What is the Tesla Powerwall and should you get one?

    July 14, 2023

The Tesla Powerwall is a rechargeable lithium-ion battery designed to store energy for home use. It is a product of Tesla Energy, a branch of Tesla Inc. that focuses on manufacturing solar energy products. Our friends at EWI Pro have a case study which is garnering regional and national awards; the project in question utilises Tesla Powerwall 2 batteries.

Features of the Tesla Powerwall

  1. Energy Storage: The Powerwall is a rechargeable battery system that stores energy from solar panels or the grid. It stores surplus solar energy not used at the time it is generated and provides that energy when needed later on, such as during the night or during a power outage.

  2. Compact and Scalable: The Powerwall is compact and entirely automated. It’s a relatively small, rectangular unit that mounts to the wall, typically in a garage or outside of the home. Multiple Powerwalls can be connected to increase the amount of power available. Up to 10 Powerwalls can be combined for homes with greater energy needs.

  3. Real-Time Energy Usage: The Tesla app gives you an overview of your home’s energy production and consumption in real time. It shows solar production, Powerwall charging and discharging, and home energy use.

  4. Touch-safe: The Powerwall has a touch-safe design, which means there are no exposed wires or hot vents.

  5. Water-Resistant and Dustproof: It is water-resistant and dustproof, allowing for installation indoors or outdoors.

  6. Storm Watch: Powerwall can detect incoming storms using internet-connected data and will automatically store energy in preparation for power outages.

  7. Self-Powered Mode and Backup-only Mode: The self-powered mode allows you to use the Powerwall to power your home independently from the grid. On the other hand, the Backup-only mode stores energy until the Powerwall detects a power outage, at which point it starts supplying power.

  8. Time-Based Control: Time-Based control lets you use the Powerwall’s stored power when energy costs are high and recharge when costs are low (this requires a compatible electricity tariff).

  9. Integration: Powerwall can be integrated with Tesla’s solar panels and Solar Roof for an all-in-one solar and storage system.

  10. Temperature Control: Powerwall uses an internal liquid cooling and heating system to keep its internal temperature stable, which can improve battery performance and lifespan.

Should you get a Tesla Powerwall?

Should you get one? The answer to this depends on a few factors:

  1. Availability of Solar Power: If you live in an area that gets a lot of sunlight throughout the year, a Powerwall, in combination with solar panels, could save you a significant amount on your energy bills.

  2. Power Outages: If you live in an area that experiences frequent power outages, the Powerwall’s backup power capabilities could be a valuable asset.

  3. Energy Prices: In some areas, electricity prices can vary throughout the day. If you live in such an area, you could save money by charging the Powerwall during off-peak hours and using the stored power during peak hours.

  4. Cost: A Powerwall is a significant investment. The cost of a Powerwall (not including installation or supporting hardware) is upwards of £15,000. You would need to calculate the potential energy savings over time to see if it would be a cost-effective choice for you.

  5. Environment: If reducing your carbon footprint is a priority, using a Powerwall in combination with solar panels can help achieve that goal by decreasing your reliance on grid energy, which often comes from fossil fuels.

  6. Local Regulations and Incentives: Some areas have laws, regulations, or financial incentives related to renewable energy installation and storage. These can influence the cost-effectiveness of a Powerwall.


Tesla Powerwall models


Technology and costs

The Tesla Powerwall, employed at an elephant sanctuary in Kenya, is designed for daily cycling, such as load shifting. The company utilises its proprietary technology for cell packaging and cooling with a liquid coolant. Musk has pledged not to pursue patent infringement lawsuits against anyone utilising Tesla’s Powerwall technology in good faith, mirroring his earlier promise with Tesla cars.

The first Powerwall utilises a nickel-manganese-cobalt composition and comes with a warranty that covers up to 5,000 cycles. With a round-trip efficiency of 92.5% when charged or discharged by a 400-450 V system at 2 kW and a temperature of 25°C (77°F), the Powerwall’s performance is top-tier when new. However, variations in the product’s age, temperature above or below 25°C (77°F), and charging or discharging rates above 2 kW may reduce this efficiency, thereby affecting overall performance.

The original Powerwall includes a DC-to-DC converter that sits between a home’s existing solar panels and the current DC-to-AC inverter. Should the current inverter not be compatible with storage, a suitable one must be procured.

The second iteration, Powerwall 2, features a DC-to-AC inverter designed by Tesla. The production of the 2170 cell type for the Powerwall 2 commenced at Giga Nevada 1 in January 2017.

In 2016, the National Fire Protection Association carried out two worst-case scenario tests, igniting Powerpacks to initiate thermal runaway. The design successfully contained the damage within the Powerwall structures.

An article published in Forbes magazine in May 2015 calculated that integrating a Tesla Powerwall 1 model with solar panels in a household would render electricity costs at about 30 pence/kWh if the home remained connected to the grid. This scenario painted the Powerwall as a luxurious, eco-friendly accessory for wealthy individuals.

Both Bloomberg and Catalytic Engineering concur that the Tesla system proves most beneficial in areas with high electricity costs, such as Hawaii and other remote islands that generate electricity using imported fuel.

Areas with time-of-use (TOU) pricing may also see potential savings. For instance, Northern California’s Pacific Gas and Electric Company 2021 charged rates as low as 12 pence/kWh during off-peak hours (12a–3p) and as high as 52 pence/kWh during peak hours (4p–9p). When configured for cost savings, the Powerwall can enable a home to go off-grid during peak hours, thus avoiding high-cost power usage.

According to the Swiss bank UBS, the Powerwall makes economic sense in countries like Australia and Germany, where electricity is exceptionally costly but solar panels are widely distributed.

As of October 2019, the recommended installation of two Tesla Powerwall 2 units costs around £11,000 (plus £1,900 to £3,400 for installation) in the US, excluding the cost of solar panels.

    Natural building materials

    April 28, 2023

Natural building materials are gaining popularity as more people become conscious of their environmental impact and seek to minimise it. This shift towards eco-friendly construction encompasses a wide range of building fabric materials such as timber, mineral wool, wood fibre, cork, wool insulation, lime plaster and render, thatch, clay and slate roofs. In this blog post, we will explore some of these materials and their benefits, focusing on cob, straw bale, cork, hempcrete, limecrete, and green roofs.

Timber, Mineral Wool, and Wood Fibre

Timber is a highly sustainable building material when sourced from responsibly managed forests, where trees are replanted, and ecosystems are preserved. Its natural aesthetic adds warmth and character to structures, and it can be easily repurposed or recycled at the end of its life. Timber’s ability to absorb CO2 during growth and store it for its lifetime significantly reduces its carbon footprint.

Mineral wool insulation, made from natural rock or recycled slag, provides fire resistance and prevents mould growth, ensuring a safe and healthy living environment. Its excellent thermal and acoustic insulation properties contribute to reduced energy consumption and a quieter indoor environment, leading to lower energy bills and increased comfort.

Wood fibre insulation, a byproduct of the timber industry, is an eco-friendly alternative that offers high insulation performance and moisture regulation. Its breathability contributes to a healthier indoor climate, reducing the likelihood of respiratory issues and allergies caused by trapped moisture and mould.

Cork and Wool Insulation

Cork insulation is harvested from the bark of cork oak trees without causing harm to the trees or their ecosystems, allowing for sustainable resource management. Cork insulation is durable, resistant to moisture and pests, and provides excellent thermal and acoustic insulation. Its insulating properties lead to reduced energy costs and a more comfortable living environment.

Wool insulation, sourced from sheep’s wool, is a natural, renewable, and sustainable option. Its breathability helps to regulate humidity levels within a building, reducing the risk of condensation and mould growth. Wool insulation also offers superior insulation performance, which reduces energy consumption and improves indoor comfort.


Lime Plaster and Render, Thatch, Clay, and Slate Roofs

Lime plaster and render are eco-friendly alternatives to cement-based products. Their breathability allows moisture to escape, preventing mould growth and contributing to a healthier indoor environment. Lime products have self-healing properties, which reduce maintenance requirements and extend the material’s life. Lime also has a lower embodied energy than cement, resulting in lower CO2 emissions during production.

Thatch, made from reeds or straw, is a traditional roofing material with excellent insulation and weather resistance properties. Its insulating capabilities contribute to reduced energy consumption, while its natural appearance adds charm and character to a building. Clay and slate roofs, made from natural materials, are durable, long-lasting, and low maintenance. Their minimal environmental impact over their lifespan makes them a sustainable choice for roofing.

Thatched roof

Cob, Straw Bale, and Cork

Cob, a mixture of clay, sand, straw, and water, offers several benefits as a sustainable building material. It is affordable and can be locally sourced, reducing transportation costs and emissions. Cob walls provide excellent insulation and thermal mass, helping to regulate indoor temperatures and reduce energy consumption, resulting in lower heating and cooling costs.

Straw bale construction is energy-efficient and resource-conscious. The high insulation levels provided by straw bales lead to a low carbon footprint and minimal impact on natural resources. The breathable nature of straw bale walls contributes to a healthy indoor environment, while their thermal performance ensures a comfortable living space. Straw bale construction is also relatively low-cost and can use locally sourced materials, reducing the overall environmental impact of the building process.

Cork, in addition to its insulation properties, can also be used as a building material for walls. Its thermal and acoustic insulation, as well as its resistance to moisture and pests, make it a sustainable and comfortable choice. Cork walls provide a natural aesthetic and contribute to a healthy indoor environment by regulating humidity levels and minimising mould growth.

Straw bale house

Hempcrete and Limecrete

Hempcrete, a bio-composite material made from hemp fibres and a lime-based binder, is a sustainable alternative to traditional concrete. Its lightweight nature reduces the need for extensive structural support, while its breathability offers excellent insulation and thermal mass, resulting in lower energy consumption and a comfortable living environment. Hempcrete is also resistant to mould, pests, and fire, ensuring a safe and healthy living space. As hemp is a rapidly renewable resource with a short growth cycle, using hempcrete significantly reduces the overall environmental impact of construction.

Limecrete, a mixture of lime and aggregates, is another eco-friendly alternative to concrete. It provides a breathable and flexible floor or wall system that allows moisture to escape and prevents mould growth. Limecrete has a lower embodied energy than traditional concrete, resulting in reduced CO2 emissions during production. Additionally, limecrete’s flexibility helps to accommodate ground movement, reducing the likelihood of cracks and improving the structure’s durability.


Hempcrete – https://www.ukhempcrete.com/gallery/gallery-hempcrete/

Green Roofs

Green roofs are an innovative and eco-friendly way to integrate nature into the built environment. They involve covering a roof with plants, which provide insulation, stormwater management, and habitat for wildlife. Green roofs can reduce energy consumption by providing additional insulation, which helps to regulate indoor temperatures. They also improve air quality by absorbing pollutants and producing oxygen, contributing to a healthier urban environment.

Moreover, green roofs contribute to urban biodiversity by providing a habitat for insects, birds, and other wildlife. They can also help to mitigate the urban heat island effect by reducing the amount of heat-absorbing surfaces in cities. By implementing green roofs, urban areas can become more resilient to climate change and provide a more sustainable, healthier living environment for their residents.

Green roofs


Natural building materials offer numerous benefits, from improved energy efficiency to reduced environmental impact. By embracing these sustainable materials, we can contribute to a greener future for our planet. Whether you are building a new home or looking for ways to upgrade your current space, consider incorporating natural building materials like timber, cork, hempcrete, or green roofs into your design. By doing so, you’ll not only create a comfortable and healthy living space but also contribute to a more sustainable world.

    How Is The UK Getting To Net Zero By 2050?

    February 24, 2023

The UK government has set a target to achieve net zero greenhouse gas emissions by 2050, which means that the country will emit no more carbon dioxide and other greenhouse gases than it removes from the atmosphere. Achieving this ambitious target requires a wide range of measures across all sectors of the economy, including energy, transport, industry, agriculture, and buildings.

What is Net Zero in global terms?

Net zero refers to achieving a balance between the amount of greenhouse gas emissions produced and the amount removed from the atmosphere. The goal of net zero is to reduce the overall level of greenhouse gas emissions to limit the increase in global temperatures and mitigate the impacts of climate change.

Achieving net zero involves reducing greenhouse gas emissions through various measures, such as transitioning to renewable energy sources, improving energy efficiency, and implementing carbon capture and storage technologies. Any remaining emissions that cannot be reduced must be offset by removing an equivalent amount of emissions from the atmosphere, such as through reforestation or other forms of carbon sequestration.

The concept of net zero is increasingly being adopted by countries, cities, and businesses as a way to address the urgent need to reduce greenhouse gas emissions and combat climate change. Many countries have set targets to achieve net zero emissions by mid-century or earlier, and there is growing momentum for a global transition to a net-zero economy.

Strategies for getting to Net Zero by 2050

Some of the key strategies that the UK is adopting to reach net zero by 2050 include:

  1. Investing in renewable energy sources: The UK government has pledged to increase the proportion of electricity generated from renewable sources to 50% by 2030 and is investing in offshore wind, solar power, and other clean energy technologies. As a result of the war in Ukraine, this push for renewable sources has grown, as the supply of fossil fuels has been cut. 

  2. Phasing out fossil fuels: The UK is gradually phasing out the use of fossil fuels in power generation, transport, and industry. The government has announced plans to ban the sale of new petrol and diesel cars and vans from 2030 and is investing in public transport infrastructure, cycling, and walking. The UK’s fossil fuel dependency is gradually dropping, however, the dependency was still at 78.3% in 2021, as per Statista. The drop is significant compared to the 96.5% in 1970 but needs to accelerate significantly to achieve the net zero target by 2050.

  3. Improving energy efficiency: The UK is taking steps to improve the energy efficiency of buildings, appliances, and industrial processes. The government has introduced regulations requiring all new homes to be built to a high energy efficiency standard and is offering financial incentives to homeowners and businesses to upgrade their properties. Previously, the Green Homes Grant was available to homeowners, however, it was vastly unpopular and ineffective. Much of the funds were redistributed at the end of the scheme, and it was replaced by the ECO4 scheme, which is due to be supported by the ECO Plus scheme.

  4. Carbon capture and storage: The UK is investing in carbon capture and storage (CCS) technology, which captures carbon dioxide emissions from power plants and other industrial processes and stores them underground.

  5. Tree planting and land use: The UK is increasing tree planting and other land-use measures to absorb atmospheric carbon dioxide. The government has targeted increasing tree planting to 30,000 hectares per year by 2025.

UK power sector e missions over time

UK power sector emissions over time – https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1128689/mission-zero-independent-review.pdf

How is the UK getting on so far?

The seminal resource for the current state of the Net Zero objective is ‘MISSION ZERO, Independent Review of Net Zero’, conducted by Rt Hon Chris Skidmore MP. He makes several conclusions that indicate what has been achieved and where more significant action is required:

So what are the benefits for the public?

The drive toward Net Zero is a goal that requires total participation amongst the public. Encouragingly, around 50-60% of the UK is already taking steps to reduce its carbon emissions in some way. If that figure continues to grow in line with increased efforts by the Government, the goal is achievable. As a result, the public can reap significant benefits, including the following:

What if we don’t reach Net Zero?

The major risk of failing to reach Net Zero is the increased impact of climate change. We are increasingly likely to see changes in temperature, rainfall, and sea-level rise.

Temperature – Increased chance of summers like 2018, wherein extra energy is required to power fans and refrigeration.

Rainfall – More rain in the winter and less rain in the summer, resulting in different water management, and potential droughts.

Sea-level rise – Continue to rise under all emission pathways.

Our partners at EWI Store post new technical, practical, and theoretical blogs about external wall insulation every Tuesday! Link below.

    Introduction to biomass boilers


What is a biomass boiler?

Biomass boilers are very similar to conventional gas boilers that you will be familiar with, providing you with space heating and hot water for the entire home, but instead of using gas (or oil) to produce the heat, they combust sustainably sourced wood pellets.

Using wood in place of fossil fuels helps to prevent long-term climate change, since the carbon dioxide released during the combustion was actually absorbed while the tree was growing, so they are essentially carbon neutral.

Each year, approximately 8.5 million tonnes of wood goes into landfill in the UK; this waste wood could be used in either biomass boilers (if converted into the pellets) or burned in wood burning stoves. This would not only provide heat and hot water, but in doing so, it would also ease the pressure on landfill capacity.

How does a biomass boiler work?

A biomass boiler works in a very similar way to conventional boilers, combusting fuel to produce heat that is then used to heat water. Biomass boilers are normally substantially bigger than their fossil fuel-burning brothers though, for a number of reasons. Firstly since they are burning wood pellets as opposed to gas, the boiler needs to be larger to hold the larger volume of fuel.

In addition, you may wish to install an automatic feed hopper on your biomass boiler, which will require additional room. This hopper stores a large volume of the wood pellets that are then automatically fed into the boiler as required, meaning that the boiler needs to be refuelled very infrequently.

It is also a good idea to have a store of the wood pellets at your property so you can keep producing heat if for some reason there is an issue with your fuel supplier. Ideally this should be close to where the fuel is delivered to your home, to minimise the distance you have to carry it.

Biomass pellet

Most residential biomass boilers can also run on logs as well as the wood chips, so if these are in plentiful supply or if you can source them cheaply or even for free, it will dramatically reduce the operational running cost of your biomass boiler.

Every four weeks or so, the biomass boiler will need to be emptied of the ash. This can be put straight onto a compost heap to help fertilise the soil.

Biomass boilers are designed to work all year round; however you may choose to turn them off in the summer. They can be coupled with solar heating or an electric shower, providing you with your hot water for washing only, during the warmer summer months.

How does biomass measure up against traditional fuels?

Biomass boilers measure up very favourably in terms of running costs vs. natural gas, heating oil and especially electricity. The numbers can all be seen in the table below.

Figures courtesy of Biomass Energy Centre

Fuel Type Price per Unit kWh per unit Pence per kWh
Wood Chips £100 / tonne 3,500kWh / tonne 2.9p / kWh
Wood Pellets £200 / tonne 4,800kWh / tonne 4.2p / kWh
Natural Gas 4.8p / kWh 1 4.8p / kWh
Heating oil 60p / litre 10kWh / litre 6.0p / kWh
Electricity 14.5p / kWh 1 13.4p / kWh

Standalone boilers

A biomass boiler might simply be too big for your home, but smaller standalone wood burning stoves are also available, which are normally used to heat one room by burning logs or waste wood. These wood burning stoves can be fitted with a back boiler that uses the heat produced when the wood is combusted to heat water, that can then be used for either space heating elsewhere in the home or for hot water only.

Both standalone wood burning stoves and biomass boilers will need a vent, designed specifically for wood fuel appliances, with sufficient air movement for proper operation of the stove. Your existing chimney can be fitted with a lined flue, which is relatively inexpensive.

Can I get a free biomass boiler?

Under the Domestic Renewable Heat Incentive scheme, you will be eligible for payments towards the cost of installing the technology.  These are quarterly, and over seven years, so you will still have to find the money to cover the upfront costs. How much funding you will receive depends on how energy efficient your home was before you installed your biomass boiler. You will start by having an EPC survey, and then payment rates are calculated by multiplying the ‘heat demand figure’ on your report by the current rate for biomass boilers. This means that some models will eventually be paid for fully by RHI payments, but many – especially top-end models – will not be covered completely. Find more information here.

Remember a carbon monoxide detector

It is really important when burning any type of hydrocarbon fuel (natural gas, coal, biomass) that you install a carbon monoxide detector in your home. In theory if all the fuel is 100% burned you produce heat, water and carbon dioxide, but in reality not all of the fuel burns. This means sometimes harmful gases like carbon monoxide can be emitted, which can be deadly. As long as you have a working carbon monoxide detector, you will be able to make full use of all the benefits a biomass boiler can bring.




Installing a biomass boiler

Are you thinking about installing a biomass boiler? We have scoured the country for the best tradespeople, so that we can make sure we only recommend those we really trust.

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    Introduction To Wind Turbines


What are wind turbines?

Windmills (now in the form of wind turbines) have been used for millennia to convert the wind’s kinetic energy into mechanical energy. As early as 200 B.C., mechanical energy was used for specific tasks including grinding grain and pumping water. Nowadays, wind turbines harness kinetic energy from the air and convert it into electricity via a generator.

Much like solar PV installations, you can purchase a domestic wind turbine to supply as much or as little electricity as you want. If you are hoping to limit your dependence on the mains as much as possible, you will need a larger turbine, or multiple smaller turbines. If you are simply looking to produce enough electricity for a light in your garden shed, you can get away with a very small turbine.

Below we look at the different types of wind turbine system you can install in your property.

Battery-less grid tied systems

Battery-less grid tied systems are the simplest, most effective and most environmentally-friendly wind turbine systems. Their role is simple: to produce the most electricity possible to provide electricity for your home and also feed into the grid. Due to the availability of grants such as the feed-in tariffs in the UK, this type of system has grown enormously in popularity in recent years. In these installations, the home owner can effectively sell the surplus energy back to the utility company. There are no batteries in the system, so this removes a lot of the system complication and maintenance. The lack of batteries also makes it cheaper to install.

If your aim is to become completely unreliant on the grid, then you need to ensure the electricity produced by your battery-less grid tied system is in excess of your total electricity usage for the year. However, this system should suit most budgets, because it will reduce reliance on the energy companies, by significantly reducing your bills. If you cannot produce all your electricity, the shortfall is simply made up with electricity from the grid.

There is one major drawback with this setup, and that is that if there is a electrical power cut then you will have no power for your home, because the inverter your energy goes through is connected to mains power, so you may require a generator (powered by diesel or oil) as a back-up policy.

Grid-tied system with battery backup

This is essentially the same as the grid-tied system above, but has a bank of batteries which means that if there is a grid power cut, the inverter can still get the electricity it requires to operate, so the installation will keep providing you with electricity. The constraints of this system are primarily associated with the batteries, which are expensive and require regular maintenance. Finally, add extra inefficiency into the system (ranging from 5 – 40%) and this is added to the constraint side.

Off-grid systems

This system has no connection at all to the grid, relying instead on batteries to operate if no wind is blowing. However if the capacity of these batteries is too low, then you could be without any power for a prolonged period of time. Having a system off-grid presents an ideal situation as you become completely independent from the grid, and you produce all the electricity you need. However, this type of system tends to be the most expensive and also is maintenance-heavy. If you have a garden shed that needs lighting then this system can work out relatively cheaply, but as soon as you are looking to upscale then it becomes very expensive.

In the next section we look at the components that you need for a successful wind turbine installation.





    What is the Green Homes Grant?

    Financial Incentives

What is the Green Homes Grant?

The Green Homes Grant is a Government scheme aimed at helping homeowners install new energy saving measures in their homes, such as new boilersinsulation, low carbon heat or double glazing.

For the latest information on the Green Homes Grant, please visit the official Green Homes Grant website here.

Unlike the previous Green Deal scheme which was loan operated, the Green Homes Grant offers grants of up to £5000 and £10,000 to wholly or partially cover the full cost of the energy saving measure.

The Green Homes Grant was set up to help improve the energy efficiency of properties across the UK, since many of the properties we live in are very inefficient, with solid walls, old heating systems and very little insulation. This scheme allows people to improve their homes without having to stump up the entire upfront costs of the works.

How does the Green Homes Grant work?

The Green Homes Grant is divided in to two separate grants, which each have different eligibility criteria.

£5000 – available to any home in England that fits the correct criteria for the specific measure. This grant covers 2/3’s of the full cost and caps at £5000. There will be a remainder in all cases using this grant and it will be paid as a customer contribution.

£10,000 – available to any homeowner receiving certain benefits listed here, and whose home fits the correct criteria for the specific measure. This grant covers 100% of the full cost up to £10,000 and the remainder is paid as a customer contribution.

A basic worked example of the Green Homes Grant

The easiest way of showing this is using an example – so lets imagine you are fitting external insulation, using the Green Homes Grant.

e.g. Fitting external insulation on a small terraced house (approx 50sqm), using the £5000 green homes grant

The average supply and fit cost of external wall insulation is £120 per sqm (inclusive of materials, labour, VAT, skip hire, any extra remedial work required, scaffolding). Therefore, a 50sqm house would cost £6000.

In this case, 2/3’s of the full cost is £4000, so this is how much the Green Homes Grant would cover. The homeowner would pay the remainder of £2000.

e.g. Fitting external insulation on the same size house (50sqm), using the £10,000 Green Homes Grant

As above, the total cost of the works would amount to £6000. With the £10,000 grant, the whole £6000 would be covered by the Green Homes Grant and there would be no customer contribution.

If the house were bigger (for instance, 100sqm) the total cost would be £12,000, the Green Homes Grant would cover £10,000 of the amount and the homeowner would have to pay £2000.

Who can get the Green Homes Grant?

In theory, any home in England can access the Green Deal considering you are eligible, but the scheme has been specifically tailored to the private home owner or the private rental sectors. The reason being is that the social housing sector already has several ways in which improvements are funded and undertaken – namely the ECO scheme.

Check if you are eligible using the Government questionnaire.

The Green Homes Grant Process

The following section talks a bit more about how the Green Homes Grant process works end-to-end – starting with a finding a Trustmark approved installer to quote for the works.

  1. Find a Trustmark approved installer to quote you for the works. The installer will also have to be registered to specific certifications regarding the measure they are installing – MCS/PAS2035. It is recommended to get three quotes for comparison.
  1. Once you have agreed a quote with an approved installer, you can apply for the grant on the government website. You must not apply without receiving a formal quotation.
  1. When you have submitted your application, it will take a few weeks until you receive your Green Homes Grant voucher. Work must not start before you receive the voucher.
  1. Your installer will be notified when you receive the voucher, however it is always a good idea to let them know yourself and arrange a start date for the work to begin.
  2. An installer will complete the work and you as the customer should be benefiting from the energy improvements.

How does the Green Homes Grant help improve homes?

By installing energy efficient measures in your home, it will help protect the environment, and lower your energy bills.

Types of measures currently covered in the Green Homes Grant scheme:

How does the Green Homes Grant help improve energy awareness?

The Green Homes Grant provides homeowners with knowledge of energy efficient home improvements. In turn, better energy awareness should drive occupiers to use their energy more wisely, which should drive down the cost people pay. For example: reducing the temperature of the hot water cylinder thermostat, installing central heating thermostats in the correct location, reducing water levels in kettles, washing clothes in ‘eco-mode’, and turning off unused high energy usage appliances like chest freezers should all help with lower energy bills.

We list 100 ways to save energy in the home here – even if you adopt a few, you should see some nice energy savings on your utility bills.

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      Should we build the Severn Barrage? – Surely a no brainer!

      June 10, 2013

    [Update: this project has been refined and the Swansea Tidal Lagoon has now been given the go-ahead. Read more here.]

    Some disappointing news today, after it emerged that a Governmental Select Committee rejected the plans for a £25bn barrage on the Severn Estuary.

    The Energy Issue Facing the UK

    In the UK, we have an impending energy crisis, with much of our electricity generating capacity due to go off line within the next 5-10 years (mainly coal and nuclear). Unfortunately demand is not going to drop off in the same way, in fact, despite increased energy efficiency via schemes like the Green Deal, new energy efficient appliances and even more efficient modes of transport, demand is expected to rise ever so slightly over the coming years.

    The result not enough power to meet demand.

    How the Severn Barrage could help

    The Severn barrage would take advantage of the tidal stream on the River Severn to produce 5% of our energy requirements. That is not just 5% of our renewable requirements – that is 5% of our total energy requirements (equivalent to 3 or 4 nuclear reactors). That is an enormous contribution to our energy cause, but that is not the best part.

    Since we are running out of North Sea gas at a rate of knots and shale gas is going to produce a fraction of the gas requirements that our Government would lead you to believe, it appears that importing fuel to power our country will be the only way to keep the lights on.

    Unfortunately, in this position we are very much bent over a barrel, since we will become so reliant on these imports we will have to pay whatever the exporters deem necessary.

    If we were to go ahead and build the Severn Barrage, then we would be producing from just one structure, fuel free, dependable electricity. Unlike other renewables that are intermittent (like solar only producing power when the sun is out), tidal is different. The tides are very predictable – they can be predicted many years into the future and Hafren Power have estimated that this particular barrage would be able to produce power for an average 15.25 hours per day and its lifespan would be 120 years or more, therefore it would be ideal to supply baseline power to the grid.

    Of course there are environmental things to consider here, birds will need to find new feeding grounds and the designs need to incorporate ways to allow fish to move freely up and down the river still, but the potential to produce all this power must surely be realised.

    This doesn’t even consider the number of jobs this has the potential to create – this would be the biggest construction project since the Eurotunnel adding an estimated 20,000 UK jobs. The funding for the barrage will also come from private investors and Sovereign wealth funds, meaning that their will be no additional hit to our public finances.

    A boost to the economy, less reliance on importing fuel to power us and a predictable renewable energy source, flying in the face of all those anti-renewable folk who hate seeing a wind turbine not spinning…

    So I for one, am incredibly hopeful that in the near future Hafren Power get the go ahead to build the power plant. We have too much to gain from this barrage for it to be consigned to the scrapheap.

      Hadera Desalination Plant, Israel

    Country Profile – Israeli Desalination Plant Strategy

    Israel is a leader in designing, building and operating desalination power plants. The climate in Israel is very dry with a low amount of rainfall, which means access to potable water is very limited. Due to its geographical location, Israel has an abundance of salt water that it can covert using desalination into drinkable water. In addition the country also has access to cheap supplies of coal, oil and gas, which makes the desalination process cost effective.

    In 1999, the Israeli Government initiated a long term, large-scale desalination program based on reverse osmosis technology. The reason for this decision was due to large periods of droughts during the mid 1990s. Having gone through a requirements phase, it subsequently revisited targets and decided to push for fresh water capacity of 750 million mby 2020.

    Summary of Key Facts – Hadera Desalination Plant

    As of 2012, desalination contributes 349 million m3 of potable water to Israel, with the Hadera plant currently providing the largest amount (127 million m3), which is currently about 20% of the total requirement. This plant which was completed in December 2009, is to date the largest salt-water reverse osmosis (RO) plant in the world. However another RO plant is currently being built at Sorek, Israel and when complete (end of 2013), will overtake Hadera as the biggest in the world.

    The Hadera plant is about 50km from the capital Tel Aviv and situated along the Mediterranean coast. It has the ability to produce about half a million cubic metres of potable water per day. The plant takes in seawater that is firstly pre-treated, and is then pushed through fine pored membranes under high pressure. In post-treatment water is adjusted for pH levels to make sure it is suitable for drinking.

    The plant supplies water at a cost of $0.57 per cubic metre. It is operated by IDE Technologies and Shikun & Binui, for a period of 25years.

    Hadera Desalination Plant and the Environment

    The Hadera plant uses significant amount of electricity, with most of this energy being supplied from the nearby Orot Rabin coal fire powered station. From this point of view, the desalination plant doesn’t get a high score for environmental sustainability. However the plant uses state of the art technology and energy recovery systems, which mitigate the fossil fuel supplied electrical energy.

    Hadera desalination plant uses the latest ERI PX Pressure Exchanger devices, which operate at high efficiency and also cost less electricity to run. For a similar sized RO desalination plant these PX devices reduce energy cost the exchanger used by approximately 60% (700MW) and saves an equivalent 2.3m tonnes of CO2 per year.

    The desalination plant can be further improved by making sure electrical energy is sourced from renewable technologies. A Solar PV farm would complement a desalination plant very well, as shown by similar projects being operated in Saudi Arabia.

      CHP Cogeneration – A Comparison of UK to Sweden

    Introduction to combined heat and power

    Sweden Cogeneration plant

    Combined heat and power (CHP) is not a new idea to the UK. Sheffield for example, has a large district heating network which makes considerable carbon savings and the Immingham plant on the Humber is a large industrial example. Yet when one compares the UK to Sweden, UK CHP seems very underdeveloped in comparison. Here I would like to discuss just what makes Swedish CHP so great and what the future holds in the UK for the technology.

    I won’t go into lots of detail on the technical aspects to CHP cogeneration. You can find that on our main technology page here. The principle is simple however; whether on a micro scale or on an industrial scale, power production and industrial processes create a lot of heat, which is effectively wasted energy. CHP cogeneration aims to take this waste heat and make it useful, increasing the efficiency of the installation. Often this will mean piping the heat to nearby buildings to be used for domestic or industrial heating.

    Example of Sweden – wide adoption of combined heat and power technology

    For the best examples of these ideals, Sweden is an excellent place to look. Here, around two thirds of heating requirements are provided through renewables in the form of biofuels, waste materials and sustainably sourced electricity. Additionally, district heating is widely implemented there, and now accounts for 43% of heating consumption. Biomass is considerably more common generally, which makes an excellent low carbon combination with district heating. But what is special about the country to make these technologies so much more widely implemented however?

    Perhaps most importantly, the Nordics have long taken on board the need for action on climate change, and as a result have policies considerably more proactive for carbon reduction than the UK. For example, coal burning is extremely expensive due to the huge taxes levied on power stations burning the fossil fuel – the tax can be as much as twice the cost of the coal. The knock on effect this has is to make renewables much more attractive for electricity production. In some instances this has meant more biofuels, but also geothermal and other renewables are found. Both of these technologies lend themselves well to CHP, due to the large quantities of heat they generate.

    This is not simply a coincidence however. The region has extremely cold winters, and heating is therefore much more important than in milder climes. As a result, many power stations of this type are ‘thermal leading’, meaning their main purpose is to provide heat rather than electricity. Electricity is more the by-product than heating in some instances.

    What does this mean for the UK?

    So are the UK and Sweden similar enough to be able to learn from their example, or are the two so different as to make the comparison irrelevant?

    Even though we are a milder country, the UK spends around £33 billion on heat across the economy per year and it is the number one reason for energy use. It therefore follows that reducing our heating’s contribution to energy use will help cut carbon emissions considerably. Of course, a multifaceted approach to reducing this burden is important. Insulation and energy efficiency are imperative, yet CHP cogeneration could offer a way to tackle this problem at the source. Immingham ConocoPhillips refinery is the largest industrial CHP facilities in Europe, located in the north-east of the UK. Sheffield on the other hand, is a good example of district heating, where its waste to energy plant converts hundreds of thousands of tonnes of waste each year into heat and energy. Running for nearly 25 years, the plant saves around 20,000 tonnes of carbon emissions per year when compared to fossil fuels. The scheme supplies electricity to the grid and helps heat hundreds of the city’s major buildings.

    Sheffield is a great example of CHP working well in an urban environment, yet after a quarter of a century of successful operation, the UK has yet to fully embrace the advantages of CHP as a tool for efficiency and carbon savings.

    The DECC last spring released their ‘Heat Strategy’, which has highlighted areas of improvement for the sector. It confirms the need for a change in Britain’s attitude to heat, looking at both supply and demand to reduce energy consumption. On the demand side it proposes 3 major areas for improvement: insulation, efficiency of heat delivery systems and better heat management. On the supply side, the main areas of focus are: low carbon building level heating systems, changing the content of natural gas in the grid and low carbon heat networks. It also specifically mentions the EU market for heat pumps and how the UK can capitalise on this.

    So is more UK CHP just around the corner?

    Looking at some of the prerequisites for CHP, the UK seems to fulfil them all; the fuel source is there, the technology is already available, the dense urban environments of major cities in the UK lend themselves perfectly to district heating and given the urgent need to new energy solutions, there seems to be an obvious gap in the market for more CHP. Perhaps it is just a cultural barrier that remains. Where northern Europe has embraced the technology long ago, the UK is only now waking up to the fact is needs to rethink its energy and heating policies.

      Renewables Obligation

      Financial Incentives

    What are ROCs?

    ROCs are a government scheme aimed at encouraging renewable energy generation across the UK. Generators and suppliers of electricity are involved in the scheme, which operates via a market mechanism, where certificates can be traded in order to meet government targets for generation. It is primarily aimed at medium to large scale businesses, but if you have a renewable generation system with over 50kW of capacity, you will be eligible to apply. The Feed in Tariff (FiT) is used to encourage uptake of small scale renewable installations.

    How do they work?

    The certificates are issued to generators for each unit of renewable energy they produce. The operators can then trade their certificates at the market rate, with energy suppliers then using the certificates to meet their ‘obligation’. Each year the obligation increases, with the current level meaning that 20.6% of generation must be met by ROCs, or by the ‘buy out’.

    Where suppliers do not have enough ROCs to meet their obligation, they must pay a buyout price currently set at £42.02 per MWh (this increases annually in line with the RPI), or buy more ROCs from the market.

    The buy out money collected by Ofgem (who regulate the scheme) from the suppliers is then redistributed in proportion to the amount of ROCs they produce, creating a ‘win-win’ for those suppliers that produce the most ROCs.

    What is the value of a ROC and how does it vary?

    The value of ROCs fluctuates with the market. If there is an excess of production in the market, the price would fall below the buyout price, whereas if there is a dearth of production, the price will rise above the buyout, as suppliers anticipate a windfall from defaulting suppliers having to make up their obligation with a large buy out.

    Although there has been some variability in the price, generally the value of ROCs has stayed fairly steady just above the buy out price, and is currently sitting at around £43 per MW. This is partly due to the government ensuring that there is always a demand for ROCs by creating an artificial excess demand of 10%.

    Who is eligible for ROCs?

    Any company generating more than 50kW of renewable power is eligible to receive ROCs. Renewables covered under the scheme include: Anaerobic Digestion, Biomass, Hydroelectric (excluding some large scale installations), Tidal, Wind, Solar PV, Landfill Gas, Sewage Gas and Wave Power. Some technologies, although eligible, tend not to receive support due to the prohibitive cost involved.

    Are all renewables treated equally?

    Originally when the scheme launched more than 10 years ago, each type of renewable covered received 1 ROC per MW. This was to allow as free a market as possible for all technologies. There have been some tweaks over the years however, and now there are a few exceptions to this rule: Offshore wind in particular receives 2 ROCs per MWh, whilst Sewage Gas now only receives half a ROC per MWh. Solar also benefits more than other technologies, with roof mounted systems receiving 1.7 ROCs per MW and ground mounted 1.6 ROCs.

    How do they compare with Feed in Tariffs?

    Feed in Tariffs are much more straight forward, and are aimed at smaller generators (less than 5MW). They offer a guaranteed price for the energy produced, whereas ROCs can vary greatly from one time to another. They are fixed for 20 years and generally offer a greater return than ROCs. If you are eligible for both schemes, you will need to decide which one benefits you more, as you cannot receive both.

    The future of ROCs

    By 2017, ROCs will be phased out in favour of the Contract for Difference (CfDs), although a grandfathering scheme will mean that those who have already signed up will be allowed to choose whether to opt for the new scheme or stay on with ROCs.

    The CfD scheme will include nuclear generation and carbon capture and storage, somewhat controversially. From mid 2014, new generating capacity will be able to apply for either scheme – you can read more about CfD here.

    How do I apply for ROCs and how do I manage them?

    An application can be submitted via the ‘Renewables and CHP Register’, where you will be expected to complete an application, make certain declarations, and submit monthly meter readings. The system also allows you to receive or transfer the certificates once accepted. Typically the ROCs are either auctioned to the highest bidder (with an administration fee), or a Power Purchase Agreement is made with a supplier.

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