Solar PV Performance Analysis: 4. Action Plan & Tracking

As we enter into a new year, it’s time to conclude on our series of posts on the performance analysis of a solar PV site.

In the previous posts we have reviewed:

1. How to check for data availability and correctness

2. How to check for equipment availability, ensuring inverters or strings are all producing

3. How to check for sources of underperformance

The last phase is now:

4. Putting together an action plan with expected % performance increase for each action and following up with the local O&M team to track that actions are put in place correctly.

Putting together an action plan is arguably the hardest part of the performance analysis, the action needs to be specific enough to avoid confusion, and also needs to be cost-effective and achievable. If for example inverter 5 has low PR, the action should not be “investigate inverter 5 performance on site”. This is too generic. The action needs to be specific enough that the team on site can go directly to the problem without wasting time.

A better example of a corrective action is “inverter 5 has 2 strings not producing, numbers #5 and #6, check these strings on site for loose module connections, broken cable, disconnected MC4 connectors, broken modules, blown fuses”.

Each action should be quantified with a % performance gain (where applicable) so that a manager or the client knows how much benefit each action will bring. Some actions may be too costly to justify the expected gain in performance. For example, when dealing with shading losses, a typical solution is to rewire strings to minimise shading losses. Depending on the quantity of shading on a site, it may not be cost effective to rewire strings once the site has been built. Rather this information should be fed back to the Engineering team for better design on new projects.

Below we see an example action plan for one site. All actions are listed one by one, the Asset Management team then needs to organise works on site by creating a work request to be assigned to the local O&M team. Target completion dates need to be added along with actual dates when the actions have been completed, for tracking.

In the last column the % PR (performance ratio) impact is added, the actions are filtered from highest to lowest. Highest priority actions are those that either have high performance impact (e.g. strings or inverters not producing) or a potential safety risk to equipment or personnel (e.g. insulation resistance faults or negative current).

Meetings should be held at regular intervals (e.g. at a minimum weekly) to review all actions and track progress. If new performance actions are found, then these should be added to the list.

Below is another example site once the performance actions had been carried out. On this site the actions allowed for a 13.2% improvement in the PR! But even when all initial actions are completed this doesn't mean the site performance cannot improve! The asset management and O&M teams should be continually checking site performance for ways to optimise output.