Energy from Waste

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Written by: J C Burke

Category: Utilities

Published: 25 April 2023

Last Updated: 25 April 2023

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Key Situations:

Outline of the waste streams available that could be used for energy production - ideally bio-methane. However, plastics are today's "pollutants" to the viability of waste streams to energy. The plastic need a different method of treatment. Overall, we wish to avoid the less efficient {and problematic emissions} of incineration technologies.

WORK IN PROGRESS:

TYPES OF WASTE STREAMS

Homogeneous Organic Wastes, typically farming wastes These typically farm based bio-digesters, can create good volumes of bio-methane [with some CO2 and other contaminants - which can be removed] from a wide variety of soft organic wastes - from cattle slurry to oil-rich seeds. We have a database of the energy values of most farm wastes to be able to estimate economic viabilities in terms of exporting to the gas grid, generating electricity and exporting to the electric grid or even as transport fuels {compressed natural gas} CNG.

Palm Oil Wastes and other industrial processes In regions where Palm Oil production is prevalent, the waste lagoons associated with Palm Oil production, with the husks etc can be utilitise as rich source of bio-methane. The waste from these processes can be problematic in environmental terms - so bio-digestion is an ideal transformation into a commercial fuel or used in energy and heat production as a feed back into the industrial process itself.

Mixed Wastes and Rubbish Tips There are a great many pre-existing waste tips of varying sizes and "conditions" globally - [Some tips can be on-fire or explosive with the methane generation]. Comprehensive treatment and separation of the leachate and methane can produce vast quantities of bio-methane [again with CO2, H2S etc - all of which can be separated]. The Leachate is also rich in Ammonia and other compounds. Experience in the UK shows that a waste tip can produce methane [and other smaller impurities] for up to 30 years. The London Brick Works in Bedfordshire used bio-methane from the waste tip on their clay pits {as supplied from London}, to fire their brick kilns for decades.

Plastic Waste "Pollution" The vastly increased usage of plastics over the last decades, has changed the composition of waste globally. Plastic themselves are difficult {not impossible} to break down and thus make bio-digestion more difficult. In practice the separation of Plastic {and metals, builders rubble etc} needs to be carried out before digestion. Other technologies to deal with plastics {see below} like Cold Plasma Pyrolysis can yield methane and Hydrogen.

Anaerobic digestion can be used to generate energy from organic waste like food and animal products. In an oxygen-free tank, this material is broken down to biogas and fertiliser.

It’s an approach with big potential. If we treated 5.5 million tonnes of food waste this way, we’d generate enough energy to serve around 164,000 households while saving between 0.22 and 0.35 million tonnes of CO₂, in comparison to composting.

Extracting the biogas produced by biodegrading materials on landfill sites is another way of getting useful energy from waste. Although it’s an approach that’s in decline due to the reduction of the amount of organic matter going to landfill, it’s making a notable contribution to UK energy supply: the source 3.04TWh of green electricity in the last year, in fact.

Tackling the plastic problem

Plastic waste has risen to significant levels of public consciousness in recent years, for its negative impact on habitats and species. In response, the UK Government’s 25-year Environment Plan pledges to eliminate all ‘avoidable’ plastic waste by the end of 2042 – and it’s not alone in making such political commitments. Can waste-to-energy step in here?

Converting plastic waste to energy certain makes sense from a chemical perspective, given plastics come from the same origin as fossil fuels. We’ve already looked at the two main techniques involved: pyrolysis, where plastic is heated in the absence of oxygen, and gasification, where air or steam heats the waste, creating gases that either produce petrol or diesel, or are burned to generate electricity.

New techniques such as cold plasma pyrolysis, provide the potential to create fuels such as hydrogen and methane, as well as useful chemicals for industry.

But there are barriers in the way of wider uptake of plastic-to-energy techniques. Gasification of plastics requires significant investment, including advanced controls and pre-treatment facilities. Also, developing plastic-recycling plants presents a risk of limiting those facilities, when decision-makers may instinctively opt for waste strategies where general waste is processed together, rather than separating out different elements.

Novel approaches to waste management in the UK will surely rise in the coming years. Recycling rates seem to be plateauing, with minor increases only  seen. While generating energy from waste has a lot of promise, we need to focus on making products last longer, and when they really can’t be fixed, finding ways to recycle and reuse them. Only when those options are exhausted should we turn to waste-to-energy.

the prospect of using rubbish for fuel isn’t too far from reality. Plastics, in particular, contain mainly carbon and hydrogen, with similar energy content to conventional fuels such as diesel.

Plastics are among the most valuable waste materials – although with the way people discard them, you probably wouldn’t know it. It’s possible to convert all plastics directly into useful forms of energy and chemicals for industry, using a process called “cold plasma pyrolysis”.

Pyrolysis is a method of heating, which decomposes organic materials at temperatures between 400℃ and 650℃, in an environment with limited oxygen. Pyrolysis is normally used to generate energy in the form of heat, electricity or fuels, but it could be even more beneficial if cold plasma was incorporated into the process, to help recover other chemicals and materials.

The case for cold plasma pyrolysis

Cold plasma pyrolysis makes it possible to convert waste plastics into hydrogen, methane and ethylene. Both hydrogen and methane can be used as clean fuels, since they only produce minimal amounts of harmful compounds such as soot, un-burnt hydrocarbons and carbon dioxide (CO₂). And ethylene is the basic building block of most plastics used around the world today.

As it stands, 40% of waste plastic products in the US and 31% in the EU are sent to landfill. Plastic waste also makes up 10% to 13% of municipal solid waste. This wastage has huge detrimental impacts on oceans and other ecosystems.

Interview with AI Chat Bot

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Written by: J C Burke

Category: Utilities

Published: 07 March 2023

Last Updated: 08 March 2023

Hits: 8706

A discussion regarding electricity production and energy efficiencies {mainly UK, but some USA}. AI is starting to learn - but needs to watch out for "settled-science" {an oxymoron} and the volume of material covering the "conventional wisdom." We have also added some additional commentary to help the {Child} AI as it learns, and to assist it to innovate, if this is possible.

Here are the questions asked of ChatGBT, and its corresponding answers. Some development of its answers have also been explored too. We found it a quite interesting exercise. But please note {with some alarm} AI's concern with "Regulatory Authorities", "Policy" and "Policy Makers" - the modern "evils" of our times!!

Q 1) Given that in winter the UK still needs 60% of electricity demand provided by Natural Gas and Coal, how can we reduce demand to allow renewable's to provide a greater percentage

1. There are several ways in which we can reduce the demand for natural gas and coal in the UK during the winter months to allow for renewable's to provide a greater percentage of our electricity supply: 
   1. Energy efficiency: The most effective way to reduce energy demand is to improve the energy efficiency of buildings and appliances. This can be achieved through better insulation, more efficient heating and cooling systems, and more energy-efficient appliances. By reducing energy waste, we can lower our overall energy consumption and reduce our reliance on fossil fuels. {an agenda driven statement indeed - bad AI!}
   2. Demand-side management: This involves shifting energy use to times when renewable energy sources are available, such as during periods of high wind or sunshine. This can be achieved through time-of-use tariffs, which incentivise customers to use energy during off-peak hours when renewable energy is more abundant. {pricing strategies are not an ideal route - old age pensioners could die with this approach, frightened to turn on their boilers} bad, bad, AI
   3. Energy storage: Battery storage technology is rapidly advancing, and large-scale battery storage can help to smooth out the intermittent supply of renewable energy. This allows excess renewable energy to be stored for use when demand is high, reducing the need for natural gas and coal. {Please add alternative "storage solutions, eg. "pumped storage" as at Dinorwig Peak Lopping _ too much battery talk AI!}
   4. Smart grids: Smart grids can help to manage the supply and demand of energy more efficiently. By using advanced sensors and communications technology, smart grids can match energy demand with the available supply of renewable energy.
   5. More renewable energy generation: Of course, the ultimate solution is to increase the amount of renewable energy generation in the UK. This can be achieved through a combination of onshore and offshore wind, solar, and other renewable sources, such as hydro-power and geothermal. With more renewable energy generation, the need for natural gas and coal can be gradually phased out. We threw this statement straight back at AI, as no time scale aspects have been considered - its almost a "slogan" not information - but the "blame" here lies with those promoting this mis-information {generally at State level}

Q 2) "With more renewable energy generation, the need for natural gas and coal can be gradually phased out." Please critique this statement given the timescale involved to achieve these targets 

Read more: Interview with AI Chat Bot

Heat Pumps their Usage and Preconditions

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Written by: J C Burke

Category: Buildings

Published: 02 March 2023

Last Updated: 08 March 2023

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With air source and ground source heat pumps what are the key requirement to enable cheap and efficient heating and hot water in the UK?

In order to enable cheap and efficient heating and hot water with air source and ground source heat pumps in the UK, there are several key requirements:

• 'Adequate' {Extremely High Levels of:} insulation: The building must have adequate insulation to minimize heat loss and improve the efficiency of the heat pump system. By "Adequate" we mean' substantially in excess of current building regulations standards'. Like the German Passivehaus standard. This would also presuppose an efficient {mechanical or passive} ventilation system with heat exchanger technology and "Earth Pipes" to pre-heat [winter] or pre-cool [Summer] incoming fresh air. See Passivehaus article HERE AT THIS WEB LINK.
• Proper sizing of the system: The heat pump system must be properly sized to match the heating and hot water demands of the building. Over-sized or undersized systems can result in inefficiencies and higher costs.
• Suitable location: For ground source heat pumps, the site must have suitable geology and hydrology to support the installation of the ground loop. For air source heat pumps, the location must have adequate airflow and temperature differentials to enable efficient operation.
• High-efficiency heat pump equipment: Choosing a high-efficiency heat pump with a high coefficient of performance (COP) can significantly improve the efficiency and cost-effectiveness of the system.
• Energy-efficient hot water storage: Using an energy-efficient hot water storage tank can reduce the amount of energy required to heat water and improve the overall efficiency of the system. This is because an highly insulated hot water storage tank can act as a 'buffer' or heat-store, between energy supply and demand - particularly relevant at colder period, say night time in winter - so supplement the energy needs from the heat store.
• Climate-appropriate design: The design of the building should take into account the local climate and weather conditions to optimize the performance of the heat pump system. This would also include aspects of the property and its orientation {to the Sun, and prevailing winds}, earthworks and planting to mitigate 'wind chill' effects on walls, windows and roofs. PDF scan of 1981 Research Article {Wind and Building Energy Consumption: an Overview} HERE

By meeting these requirements, air source and ground source heat pumps can provide cost-effective and efficient heating and hot water in the UK. As can be seen in some of the photo's, particularly with Ground-Source Heat Pumps, associated equipment, controllers, buffer tanks and installation, considerable space is needed. Therefore we strongly recommend new properties be build with a basement {in light of the deeper foundations required from Building Control this may not be as expensive as imagined}. Additional benefits of basement include, Rainwater Storage, Computer Sever Room, Distribution to the floor above for Internet, Telephone, Sound Systems etc.