Solar Microgrids and Battery Storage

Achieving electricity cost reductions through energy storage

Achieving electricity cost reductions through energy storage: what Business needs to know

Energy storage represents the major opportunity for the electricity sector, as affordable energy storage promises to solve the intermittency issues that occur with cheap renewable power such as solar PV and wind energy. Over the past few years, rapid declines in the cost of energy storage technologies, such as lithium-ion batteries, have made the topic of energy storage enter mainstream conversations. However, does energy storage as it currently stands translate into cost savings for business? 

From electric vehicles to large-scale utility batteries: the global market context

The popularity of electric vehicle (EV) technology in many ways has facilitated rapid growth in the energy storage services market, driving down the costs of Lithium-ion batteries and associated technology. Daniel Goldstuck, head of Energy Storage and Microgrid Services at SOLA, believes that the progression of storage products and services can be clearly seen in the increasing presence of battery suppliers and other industry service providers at conferences, who tout their ability to provide reliable, high-tech solutions to intermittency battles. In addition, the mushrooming of utility-scale battery programmes globally indicates that interest in energy storage is entering the large-scale energy services market, leading potential clients to see energy storage as a potential solution to some of their needs. “The procurement of large-scale transmission assets ‘in front of the meter’ shows that utilities are starting to use energy storage to provide a number of services, including frequency response, renewables smoothing, and transmission deferral,” Goldstuck asserts. 

The uptake of such solutions is expanding globally. California, for example, has over 1 GW of storage solutions installed, and the state also provides rebates for residential storage systems. In Africa, Microgrids that combine energy-storage technology with clean energy generation are lauded for their ability to provide stable power to communities with weak or no grid access. Pico-grids, or home solar kits, are also increasingly seen as ways to assist rural homesteads and villages with electricity provision. 

However, the application of microgrids and energy storage solutions do not only apply to rural and utility scale efforts, but also to the large segment of commercial and industrial energy consumers in between. Rurally-located mining operations, for example, can benefit from energy storage applications that link to cheap and reliable renewables, moving operations to electricity that is less cost- and carbon- intensive than diesel.

storage and solar PV: a perfect match

Solar PV is the cheapest form of energy in most countries globally. This is because it is solar power is an abundant renewable resource, the technology to harness it is relatively cheap to install, and it lasts for 20-plus years. However, solar PV is most abundant in the middle of the day, and starts to wane during “peak” energy hours such as early morning and evening. When combined with energy storage, the abundant, cheap electricity generated by the sun during midday can be stored and deployed during these peak usage times. Because storage is also programmable, it can be deployed when most needed – preventing wastage and increasing the economic value of each kWh stored. 

However, this programmable aspect of microgrids also make them more expensive than the typical grid-tied solar PV facility. “Solar PV and storage microgrids need to function seamlessly, so that power is not interrupted, and battery life needs to be managed carefully in order to ensure their longevity. This takes quite specific and extensive engineering to get right,” Goldstuck adds. 

Issues such as cycling the battery every day can affect the warranty of the product, depending on the type of battery and warranty arrangement. Energy throughput of the battery has the largest impact on the life of the battery, and therefore the warranty. Unlike solar modules that have a 25 year lifespan and relatively low operations and maintenance requirements, batteries need to be very carefully sized and configured, taking into account things like days with low-irradiance or cloud cover, where batteries may be put under pressure.

Although renewables and energy storage solutions are a perfect combination in a world headed towards increased renewables, the above factors mean that at the moment, the combination of solar PV and batteries into microgrids is more costly than straight grid-tied solar PV.

When does storage make sense economically?

However, the business case for storage and microgrid solutions is very clear for certain business sectors. “Rurally located agro-processing units such as medicinal cannabis farms are particularly well-positioned to make use of renewable energy storage microgrids,” contends Goldstuck. “They require consistent, large amounts of reliable electricity in order to power greenhouses and other farming equipment – yet are often situated on constrained grid networks and may rely heavily on diesel to run effectively,” he adds.

Diesel is expensive, both monetarily and environmentally, and yet diesel generators are widely used to power remote facilities. Diesel generators have even been used in South Africa to maintain the grid supply whilst there was constraint to major power stations. And despite energy storage solutions still being pricier than solar PV, diesel is still more expensive than the combination of both. Given that diesel is so expensive, the business case for implementing a clean-energy microgrid is particularly good  in relation to diesel saved.  

In contrast, storage for grid-tied facilities seeking a tariff-optimization solution generally requires closer analysis to determine the business case. “In South Africa, only a few tariff structures are currently at the price point to justify adding a storage asset. This is rapidly changing as the cost of storage decreases, and the costs of centralised electricity supply increases,” adds Goldstuck.

Energy storage economics cheat sheet

As a rule of thumb, energy storage microgrid solutions will make economic sense if they prevent at least 30% of the facility’s current or proposed diesel usage. Such cases are typically:

  1. Facilities on a weak or constrained grid network that need additional power to function
  2. Facilities without electricity grid access
  3. Facilities requiring consistent power that the grid is not able to provide for at least 30% of the time. 

Based on the above criteria, the following industries lend themselves particularly well to solar PV and energy storage microgrids:

  1. Islands without electricity grid access, or where the grid itself is powered by diesel (such as Robben Island)
  2. Game lodges or hotels that do not have access to the grid
  3. Large developments in rural settings that require more power than the grid can provide (such as the Cedar Mill Mall development)
  4. Mining operations situated remotely
  5. Farms that have extensive greenhousing requirements such as Medicinal Cannabis facilities 
  6. On-grid buildings experiencing outages for more than 30% of the time.

In conclusion, Goldstuck admits that there is a long way to go before large-scale energy storage solutions can be broadly implemented. However, he remains optimistic. “We’re just scratching the surface of what’s possible in terms of storing the abundant renewable resources we have available. In the years to come, energy storage solutions will become widespread options for commercial and industrial facilities”.

Solar Microgrids and Battery Storage

Aries utility solar PPA in South Africa

Electricity in SA seems bleak, but it’s loaded with opportunity.

Originally published on LinkedIn

What the Eskom’s current state of nation-wide load shedding and their 15% tariff increase appeals are teaching us, it is that the fate of South African industry is tied fundamentally to the availability of stable and affordable electricity supply. The sustainability of the utility requires brave, informed and decisive leadership: but it is possible.

We’re in a landmark year that will determine not only the fate of Eskom, but South Africa more broadly. In May, the country will vote on whether to extend the term of the ruling party in a an uncertain global market.  The ANC’s latest manifesto has clear intentions around energy: more renewables, more private partnerships (IPPs), repositioning Eskom and ensuring fair treatment of South Africans as part of a Just energy transition. It also plans to integrate solar PV in state buildings and new developments.

This year, we’re looking at a year of continued change in a sector that badly needs a modern restructure.

Arriving at today’s energy market

In South Africa, 2018 held much in the way of energy sector developments. The renewables-vs-nuclear stalemate came to an end with new energy minister Jeff Radebe signing 27 long overdue renewables projects. Eskom’s mismanagement was placed under the spotlight and a new CEO, Phakamani Hadebe, was appointed in May. In August, the much-awaited draft Integrated Resource Plan (IRP) was released, showing favour toward renewables and gas and less coal and nuclear. Why the sudden change in South Africa’s energy landscape after years of stagnation?

One answer is that South Africa has started to take heed of global trends toward renewable energy. This is not simply a fad: the upsurge in solar PV technology, in particular, is part of a global market context. According to the Global Market Outlook report for solar energy, solar PV accounted for nearly 40% of all new generation technology during 2017: more than any other power generation technology. This was mostly driven by China, US and Japan, whose overall manufacturing influence also drove the costs of solar modules to record lows. It is undisputable that Solar PV’s cost per unit is now cheapest in the world by a significant margin.  Even more growth is expected in coming years.

The challenges for the energy landscape

Back in South Africa, Eskom has a major debt-service problem on its existing assets. The assets aren’t able to cover their own costs at Eskom’s current tariff rate, which is why they are asking for 45% increase over the next 3 years when inflation is just 5% p.a. Put another way, these assets are worth less than the R420Bn of debt that Eskom borrowed when building them in the first place.This is the primary cause of  Eskom’s death spiral.

The challenge for Eskom, and South Africa, remains that a different electricity path is cheaper. The cold numbers show that the lowest cost model is renewable energy and gas, with no new nuclear builds and limited further coal. This has brought up some valid social issues around transformation and the displacement of employment. These issues are important and need to be tackled head on, they also need to be seen in the light of education, upskilling, entrepreneurship and opportunity.

The opportunities for the energy landscape

The energy minister has recently said that the IRP will be signed off in mid-February.  The IRP draft, combined with the ANC’s policy manifesto, does show willingness to dissolve the electricity monopoly, bring private players into the market, reduce the costs of electricity and stimulate the economy, allowing the government to focus on the key areas of the country that need it most.

The President’s recent announcement of his intent to divide Eskom into separate Generation, Transmission and Distribution entities is not only in line with global trends, but it will also ringfence Eskom’s unprofitable generation assets from affecting its profitable grid infrastructure, which is crucial to our country’s stability as an economic entity.  It is hard to know the series of actions that will follow, but we can be sure that it will be done sensitively in an election year.

We’re already seeing large users of electricity investing in their own power consumption, and when the IRP is released, we’ll see generation licenses starting to be awarded to private embedded generators.  Most of this is, and will be in future, solar PV due to the ease of implementation and abundance of solar resource in South Africa. However, there will also be some cogeneration and biowaste projects too.  These steps are very positive, as they set the stage of a socialised electricity grid with multiple power sources, allowing the most affordable energy to be available to South African industry and encouraging economic growth.

The Future is Bright

We have an extraordinary opportunity for electricity reform in South Africa.  If our renewable resources are harnessed, we not only have 20 years of upskilling and job creation, but with our natural resources we could have, sustainably, the cheapest electricity in the world. If we get the structure right, and manage the transition in the best interests of all of our people, it will be a positive boon for South Africa’s economy. This is a major task, but if achieved, we have a lot to look forward to.

A reflection on South Africa’s energy landscape in 2018

South Africa’s renewable energy sector received a new lease on life in 2018, after years of uncertainty and lack of movement.

With the Ramaphosa government signing nearly R56 billion worth in contracts with 27 independent renewable energy producers during 2018, the way forward, notwithstanding legislative and business challenges, is looking much brighter.

Significant progress has been made in the private sector in adopting renewable energy as a viable and consistent energy supply, often beating the costs of Eskom-supplied power.

We believe that more businesses will make use of renewable energy sources either to supplement their power, or for their primary electricity supply, as batteries and solar PV costs continue to fall.

Robben Island is saving millions of rands on its electricity bill though its microgrid. Earlier this year, Cedar Mill Mall in Clanwilliam opened its doors after Eskom told the developers it could not provide the power needed to supply the large building. These project show that despite inertia and a struggling economy, South African business can still benefit from renewable energy.

Uptake is particularly impressive in the retail sector, with malls catching on to the value of solar to produce low cost power during their busiest hours of operations. Ilse Swanepoel, Head of Utilities at Redefine Properties, whose solar PV fleet produces about 35 754 600 kWh per annum, stated “Solar is no longer niche and is a well-entrenched renewable energy source underpinning the achievement of green-building goals. Demand has grown in recent years, with many large blue chip tenants prioritising their own sustainability efforts, expecting the developer to dovetail and help achieve their objectives.”

This is encouraging. However, uptake in renewable energy should not just be supported by the private sector. For the economy to benefit from renewable energy’s reduced costs, the contracts signed by the government with the 27 independent renewable energy producers must translate into action that is sustainable, consistent and measurable.

Independent Power Producers (IPPs) have reportedly created 35 702 jobs and have spent R766 million on education, health, social welfare and enterprise development, according to figures provided by the ministry.

I’m optimistic about the renewable energy sector, given the government’s willingness in 2018 to acknowledge and engage with alternative energy suppliers, which were on hold for several years. REIPPP’s Round 5 is crucial in terms of accelerating the government’s transformation plan as it is set to bring about higher levels of transformation, localisation and community upliftment requirements.

In addition to this, the successful implementation of the Small IPP programme, aimed at smaller scale projects with a focus on SMMEs, high black ownership and local supply chains is exactly what the renewable sector needs. Going forward, we will need to work closer with all role-players as we better understand the sector and its ability to grow and develop South Africa.

Solar will be a boost for SA's economy

One of the most significant documents is the government’s draft Integrated Resource Plan (IRP), which outlines the way for South Africa to meet its growing national electricity demands by 2030.

The IRP was released for public comment in August. The construction industry (with its high electricity costs it incurs) has already welcomed the IRP, with some saying it could revive the industry. It has also been praised for its proposed increased allocation to renewable energy and the phasing out of coal and the pursuit of the ‘least cost option’ which rules out nuclear at least until 2030.

However, the IRP still lacks in clarity and allocation for embedded generation – which is one of the fastest growing energy sources and key to reducing corporate energy costs. A future-facing IRP takes into account not only the cheapest form of energy, but also the changes in the energy environmental happening globally. Coal-based, heavily centralised energy systems are fast becoming redundant with the introduction of smarter technology.

South Africa is no exception in this picture, with state utility Eskom plagued with difficulties in 2018. Still, Nersa’s (National Energy Regulator of South Africa) announcement giving Eskom the go-ahead to recover R32.7 billion (already approved as part of its adjudication of three separate Regulatory Clearing Accounts), will result in further tariff increases.

Embattled state utility Eskom

This will encourage businesses to look at alternative, consistent and cheaper forms of electricity – resulting in less income for Eskom and municipalities that rely on selling power through their grid.

Nersa continues to agree to Eskom’s requests for increasing tariffs. The embattled parastatal has again asked the regulator to push up tariffs – this time a 15% tariff increase per year over three years – this is on top of a 4.41% price increase Nersa has already granted Eskom. This proves to be one of the many reasons why a balanced energy mix should be put in place.

Another piece of legislation crucial to the sector is the so-called Carbon Tax (revised Draft Regulation on the Carbon offset), which Treasury published on 12 November for a second round of public comment.

Small and medium-scale renewable energy projects with a generating capacity of up to 50MW have been listed by Treasury as eligible for carbon offsets, but Nersa’s regulations might hinder national uptake.

Renewable energy trading, embedded generation and renewable IPPs needs to be supported by South Africans. Renewable energy solutions have the potential to jumpstart our economy; legislation is a step in the right direction. It will be interesting to see how the energy sector will develop in 2019.

solar could help Africa's economy to grow

Going wire-free in Africa: Two examples

Our last blog post focused on how microgrids in Africa can enable electrification in rural communities to encourage economic prosperity without the need of centralised grid infrastructure. This blog explores two examples that SOLA Future Energy has designed, engineered and built – and how these might be replicated in African communities.

Robben Island – an isolated microgrid

Robben Island’s state-of-the-art microgrid is the largest combined solar and lithium-ion storage facility in South Africa. The microgrid, consisting of a combined solar PV facility and a battery bank, has enabled the island to move away from its diesel generators. Since adopting this green energy system, the island has already produced 650 000 kWh of solar energy – an average of 3250 kwh per day – which has significantly reduced its reliance on traditional diesel generators, a noisy and expensive feature of the energy system.

In the past, diesel had to be transported by ship from the mainland to fuel the diesel generators. The island’s load is primarily occupied by a desalination plant and to provide power for the 100 residents who live on the island. The cost of purchasing and transporting the diesel formed a substantial portion of the island’s operating budget. Over and above the financial considerations, the noise and dust emanating from the generators were not creating a tourist-friendly environment.

Robben island is now powered by the sun
Cedar Mill Mall – solar and batteries enabling development

Robben Island is a perfect example of how microgrids can provide electricity supply in rural contexts that are isolated from electricity grids. However, even grid-connected businesses can benefit from microgrid technology.

This is exactly why Noble Property Fund, developers of Cedar Mill shopping centre in Clanwilliam, a rural town in the Cederberg region of the Western Cape in South Africa, approached SOLA Future Energy to help with their power supply needs. Initially, the developers had applied for a 500 kVA connection from Eskom to power the facility, but the parastatal was only able to approve half of their demand requirements due to local constraints to the grid.

Faced with a major supply shortage, the developers were forced to consider utilising noisy and expensive diesel generators to make up the shortfall. As an alternative, SOLA suggested the use of solar PV and batteries to make up for the shortage, and has subsequently been appointed to integrate a microgrid into the shopping centre. Consisting of a 851kWp solar PV system with a 700kWh lithium ion battery, the microgrid makes up for the power shortfall – allowing the mall’s development to continue.  

“Incorporating a microgrid into the shopping centre turned out to be a financially attractive solution when considering how much energy could be harvested and stored from solar PV,” said Mario Dos Reis, director of Leasing at Noble Property Fund. “The shopping centre will be a blessing for small business owners in the town looking for an accessible and safe location to trade”.

As such, although the mall already had grid connection, the solar PV microgrid enabled the building of the mall to go ahead. This mall will become an economic hub of activity in the mostly rural region, providing jobs and economic spinoffs to the local community. The cost-savings of the building owners will trickle down to tenants, and hopefully make businesses more profitable as a result.

Cedar Mill Mall goes solar

Entasopia Kenya, powered by solar microgrid

Microgrids in Africa: rethinking the centralised electricity grid

Think about it: just two decades ago, many African towns were barely accessible because of the lack of telephone line infrastructure to key development areas. Today, cellular technology has allowed communications to leapfrog telephone line technology and provide communications without expensive, centralised infrastructure.

Mobile technology in Africa

A similar argument can be made about electricity. Now that both solar PV and battery costs have reduced significantly, microgrid technology promises to be an opportunity for Africa to leapfrog traditional grid-based electricity – a typically fossil-fuel heavy, centralised mode of providing power. 

Africa is a uniquely positioned continent, because of its widely-dispersed nodes of development over large geographic areas. As a result of this, the costs of building electrical infrastructure over geographically large areas have typically inhibited electrification, leaving large parts of African countries without electricity – in fact, Africa remains the least electrified continent in the world with only 35% of the continent having access to electricity.

Much of Africa remains disconnected from electricity grids

Microgrid technology is inherently decentralised, as it operates as a smart grid on its own, smaller scale, often using wireless technology. A cornerstone of microgrid technology is solar PV and batteries, since they are deployable in decentralised areas and do not require massive infrastructure to function. Combined, microgrids would seem to carry immense potential for Africa.

Despite this, a report published on PV magazine found that only 1% of electricity investment in the 20 least electrified countries was spent on decentralised energy production, despite at least 40% of electrification being suitable for microgrid deployment in these countries. This presents a massive opportunity – both for the unelectrified communities, as well as for electricity developers in Africa. Microgrids could be a sustainable – and affordable – solution for energy access in Africa.

But are microgrids proven to work? Take an example of Entasopia, a small village in the south of Kenya. The village, disconnected from Kenya’s national electricity grid, is supplied power by a small solar PV microgrid.  This microgrid enables 60 homes, small businesses, and even a petrol station to run, making the area a hive of economic activity and enabling growth even in the remote area. With this technology, schools and clinics can access electricity and businesses can sprout up, enabling economic empowerment in previously isolated areas.

Entasopia Kenya, powered by solar microgrid

Entasopia, Kenya, powered by solar microgrid

The Robben Island solar PV microgrid is also a great example of converting an existing diesel generation system to a smart PV and battery coupled microgrid. Even though the island was already supplied by diesel generators, the cost of diesel meant that the addition of solar PV and batteries still made perfect business sense – it’ll pay itself back in about 5 years. The island’s activities – including the bustling harbour and desalination plant – are now powered almost entirely by clean energy, and the ecologically sensitive island is no longer affected by the diesel and noise emissions from the generators.

Robben Island solar PV microgrid

Robben Island solar PV microgrid

The fact that microgrids make business sense not only for completely disconnected communities but also for those with existing, fossil-heavy grids (such as Robben Island) show demonstrable effectiveness for further applications – such as mining. Mining activities can now rely on PV and battery coupled microgrids, where previously they relied on diesel generation. These microgrids provide a solution that can not only save mining operations money, but also reduce the environmental impact of the mining activity.

SOLA Future Energy is a proudly African company, and we believe in the potential that affordable, clean energy can bring for the whole continent. Despite its historically slower economic growth, we believe that Africa is in a unique position now, particularly because of the way in which new technologies can assist the continent to spur development. Get in touch with us to find out how microgrids could assist your business or community.

Langeberg Mall - Mossel Bay

Reflections on the last 5 years of solar PV

Over the last five years, solar PV has moved from a peripheral energy option to the fastest growing energy source in the world, and is predicted to stay that way. What has changed over the last five years, and what does the future look like?

LCOE: then and now

The debate around adopting solar PV, in 2013, remained largely around cost. Although already starting to look competitive, solar PV’s merit still needed to be largely proven and accepted – as argued Bloomberg New Energy Finance’s paper on PV economics.  During 2011, for example, solar PV development stood at 28.5 GW, ten times as much as ten years earlier.In 2013, investing in solar still seemed somewhat risky – even though predictions were that it would become cheaper and more reliable than ever before. It’s potential and appeal as a renewable energy source (with no moving parts or emissions during generation) however, was widely acknowledged.

Fast-forward 5 years, we see a very different picture. According to a study by the International Renewable Energy Agency in 2018, renewable LCOE was the same cost, and at times significantly lower, than fossil-based generation – and the prices are predicted to drop even further. In fact, costs came so low that even with the optimistic predictions in 2012, they were inconceivable – the renewables market outperformed its predictors. It is now widely accepted that solar PV remains one of the cheapest forms of energy available.

Global investment in solar PV - BNEF

Source: Bloomberg New Energy Finance

From REIPPP to Rooftop: the South African market

In 2013, government had received its second round of IPP submissions as part of its world-renowned REIPPP programme. It’s competitive auction model meant that Independent Power Producers (IPPs) needed to be competitive to win projects – and it was hailed as one of the most successful public-private partnerships. In just the first round of submissions in 2012, the cost of solar PV dropped by 40%. In each successive round, the costs dropped further.

Unfortunately, due to state-utility mismanagement and state capture, Eskom’s blatant rejection of this perfectly set up procurement mechanism meant that the IPPs have all but died out. The REIPPP programme was halted, and its fate is yet to be seen (although recent political developments indicate that it will hopefully come back online – at least for the final round of projects).

Nevertheless, what the REIPPP programme did was bring the efficacy of renewables into the public eye – and into the eyes of business and property owners, who prized affordable, clean energy over the uncertainty of Eskom’s intermittent supply and tariff hikes. During 2016, it was estimated that  80 MW solar PV was installed on rooftop projects in South Africa, a figure 10 times higher than 5 years before.

When storage became a real player

5 years ago, although energy storage was part of the conversation, it certainly wasn’t centre stage. Market efforts remained on improving LCOE for solar PV, and storage technology was relatively new and less developed. In fact, despite the fact that storage frequently came up in energy conversations, it was still touted as too expensive to have any long term, significant impact. Even the overall efficacy of solar PV was questioned because of “the storage problem”.

Robben Island battery bank

Lithium-ion batteries store excess solar PV at Robben Island Microgrid

The picture today is different – storage is a topic not only central to conversations about solar PV, but is viewed as less of a problem and more of an opportunity. Indeed the price of lithium-ion storage dropped by 24% in 2017 alone, and we’ve seen the first energy-storage conference in Africa take place at the end of 2017.  Batteries and storage solutions now provide exciting opportunities for linking renewables to grid, peak-shaving and grid-flexibility.

Participants in the first energy storage conference in SA hosted by EE Publishers

Participants in South Africa’s first Energy storage conference. Source: EE publishers

We saw, ourselves, the immense power of storage through our Robben Island solar PV microgrid project. The microgrid now enables Robben Island to save on diesel fuel costs, whilst providing a superior and uninterrupted energy supply for the entire island. In fact, the potential of batteries to supplement both off-grid and grid-connected solutions is, I believe, one of the key areas we will see energy storage deployed in the coming years.

In conclusion

Over the past 5 years we have seen solar PV take centre stage as one of the most affordable, reliable and deployable forms of energy in the world. The expansion of the rooftop market – particularly in South Africa – has meant that businesses can benefit from clean, cheaper energy now more than ever before. Added to this, the development and accessibility of storage solutions now means that completely off-grid, or supplemented grid options, are now available. These developments have taken place  rapidly, and continue to change the face of available energy options in the world. It will be exciting to see what the market brings in the next 5 years.

Dr Dom Wills is the CEO of SOLA Future Energy. The company is 5 years old on the 5 March 2018.

Robben Island battery bank

Robben Island’s 666.4 kW solar PV and battery storage microgrid

Last week, the Minister of Tourism opened the Robben Island solar PV microgrid, designed and constructed by SOLA Future Energy. This system, incorporating one of the southern Hemisphere’s largest battery banks, is made of 1960 mono crystalline solar modules, ready to produce 666.4 kW of power and 2420 lithium-ion battery cells, able to store 837 kWh worth of electricity and supply 500 kW worth of peak power.

Designing a smart grid

SOLA Future Energy designed Robben Island’s Microgrid over the course of two months. Designing the PV plant incorporated several phases, including the replacement of a mini-substation to adequately incorporate PV into Robben Island’s existing grid, designing of the ground-mounted solar farm and placement, the battery bank and controls.

Phase 1 – Understanding the island’s energy requirements and solar resource

Robben Island Tourism - Robben Island Solar PV System

Robben Island attracts thousands of tourists each day

The first phase of the designing a solar PV microgrid was to understand the energy requirements of the island – and what solar resource is available. With thousands of tourists visiting Robben Island each day, as well as 100 staff living permanently on the island, a lighthouse and a desalination plant, the island’s energy requirements are quite significant. Understanding these requirements was the first phase to knowing what type and size of system to design.

Typically, when designing rooftop solar systems, it is important to consider shading from other buildings or large trees, but with Robben Island’s placement and shrubby vegetation, the solar resource is excellent and relatively undisturbed. In addition, the ability to place the modules at a fixed-tilt axis in a north facing area, made them ideal for solar penetration, right into the late afternoon.

Phase 2 – Understanding the existing grid and how to incorporate into it

robben island solar power supply

Robben Island power supply was traditionally provided by diesel generators. Last week, the Island officially announced it’s conversion to solar energy

Solar PV usually powers a building directly by turning its Direct Current electricity (DC) into Alternating Current electricity (AC), through solar inverters. This power is usually supplied in 400kV size, which is the power that typically supplies plug-points and electric outlets in buildings. However, incorporating into an energy grid requires a different kind of connection.

Robben Island’s energy grid runs off of a historically-erected 11kV line. In order to incorporate the PV system into the island’s grid (as opposed to, for example, a single building), a mini-substation needed to be designed and built in order to convert the PV plant’s supply of 400 kV to the grid’s 11kV. This substation replaced one of the island’s existing, but too small, substations. Once erected, it allowed the PV farm to feed into the island’s grid.

Phase 3 – Modelling and simulating the PV and battery resource

Microgrid performance on Robben Island Solar Microgrid

Data insight helps to monitor the microgrid’s performance

Once the solar farm was designed, based on the energy needs of the island, the design needed to incorporate the battery system to store excess solar power, taking into account the scope of the project. The battery bank is made up of 2420 lithium-ion battery cells. Like cell phone or laptop batteries, lithium-ion batteries have a long life and have a higher threshold to discharge and charge with larger power. Unlike their lead acid counterparts, lithium-ion batteries can use up to 96% of their capacity, making them a highly efficient choice to support the longevity of the solar PV farm, which will last over 25 years.

A large part of designing the battery system to incorporate fully with PV is the programming of the actual microgrid. The programming consists of scheduling the generators to switch off when the batteries reach 30% State of Charge (SOC). When the batteries reach 15% SOC, the generators are scheduled to switch on, making sure that there is a continuous source of power on the island. The wireless system between the three different components allows the batteries to “talk” to the PV. This decision-making ability, and intelligent control in each device, makes the microgrid a smart grid that ensures seamless power to the island.

Helping not only the efficiency, but the quality, of energy supply

Diesel generators on Robben Island Solar System

Diesel generators to provide energy when battery bank is depleted

One of the unexpected outcomes for Robben Island is a better quality energy supply for the island’s operations. Previously, the quality of supply had peaks and troughs, meaning that equipment could be affected by unbalanced supply. However, the new battery inverters are able to stabilise the grid, making the power better quality overall, and in turn affect equipment and machinery less.

Although the microgrid contains diesel generators, the Robben Island microgrid is unique because it does not rely on the diesel generators to function. Usually, solar PV works by attaching to an existing grid – or diesel generators. However, with a special inverter, the microgrid contains a virtual generator machine (VGM), which allows the PV to run without any generators at all.

Robben Island Solar Energy Microgrid Infographic

In conclusion

SOLA Future Energy has carried out the design and construction over the last year and a half on Robben Island. Although the design of the system took about two months of non-stop design time, there were several other considerations in working on the World Heritage Site. The video of the Robben Island Solar Project tells the story of the island’s symbolic transformation and its relevance as a microcosm of South Africa. The future of Africa is powered by the sun, and we’re there to make it happen.

Robben Island Tourism

Video clip shows the transformation of Robben Island into a beacon of hope

When SOLA found out that they had won the contract to build a solar PV microgrid on Robben Island, commissioned by the National Department of Tourism, they were determined to spread the story of the project far and wide. With the help of video-experts Lima Bean, they created a short film that tells the story of Robben Island’s transformation.

A perfect set for a transformation story

Robben Island is known for many things, but particularly for being world heritage site on the tip of South Africa, and “a symbol of the triumph of the human spirit over adversity”. It is also known for its beautiful, stark scenery and ecological diversity. Yet the island still requires energy – the ongoing tourism, desalination plant, and local community use 2 million kWh per year. This power was historically supplied only by diesel generators, but since July 2017, is being supplied by the sun. It is the perfect setting for a story of transformation and hope.

Robben Island solar PV microgrid

Robben Island solar PV microgrid

A symbolic transformation

“We wanted to show that Robben Island is a great example of how a difficult historical context does not prevent a brighter future,” said James Bisset, the short film’s director. A key component to the symbolic side of the story was the input from Vusumzi Mcongo, an ex-political prisoner who arrived on Robben Island in 1978. Now 63 years old, Mr Mcongo still lives on Robben Island, and works in the Robben Island Museum, taking tours through the prison. “I have a passion for this place,” he states.

As someone who not only works, but also lives on the island, Mr Mcongo is part of the new energy story: he is part of Robben Island’s transformation from old power to the new, and will benefit from the new system. Robben Island has a difficult history – one of banishment and imprisonment – but, like Mr Mcongo, the future of the island is one of hope rather than pain.

“Telling the story of the Robben Island Microgrid was very important to us,” SOLA CEO Dom Wills stated. “The transformation of Robben Island is symbolic: it shows that there is hope and inspiration for South Africa and potential for innovation in the future. We want South Africa and the region to see that affordable, clean energy is here today.”

Robben Island Tourism

Robben Island attracts thousands of tourists each day

Solar PV and batteries: the future of energy

The Robben Island solar PV microgrid is a story of hope because of the technological innovation at its core. Solar energy uses the sun’s power to create electricity. Traditionally, solar PV works during the day and requires additional power sources at night, when the sun doesn’t shine. However, with the strides in battery technology over the last few years, battery storage has huge potential to change the game and make solar a viable option for going completely off-grid.

The Robben Island solar microgrid is an example of such a game-changer. The generators on the island historically used an expensive and fossil resource, diesel, which was shipped to the island in order to generate the electricity required. The new solar microgrid stores the excess energy created by the sun in the middle of the day in lithium ion batteries, powering the island well into the night. By the time the generators kick in, the consumption of the energy is low, and ultimately Robben Island can significantly reduce its reliance on diesel, even during the winter months.

Robben Island solar PV construction

Construction of the Robben Island solar PV farm

Partnerships make the video possible

Suppliers to the project partnered with SOLA and Lima Bean to make the creation of the video story possible. ABB, the inverter supplier to the project, and Canadian Solar, who supplied the solar modules, were both key partners in enabling the video to take place. “Making a video like this is not cheap, and we were grateful for the support of our partners to make the video possible,” said Dom Wills.

The Robben Island solar microgrid shows the power of solar PV and batteries

It has been almost a year and a half since the Robben Island Solar Microgrid project was awarded to SOLA Future Energy. After a thorough process of designing, planning and implementing, the project has been launched – and is a demonstration of how solar PV, combined with batteries, can make an excellent combination. This blog post describes just why the solar microgrid is so effective, and how the rest of South Africa can follow suit.

A microgrid on a historic monument

Many people know Robben Island for its reputation as the prison that held several high-profile political prisoners such as Walter Sisulu, Ahmed Kathrada and Nelson Mandela. Over the years, the island has also been a leper colony and a host site of WW2 garrisons. The island, therefore, has a rich political history – one which draws the thousands of tourists to its shores daily.

In addition to the historical significance, Robben island is also a biodiversity hotspot, with several bird species finding refuge and breeding grounds on the rocky shore. The African jackass penguin – an endangered bird found only on the southern coast of Africa – also calls the island home.

Robben Island Solar Microgrid protects islands biological diversity - Penguins

Robben Island is a world heritage site with biological diversity

Energy to Robben Island has historically been supplied by diesel generators. To fulfil the energy requirements of the island, around 600 000 litres of diesel were consumed on an annual basis – at great cost to the island’s administration, and at great cost to the sensitive environment on the island.

The solar microgrid was commissioned by the National Department of Tourism in order to promote sustainable tourism at key monuments around South Africa, as part of their Tourism Incentive Programme. The microgrid, consisting of a 666.4 kW solar farm, 837 kW powerstore and multiple controllers, will move the island away from its reliance on diesel generators and toward the sustainable resource of the sun.

The World Heritage status of the island made it a very sensitive area to carry out construction, and environmental and political considerations meant that the site for the PV farm was carefully chosen. SOLA staff had to also be sent for training to handle penguins, snakes and wildlife and how to handle archaeological artifacts that might be discovered underground.

What’s so great about a solar microgrid?

A combination of tourism, desalination plant and local community means that Robben Island uses over 2 Million kWh of electricity annually. The solar microgrid consists of several elements that will produce almost 1Million kWh of electricity annually, significantly reducing costs of buying diesel, ferrying it to the island and burning it for electricity generation.

The solar microgrid uses the most abundant resource on the island – the sun – and converts this energy seamlessly into electricity, which can be used for operations. In combination, the battery system stores any excess energy produced by the sun, for use during the night or on cloudy days. If both the battery system and the sun are low, the smart microgrid controllers trigger the diesel generators to start up, ensuring that the island never experiences energy shortages or blackouts.

Robben Island Replace Diesel Generators With Solar Power PV Microgrid

Robben Island has historically used diesel generators to provide the power needed on the island.

The combination of solar and batteries, a revolutionary step, is the key aspect of the return on investment for the island. The solar microgrid will ensure that the island reduces its fossil fuel consumption dramatically, by nearly 250 000 litres of diesel per annum. This will result in a reduction the Island’s carbon emissions by 820 tons, as well as a significant monetary saving. The system will last over 20 years.

How a smart solar microgrid works

Usually, solar systems are grid-tied – meaning that they supplement power supply and remain connected to the central electricity grid. Some also produce excess power which feeds back into the grid. A microgrid, in contrast, works independent of a centralised electricity grid, yet retains the functionality of it. This means that it contains multiple controllers that switch power sources as and when necessary, without ever interrupting the power supply.

In the Robben Island Microgrid, there are three key power production aspects. The first of these is a solar farm, consisting of 1960 mono-crystalline modules that produces 666.4 kW of power.

Robben Island Solar Microgrid Uses 1960 solar modules

1960 solar modules to provide energy on Robben Island

The second is a battery bank, consisting of 2420 lithium-ion battery cells, ready to store 837 kWh worth of electricity and supply 500 kV worth of peak power.

Robben Island Solar Power PV Microgrid battery bank

2420 lithium-ion batteries store solar energy for use after hours

The third aspect is the diesel generators, which supply power to the island when the solar farm is not producing energy (for example at night), and the battery bank is depleted.

Old Diesel generators on Robben Island Replaced With Solar Power

Diesel generators to provide energy when battery bank is depleted

Combined, these three power production elements, coupled with a set of smart controllers, supply Robben Island power – all of the time.

Microgrid controls a smart approach to energy management

The microgrid control system is based on a distributed intelligence approach which ensures that the grid behaves smartly for seamless power production. Each of the points of power production have a logic controller that controls the power output at each of these points, whilst reporting back to the other controllers. The system monitors the current load by adding the current production of each of the power sources; each of the controllers then adds a safety factor to the current load and always makes sure it has enough power, immediately available, to supply the load and handle sudden increases in load, such as the operation of the 200 kW desalination plant. The only centralised component in the system is a data-collection system, similar to a small SCADA (Supervisory Control and Data Acquisition), which allows for set points to be altered and measured values to be recorded.

The potential of solar and batteries: a Robben Island case study

Solar PV has long been a more cost-effective energy source than the central grid in South Africa, but it’s the combination of solar with batteries that will make the technology truly disruptive, as it has the potential to make the centralised grid redundant. The Robben Island Microgrid is a great case study to explore the true value of solar PV and battery combinations, because it is already independent of the central grid. During its first two months of operation, the island produced 187 000 kWh clean electricity through solar power, resulting in 53 685 litres of diesel being saved, an equivalent of 495 tons CO2 emissions.

Solar PV Microgrid performance on Robben Island

Data insight helps to monitor the microgrid’s performance

The above graph shows Robben Island’s energy demand (blue line), supported by the generator through the evening. Around 6.30 am, the solar system (green line) starts to produce power, and by 9.30 am, the solar system starts to supply the entire island’s energy demand. By 10am, the solar power starts to surpass the island’s demand, and charges the batteries. Once the batteries are full, the solar power curtails to meet the demand of the island. Once the power starts to go down at 6pm, the batteries are activated and start to discharge, finishing their power around 8.30 pm when the generators start up again.

This graph demonstrates that the solar farm can easily meet – and exceed – the needs of the island during hours of light, even in winter. The rate at which the battery bank charges suggests that an even bigger battery bank could be possible – and the island could rely even less on the diesel generators.

The rapidly decreasing price of battery tech

Based on the above graph, it is clear that an even bigger battery bank on Robben Island would further decrease the already substantially reduced spend on diesel and its accompanied environmental degradation. As such, how can projects start to install solar PV and batteries to meet enough demand to go off grid entirely? The future is closer than we think.

In 2016, the costs of a lithium-ion battery cell had come down 73% from 7 years prior. Even during the building of the project over 12 months, the cost of the tech went down significantly. The graph below, published by Bloomberg New Energy Finance, demonstrates the cost reduction of batteries over the last 7 years.



decreasing costs of lithium-ion batteries with Solar PV Microgrids

Source: Bloomberg New Energy Finance

 Conclusion: how South Africans can learn from Robben Island’s Example

Robben Island has a difficult history – one of banishment and pain – yet today it serves as a heritage site and a reminder to thousands of the triumph of the human spirit over adversity. In a similar vein, Robben Island’s energy history is one marred by reliance on fossil fuels and environmental degradation. The Robben Island solar microgrid shows an inspiring example of the way in which communities can adopt clean, efficient and more affordable energy – to the benefit of the local community and the surrounding environment.

“It’s been inspiring to work on a project like Robben Island,” said SOLA CEO, Dom Wills. “The island is in many ways a microcosm of South Africa, and we hope that its example will inspire other African communities to follow suit. Adopting clean energy is not only possible – it is now affordable. What Robben Island has taught us is that the future of efficient energy is within our reach.”

Robben Island Microgrid Infographic

Do you know of a community who could benefit from solar microgrid technology? Contact us or use our solar calculator to find out if it is viable. The future of Africa is powered by the sun.


Intersolar Europe SOLA Future

Takeaways from Intersolar 2017: the latest and greatest in solar technology

​SOLA CEO, Dom Wills, and CTO, Ian Burger, attended the world’s largest gathering of solar professionals in Munich last week. Below follows a few takeaways from the conference.

A positive outlook

Much of the Intersolar conference focused on the global outlook of the industry during 2016 and using that perspective to predict on the future of solar and its applications. Looking back is informative: in 2016, the world built 76 GW of solar power, which amounted to a conservative turnover of around US$ 85 billion. Much of the market was in China; the US, Japan and India were also very big players.

The pricing of solar is steadily shrinking; as more solar PV is deployed, investors’ confidence increases and increased volume and efficiency means that capex costs are coming down. Although this is a fantastic outlook for solar – and has been the reason for the sector’s exponential growth over the last few years – it is changing the way in which solar is deployed and potentially sold.

China, for example, curtails around 15-20% of its solar power: in other words, the spot price for solar energy is 0, 20% of the time.  The curtailment is factored into the financial model, but an obvious opportunity exists to harness and sell that energy as the penetration of solar increases.  This has huge potential for utility battery storage, because businesses – or even individuals – can buy power for nothing at time of excess, and then sell in high times of need.  Business opportunities also exist to sell ancillary services to the grid, such as frequency or voltage support.

This is great news for people and for industry as a whole – the future could easily see energy being extremely cheap, if not free. For businesses in energy, the business model will be built around power – storing the cheap energy produced by the sun, and selling it back to consumers when it is not shining. It’s likely that tariff structures might change to accommodate this, and that manufacturers and other energy-guzzlers are incentivised to ramp-up operations during the day, when the sun is shining and energy will be cheap.

Away from baseload

The outlook on heavy baseload and centralised grid energy infrastructure is not only becoming more unpopular, the general perception is that the forward costs of nuclear and coal could potentially put economies at risk. Because manufacturing competitiveness relies heavily on energy costs, countries with the lowest energy costs will thrive and those with expensive power will fail.  As such, careful consideration needs to be made as to which energy sources to prioritise. Centralised, baseload-heavy grids are no longer required, competitive or appealing in the global market.

On the positive side of this, microgrid tech is an exciting prospect for countries with little or fragmented access to energy. It’s predicted that microgrids are going to be cheaper than fossil fuels, and Africa is a perfect market for microgrids because of its lack of fixed-line infrastructure. The potential for many more to have access to power is within reach and will not be expensive to deploy.

Storage, storage, storage

Storage was, predictably, one of the major topics at the conference. The general sentiment amongst technical experts is that for every unit of solar PV that is installed from now on, some storage must be included – even if it has to be subsidised at first. The inclusion of storage will be important to avoid large-scale solar PV becoming a nuisance to the grid or having large amounts of curtailment. If storage is incorporated with every PV system, the scale will also assist in bringing down the cost of lithium ion technology – and thus the price of batteries.

Storage came up for other technologies, too. Electric vehicles will increase the demand for electricity in coming years, an flexible charging will be important with on-board storage, so that they can buy electricity when it is cheapest and during peak PV hours. However, there is still much to be done in the way of making cars and their systems smarter.

Hydrogen and Methane were also a topic of discussion on the storage front, as both gases can be created from electricity using chemical processes. Exploring this link opens up the opportunity for long term seasonal and annual storage options which will be particularly useful in countries with large imbalance between summer and winter.

Smart and automated

In line with global technology trends, the Internet of Things is popping up in the energy world, too. Experts believe that IoT It will play a role in allowing ‘smartification’ of devices to use energy efficiently or use energy at specific times, depending on the cost.  This links heavily with the substantial amount of ‘smart home tech’ that is being developed to automate and increase efficiency in households. Drones and robots, too, are a hot topic up for debate. From operations and cleaning to testing and surveillance, they are going to become a useful player in making solar PV more efficient.

SOLA will be hosting an information session on findings from Intersolar Europe on 29 June. If you would like to attend, please get in contact.