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How does Trine calculate the impact of Solar Home Systems?
How does Trine calculate the impact of Solar Home Systems?

How do we estimate the CO2 avoidance and social impact? Here we explain the data and methods behind the numbers for Solar Home Systems.

Christoffer Falsen avatar
Written by Christoffer Falsen
Updated over a week ago

Investments at Trine come with an environmental, social and financial return. We estimate the future impact in terms of carbon dioxide equivalent (CO2e) emissions avoided and how many people will get access to electricity, displaying the relevant numbers on the loan offer page.

If you're wondering how we get to those numbers here are a few details for you. Currently we use different methods depending on the industry and this article will focus on Solar Home Systems. There is another article with more details on how we calculate the impact of Commercial and Industrial solar energy.

Solar Home Systems (SHS)

Please note that we are using the industry standard of impact calculation approved by the Global Off-grid Lightning Association (GOGLA). The industry standard for impact calculation is continuously improving and therefore the calculation is subject to change over time. Our policy is to reflect the latest standardised impact metrics for lighting products launched by GOGLA, currently version 4.0. An update to the standardised impact calculation will affect new loans available for investment but not loans that are already funded.

In order to be as transparent as possible we have included the old calculation in this article so that you can also see how the impact was calculated for your previous investments.

Environmental Impact

The avoidance of CO2 emissions is calculated by counting how many fossil fuel based lanterns each solar system or solar lantern will replace. The calculation is based on:

  1. Number of solar systems (S)

  2. Discount for loss factor, products not used for full lifetime (DF) - the discount for loss factor should estimate the fraction of customers for whom the impact of a product is not fully realised. This could for example be due to product loss, default or churn. DF is a variable metric and Trine calculates this based upon estimated breakdown (3 %) and churn / default (10 %).

  3. Replacement rate of kerosene lanterns per solar product (R) - assumed to vary between 0.2 up to 1.3 depending on region (East Africa, West Africa, South Asia, Global Default) and size of the solar systems

  4. Average annual carbon dioxide and black carbon (tons of CO2e) emissions per kerosene lantern, in metric tons (G) - assumed to be 0.431

  5. Estimated solar product lifespan (1.5x warranty), usually 3-4 years (PL)

So the calculation to estimate the impact of a loan is S x ( 1-DF) x R x G x PL = CO2e emissions avoided

We also reduce this calculation of the CO2e emissions avoided by 5%. We have made this general reduction as a margin for error.

These are conservative estimates considering the batteries can last for more than 8 years and solar panels have an even longer lifetime of 25 years or more.

Long-term Impact

The environmental impact we display on our site is limited to the amount of CO2e avoided in the short term, the long-term environmental impact is much broader. By supporting the introduction of clean, renewable solar energy early in developing countries, your investment helps solar become the energy of the future.

Social Impact

We calculate how many people will get access to electricity by taking into consideration the average household size where one system equals 5.5 people getting access to electricity. The calculation will equal the number of people with improved energy access, cumulatively.

The calculation is based upon :

  1. Number of solar systems (S)

  2. Discount for loss factor, products not used for full lifetime (DF) - the discount for loss factor should estimate the fraction of customers for whom the impact of a product is not fully realised. This could for example be due to product loss, default or churn. DF is a variable metric and Trine calculates this based upon estimated breakdown (3 %) and churn / default (10 %).

  3. Discounting for repeat sales (DR) - to avoid double counting of customers - assumed to be 3 - 10%

  4. Household size (H) - Assumed to be 5.5

So the calculation is S x ( 1-DF ) x ( 1-DR ) x H = Number of people with improved energy access, cumulatively

We also reduce this calculation by 5%. We have made this general reduction as a margin for error.

Calculations for loans before 31st November 2020

Old calculation related to loans that were fully funded before end of November 2020.

Environmental impact
โ€‹S x G x PL = CO2e emissions avoided

Social impact

S x ( 1- DR ) x H = Access to energy

The estimations were reduced by 15% as a margin for error and to take into account losses. In the new calculation this is now partly included in the formula.

Sustainable Development Goals

Impact can mean so much more than just the number of people gaining access to electricity or the amount of CO2e emissions avoided. To give you a better view of this we have decided to use the UN's 2030 Sustainable Development Goals. You will find the goals on each loan page that we assess to be directly affected through an investment in that loan.

All Trine loans directly impact goal 7 for affordable and clean energy and goal 13 for climate action, but it does not stop there. Solar home systems contribute to better health through cleaner air (goal 3) and quality education (goal 4) as children are able to do their homework after dark.

The UNDP evaluated our impact after visiting one of our partners and found an investment to have an impact on 10 out of 17 sustainable development goals.

How impact data is presented in your Dashboard

Once the solar systems have been installed and the borrower starts reporting these numbers to Trine, we can measure the real impact of your investment, each day. These numbers are the ones shown in your Dashboard.

The calculation used to measure the CO2 avoidance is:

R x G x PL = CO2e emissions avoided

The CO2 emissions avoided are presented in metric tons (1000kgs).

The calculation used to measure how many people have access to electricity is:

S x ( 1-DR ) x H = Number of people with improved energy access, cumulatively

These are very similar to the formula's used to estimate the future impact but as it is used for systems that are installed and functioning, there is no discount for loss.

Find out more on how impact is later reported and measured for loans in the Solar Home System Sector.

Please note that we do not sell carbon credits.

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