Tag Archives: energy efficiency

Anaerobic digestion solution for waste & energy

Anaerobic digestion

Anaerobic digestion (AD) can be used for farms, businesses and municipalities as a productive solution to a growing waste problem throughout the world. In addition to AD, waste-to-energy is done in landfills using landfill refuse and landfill gases (such as methane). The use of AD in a biomass plant is a cost-effective way to produce renewable energy. AD also leads to less landfill waste and is a constructive way for farms, businesses and municipalities to dispose of waste. AD is the process of turning agricultural waste (such as livestock manure), wastewater, or municipal, commercial and industrial waste streams (such as food processing waste), into energy. AD uses micro-organisms to break down organic material and create biogas (biogas consists mostly of methane and CO2).

Instead of waste simply ending up in landfills, or being incinerated, waste can be turned into energy. Farms can be entirely powered by waste from their livestock, food waste and wastewater. Use of AD can make also make wastewater treatment facilities energy neutral or even energy positive, translating to huge cost savings for municipalities.

Organic waste finds a purpose in an AD biogas plant, as it is put in a digester, along with various types of micro-organisms (enzymes, bacteria etc…), to transform the waste into energy (methanation). The molecules of the organic material are broken down in the plant into a useful form like glucose. The “digested” raw material is then used to create biogas (and digestate which can be used as fertilizer).

The biogas can then be purified (and also optionally be upgraded with hydrogen) and turned into pipeline-quality synthetic natural gas for the grid. Biogas can also be turned into compressed natural gas (CNG) for vehicles. The anaerobic process also occurs naturally (as in landfills), in addition to the man-made construct in a biomass plant.

An anaerobic digester and biomass plant generate biogas (and/ or biomethane) which can be burned on-site to generate heat, power or both (so, combined heat and power – CHP). AD is mostly used by farms and wastewater treatment facilities for on-site electrical and heating generation, although it can also be used in a variety of other applications. Biogas can also be purposed as an energy source for the grid when purified, and turned into pipeline-quality synthetic natural gas (or turned into biomethane and used for heat or transportation as CNG). Also produced in the process is digestate, which is a source of nutrients that can be used as a fertilizer.

Biogas can also be upgraded with hydrogen, combining the outputs of a biogas plant and an electrolyzer, creating biomethane. Like conventional natural gas, biomethane can be used as a transportation fuel in the form of compressed natural gas (CNG), or liquefied natural gas (LNG). When biogas is used for heat or transportation, as biomethane, CNG, (biomethane – CNG – can be used in place of diesel, given modifications to the vehicles in question), there are tremendous greenhouse gas reductions.

The entire bus fleet in Oslo, Norway, is run on CNG from sewage treatment and organic waste, and they see a dramatic (around 70%) reduction in greenhouse gas (GHG) emissions compared to fossil fuel burning vehicles. Food waste and other waste processed through AD also brings the benefit of reducing GHG emissions substantially by reducing landfill waste. When AD is used for on-site electrical generation, energy generation for a municipality, farm or wastewater facility, GHG emissions overall are greatly reduced. Energy produced by AD has a very low overall carbon footprint.

Poplars AD plant

Poplars AD plant

The AD plant at Cannock, Staffordshire, England (called the Poplars AD plant) is an example of a successful, large-scale AD plant. The £24 million project treats commercial and industrial food and waste to create, through methanation, around 6MW of renewable energy, synthetic natural gas, for the national grid. The Poplar plant shows that a large-scale anaerobic digestion project is viable. AD has been successful in many commercial operations as well. For example in Orlando, Florida, food waste sourced primarily from the Walt Disney World Resort is fed through an anaerobic digester, producing enough electricity to meet the needs of over 16,000 homes.

Please see: renewable energy: biomass and biofuel

Gasification – syngas from fossil fuels and environmentally friendly versions

Algae : the future of biofuel

Cellulosic biofuel – one fuel option

world energy mix

Shortfall in International GHG Pledges

There is a shortfall between the pledges that the nearly 200 countries independently, and internationally as a whole, have made at the COP 21 in Paris last November, compared to the reality of what the planet has in its future. There is also a genuine effort to limit global temperature rise to 2 degree celsius average global temperature increase above the normal numbers (using historical numbers as a baseline for comparison) by the end of this century – the number that represents saving the planet from the worst effects of climate change.

In order to prevent the most damaging effects of climate change, the international community has pledged, in Paris, to increase the use of such sustainability technologies as renewable energy and energy efficiency measures, while decreasing fossil fuel use, in order to mitigate GHG (greenhouse gas) emissions…emissions which lead to global temperature rise. The idea is to keep global temperature rise to under 2 degrees celsius above normal (compared to historical values) by the end of this century.

scoreboard banner: result of international climate change action

The reality is that the average global temperature rise will be significantly greater than what was promised at Paris. A 5-8+ degrees fahrenheit rise in average temperature would result if the world simply maintains the status quo. The pledges in Paris, as well as actions by nations and private investors before and after COP21, demonstrate a genuine global effort in the research, development and effective use of sustainable technologies and measures. Of course, this is great, but global temperature rise still will be over the global temperature goals committed to in Paris.

In other words, at least 2+ degrees celsius change over the acceptable 2 degrees limit by the end of this century will result, even if all pledges by all countries are actually met. Even in this positive scenario (and the best-case scenario discribed below), as of now, there is still a shortfall – this NYTimes infographic clearly illustrates this problem — http://tinyurl.com/gct333

If all nearly 200 nations keep all of their promises from COP21, temperature rise will be limited to just 0.035°C (0.063°F) annually (best case). Even if every government on the planet that participated not only keeps every Paris promise, reduces all emissions as promised by 2030 (2030 was the year of note discussed in Paris), and shifts no emissions to other countries, but also keeps these emission reductions going throughout the rest of the century, temperature rise will be kept to just 3°C (5.4°F) by the year 2100.

Obama’s Clean Power Plan, his moratorium on drilling for oil in the Atlantic, the U.S.’s 3 year moratorium on building coal mines on federal land, China’s 3 year ban on building new coal mines, and their shutting down of thousands of older coal power plants are all very positive signs. Other promising signs include the U.S.’s increased development and use of renewable energy and energy efficiency technologies (as well as in China, India and much of the developing world). Europe has been leading the way for many years, in many respects, in terms of sustainability technologies. However, optimism, in the face of the undeniable math of climate change which clearly tells us more needs to be done, should be weighed carefully against climate change realities.

Green City Times is a resource on sustainability, urban planning, renewable energy, sustainable mass transportation, energy efficiency and green building. Find facts on renewable energy including: hydroelectric (from dams, mills, waves, currents and tides), solar, wind, geothermal, biomass (and biofuel). Also get info. about everything from recycling to clean coal…

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coal plant

Carbon Cap and Trade: putting a price on carbon

Carbon cap and trade systems are plans in which countries, provinces, states and even cities set regulations (a cap) on the amount of carbon dioxide and other greenhouse gas (GHG) emissions industries/ power plants can emit, and then implement an Emissions Trading System (ETS). Companies included in cap and trade systems, often companies that operate power plants, have a limit (cap) on the amount of GHG emissions they can produce that is set by the government. Governments may either “grandfather in” GHG allowances (essentially give away credits based on past GHG production) or auction allowances off. Companies with extra carbon credits because their plants go under the limits can then trade their excess carbon allowances to companies that need to buy carbon credits to avoid going over the limit.

Auctions for carbon permits (one carbon permit is usually = to 1 metric ton of GHG pollution) are an essential part of the carbon cap and trade system, helping to establish a price on carbon, and are  much more effective than the system where credits are just ‘”grandfathered in”. The cost of carbon permits is essentially the price of carbon. As GHG emission credits are auctioned off, a price on carbon is established. Companies can also keep carbon credits for future use in trading or for their own allowances. For companies that run over their GHG emissions limits and don’t cover their allowances, a heavy fine is imposed. Carbon cap and trade systems are designed to lower the cap annually, gradually reducing the allowable limit of GHG pollution for those industries targeted by the cap and trade system.

There are trades that offset GHG emissions; trades for credits with companies that have forestry projects and that are reforesting areas or that limit deforestation, or companies that have livestock projects that incorporate sustainable practices, or companies that invest in clean coal technologies such as carbon capture and storage (CCS) or other carbon sequestration measures. To make cap and trade systems even more effective, there should be more offset credits allowed for trades with companies that implement GHG emission saving and energy efficiency technologies like renewable energy, integrative gasification combined cycle (IGCC), and anaerobic digestion (AD), combined heat and power (cogeneration) (CHP) etc…

For some companies, it might make more financial sense and be more cost-effective to make the effort to reduce emissions through emission saving and energy efficiency technologies and/ or expanded use of renewable energy, and then sell their allowances to companies that are over their GHG limit. However, usually most companies tend to buy carbon allowances if it’s cheaper to buy them than to try to lower emissions. Carbon permits can be invested in by businesses, industries, or even the public in some regions, via a carbon futures market.

Carbon cap and trade systems are in effect in about 40 countries and 25 states/ provinces/ cities globally. The largest market for cap and trade is in the EU with the European Union Emissions Trading System. The EU ETS covers more than 11,000 power plants and industrial stations in over 30 countries, as well as airlines (for flights within Europe until 2016). The primary focus of the EU ETS is to fight climate change by lowering GHG emissions.

The EU ETS remains the largest (and first) international trading organization for trading GHG emission allowances. The EU ETS has successfully put a price on carbon, with its system of trading allowances of GHG emissions, and has also watched GHG emissions fall by a few percent annually since it began in 2005. The cap, or limit, set on GHG emissions will be, on average, over 20% lower on all power plants and industries by 2020 from 2005 levels (when the program started), as the EU continues to make efforts to reduce pollution.  Clean, energy efficient, low-carbon technologies like CCS, IGCC, CHP and AD, as well as renewable energy, have grown in popularity throughout Europe, in part, because of the rising price of carbon resulting from cap and trade programs.

All countries deal with cap and trade differently. Most have cap and trade for industry and power sectors. South Korea has cap and trade for heavy industry, power, waste, transportation and building sectors. China has six provinces testing out cap and trade, and along with South Korea, represents a very large carbon market (with just those 6 provinces China is a large market, the entire country represents the single largest carbon market, by far). The U.K., Ireland, Iceland and the Scandinavian countries Norway, Sweden and Finland have legislated both a carbon tax and cap and trade programs.

The nine state agreement in the U.S. northeast (the Regional Greenhouse Gas InitiativeRGGI) is another major carbon cap and trade trading pact, and is, at least partially, based on the pioneering EU program. These states have auctioned off carbon allowances to industries in RGGI states, and have thereby collected well over $1 billion from carbon cap and trade programs, much of which has been reinvested in energy efficiency, renewable energy and other clean energy programs. Since carbon cap and trade has started in the U.S. northeast, GHG emissions have steadily dropped. Like the EU, this in part due to investment in clean energy technologies, but also because some companies in the U.S. northeast have switched from dirtier fossil fuels like coal to cleaner natural gas generators in power plants, or to renewable energy.

Some carbon cap and trade markets are:




The U.S. Northeast region:



“To comply with the federal Clean Power Plan’s requirements for cutting carbon pollution from power plants, states have several options—including joining RGGI or similar schemes such as California’s cap-and-trade system.” – from: Cap & Trade Shows Its Economic Muscle in the Northeast, $1.3B in 3 Years (Regional Greenhouse Gas Initiative offers blueprint to all states as they begin to think about how they will comply with Clean Power Plan.) By Naveena Sadasivam, InsideClimate News

The RGGI states and California are ahead of the curve as far as complying with the Clean Power Plan.

California, Quebec:


http://www.huffingtonpost.com/rosaly-byrd/an-introdu put a quotaction-to-carbon-cap-and-trade_b_6737660.html

Please also see: Carbon Tax – a levy on pollution whose time has come

cap and trade


Combined heat and power

Combined heat and power (cogeneration) – making the most of energy

Combined heat and power (CHP, also known as cogeneration) is the simultaneous production of power (electricity) and heat from: natural gas (dominantly), coal, oil, biomass, biogas and waste heat (recovery), among other sources. Waste heat can be heat from waste incineration, waste heat from power production and/ or industrial/ commercial/ even residential waste heat. Fuel sources vary from project to project, country to country.

For example, in Iceland, the dominant source for CHP is geothermal. Over half the energy use in Iceland, which has the highest energy use (per capita) of any nation in the world, is geothermal, and much of it CHP. This is energy production for electricity and heated water/ steam for fish farms, pools, etc… and also for geothermal district heating and space heating in general.


CHP can be seamlessly integrated in a number of energy technologies. Often, systems are developed exclusively for onsite generation of electrical and/ or mechanical power, in addition to HVAC and water heating. CHP is most often developed with a gas turbine and  a heat recovery unit or a steam boiler with a steam turbine. CHP exists in industrial and commercial buildings, institutional campuses, municipal facilities (district energy systems, wastewater treatment facilities, etc…) and is also implemented for residential properties.

CHP significantly reduces greenhouse gas emissions by 1/3 to ½ or more, and is significantly more efficient, requiring less fuel to produce a given energy output. CHP can produce electricity and thermal energy on site, avoiding the grid and avoiding energy losses that occur via standard transmission and distribution, as well as power outages. The high efficiency inherent in CHP saves consumers money on their utility bills, offering a reliable source of high-quality energy.

From: http://www.greencitytimes.com/


Carbon tax is a levy on pollution

Carbon tax – a levy on pollution whose time has come

A carbon tax is a levy on pollution, for the relative cost to humanity of the use of fossil fuels. This cost cannot be tabulated in exact terms, for it’s the accumulated cost of the damage to the environment, human health, and related costs of the use of fossil fuels that can only be estimated. The carbon tax itself is a fee on the production and distribution of fossil fuels. The government sets a price per ton on carbon, then that translates into a tax on oil, natural gas or such things as the electric bill.

Businesses and utilities then have the incentive to reduce consumption, and/ or maintain the market price and absorb the cost of the tax, or pass the added fee on to individual consumers. Individuals would then have the incentive to reduce consumption, increase their energy efficiency habits or face a steeper cost for energy and gas.

The principle of mitigating negative externalities (such as the damage caused by fossil fuels), and having the relative costs of pollution paid for, is the primary purpose of the carbon tax. Who bears the ultimate burden of the tax is a hypothetical question that has a couple of answers. The businesses that produce and distribute fossil fuels should consider bearing the brunt of the tax. In practice, individuals pay more.

A carbon tax is enacted to lower greenhouse-gas emissions. Public transportation, energy efficiency products, and things like clean coal technology become great alternatives to traditional means. One other benefit of a carbon tax, besides the incentives to reduce consumption and increase energy efficiency, is the increased attractiveness of the cost of alternative energy, which is made closer to cost parity with fossil fuels.


Denmark, Finland, Germany, Ireland, Italy, the Netherlands, Norway, Slovenia, Sweden, Switzerland, and the UK have all successfully implemented a partial carbon tax on some goods and services, while not being able to implement a broad, universal carbon tax. Generally, reports of lower greenhouse-gas emissions follow the passage of a carbon tax. In addition, India and Australia, among many other countries, have also successfully enacted carbon tax policies. The province of British Columbia, in Canada, has reported drops of around 5% annually of greenhouse gas emissions due to its aggressive carbon tax policies. 

Home Energy Management (HEM)

Home Energy Management (HEM)

Home Energy Management (HEM) refers to technology that helps homeowners improve home energy efficiency while also giving them access to household products from tablets, smartphones and computers. HEM systems save people on energy consumption (thus money) and time. With the remote controlled access, one can control thermostats, lights, other appliances or home monitors via the internet.

HEM systems include smart thermostats, smart appliances that regulate energy consumption, smart outlets and smart plug strips that turn completely off when not in use. An increasingly common addition to HEM systems are home monitors, including ones that provide home security systems. However, the product that best exemplifies HEM is the programmable thermostat.

Of the smart thermostats, The Nest (the pioneer of this technology, introduced to the mass market in 2011), continues to be the most popular brand. The Nest makes it simple to change the temperature of your home from your computer, mobile device or tablet. Another popular and innovative smart product, the Ecobee3, is an example of a smart thermostat that offers an additional unique feature. With the Ecobee3, thermostats can be programmed to control the temperature in up to 32 rooms (with additional sensors). If the temperature in a multistory home varies from room to room due to a standard HVAC, the Ecobee3 offers a solution. These are two examples of user-friendly smart thermostats.

Another HEM product is the smart outlet. With the smart outlet, the power of any home appliance can be measured. Through a tablet, smartphone, or PC, the outlets can also be used to set schedules for lights or electronics. The schedules can be coordinated with the grid to have a reduction in energy consumption during peak energy production hours, if the utility offers such data. Smart appliances (like a smart washer/ dryer) can reduce their energy consumption during peak hours as well. In addition, the latest in HEM offerings is a complete home monitoring system with smart outlets, combined home alarm and security system and a a remote controlled thermostat.


Today, service providers other than utilities are at the forefront in the smart grid, in part due to HEM products. Companies that provide cable, internet and smart phone services are now adding energy monitoring, control and optimization services to their offerings, pushing utilities into a supporting role. Utilities and service providers are both experimenting with different approaches. The service provider is a promising alternative to utilities to extend the smart grid into more homes.

First NZE home in CA

The Cottle Zero Energy Home (1st ZNE home in CA)

All over the world, a higher level of emphasis is being placed on environmental sustainability as evidenced by the increase in efforts towards energy efficiency and green building. Countries are in constant search of new technologies with the promise of reducing carbon footprint and optimizing the use of available energy without causing harm to the environment. The state of California is one of a few places that is achieving this goal. This is best represented through their ambitious goal of making all new homes zero net energy by the year 2020. Some might think that this is too big of an endeavor, but the state is slowly making the necessary steps to finally show the world that this is possible.

The Cottle Home

As part of commencing the efforts towards zero net energy, One Sky Homes has introduced The Cottle Zero Energy Home, which is the very first of its kind and has been lauded by the California Energy Commission. For those who would like to experience what it is like to be living in such a place, it may not be an easy feat as it comes with a hefty price tag of $2.2 million. More than the luxurious build of the home, obviously, its biggest selling point is its efficient use of energy. Generally speaking, one house in California will most likely consume energy worth over $100 monthly. On the other hand, with The Cottle (in San Jose, CA), the energy consumption is $15 (or usually less, due to standard utility connection fees) monthly.

The Mandate for a Greener Future


The inception of the Cottle Home was part of the idea of transforming the entire state into a greener place and it serves as an example for other states to have similar initiatives. California has recently mandated that all new home construction must be zero net energy (ZNE) by 2020. All new commercial buildings in the state must be ZNE by 2030


US LEED and LEED 2009 BD+C ACP’s

LEED certified buildings exist to save money and other resources. LEED certified houses give the occupants better health and wellness while being able to promote renewable and clean energy. LEED (Leadership in Energy and Environmental Design) is one of the best green building certification programs in the world right now.

Until recently, some of these features have only been LEED certified in certain countries. However, with recent developments, LEED has begun to spread these certifications to other countries, such as Europe. Many people in Europe want to change the way houses are built, and new developments have taken root and made these programs possible in Europe. This means that more people will have access to the amazing LEED program and reap the benefits for years to come.

Features of LEED

LEED homes and buildings are sustainable and provide people with an environment that is healthy, and that will save energy at the same time. When you get a LEED built house, you are quite literally getting the best of the best. Some of the basic features of a LEED building are:

indoor air quality

– well insulated and air sealed buildings

daylight & views, daylighting up to 75% of spaces

– this provides some of the heat for the building and overall well-being for the people inside

construction waste management and use of renewable or recycled materials
energy efficient lighting

optimize energy performance


water efficiency and storm water management

Rating System

Each project that LEED does has different prerequisites and aspects to rate. LEED has many different rating levels, here are a few:

“BD+C” means building design and construction. This deals with new constructions or major renovations that will dramatically change the existing structure. “ID+C” means interior design and construction, which deals with projects that make changes the interior.

The “O+M” rating deals with operations and maintenance, which only applies to buildings that already exist. There is only improvement work and little to no construction involved. LEED can also give a building a “ND”, which is neighborhood development. This deals with more than one building or home.

LEED BD+C 2009 ACPs Europe

In February of 2014, the USGBC hired the Sweden Green Building Council, and members of the LEED International Roundtable came together to introduce a special, Europe-specific program for the LEED BD+C. This is called the Alternative Compliance Paths (ACPs), and it will make a lot of things that were not possible before possible in Europe.


For the whole article, please see: http://www.greencitytimes.com/Sustainability-News/us-leed-and-leed-2009-bd-c-acp-s.html


Other recent articles on LEED:




micro-grids: powering the future

Micro-grids spread across Africa

Communities in developing countries (such as India and countries in Africa), especially those in remote locations, benefit from the deployment of micro-grids. As African nations push for rural electrification, they look to micro-grids as a solution to the problem. Micro-grids that use renewable energy are more cost effective and safer compared to diesel generators and kerosene, that are widely used in Africa today. Kerosene often uses up to 20% of an average African’s income, can cause fires, and unhealthy air quality.

A medium-sized solar power system with battery storage, on other hand,  can be easily used by over 50 households, an entire village, in many rural locations in Africa. Smaller, individual units, can power single, or a few, households. The power can be used for lighting, cell phone charging, cooking, etc…

Micro-grids are important for remote communities in Africa. Electrification of rural villages has been made possible through them. Power needed for water pumping, and purification, is done with the help of various micro-grids in Africa and other parts of the world. Mobile communication has a wider reach in the continent through telecom towers that are powered with micro-grids.

Micro-grids are cheaper than building power lines into forests and mountains, especially in the most remote locations in Africa. Poor communities in other third world countries will also benefit from having micro-grids installed, especially when the utility grids don’t want to build long power lines to connect them to the grid.

Many African rural communities have already built micro-grids as their energy source. Every time a new installation is made, the skill base of the locals is developed. Their infrastructure is improved as well. However, despite the recent momentum of micro-grids, one of the reasons there are not enough micro-grids in Africa is because of the prohibitive cost and lack of reasonable financing. Policy is needed to ensure that they are more affordable to the poor, remote villages in the continent.


Please see: http://www.greencitytimes.com/Sustainability-News/micro-grids-powering-the-future.html for the whole article.


Other recent articles on micro-grids in Africa:



2014 smart grids

Improving energy efficiency

When it comes to saving on your electricity bill, improving the energy efficiency of your home is certainly the way to do it. However, there are two ways of achieving this through the various kinds of HVAC systems that are available.

One kind of system is known as the residential demand response (DR) program, and is sometimes a part of today’s smart grid. Although we just use the example of HVAC here, DR can be applied to many home electrical systems and appliances. Residential demand response is where utility companies are given control over the HVAC units that are in people’s homes, and reduce the power settings and temperature of the home during the afternoon and early evening hours, as there is less need for them when people are at home. This is partly because the presence of people within buildings adds to the warmth of the home so that there is less need to use more electricity from the grid in order to turn the HVAC unit on. This can be very useful for those who don’t remember to turn down their thermostats at night, so it can help to save them a lot of money in the long run and increase the energy efficiency of their homes.

Alternatively, there is the behavioral demand response program, which leaves control in the hands of the homeowner. A smart device – a smart meter – is set up in the home, reads and records data from the home, such as the time people get home and wake up in the morning, and the changing temperatures throughout the year. This data is then used in order to tell consumers how much energy was saved and how this amount can be increased in the future by altering the settings of the thermostat and HVAC system. Communication is sent via a smart phone, PC, or tablet on how much energy they saved, what the financial benefit was and what customers can do better in the future. In response, customers can appropriately adjust their devices – “two-way communication”.

This smart meter method makes it much easier for the homeowner to determine how much energy to save, rather than leaving it in the hands of the utility companies. The use of the smart meter allows people access to the device from home, so changes can be made over one’s smartphone or tablet device.

Both methods are quite beneficial and make it easy for homeowners to focus on energy efficiency. With residential demand response program, even when the energy levels are lowered by the utility companies, the thermostat within the home is going to register the change in temperature and turn on at the appropriate time anyway. Depending on the season of the year, this can still lead to the overconsumption of energy that is not needed. With behavioral demand response programs, the smart meter has to be purchased and installed within the home, and only requires some time for it to record all of the data necessary in order to produce the best results that can be used to alter the thermostat. This does not necessarily make one system better than the other, but homeowners should be aware of the differences between the two in order to come to an informed decision.