also energy prices,” says IRENA’s Programme Officer Francisco Gafaro. “Scaling up non-hydro renewables like solar can diversify Fiji’s energy mix and improve energy security. Existing mini-grids on the islands could be made more sustainable through the hybridisation of solar PV systems with battery storage.”

Moreover, renewables go further than access, according to Inia Seruiratu, Fiji’s Minister for Agriculture, Rural and Maritime Development and National Disaster Management, and this year’s Climate Champion at COP23, “Fiji has tremendous renewable energy potential, and our strong commitment to renewables goes beyond improving energy access. Renewables feature prominently in Fiji’s NDCs and are planned to spur economic growth across various sectors and to improve livelihood.”

Dr Atul Raturi, a professor at the University of South Pacific and lead in the Wainika project, began Fiji’s solar-refrigeration projects with the assistance of the French embassy in Suva. Leading a team of students, Dr Raturi began by first surveying the needs of local communities and identifying effective ways to improve livelihoods and generate new sources of income with better energy access.

“Renewable energy plays a big role in Fiji, and on the larger islands almost 60% of electricity comes from hydropower and biomass, while numerous solar home systems fulfill basic electricity needs of smaller island populations,” explains Dr Raturi.

“Fiji is making considerable headway towards its target of 100% renewables-based electricity by 2030,” he continues. “We want to show the promise of the sustainable development goals and how SDG 7 (affordable and clean energy) can support many other goals. Energy should be used for productive use.”

Solar PV refrigerations system in MaliSolar PV refrigerations system in Mali

According to IRENA, in 2014 Fiji generated 55% of its electricity from renewables and had the lowest oil dependency and electricity tariff among all Pacific Island states. The government of Fiji is strongly committed to the global effort to address climate change, and is the organising country of COP23 — the United Nation’s annual climate conference. In Fiji’s Nationally Determined Contribution — a pledge to reduce carbon dioxide emissions as part of the Paris Agreement —  the country has set an ambitious target to increase its share of renewable electricity generation to 100% by 2030.

At the request of Fiji’s government, IRENA is conducting a grid integration study to provide national authorities with the technical background to design and put in place a sound policy framework for facilitating the deployment of more solar PV. Resources from Norwegian Voluntary Contributions to the SIDS Lighthouses Initiative is supporting this work.

The first e-mobility Plugfest of the EEBUS initiative in June is now followed by the second one. Put to the test: All generators and loads in the home are interconnected to communicate via energy management platforms, such as ennexOS from SMA. PV systems, heating, home appliances and even charging stations for electric cars will thus have to be optimally connected with each other for optimized use of energy in all areas of application.

Today, a modern residential building can produce significantly more energy than it needs with a PV system. It’s already extremely economical to charge the growing number of electric cars using this excess electricity. This is one of the reasons why over 80% of electric cars are charged at private charging stations.1

In the domestic network, communication is organized by a control center, such as the ennexOS energy management platform.

frank blessing“With the EEBUS specifications, we integrate all energy generators, loads and storage systems across the electricity, heating and e-mobility sectors into the system and use a fully automated approach to ensure that energy is being used efficiently, without sacrificing convenience. This means that households and companies can make significant savings on electricity costs.”

Frank Blessing

Networking with EEBUS prevents conflicts in electricity supply

The electricity demand of electric cars may compete with other loads in the house. The EEBUS initiative is developing a common, standardized language that makes communication across all energy sectors possible.


“At Plugfest, we saw that the result of last months’ work on paper was that different devices can actually communicate with each other.

Together, e-mobility and renewables can thus make a big step forward.”

Matthias Groene

In practice, the EEBUS specifications define three core e-mobility areas via which energy managers and charging equipment communicate:

  • Increasing efficiency: As much self-generated electricity as possible will be used for charging electric cars.
  • Relieving the utility grid: The charging process will be agreed with the grid operator.
  • Overload safety: The electric car and its charging technology always take the entire house into account. If a boiler switches on, for example, the charging current will be reduced to prevent an overload.

kevinmeyers“It was inspiring to see active cooperation across industries and amongst competitors on a unified communication protocol toward the development of the future grid. What is being accomplished with the EEBus Initiative and demonstrated at the PlugFest events is a strong example for international markets on what is achievable through cooperative effort and standardization on automated EMS control logic.”

Kevin Myers

Networking through EEBUS will enable a quick expansion of charging technology infrastructure. In many cases, the power required by charging stations already exceeds the available capacity of the utility grid. Intelligent energy management avoids intervention in the utility grid and can save on expensive construction works.

bolonborgmueller“Developing the framework of tomorrows Energy Management and eMobility takes a unified approach, and this is exactly what I witnessed at the EEBus PlugFest. Players from various segments coming together to engineer this common infrastructure to the benefit of everyone, not least of which the consumer!”

Bo Lonborg Mueller

Impressions of the second plugfest e-mobility

Read more

The press release on the second e-mobility Plugfest can be found here.

1Investigation by the German National Platform for Electric Mobility, as of September 2017. 

0.00 avg. rating (0% score) - 0 votes

The pressure to reduce carbon dioxide emissions and the prospect of a world running largely on renewable electricity has sent research and development teams in every sector back to their respective drawing boards to look at options that might exist for electrification. Perhaps the most challenging sector is aviation, where liquid hydrocarbon fuels are the only form of energy carrier available (mainly of fossil origin, but with some bio-origin fuels now appearing). The dependency on hydrocarbons is due to their high energy density and the challenge with fuel to weight ratio that planes have. However, fuel costs can represent up to 70% of total costs for an airline, so the business model tends to focus on efficiency as a primary consideration. Efficiency isn’t just about the plane itself, but about maximising passenger load, minimising extraneous weight, limiting taxiing and air traffic delays, using electricity for power at departure gates and optimising routes.

In the light of all the above, the idea of electrification in aviation is tantalizing, but there is little sight of this happening. At one end of the spectrum there is the prospect of single person electric drone taxis for short hops in cities, but after that there is nothing, until last week. EasyJet, in conjunction with the startup, Wright Electric, announced that they hoped to be flying a short-haul battery electric passenger plane within a decade.


The concept illustration looks impressive, but is this really feasible? Battery energy density is a key determinant and it is moving rapidly in the right direction. The energy density difference between the traditional Lead-Acid battery, still the standard for starting most cars and the best lithium based batteries is nearing a factor of 10, but lithium based batteries are still a long way from Jet A1 fuel as shown in the table below. The difference in energy density on a weight basis is around twenty times, in favour of Jet A1.

Jet A1 Current Li-Ion Battery Emerging Li-Metal batteries
Energy MJ/kilogram   42.8   ~0.7   1.8
Energy MJ/litre   37.4   ~2.0   4.3

Like an electric car, the efficiency of a battery electric aeroplane would be significantly higher than the combustion engine equivalent, although the starting point for a modern jet engine already exceeds that of vehicles. The chart below (IPCC Report on Aviation 1999, chart from 1991) shows that overall efficiency of jet aircraft falls in the range 20-40%, but significant improvements have been made since then. A modern Boeing 787 would show an overall efficiency approaching 50% on the same chart.

Jet Engine Efficiency

Even with near 100% efficiency for the battery electric aeroplane, the energy density of Jet A1 still gives that fuel a factor of ten advantage. As such, it will be distance that suffers, given there is a weight restriction for aeroplanes.

I am a regular traveler out of London City Airport and often see the Embraer 190 plane, which is similar in size to the easyJet concept photograph distributed with their announcement. But the Embraer 190 has a range of over 4,500 km, so one tenth of this gets near to the 335 mile range goal mentioned by easyJet, ideal for the flight I often take from London City to Rotterdam. So on paper, this would appear to work, but a plane with a range limit of a few hundred miles might significantly restrict the operational flexibility that airlines enjoy; for example, it couldn’t be swapped at short notice for a London City to Rome flight, should that be necessary.

Battery electric planes also bring with them a particular design change – apart from the obvious. Currently, planes land some 20% lighter than they take off, as they burn the fuel. With battery electric planes, they will land heavier than they take off, because the discharge of the battery means oxidation, meaning it gains mass. This will require very different landing gear.

Another facet of the EasyJet announcement is the desire to see these planes carrying passengers within 10 years. Given that the plane is concept only and doesn’t come from an existing family of similar planes, this may be ambitious. The 787 Dreamliner was announced in concept by Boeing in early 2003, finally receiving certification in late 2011. That’s nearly nine years for what is essentially a new version of an existing product, albeit with some significant changes such as the use of carbon fibre in the fuselage. But the 787 then had problems with its battery system for on-board electronics, leading to a temporary grounding and eventual regular flights from April 2013.

The 787 was not Boeing’s first attempt at a new aircraft following the 777 series. In the late 1990s it started development of the Sonic Cruiser, releasing a concept proposal in March 2001. With aviation business models changing rapidly at that time, Boeing abandoned this concept and instead moved to the 787, but this evolutionary process still consumed valuable design years. At least from one perspective, it could be argued that the 787 took over 13 years to go from concept to regular use.

The Wright Electric concept represents a revolutionary change in aircraft design and propulsion, so there is every chance that this may take longer than anticipated to get going. It will require extensive certification and testing by airlines, airports and the aviation authorities and may go through more than one design iteration, depending in part on the evolution of battery technology and the resultant changes in energy to weight and volume ratios. The story of the Mitsubishi Regional Jet is outlined here, and is a saga of changes and delays spanning 17 years. It is a conventional jet aircraft, but represents a first for Mitsubishi for a very long time.

A further ambitious aspect of this project is the notion that a start-up can take on the likes of Boeing and Airbus and find the necessary investors to back what is typically a multi-billion dollar investment in design, engineering, prototype development, manufacturing, testing and certification of a new aeroplane.

Behind all this is the pressing need for electrification across society, so this type of thinking and risk taking is essential. The question that remains though, is whether I will be able to ride in such a plane from London City Airport before 2030.

This screencast demonstrates how to make the Sunny Island ready for operation for self-consumption systems on the utility grid in only eight steps. Thanks to the integrated web interface, commissioning can be performed easily using a smartphone, tablet or PC. Jan Rössler, trainer at the SMA Solar Academy, provides handy tips and tricks on the settings required for storage systems on the utility grid.

[embedded content]

0.00 avg. rating (0% score) - 0 votes


SolarQuarter Tweets

Follow Us For Latest Tweets

SolarQuarter Announcing Solar Power Developers Night, Register Now, 5 Dec, Mumbai -
Friday, 17 November 2017 11:18
SolarQuarter Announcing Solar Power Developers Night, Register Now, 5 Dec, Mumbai -
Friday, 17 November 2017 11:07
SolarQuarter SolarQuarter Mobile APP Launched, Download Now -
Thursday, 16 November 2017 09:14