To counteract loadshedding effectively, universities first need to monitor their energy needs 

The first step in addressing electricity supply at universities in this time of rolling blackouts is to do an energy audit. Institutions can start with assessing their monthly electricity bills but, to really develop “loadshedding resiliency”, said Dr Lawrence Pratt, they need to work out how much power they need and when, down to per hour or even shorter durations.

“You have to understand things like your peak load and base load so that you can design a system to protect you for the two-hour, four-hour or six-hour block of loadshedding,” he said. “Having this data at your fingertips is absolutely critical for the planning, modelling, and implementation of your strategy.”

He said the webinar aimed to assist institutions to finalise their energy strategic plans, to share information on best practices and lessons learned from their renewable energy resources and, “for us to work together towards a framework for developing an energy strategy, and a bank of resource documents.

“This is one of those areas that does not need us to compete but rather to work together. USAf can assist with that process,” said Mabizela.

The process had started earlier this year when Dr Pratt made a presentation to a DHET meeting with heads of infrastructure departments on 28 March. He made the same presentation in the webinar.

He explained how knowing their peak load would help institutions choose the correct size inverter. If, for an example, their hourly base load was 2400 kilowatts and the university needed four hours of battery storage, then it needed to multiply that number by four and add some redundancy.  “If the PVs are not designed big enough and the batteries are not designed big enough, during loadshedding, you’re just going to shut down,” said Pratt.

The CSIR is a national key point and therefore exempt from loadshedding, although that could change, Pratt said. They had taken energy interventions both to reduce costs and to demonstrate their effect to model loadshedding scenarios and solutions for external clients.

He said the CSIR had installed ground-mounted and rooftop PV plants and set up an indoor PV module quality and reliability test lab — of which he is the manager — and a battery testing lab.

At capacities of two megawatts in total, the CSIR’s PV plants generate about 15% of the institution’s total consumption. “We’re not anywhere off grid, nor is that our goal. But the idea was to save some money on our energy bills starting in 2015,” he said. With a capital expenditure of almost R35m, by February this year they had reduced their electricity bills cumulatively by about R20m.  ‘’And it should be just a matter of another five years before we recoup at least the nominal investment.‘’

They also have lots of generators but “they’re not all in the best state of repair”.

He said it was important to remember that grid-tied PV generators are not operational during load shedding. “So just focusing on PV does nothing with respect to load shedding resiliency. They are quite a clever solution for a very small load for a short period of time. But they don’t meet the requirements of an examination hall of 500 to 1000 students who need good air conditioning while they sit for exams.”

He said keeping a small load up and running for a couple of hours was straightforward. He recommended focusing on a hybrid battery inverter system designed with metered data, and with inputs for fossil fuel generators. That could feed a building or maybe even an entire campus if the university has multiple generators.

“If it’s a small enough load, and a big enough battery bank, you don’t have to do anything else,” said Pratt. “Then you could choose to add PV systems later. The PV systems are going to help you extend the life of the battery because during the daytime, if the PV system is big enough, that can go directly to the load as well. You’re not going to be discharging your batteries during the day.‘’

He said these solutions were long-term investments. “In my view, it’s worth spending a little bit more money upfront to make sure you get good quality products with good warranties and good aftersales. These are complex systems, and they need some TLC to keep up,” he said.

Diesel generators, for one example, were expensive to run but it was hybrid energy systems, not grid-ties, that delivered power during loadshedding. He said although it was expensive to install high-capacity PV systems, they were cheap to run because the fuel, coming from the sun, is absolutely free. Diesel generators, on the other hand, were relatively cheap to buy but very expensive to run, about R5 per kilowatt hour. But if the institution needed a lot of capacity for just an hour a week, they delivered the best cost-effective solution.

However, if institutions needed to run six to eight hours off grid during loadshedding multiple times a week, they needed to look at the investment of PV and batteries. These should be sized to 80% to 90% of the required load. “And then the generator is there to pick up the other 10% when you have an unexpected high peak demand or some unexpected sort of extended period of bad weather,” he said.

He said an energy management plan included these key components:

• Energy audits — having metered data such as the meters the CSIR is installing at each of Mangosuthu University of Technology’s substations, makes the audits straightforward. The audits provide a baseline and later help in gauging the effectiveness of their implementation plan;
• Energy efficiency – finding out where the most energy is used and how to make that efficient;
• Education and awareness — such as making students aware of energy wastage by using electric hotplates to light cigarettes; and
• Monitoring and evaluation – from before the intervention to a year later; envisioning where they hope to be in five years.

He said if universities were struggling or needed extra resources, the CSIR’s services include energy audits and planning, PV procurement to help make it a less risky investment, and quality and reliability testing of PV modules and batteries. He added that their PV procurement process was based on the cost of electricity and not the cost of the capital expenditure.

“So rather than saying ‘who’s going to give us the cheapest PV plus storage system’, it’s ‘who’s going to give us the lowest price for the cost of electricity over the life of this generator’.  This still gives a lower cost of electricity, which is what you really care about here. You are buying kilowatt hours, not PV systems and diesel generators. You want electricity,” said Dr Pratt.

They also ensure that the company which designs and installs the plant operates it for three years, which incentivises that it’s a good quality system. And if the output doesn’t match the performance guaranteed at the time of winning the contract, the installation company pays a financial penalty.

“That has been effective for us because three of the four PV plants that we had installed at the CSIR did not meet their performance guarantees. And we were able to recover what would have been losses,” he said.

“Sometimes we still see catastrophic failures, even during the pre-construction testing. On one of our rooftop systems, 50% of the modules failed basic safety tests. We had to go back to the supplier who came on site and did a field repair on all the modules at their cost. So, you never know what you’re going to find. And that’s why we’re here to support PV installations and battery installations.

“I like to think about this as your prepaid electricity meter,” he said. PV, batteries, inverters and generators operated on the same principle of paying before use. “In this case, you’re pre-paying for 20 years’ electricity.  It’s a big hit. But then it does come back and help you at the end,” said Dr Pratt.

Gillian Anstey is a contract writer for Universities South Africa.