A homeowner in Jakarta was interested in solar energy / PLTS, but only as his new “toy”. However, when I visited the client’s home, I noticed large electricity usage: lights, fridge, AC, water heater. Could you imagine the electricity costs?

In solving this problem, Inspecro considered a PLTS system to save his costs. Before deciding whether solar energy is a great fit for the client or not, we had to answer 3 core questions:

  1. Is the sun strong enough in the client’s roof?
  2. Is the client’s roof suitable for solar panels?
  3. Will I add any value to the client? (not as a “toy”)

Question 1: Is the sun strong enough in the client’s roof?

We measured the sun radiation profile at the client’s roof. The client’s home has a strong sun radiation of 4.76 kWh/m² day. This is 73% stronger than a house in Berlin, in which solar panels are already widespread. (See Exhibit 1.)

Question 2: Is the client’s roof suitable for solar panels?

We took measurements and mapped roof obstacles. Next, we created two possible design options using guidelines from AS/NZS Standards. (See Exhibit 2.)

To decide which option is more profitable for the client, we asked about the client’s daily lifestyle. Using this information, we chose the smaller option as it better fits the electricity usage pattern.

Question 3: Will I add any value to the client?

Assisted by our NASA solar database, we forecast electricity savings of Rp 1.4 million per month on average. Slight variations occur between months due to panel positioning and sun revolution angles. (See Exhibit 3.)

However, is PLTS more profitable than saving in a bank?

If solar earns less “interest rate”, then there is no point for the client to go forward with solar. To address this issue, we compared the return on both investments. (See Exhibit 4.)

After discussing 3 core questions above, what is your own conclusion?