Solar energy for businesses and retail

In a home, a good share of consumption happens at night, when the system does not produce. In a business with daytime opening hours the opposite is true: the activity, the refrigeration, the lighting and the equipment all run precisely during the hours of highest generation.

That overlap is the variable that moves the return the most. The energy you consume at the moment it is produced saves you the full tariff, whereas what you export is offset according to what the regulation sets, at a value that need not match it. A daytime profile maximises the valuable part.

On top of that, commercial and industrial tariffs are usually higher than residential ones and these users pay a solidarity contribution. Every kWh you stop buying is worth more.

Laws 1715 of 2014 and 2099 of 2021 establish mechanisms that reduce the effective cost of a non-conventional generation project: an income tax deduction on part of the investment, VAT exclusion on equipment and services, exemption from import duties on goods not produced in the country, and accelerated depreciation of the asset.

The relevant detail is that these are not an automatic discount on the installer's invoice. They are granted on a project certified with UPME under Decreto 829 de 2020, and their real effect depends on your tax situation: a company without sufficient net taxable income does not benefit from a deduction in the same way as one that has it.

So it is worth involving your tax adviser in the assessment from the start, and being wary of proposals that present the benefits as part of the price rather than as a possibility to be assessed.

Not every business wants or is able to tie up capital in an installation, and there are three routes with different implications.

An outright purchase gives you ownership of the asset from the start and full access to the tax benefits, in exchange for the outlay. It is the option with the best return when there is cash and the capacity to use the deduction.

Leasing lets you use the system by paying an instalment, with a purchase option at the end. It changes the accounting and financial profile of the operation and usually fits when the goal is to preserve liquidity.

A PPA — power purchase agreement — goes a step further: a third party installs and operates the system on your roof and you buy the energy generated at an agreed price, normally below the tariff. There is no up-front investment and no maintenance responsibility, but there is also no ownership of the asset and no direct access to the incentives, and the contract is usually long-term. It is worth reading carefully the term, the price escalation formula and what happens if the property changes hands.

Warehouses and retail units usually have lightweight sheet-metal roofs on a steel structure, designed for their own weight and little more. Before designing the system you have to verify that it can take the additional load and the wind loads for the area.

The condition of the roof also drives the timeline: installing over sheeting close to the end of its life means having to dismantle the system when it needs replacing. If the roof is ten years old or more, it is worth considering renewing it before rather than after.

And an advantage of this segment: commercial roofs tend to be large, flat and clear, which reduces the shading problem and allows freer orientations and tilts than on a house.

A grid-connected system shuts down during an outage for safety. If your operation cannot tolerate interruptions — cold chain, processes that cannot stop, customer service — that has to be solved separately, with a hybrid system or with conventional backup.

The decision is made by listing which loads must keep running and for how long, not by sizing backup for the whole installation. Almost always the critical set is a small fraction of the total.

It is worth separating this from the profitability analysis: backup is not justified by savings but by the cost of having no power, which in a business is usually far higher than in a home.

Beyond what applies to any installation — equipment brand and warranty, price per watt, estimated output with its assumptions, inclusion of legalization — a business project has points of its own.

The first is the load profile analysis: a serious proposal asks for the hourly consumption history if it is available, not just the monthly total, because that is what tells you how much generation is self-consumed. The second is the connection point and whether the project requires upgrades to the panelboard or the service entrance.

And the third is maintenance: on a larger system and on an industrial roof, an operations and maintenance plan with periodic inspection and monitoring stops being optional.