Eskom launches microgrid pilot plant
Eskom launches microgrid pilot plant in Free State
State-owned power utility Eskom has launched a pilot solar-powered microgrid at Wilhelmina farm, in Ficksburg, in the Free State.
The microgrid demo plant is capable of providing electricity to 14 households with 81 family members, making up the Wilhelmina community.
The plant harnesses solar energy and converts it to a peak of 32 kW electrical energy through photovoltaic panels and power inverters.
The remaining energy from the solar panels is stored in three sets of lithium-ion batteries, totalling 90 kWh of storage. This storage facility provides electricity when there is low or no sunlight available to the solar panels.
“The project symbolises innovation, growth and development, while being consistent with Eskom’s future strategic objectives, since microgrids [that are] incorporating renewable and smart energy technologies will play an important role in Eskom’s future,” Eskom research, testing and development centre representative Nick Singh said in a statement issued at the weekend.
INCREASING NEED FOR SOLAR ENERGY
CITY OF CAPE TOWN TO STIMULATE INCREASING NEED FOR SOLAR ENERGY
The City of Cape Town is working its plans to establish an appropriate business model to stimulate the uptake of solar photovoltaic systems. This announcements follows the need for aggressive renewable energy targets.
The number of increasing customers installing rooftop solar photovoltaic infrastructure is evident and the costs are perceived to be prohibitive by most residents. The City has announced that a letter of collaboration has been signed with the United States Agency for International Development and the Southern Africa Energy Program to investigate appropriate mechanisms to unlock access to the benefits of this technology for more of Cape Town’s residents.
With the investment in and the rolling out of renewables is the obvious way forward for a progressive city, Cape Town intends to grow its status as the green economy hub of Africa. However, this comes with certain barriers.
The City recognises that the facilitation of the move to sustainable models are necessary for creating an environment which allows for the private sector to move safely and legally towards investment into and adoption of these options. Solar projects will become more economically viable only if adoption rates are increase, solid public-private partnerships are formed and clear regulatory frameworks are put into place.
There are various models to institute this, for instance:
Nelson Mandela Bay municipality’s model prescribes that investors can pay for solar panels to be installed at private homes and then be reimbursed according to how much energy is transmitted back onto the network
the City could invest in the capital cost of the infrastructure and then have residents pay this back either via their electricity invoice or property rates.
through community or co-operative funding mechanisms.
The study’s aim is to identify the most appropriate mechanisms for Cape Town’s customers, based on legal and technical factors which would be most attractive to residents.
The City’s Mayoral Committee Member for Informal Settlements, Water and Waste Services; and Energy, Councillor Xanthea Limberg comments:
‘The City is determined to build a more secure, cleaner and affordable energy future and we know that the technological solutions already exist to enable us to do this. This collaboration will bring us that much closer towards meeting our renewable energy targets by identifying solutions to the barriers that make it difficult for residents to access to clean and affordable electricity”.
“We have a number of initiatives under way to release Cape Town from its heavy reliance on Eskom. I am confident that the outcomes of this work will be hugely valuable in our committed drive to building a low carbon, resilient and resource-efficient city.”
“This move also helps to position the Cape Town as a centre for green business and the growth of the renewable sector helps to preserve our environment. Apart from this though, research and development, design, manufacture and the installation and maintenance of small-scale embedded generation systems and services all provide economic opportunities.”
Residents will be required to register and to obtain authorisation for their rooftop PV systems in accordance with the City’s Electricity Supply By-Law.
Connecting a small-scale embedded generation system to the grid can pose a safety risk. It is important to ensure that all generating equipment is approved and install correctly. Residents have until the 28th of February 2019 to register their systems after which they will be liable for a service fee and possible electrical disconnection if fount to have installed this system without the relevant approvals in place with the exception of solar water heaters.
Roads paved with solar panels
Why roads paved with solar panels are not such a bright idea
our years ago, a viral campaign wooed the world with a promise of fighting climate change and jumpstarting the economy by replacing tarmac on the world’s roads with solar panels. The bold idea has undergone some road testing since. The first results from preliminary studies recently came out, and they’re a bit underwhelming.
A solar panel lying under a road is at a number of disadvantages. As it’s not at the optimum tilt angle, it’s going to produce less power and it’s going to be more prone to shading, which is a problem as shade over just 5 per cent of the surface of a panel can reduce power generation by 50 per cent.
The panels are also likely to be covered by dirt and dust and would need far thicker glass than conventional panels to withstand the weight of traffic, which will further limit the light they absorb.
Unable to benefit from air circulation, it’s inevitable these panels will heat up more than a rooftop solar panel too. For every 1 degree Celsius over optimum temperature you lose 0.5 per cent of energy efficiency.
As a result, a significant drop in performance for a solar road, compared with rooftop solar panels, has to be expected. The question is by how much and what is the economic cost?
The road test results are in
One of the first solar roads to be installed is in Tourouvre-au-Perche in France. This has a maximum power output of 420 kW, covers 2,800m² and cost €5m (£4.5m) to install. This implies a cost of €11,905 per installed kW.
While the road is supposed to generate 800 kilowatt hours per day (kWh/day), some recently released data indicates a yield closer to 409 kWh/day, or 150,000 kWh/yr. For an idea of how much this is, the average UK home uses about 10 kWh/day. The road’s capacity factor – which measures the efficiency of the technology by dividing its average power output by its potential maximum power output – is just 4 per cent.
In contrast, the Cestas solar plant near Bordeaux, which features rows of solar panels carefully angled towards the sun, has a maximum power output of 300,000 kW and a capacity factor of 14 per cent. And at a cost of €360m, or €1,200 per installed kW, one tenth the cost of our solar roadway, it generates three times more power.
In the US, a company called Solar Roadways has developed a smart highway with solar panels, including sensors and LED lights to display traffic warnings about any upcoming hazards, such as a deer. It also has heating pads to melt snow in winter.
Several of its SR3 panels have been installed in a small section of pavement in Sandpoint in Idaho. This is 13.9 m² in area, with an installed capacity of 1.529 KW. The installation cost is given as $48,734 (about £37,482), which implies a cost per installed kW of €27,500, more than 20 times higher than the Cestas power plant.
Solar Roadway’s own estimates are that the LED lights would consume 106 MWh per lane mile, with the panels generating 415 MWh – so more than 25 per cent of the useful power is consumed by the LEDs. This would reduce performance even further. The heating plates are also quoted as drawing 2.28 MW per lane mile, so running them for just six days would cancel out any net gain from the solar panels.
And this is before we look at the data from the Sandpoint installation, which generated 52.397 kWh in six months, or 104.8 kWh over a year. From this we can estimate a capacity factor of just 0.782 per cent, which is 20 times less efficient than the Cestas power plant.
That said, it should be pointed out that this panel is in a town square. If there is one thing we can conclude, it’s that a section of pavement surrounded by buildings in a snowy northern town is not the best place to locate a solar installation. However, perhaps there’s a bigger point – solar roads on city streets are just not a great idea.
Running out of road
Roads don’t represent as large an area as we assume. The Department for Transport gives a breakdown of the length of the UK’s different road types.
Assuming we can clad these in solar panels, four lanes of every motorway, two lanes on the A and B roads and half a lane for C and U roads (a lot are single track roads and just won’t be suitable) we come up with a surface area of two billion m².
Which sounds like a lot, until you realise that buildings in urban areas occupy an area of 17.6 billion m². So just covering a fraction of the UK’s rooftops with solar panels would immediately yield more power than putting them on roads. That’s quite apart from the benefits that a more elevated position would yield for greater power generation.
All of this suggests that only a small fraction of the road network would be suitable. And, given the relatively small size of the road network, solar roads could only ever become a niche source of power and never the shortcut to our future energy supply.