Although it seems counter productive to talk about decommissioning solar farms when the world is deploying solar faster than ever before, decommissioning is something that needs to be factored into any asset life cycle and in particular the LCOE financial models. After all, they will not last forever.
In most planning conditions, local authorities will call for the site to be returned to its natural state at the end of the asset’s life. However, if you look at traditional energy generation assets such as power stations, they all had an original 25-year planning period and of course in the UK at least, many of these are 35-40+ years old now, so the reality is that the planning permissions will be extended. In solar this will be similar I believe, and most solar farms won’t be decommissioned at all, but rather they will be revamped and/or repowered.
Looking at existing operational sites around the world, planned asset life is typically 25-30 years, however in some more modern sites the envelope is opening to 35 to 40 years. Personally, I believe that without substantial investment in the CAPEX (in an ever-decreasing price pressured market), assets will not last 25 years, let alone 35-40 years without either a step change in design and construction quality or significant revamp and repower injections of capital investment for operational sites, asset life cycle periods are simply unrealistic.
Decommissioning is a topic which is relatively straight forward in terms of the individual tasks that need to take place, however the complexity comes in planning and executing the logistics of huge volumes of components on the massive scale of the assets in question. Similar in many regards to construction, only in reverse and without the packaging.
Just as you will finish a construction project with the connection to the electricity network and have subsequent tests, connection agreement measures and controls in place. For a decommissioning project, the first thing you need to do is to disconnect to the electrical network and make all necessary bodies and authorities aware well in advance of the termination of the electrical generation of the plant. Part of this will be ensuring that records are kept of the final export meter values, much like when you finish with your home electricity supplier. Essentially the initial focus in the first phase of decommissioning will be about making the site safe and removing the risk of electrical hazards under tension. However, the electrical risk will always be present if the sun is shining due to the nature of the technology we are working with. Therefore a particular focus on DC electrical safety is crucial, particularly if asset owners are lured into the using cheap and cheerful contractors without any solar experience.
Once electrical safety is established (as far as reasonably practicable and with continual control measures in place), then it becomes more of a dismantling, extraction and disposal exercise.
The biggest decision that needs to be made upfront, and this will depend on the age of the asset being decommissioned is what to do with the modules. Everything else (structure, cable, inverters, HV equipment, fencing etc) has established recycling and scrap routes of disposal. However, the modules are a tricky one. Do they hold a second-hand value? And is that reselling value higher than the extra costs that will be generated by the slow and careful demounting, handling and packaging, compared to getting them off and into a skip. For assets with modules over 20 years old I find it hard to believe that a re-sell option would make sense and suitable waste disposal using solar module recycling service providers would need to be utilised. For modules that are less than this age, then there may well be a case of a second-hand sale route.
2DegreesKelvin has developed our own decommissioning model to enable us to assess specific sites, enter multiple project variables & norms to project the future liabilities of decommissioning. We have meticulously engineered and planned all of the steps, and calculated all of the relevant tasks, activities, extractions and disposal costs to make the model as accurate as it can be, projecting forward 20-25 years.
Of course, there are many opportunities to save money, but from an engineering model perspective, you must start from first principles and plan for the worst case if you had to do it today. You do not have a crystal ball. The biggest opportunity to not only save money, but to extend the revenue generation ability of your solar asset is of course to revamp or repower your asset, and then comes the question when? As well as a decommissioning model, 2DegreesKelvin have also developed sophisticated Revamp & Repower tools to simulate the best options for assets to maximise their profitability and project the optimum time to pull the trigger from an investment perspective.
Back to Decommissioning, if 2DegreesKelvin was to share some tips for stakeholders when considering decommissioning solar farms, our top 5 tips would be:
1. Ensure that the relevant authorities are fully aware of the decommissioning project, including the local planning authority, Health & Safety Executive, Environmental Agency and OFGEM. There will be substantial documentation to prepare ahead of decommissioning works and you need suitable time to prepare and for relevant permissions to be granted.
2. Secure a purchaser for the steel work, cable, inverters & HV equipment. This is likely to be scrap values only but will add up. The logistics will be the big cost, so try to find a taker who will factor this into the deal.
3. If sites are due to be decommissioned when they are 10-15 years old, it’s likely that the modules would have some second-hand value, but the additional effort involved in carefully removing them and packaging them so they are not damaged, may out way the value, so this would become a cash-neutral exercise at best. However, if you are talking about 20 years plus old modules, then these are likely to be a cost to dispose of as they are essentially scrap. In this case, the cost of module removal and disposal will be significant. Ensure you factor this into your analysis and try to agree a deal with a solar module recycling service provider.
4. Be aware that the physical labour involved to unbolt hundreds of thousands of 25-year-old fixings and extract piles out of the ground will be more than you think. This will not be easy, and is likely to be more time consuming and expensive that putting them in.
5. Ensure that you ‘leave the site in the condition it was found’, which involves extracting the piles and cable from the ground, and in some cases may be significant land remediation works. This is important, and is not only unethical to leave them there, but it will be not compliant with your planning duties, will cause you a significant amount of work (much harder to extract if cut off) and could be dangerous for future developments.
We hope this article has been of interest to our network and would welcome comments and interactions.
If you have assets which you need accurate decommissioning models to be developed, or indeed wish to explore the optimum time to carry out a revamp or repower on your aging assets, then please get in touch with 2DegreesKelvin (info@2degreeskelvin.org).