As the energy industry continues to add green energy sources to its systems, people are rethinking the true meaning of energy sustainability. Renewable does not mean the same thing as sustainable.
— By James Hsu

The energy industry continues to make progress in including renewable energy sources in the existing energy generation system. Most of the time, renewable energy resources are identified as wind, solar, biomass, geothermal and hydro. But renewable energy is not the same as sustainable energy.

Renewable energy sources are one element of sustainability, but energy sustainability does not only concern the type of energy. It also includes a mindset that drives sustainable behaviors so that clean energy is available now and able to meet future needs of people. Shale gas offers a good example of the difference. It can supply energy needs now and for another hundred years, but at what cost to the environment and people?

Sustainable Energy vs. Renewable Energy
The terms “renewable” and “sustainability” are used interchangeably in discussions about energy production and usage, but they are not the same. Renewable energy or clean energy comes from natural resources that are regularly replenished, offering an unlimited supply of energy. Wind blows on and off and the sun shines on some days but not others, but the wind and sunny days always return over and over again.

Using a renewable energy source does not necessarily require people to make changes. For example, a house can install solar panels to generate electricity, but a house that uses electricity generated by a solar production plant does not have to make intentional decisions around sustainability.

A renewable energy source is not necessarily a sustainable one. Sustainability has three elements which are environmental, social, and economic. From an energy perspective, environmental sustainability means producing the energy does not harm the environment.

It sounds simple, but it is not. Everyone agrees that mining coal may harm the environment, but mining earth metals for use in wind turbines and solar panels is environmentally destructive. Most hydropower facilities require building dams which will change the natural migration path and habitat of fish, and submerge ecosystems. Is submerging areas where people live and enjoy recreational activities a socially sustainable practice?

Making Choices Today for Tomorrow
So energy sustainability means making choices and changing behaviors to ensure the lowest impact on people and the environment is achieved.

Remember the house that gets “green electricity” but is unaware of their energy source or if there is an environmental impact? A household can choose to install solar panels after comparing the impact of various renewable resources, followed by installing a heat pump and energy–efficient windows, and developed a plan to reduce energy consumption.

Sustainability is a mindset. Sustainability means making conscious decisions about energy type and use with the goal of having the least environmental impact but the greatest positive social and economic impacts.

The greatest social impact means being able to meet the growing energy demand now without threatening the ability to meet energy needs in the future. It is one reason why clean energy supporters say that energy producers and users should focus on minimizing energy use now.

Innovative Technologies are the Solution
Technology is already at the heart of sustainable energy, and innovators are developing new ways to produce and store energy with minimal environmental impact and to increase energy efficiency. If renewable energy forms require critical metals like silver, cadmium, and indium, there will eventually be a shortage because these are not renewable or take so long to long to form that they cannot be considered renewable.

The real answer to sustainable energy is developing innovative technologies that eliminate the use of resources that will eventually run out, and create renewable energy that is scalable, accessible, and affordable to generate and to end consumers.

This is a wide open opportunity for innovative suppliers. For example, there is a need for innovators to develop a way to decarbonize the electric grid when it has to work during seasonal weather variations or intermittency which occurs even in areas where there is high utilization of renewable energy sources. Efficient and inexpensive energy storage remains a need. Green hydrogen is not new, but new ways of producing it are being investigated as the hydrogen industry looks to move away from carbon intensive production methods. This is just a sample of needs.

Is Shale Gas Production an Environmentally Sustainable Process?
Shale gas is a good example of the difficulty in separating renewable energy from sustainable energy.

Shale gas is unique in that it is a non-renewable fossil fuel, yet it is renewable in the sense that it comes from organic material trapped between shale rocks that produces natural gas. There is enough shale gas to last almost a century, and enough is produced now to make the United States energy independent. These facts make people think of natural gas as renewable and sustainable.

Visit a Midwest shale gas mining field and there will be large orange and yellow flames emerging from pipes extending out of the earth. Extracting the natural gas from shale rock through fracking (hydraulic fracturing) and directional drilling produces gas, and that is what is burned. It seems ironic that mining for natural gas leads to burning gas, but flaring (burning gas) is considered the most economical way to get rid of excess gas that is not economically feasible to collect and sell. Flaring is also used to convert dangerous gases like hydrogen sulfide into a less toxic compound.

Studies have shown that natural gas flares produce a number of air pollutants that include formaldehyde, propylene, polycyclic aromatic hydrocarbons, propylene, and more. The main gas released is methane, and research has indicated that as much as 13 million metric tons of methane are released each year from fracking. They are released due to flaring, venting, and leakage.

Studies of shale gas released during fracking estimate that it is a substantial amount of the overall methane increase in the atmosphere since 2008. Approximately two to six percent of methane is leaked, vented, or flared during production. Methane is a greenhouse gas, so releasing tons of methane gas is contributing to global warming.

Shale gas development is associated with other environmental impacts. They include large amounts of water consumption that threatens local water resources, contamination of ground water with heavy metals and radioactive elements, and inducement of seismic activity. These impacts mean shale gas is not sustainable. It is a fossil fuel that some believe is distracting efforts to make more progress in increasing utilization of renewable energy sources. People who support fracking say that the impact it has on future energy security overrides arguments against it.

The Big Goal: Striving for Sustainable Energy
The energy industry is moving toward utilizing more renewable energy sources, but it has been slow. Many experts believe it should be working more on developing sustainable energy.

Change is slow in an industry in which there is such an enormous capital investment in the infrastructure, but change is coming. It has to as the nation and the global community continue to deplete fossil fuels at an alarming rate.