Many households are becoming “energy citizens,” installing solar panels and other renewable energy on their private properties.
In theory, this is positive for everyone. Including renewable energy lowers energy costs and, by replacing fossil fuels, reduces planet-warming carbon dioxide emissions. However, as solar panels and other renewable infrastructure are installed, fears are growing that local power grids will become congested.
To understand this problem and propose a solution, we carried out research on it. Although we focus on Ireland, where we live and work, we are aware of something similar happening in many parts of the world.
There is no room for everyone
To start, we studied the electrical infrastructure of the entire country and discovered that if everyone wanted to install solar panels on their roofs, only 5% of the 1.6 million electricity users included in the analysis would be able to connect them to the national grid.
The calculations have been made considering what would happen if each household wanted to install 6 kilowatts of renewables – solar on a portion of the roof of a typical house, for example, or a small wind turbine – which is the maximum limit supported by the scheme. support for microgeneration in Ireland.
What is happening in Ireland is similar to the problems that exist in electrical networks in California, Spain and Germany, where the “pioneers” in installing these technologies are blocking access for those who join later. Although all of these countries are well advanced in their solar PV development, some parts of the power grid are no longer available for new installations.
The most unfair thing is that, often, the wealthiest households are the first to install solar photovoltaics and benefit from subsidies. Without forgetting that it limits how useful microgeneration is for the global objective of decarbonizing society.
The “game of chairs” of energy
The situation can be compared to the classic game of chairs.
The first problem is the number of chairs: the electrical grid was not designed for each home to produce large amounts of renewable energy.
As long as the sun shines, every user with a solar panel can use electricity instantly or deliver it to the grid. That works as long as few users are contributing power to the grid, but on a national scale all that power can exceed the physical capacity of the cables, causing surges that damage equipment or interrupt service. To avoid this, the grid operator has no choice but to limit the amount of connected renewables.
There are some ways to tackle this problem from a technical point of view or, continuing with the metaphor, so that there are more “chairs” available. This may include investing in new cables, or installing residential battery banks and timed electric vehicle chargers to make energy use more coordinated. With one drawback: all these solutions involve a high cost.
Power grids in rich countries – the Irish grid is a good example – have been under construction for over a hundred years, and retrofitting them is no simple job. This readaptation is even more problematic in emerging economies, in many cases unable to cover these costs.
The second problem is deciding who can “sit” first. The current policy allows renewables to be allocated on a “first come, first serve” basis. Inevitably, that gives priority to high-income parts of society to occupy an empty chair to sit down first, and therefore to benefit economically.
How to avoid injustice
Imagine you move and, once installed, you discover that the entire grid is busy and it is not possible to connect new solar panels. It does not have access, therefore, to the direct benefits of having a clean energy installation. And that is an injustice.
To make network unavailability no longer a problem, instead of general limits – such as 6 kilowatts in Ireland – we will need detailed analysis of the network. This way we will be able to quantify the maximum amount of renewables that a home can have without impeding access to others.
This calculation is necessary because the limitation differs for different users depending on their location on the network. Do not forget that technical restrictions depend on how close they are to a substation or how many people are connected to this substation, among other factors.
The second way to share the network is to accept that some households have the money to install more than their fair share, and in return they can help everyone collectively. For example, less-advantaged user shares can be used by wealthier households to install new solar panels and wind turbines in exchange for cheaper electricity derived from those installations. This way, the benefits from the use of shared network capacity can be shared.
Take equity into account
The progress is unquestionable. Globally, institutions are striving to achieve decarbonization goals, and the installation of renewable energy is booming. The transition to low carbon energy is now inevitable. The question is no longer whether the transition takes place, but how it becomes a reality
Renewable energies should not worsen pre-existing inequalities. Policies for domestic wind and solar should be developed using equity criteria. Only in this way will they allow all electricity users to benefit economically from clean energy equally.