- On June 25, 2021
It’s time to add up the cost of your new solar plant. Even with continuing decreases in cost, your modules will make up the biggest item on your capital expenditure (CAPEX) bill. Other installation materials, including trackers and balance of plant, will add another big chunk of CAPEX.
Then you’ve got the cost of labour, land, inverters, interconnection, civil works, permitting, and a long etcetera. The name of the game is to get each of these costs down as far as possible without compromising the integrity of your project.
And with so many big-ticket items to deal with, it can be easy to overlook a critical part of the project that is often taken for granted.
Accounting for only around 0.7% of total plant CAPEX, the supervisory control and data acquisition (SCADA) system is so financially irrelevant that it usually doesn’t even show up in industry cost breakdowns.
As a result, there is a danger you could assume the SCADA system is unimportant. That would be a mistake, as you could soon find out once you start operating your plant.
Your SCADA system is your solar plant’s nervous system, giving you access to data that can be critical in improving production. The data is valuable when you get it and remains so thereafter: an incomplete picture of plant performance can hamper your ability to sell or refinance a project in the future.
SCADA systems are usually mandatory for utility-scale solar plants. But that doesn’t mean all SCADA systems are the same. On the contrary, there is a wide range of systems on the market.
And trying to get by with the most limited models could have a significant impact on your plant operations and management (O&M). Take inverter malfunctions, for example. In around 30% of cases, these can be resolved simply by resetting the inverter.
Saving money on O&M
But if you have to send out a technician to reset the inverter then you could face a bill of hundreds or thousands of euros for the truck roll, not to mention the cost of lost production while the fault is waiting to be fixed.
An advanced SCADA system would allow you to reset the inverter remotely, saving money and safeguarding production.
According to an Inaccess calculation based on a 40 MW PV plant, a SCADA that offers integrated monitoring and control could reset a remote recloser within an hour, compared to a six-hour delay for a traditional O&M setup. This simple feature could result in savings of $9,000 per event.
Not all SCADA systems can do this, though. Plus, there are numerous potential faults that can be avoided through careful SCADA system selection.
If someone cut through your data network during vegetation clearance, for example, a SCADA system with redundant fiber-optic loops would be able to auto-reconfigure communications so you could carry on operating the plant as usual.
Similarly, if you lost irradiation readings from a pyranometer then a good SCADA system might be able to complete your data set using information from other pyranometers or even satellites.
Beyond what happens in the event of a fault, a high-end SCADA system can help improve the profitability of your plant by carrying out analytics to identify sources of under performance or areas for preventive maintenance.
Essentially, a good SCADA system can go much further than simply acting as your eyes on the ground. It can help you reduce O&M costs and make intelligent decisions around how to improve production and profitability.
What to look for in SCADA systems
And it should be obvious by now that differences in SCADA systems mainly relate to the availability of added functionalities and redundancies that help to de-risk your solar operations. The cost of these extras is not that great in the scheme of things.
But skimping on them can have expensive consequences. That is why it is important to take an active role in the selection of your SCADA system and not just accept the first option available.
So, what should you look for in your system? Here are eight things to watch out for:
- Industry-specific features. SCADA systems are used widely across industries, in areas ranging from manufacturing to access control. And while a generic SCADA system might provide the basics you need for a solar plant, it will hardly work as well as one that has been designed specifically for PV.
- Ideally, your SCADA system will last for the entire 25 to 35-year lifespan of your solar project. And a lot can happen in that time, from increases in capacity to the installation of new sensor devices. You want to have a SCADA system that can scale up without problems in space and time.
- High-quality data. The principle of garbage in, garbage out (GIGO) applies to solar data as much as it does to any other form of analysis. Hence, you want a system that offers the highest possible data quality, along with processes to address missing data points.
- Vendor support. As with PV panels and inverters, you want to work with a supplier that will be around to honor warranty conditions and carry out servicing and repairs for the lifetime of your solar plant. That means sticking with leading names in SCADA and power electronics technology.
- As the Colonial pipeline ransomware attack showed this year, energy infrastructure is increasingly being targeted by hackers. Hence, if you are concerned about risk then it is key you select a SCADA system that complies with cyber security standards such as ISO 27001 and NERC CIP.
- Redundancy options. As described above, redundancy can be a major contributor to SCADA system uptime and, with it, enhanced solar plant operations. Redundancy options should extend to the ability for independent data backup in the cloud and on the local system.
- Hardware and software integration. You can easily cut corners by buying SCADA hardware and software separately. But don’t expect optimum performance. The best possible option is a fully integrated system from a single vendor.
- Technological flexibility. Notwithstanding the desirability of industry-specific features, it is also useful to have SCADA systems that can work well in hybrid plant contexts, for example where solar is tied to battery storage.
In addition to these SCADA platform characteristics, you should pay attention to the following points during the design and installation phase of your solar plant:
- Make sure the size and setup of your SCADA system are co-optimized along with your sensor systems to provide the highest-quality data at the lowest possible cost.
- Design your data networks for fast and reliable plant communications, with separate paths for acquisition and control.
- Choose a leading power plant controller to allow for seamless grid integration.
- Set appropriate parameters for data sampling, cleansing, and averaging.
- Put ISO 27001 cyber security practices in place.
What’s this all worth? At Inaccess, we estimate that identifying performance issues and minimizing unexpected downtime could result in a 2% performance ratio improvement, adding around $280,000 in revenue a year for a 100 MW.