Going Off-Grid: Is It Worth It? A Pictorial Exploration of Energy Self-Sufficiency

Michael Pullinger

The COVID-19 pandemic has seen disruption on a scale few of us have seen in our lifetime. This may prompt many to think about how to be more self-sufficient during future upheavals.

Using my own household, this article illustrates the challenges involved in energy self-sufficiency. But this could easily apply to businesses, buildings, or industrial sites.

My house, dressed up in its energy modelling splendour especially for this article.

1.     How Much Energy Do We Need For Self-Sufficiency?

We use a lot of electricity in my household. Most of our heating is electric, and we own an electric car. But since we’re fully electric, all our energy needs are met if we can supply our own electricity.

So, how much solar energy can we produce?

Suppose we packed our roof with as many solar panels as it could fit. This would produce slightly more electricity in a year than we consume.

The rooftop of our house, adorned with solar panels.

Our energy consumption compared to energy we could produce with solar power covering our rooftop.

But solar works best in summer. We use more energy in winter.

There’s simply not enough sun to provide our energy in winter without relying on the grid.

So, how do we overcome this issue? Let's start with using brute force.

2.     Brute Force Approach #1 – Build More Solar
We could just add more solar panels to increase winter energy production. By adding a battery, we can store excess daytime energy for use at night.

On January 18, we used the most energy and a solar power system would produce close to its minimum.

On the cold, dreary days, rooftop solar hardly makes a dent.

Energy on the coldest, darkest day of the year with rooftop solar.

Energy on the coldest, darkest day with a solar power system big enough to meet the entire day's energy use.

We need a much bigger solar power system to provide enough energy on this day.

However, we can’t build a system that size on our roof. We would have to surround our house with a sea of solar panels.

My wife would be happy that we left our backyard intact. The two dozen neighbours whose houses we’d have to bulldoze would probably be less than thrilled.

This is probably not going to work.

LESSON 1: Solar power is an excellent renewable energy source. But getting to 100% renewable energy isn’t as simple as installing more solar panels.

3.     Brute Force Approach #2 – Build More Batteries

Instead, why not just store the excess summer energy until the winter?

A solar power system would produce more than we need in the summer. With a big enough battery, we could just store that energy and make it available to use in the winter.

Using a solar energy modelling program, we can calculate how many batteries we’d need and estimate the cost based on typical residential batteries.

Without batteries, our house could supply our energy (without needing the grid) 30% of the time. With a single battery pack, this jumps to over 40%. A second battery pack brings us to 50%.

We can keep adding batteries until we get to 100% self-reliance.

How much would that cost?

By adding batteries, we are able to avoid being reliant on the electric grid for more of the year.

We can keep adding batteries, but each new battery has less effect. It gets expensive quickly.

Using industrial batteries, we could bring the cost down to “only” $2-3 million.

Unfortunately, this is still way out of our budget.

LESSON 2: A little energy storage goes a long way to improving energy system reliability. However, long duration energy storage can be extremely costly.

4. Balanced Approach

This demonstrates a stark point. Brute force doesn’t work.

In the real world, balancing competing options of energy supply, storage and conservation is part of any well-planned project. The final piece of that trifecta is energy conservation.

We can meet all our essential energy needs on the coldest, darkest cloudiest day with solar energy alone. By “essential”, I mean Wi-Fi, phone charging and a couple of hours of Netflix.

After Netflix, the next most important things might be a little cooking, a few lights, and running a small refrigerator. This would increase our energy use four-fold, and we’d fail to meet our energy needs 12 hours each year.

We could plug air leaks, replace our older windows, switch to heat pumps, or simply be more diligent with thermostats. Combined, such energy efficiency measures could save 40% of our energy and reduce our dependence on the grid.

How much of the year (or for how much of our energy) would we be reliant on the grid?

This moves us away from the utopian ideal.

We must either sacrifice our dream of total self-reliance, or we need to be more judicious in our energy use. But clever planning can still deliver excellent outcomes.

LESSON 3: Trade-offs are unavoidable. Expectations must be realistic. The best outcomes are achieved by balancing energy supply, consumption, and storage.

5.     Conclusions

Once we accept that we rely on the grid, our options vastly increase.

On a dark winter’s day, we can be supplied by a wind farm in Oregon, or a hydro facility in the Rockies. With a smart grid, my electric car could one day power your dishwasher.

The COVID-19 pandemic forces us to scrutinize the resiliency of everything we rely on, including our energy supply. But the reliability of an electric grid is difficult to match on a small scale.

The electric grid is a key technology enabling diversity of options and reliability of supply.

LESSON 4: Embrace the grid. Embrace diversity. The electric grid maximises our options for a reliable, low-cost, and environmentally friendly energy system.

Using solar energy to become self-sufficient is a great ideal. But, we can get to a point where we're "nearly" self-sufficient for a much lower cost. The grid gives us flexibility, and a diversity of options.

In this article, I haven't attempted to find the "optimum" solution, but have demonstrated the wide range of extremes for tackling this sort of problem. In some upcoming articles, I'll focus on how to find the best balance between renewable energy, energy efficiency and energy storage.

If you've enjoyed this article, please stay tuned for more.