Solar Energy Company: Customer Portal and Automated Invoicing

SolTejo (real case — data altered under NDA), a solar panel installation and maintenance company in the Lisbon region with 420 active customers and 9 employees, was invoicing every maintenance contract manually, answering individual questions about solar production and had no way of remotely monitoring customer installations. When we implemented a customer portal with a production dashboard, automated recurring invoicing and remote monitoring, support calls dropped 60%, invoicing time fell from 5 days/month to 2 hours and recurring maintenance revenue rose 28% thanks to automatic renewal and intelligent upselling.

The Scenario Before: Growth That Suffocates

SolTejo was founded in 2019 by engineer Ana and grew rapidly, driven by the self-consumption solar boom in Portugal. In six years, it installed more than 420 photovoltaic systems — residential and commercial. Each installation included an annual maintenance contract that guaranteed periodic inspection, production monitoring and technical support.

The problem was that the company was drowning in its own success. Each new customer meant one more manual invoice per month or quarter, more support calls ("my production seems low this month — is everything alright?") and one more installation to monitor without adequate tools.

Invoicing was the most painful point. Maria, the administrative assistant, spent the first 5 working days of every month issuing maintenance invoices. For each of the 420 customers: open the customer file, verify the contract type and amount, issue the invoice in the accounting software, send by email. Five days. Every month. And whenever there was an error — wrong amount, bounced email, customer who changed bank account — it was Maria who resolved it, one by one.

Technical support was another time sink. The most frequent question from customers was: "Is my installation producing normally?" The answer required a technician to remotely access the customer's inverter (when the WiFi connection was functional), check the data and respond by email or phone. On average, SolTejo received 15 to 20 calls of this type per week — each consuming 15 to 30 minutes of a qualified technician's time.

Proactive monitoring was virtually non-existent. SolTejo only knew that an installation had a problem when the customer called to complain about low production — often weeks after the problem had appeared. A panel shaded by a growing tree, a faulty inverter or a tripped circuit breaker could go undetected for months, with the customer losing production and blaming SolTejo.

The Numbers Behind the Problem

• 5 days/month spent on manual invoicing of 420 contracts.
• 15–20 calls/week for technical support — the majority about production.
• Zero customer portal — all communication by email and phone.
• Reactive monitoring: problems detected on average 23 days after they appeared.
• Contract renewal rate: 72% — customers cancelled due to a lack of perceived value.
• Recurring revenue/customer/year: €168 (basic maintenance only, no upselling).

The Solution: Digital Solar Management Platform

Phase 1 — Customer Portal (Weeks 1–6)

We developed a responsive web portal where each SolTejo customer has access to their personal area. The central element is the solar production dashboard, which shows in real time — through integration with the installed inverters — how much energy the installation is producing, the production history by day, week, month and year, and the comparison with the expected production for that location and installed capacity.

The dashboard translates production into language the customer understands: not just kWh, but euros saved. "Your installation produced 412 kWh this month — the equivalent of €82 in savings on your electricity bill." This translation of technical data into financial value proved crucial for the perceived value of the service.

The portal also includes: history of completed maintenance (with report and photographs), invoices and receipts, installation documents (technical datasheet, warranties, certificates), a support channel with ticketing (instead of phone calls) and anomalous production alerts.

The impact on support calls was immediate. Customers who previously called asking "is everything alright with my installation?" now open the portal and see for themselves. Support calls dropped 60% in the first month after the portal launch.

Phase 2 — Automated Invoicing (Weeks 4–8)

We implemented a recurring invoicing system integrated with SolTejo's accounting software. Each maintenance contract is configured once: customer, amount, frequency (monthly, quarterly or annual), payment method and renewal date.

On the defined date, the system automatically generates the invoice, sends it by email to the customer with a payment link (MB Way, Multibanco or direct debit) and records it in the accounting software. If payment is not received within 7 days, it sends an automatic reminder. If the debt continues after 15 days, it alerts Maria for manual intervention.

The result: the 5 days of manual invoicing became 2 hours — the time Maria spends reviewing the automatic report and handling exceptions (2 to 3% of cases). The other 4.5 days were redirected to higher-value activities: managing old receivables, supporting the commercial department and bank reconciliation.

The automated invoicing included an automatic contract renewal mechanism. 60 days before expiry, the customer receives an email with the contract summary, the renewal amount and a link to confirm. If they do not respond, they receive a second email at 30 days. The renewal is processed automatically unless there is an explicit refusal. This simple automation raised the renewal rate from 72% to 89%.

Phase 3 — Remote Monitoring and Alerts (Weeks 6–10)

We integrated the system with the inverters of 380 installations (of the 420 customers, 380 had inverters with remote monitoring capability). The system collects production data every 15 minutes and compares it with the expected output — calculated based on actual solar irradiation (IPMA data), installed capacity and the installation's history.

When an installation's production drops below 80% of expected for more than 24 hours, the system generates an automatic alert. The SolTejo technician receives the notification with diagnostic data: which inverter, which string is affected, whether it is a gradual problem (suggesting dirt or shading) or sudden (suggesting component failure or tripped breaker).

The technician can, in many cases, resolve the problem remotely (restarting the inverter, for example) or contact the customer with a diagnosis and solution before the customer even notices the problem. This proactivity — "we're calling because we detected that your installation has below-normal production; we've already scheduled a visit" — transformed the perception of the maintenance service from "unnecessary cost" to "essential insurance".

Additionally, the system identifies upselling opportunities. When an installation's production is consistently at maximum capacity (or above the customer's consumption), the system suggests the sales team contact the customer to propose system expansion or the addition of a storage battery.

The Results: Before vs. After

Eight months after full implementation:

• Support calls: from 15–20/week to 6–8/week (−60%). The majority of queries are answered by the portal.
• Invoicing time: from 5 days/month to 2 hours/month (−97%).
• Contract renewal rate: from 72% to 89% (+24%). Automatic renewal and perceived value were decisive.
• Problem detection time: from 23 days to under 24 hours (−96%).
• Recurring revenue/customer/year: from €168 to €215 (+28%). Upselling of premium services and batteries contributed significantly.
• NPS (Net Promoter Score): rose from 34 to 62. Customers value the portal and proactive monitoring.
• Problems resolved proactively: 47 in the first 8 months — problems that would previously have been detected weeks later by the customer.

The Financial Impact

The total investment — customer portal, invoicing system, remote monitoring and training — was €16,500. The increase in recurring revenue (€47/customer/year × 420 customers = €19,740/year), combined with the saving in administrative time (equivalent to €12,000/year in freed-up salary) and upselling revenue (estimated at €35,000 in the first year), totals a return of €66,740 in the first year. Payback occurred in under 3 months.

But the strategic gain was even more significant. SolTejo can now grow to 800 or 1,000 customers without hiring additional administrative staff. The portal, automated invoicing and remote monitoring scale without proportional effort — the marginal cost of each new customer is practically zero in terms of management.

Lessons for Other Solar Energy Companies

1. The customer portal eliminates 60% of calls. The majority of customer questions are variations of "is everything alright?" A dashboard that shows production in real time, translated into euros saved, answers that question 24/7 without human intervention.

2. Automated invoicing is the first process to automate. In a company with hundreds of recurring contracts, manual invoicing is a criminal waste of time. Automation not only saves time but also reduces errors and improves cash flow.

3. Proactive monitoring transforms service perception. When the company calls the customer before the customer calls the company — "we detected a problem and already have a solution" — the maintenance service stops being seen as a cost and starts being seen as an investment. The renewal rate responds accordingly.

4. Data-driven upselling is natural and effective. When the system identifies that a customer produces more than they consume, the suggestion of a storage battery is a genuinely useful recommendation — it is not aggressive selling. The customer appreciates the suggestion.

Conclusion

The solar energy sector is growing rapidly in Portugal, but many installation companies continue to manage hundreds of customers with manual processes that do not scale. SolTejo demonstrated that the digitalisation of after-sales management — customer portal, automated invoicing and remote monitoring — is not merely an operational improvement: it is the difference between a company that grows and a company that suffocates under its own growth. Technology allows you to scale without proportionally scaling costs — and in the recurring services market, that is the formula for sustainable profitability.