Navigant Research Blog

The Positive Side of Negative Emissions

— February 15, 2018

In recent years, awareness has grown on the need for CO2 removal to avoid dangerous levels of climate change, and companies are increasingly looking to include negative emissions in corporate climate strategies. As a part of Navigant, Ecofys finds that sufficient scalable and affordable options for negative emissions exist, and that instead of being a burden, they carry many environmental and social co-benefits.

The Need for CO2 Removal

A key element of Paris-consistent scenarios are technologies that enable the removal of CO2 (greenhouse gases [GHG]) from the atmosphere, which need to absorb up to 3 GtCO2 per year as soon as 2030 to meet the “well below 2˚C target.” This is comparable in scale to roughly all of the European Union’s current annual CO2 emissions. The rationale of engaging in CO2 removal (CDR) is threefold:

  1. Even the most ambitious mitigation strategies will see residual emissions in hard-to-abate sectors, such as aviation or agriculture, and in order to reach net-zero emissions around mid-century, compensation with CDR is essential.
  2. The speed at which global emissions are reduced is limited because of inertia in the global energy system, but with CDR this process can be accelerated. An immediate, steep downward trajectory is needed to avoid overshooting climate targets and to avoid more negative emissions later this century—CDR can support such a trajectory.
  3. CDR puts a cap to the cost of emissions reductions, thereby improving the cost-efficiency and feasibility of achieving carbon budgets.

This makes CDR especially relevant for organisations that will play a key role in the transition to a zero-carbon economy, such as energy-intensive industries, agriculture and food companies, and governments. Through studies for the UN Environment Programme and the UK Committee on Climate Change (amongst others), Ecofys, a Navigant company, is at the forefront of developments in this field. The team observed that these projects often carry more benefits than their potential to draw carbon from the atmosphere.

A Worthwhile Investment

Methods for GHG removal are incredibly diverse, and some options are already being deployed at limited scale, while others are facing obstacles or may appear futuristic, such as bioenergy with carbon capture and storage, or the direct capture of carbon from the atmosphere. Given the multiple co-benefits CDR can deliver, some of the more developed methods are frequently referred to as no-regret options and reflect the social, environmental, and financial ROI that may result from their application. Such options are illustrated in the figure below.

Environmental Benefits of CO2 Removal Options

(Source: Ecofys, a Navigant Company)

Looking at opportunities with investment costs <$20/tCO­2, the global potential for these methods is estimated at 4.1 GtCO2/yr in 2030, which indicates that a significant share of the 3 GtCO2/year removal needed by 2030 to meet the well below 2˚C target could be achieved through the discussed methods. The examples provided illustrate that, while beneficial to the environment and people, CDR can make economic sense as well. However, it should be noted that business cases may differ strongly between regions and policy context, meaning that opportunities for negative emissions should be identified on a case-by-case basis—first within the scope of existing business activities and lastly by looking outward for other low-hanging fruits.

Get in touch with one of our experts to discover the potential options for CO­2 removal related to your business supply chains.


Zero Emissions from a Fossil Fuel Plant … Really?

— June 6, 2017

The claim of zero emissions from a fossil fuel plant sounds too good to be true. I was skeptical when I first read the headline, “Goodbye Smokestacks: Startup Invents Zero-Emission Fossil Fuel Power,” on the Science website. But on second glance, this does appear to be a big deal in the carbon capture realm.

Oxymoron or Innovation?

Author Robert Service notes: “Zero emissions fossil fuel power sounds like an oxymoron.” And indeed, it does. But the people behind startup NET Power believe its technology makes this possible. The company is backing a 25 MW demonstration plant in the Houston area that will be activated later this year. Basically, the plant will burn natural gas in a pure oxygen combustor. By using mostly pure, high pressure CO2, the plant can avoid the phase changes of traditional steam cycles. And instead of driving a steam cycle and losing heat up a smokestack, the NET Power plant retains heat within the system, resulting in less fuel used for a turbine to reach the necessary temperature.

The result, the company claims, is a stream of nearly pure CO2 that is then piped away and stored underground, or that can be shot into sapped oil reservoirs to recover what oil remains. This latter process is called enhanced oil recovery. In either case, the CO2 is kept out of the atmosphere. The system is based on work done by Rodney Allam, a retired British engineer, and is called the Allam Cycle. The key to Allam’s idea is the recycling of the CO2 in a loop.

A Fossil-Fueled Game Changer

NET Power says it can produce emissions-free power at about $0.06/kWh, which is about the same as the cost from a state of the art, natural gas-fired plant. And lower than most renewable energy. If the demonstration meets expectations, the company intends to move to a full-scale, 300 MW version that could be operational in 2021 at a cost of about $300 million. Such a power plant could supply more 200,000 homes. One expert, John Thompson from the Clean Air Task Force, says the breakthrough plant would be “a game-changer if they achieve 100% of their goals.”

We shall see. The NET Power facility could fail to reach its goal; as carbon capture expert Howard Herzog says, “There are only a million things that can go wrong.” But if successful, the zero emissions plant could be a bridge to a cleaner environment, and could drive more aggressive use of renewable sources. So, what’s not to like about this kind of audacious engineering that aims to solve a problem in a practical way? Failure is a possibility, but success is, too.


Blog Articles

Most Recent

By Date


Clean Transportation, Digital Utility Strategies, Electric Vehicles, Energy Technologies, Policy & Regulation, Renewable Energy, Smart Energy Practice, Smart Energy Program, Transportation Efficiencies, Utility Transformations

By Author

{"userID":"","pageName":"CO2 emissions management","path":"\/tag\/co2-emissions-management","date":"2\/18\/2018"}