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Cement Structures Are Significant, Overlooked Carbon ‘Sinks’

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Cement Mixer III by dailyinvention via flickr

The University of East Anglia (UEA) have recently released a study which indicated that cement structures are a substantial, yet overlooked, absorber of carbon emissions – offsetting some emissions released during cement production.

Conducted by the China Emission Accounts and Datasets (CEADs) group, an international team of researchers led by UEA’s Prof Dabo Guan, it found that the natural carbonation process of cement materials represents a large and growing ‘sink’ of CO2. However, while the Intergovernmental Panel on Climate Change (IPCC) guidelines for emissions inventories provide methods for quantifying CO2 emissions during the cement production process, they do not consider carbon absorbed through cement carbonation.

Carbonation is a slow process that takes place throughout the life cycle of cement-based materials. As they weather, CO2 spreads into the pores and triggers a chemical reaction, starting at the surface and gradually moving inwards.


Using new data from field surveys in China and existing data and studies on cement material during its service life, demolition and secondary use of concrete waste, the researchers modelled the regional and global atmospheric CO2 uptake between 1930 and 2013.

The findings, published today in the journal Nature Geoscience, indicate that existing cement stocks worldwide absorb approximately one billion tons of atmospheric CO2 each year. The researchers focused on four cement materials – concrete, mortar, construction cement waste and cement kiln dust – in China, the US, Europe and the rest of the world.

It is estimated that 4.5 gigatons of carbon (GtC) has been reabsorbed in carbonating cement material from 1930 to 2013, offsetting 43 per cent of the CO2 emissions from production of cement over the same period, not including emissions associated with fossil fuel use during cement production. An estimated 44 per cent of cement process emissions produced each year between 1980 and 2013 has been offset by the annual cement sink.

The process CO2 emissions from cement production make up approximately 90 per cent of global CO2 emissions from all industrial processes and five per cent of global CO2 emissions from industrial processes and burning fossil fuels combined.


Prof Guan, the study’s lead UK author and a professor in climate change economics at UEA’s School of International Development, said the overall size of the cement sink between 1930 and 2013 was significant for the global carbon cycle.

“Existing cement is a large and overlooked carbon sink and future emissions inventories and carbon budgets may be improved by including this,” said Prof Guan. “Also, efforts to mitigate CO2 emissions should prioritise the reduction of fossil-fuel emissions over cement process emissions, given that produced cement entails creation of an associated carbon sink.

“We suggest that if carbon capture and storage technology were applied to cement process emissions, the produced cements might represent a source of negative CO2 emissions. Policymakers might also investigate ways to increase the completeness and rate of carbonation of cement waste, for example as a part of an enhanced weathering scheme, to further reduce the climate impacts of cement emissions.”

Before 1982, the majority of CO2 capture occurred in Europe and the US, corresponding to the legacy carbon sink of cement building and infrastructure built during the 1940s and 1950s. Since 1994, cement materials used in China have absorbed more CO2 than the other regions combined, due to its rapidly increasing cement production.

Mortar cement captured the most carbon, even though only approximately 30 per cent of cement is used in mortar. This is because it is frequently applied in thin decorative layers to the exterior of building structures, with higher exposure surface areas to atmospheric CO2, and therefore a higher carbonation capacity.

Despite a relatively smaller exposure area, and therefore lower carbonation rate, concrete cement is the second largest contributor to the carbon sink because approximately 70 per cent of all produced cement is used in concrete.

The researchers also highlight the legacy effects of accumulating cement stocks. On average, between 2000 and 2013, 25 per cent of the carbon captured each year was absorbed by cement materials produced more than five years earlier and 14 per cent produced more than 10 years earlier.

Demolition causes an increase in carbonation rates by exposing large and fresh surfaces. Because the average 35-year service lifetime of structures in China is shorter than the average 65-70 years in the US and Europe, the turnover of cement with respect to carbonation has been increasing over time, accelerating the uptake of CO2.
Between 1990 and 2013 the annual carbon uptake has been increasing rapidly by an average of 5.8 per cent a year, as the stock of cement buildings and infrastructure increases, ages and gets demolished and disposed. This is slightly faster than process cement emissions over the same period, on average 5.4 per cent a year.

Given expected demolition, waste disposal, and reuse of cement materials from the large amount of concrete structures and infrastructure built in the past half-century, and the still-increasing cement consumption in China and other developing countries, the carbon sink of cement materials can therefore be anticipated to increase in the future.

CEADs aims to improve methods of data collection and provide the most up-to-date emission inventories for China and its provinces and cities. The datasets published by CEADs are available to download for free from its website: http://www.ceads.net

The paper ‘Substantial global carbon uptake by cement carbonation’ is published in Nature Geoscience.

Energy

Are the UK Governments Plans for the Energy Sector Smart?

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The revolution in the energy sector marches on, wind turbines and solar panels are harnessing more renewable energy than ever before – so where is it all leading?

The UK government have recently announced plans to modernise the way we produce, store and use electricity. And, if realised, the plans could be just the thing to bring the energy sector in line with 21st century technology and ideologies.


Central to the plans is an initiative that will see smart meters installed in homes and businesses the length and breadth of the country – and their aim? To create an environment where electricity can be managed more efficiently.

The news has prompted some speculation about how energy suppliers will react and many are predicting a price war. This could benefit consumers of electricity and investors, many of whom may be looking to make a profit by trading energy company shares online using platforms such as Oanda – but the potential for good news doesn’t end there.

Introducing New Technology

The plan, titled Smart Systems and Flexibility is being rolled out in the hope that it will have a positive impact in three core areas.

  • To offer consumers greater control by making smart meters available for all homes and businesses by 2020. Energy users will be able to monitor, control and record the amount of energy they use.
  • Incentivise energy suppliers to change the manner in which they buy electricity, to offer more smart tariffs and more off-peak periods for energy consumption.
  • Introduce new standards for electrical appliances – it is hoped that the new wave of appliances will recognise when electricity is at its cheapest and at its most expensive and respond accordingly.

How the Plans Will Affect Solar Energy

Around 7 million houses in the UK have solar panels and the government say that their plan will benefit them as they will be able to store electricity on batteries. The stored energy can then be used by the household and excess energy can be exported to the national grid – in this instance lower tariffs or even payment for the excess energy will bring down annual costs significantly.


The rate of return on energy exported to the national grid is currently between 6% and 10%, but there are many variables to take into account, such as, the cost of battery storage and light levels. Still, those with state-of-the-art solar electricity systems could end up with an annual profit after selling their excess energy.

The Internet of Things

Much of what the plans set out to achieve are linked to the now ubiquitous “internet of things” – where, for example, appliances and heating systems are connected to the internet in order to make them function more smartly.

Companies like Hive have already made great inroads into this type of technology, but the road that the government plans are heading down, will, potentially, go much further -blockchain technology looms and has already proved to be a game changer in the world of currency.

Blockchain Technology

It has already been suggested that the peer to peer selling of energy and exporting it to the national grid may eventually be done using blockchain technology.

“The blockchain is an incorruptible digital ledger of economic transactions that can be programmed to record not just financial transactions but virtually everything of value.”

Don and Alex Tapscott, Blockchain Revolution (2016)

The upshot of the government’s plans for the revolution of the energy sector, is that technology will play an indelible role in making it more efficient, more flexible and ultimately more sustainable.

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Energy

4 Case Studies on the Benefits of Solar Energy

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Demand for solar energy is growing at a surprising rate. New figures from SolarPower Europe show that solar energy production has risen 50% since the summer of 2016.

However, many people are still skeptical of the benefits of solar energy.Does it actually make a significant reduction in our carbon footprint? Is it actually cost-effective for the company over the long-run?


A number of case studies have been conducted, which indicate solar energy can be enormously beneficial. Here are some of the most compelling studies on the subject.

1.     Boulder Nissan

When you think of companies that leverage solar power, car dealerships probably aren’t the first ones that come to mind. However, Boulder Nissan is highly committed to promoting green energy. They worked with Independent Power Systems to setup a number of solar cells. Here were the results:

  • Boulder Nissan has reduced coal generated electricity by 65%.
  • They are on track to run on 100% renewable energy within the next 13 years.
  • Boulder Nissan reduced CO2 emissions by 416,000 lbs. within the first year after installing their solar panels.

This is one of the most impressive solar energy case studies a small business has published in recent years. It shows that even small companies in rural communities can make a major difference by adapting solar energy.

2.     Valley Electric Association

In 2015, the Valley Electric Association (VEA) created an 80-acre solar garden. Before retiring from the legislature, U.S. Senate Minority Leader Harry Reid praised the new project as a way to make the state more energy dependent and reduce our carbon footprint.


“This facility will provide its customers with the opportunity to purchase 100 percent of their electricity from clean energy produced in Nevada,” Reid told reporters with the Pahrump Valley Times. “That’s a step forward for the Silver State, but it also proves that utilities can work with customers to provide clean renewable energy that they demand.”

The solar energy that VEA produced was drastically higher than anyone would have predicted. SolarWorld estimates that the solar garden created 32,680,000 kwh every year, which was enough to power nearly 4,000 homes.

This was a major undertaking for a purple state, which may inspire their peers throughout the Midwest to develop solar gardens of their own. It will reduce dependency on the electric grid, which is a problem for many remote states in the central part of the country.

3.     Las Vegas Casinos

A number of Las Vegas casinos have started investing in solar panels over the last couple of years. The Guardian reports that many of these casinos have cut costs considerably. Some of them are even selling the energy back to the grid.

“It’s no accident that we put the array on top of a conference center. This is good business for us,” Cindy Ortega, chief sustainability officer at MGM Resorts told Guardian reporters. “We are looking at leaving the power system, and one of the reasons for that is we can procure more renewable energy on the open market.”

There have been many benefits for casinos using solar energy. They are some of the most energy-intensive institutions in the world, so this has helped them become much more cost-effective. It also helps minimize disruptions to their customers learning online keno strategies in the event of any problems with the electric grid.

4.     Boston College

Boston College has been committed to many green initiatives over the years. A group of researchers experimented with solar cells on different parts of the campus to see where they could produce the most electricity. They discovered that the best locationwas at St. Clement’sHall. The solar cells there dramatically. It would also reduce CO2 emissions by 521,702 lbs. a year and be enough to save 10,869 trees.

Boston College is exploring new ways to expand their usage of solar cells. They may be able to invest in more effective solar panels that can generate far more solar energy.

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